Android:我无法拥有ViewPager WRAP_CONTENT

小开

我只是在回答一个非常类似的问题，在寻找一个链接来支持我的说法时，碰巧发现了这个，你很幸运:)

< p > 我的另一个回答是: < br > ViewPager不支持wrap_content，因为它(通常)不会同时加载它的所有子元素，因此不能获得适当的大小(选项是有一个分页器，每次你切换页面时都会改变大小) 然而，你可以设置一个精确的尺寸(例如150dp)， match_parent也可以你也可以通过改变LayoutParams.

中的__abc0属性，从你的代码中动态修改维度

满足你的需要你可以在它自己的xml文件中创建ViewPager, layout_height设置为200dp，然后在你的代码中，而不是从头创建一个新的ViewPager，你可以扩展这个xml文件:

LayoutInflater inflater = context.getLayoutInflater();
inflater.inflate(R.layout.viewpagerxml, layout, true);

小开

我也遇到了同样的问题。我有一个ViewPager，我想在它的按钮上显示一个广告。我发现的解决方案是让寻呼机进入一个RelativeView，并设置它的layout_above的视图id，我想看到它下面。这对我很管用。

这是我的布局XML:

  <RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent" >


<LinearLayout
android:id="@+id/AdLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:orientation="vertical" >
</LinearLayout>


<android.support.v4.view.ViewPager
android:id="@+id/mainpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_above="@+id/AdLayout" >
</android.support.v4.view.ViewPager>
</RelativeLayout>

小开

另一个解决方案是根据PagerAdapter中的当前页高度更新ViewPager的高度。假设你这样创建你的ViewPager页面:

@Override
public Object instantiateItem(ViewGroup container, int position) {
PageInfo item = mPages.get(position);
item.mImageView = new CustomImageView(container.getContext());
item.mImageView.setImageDrawable(item.mDrawable);
container.addView(item.mImageView, 0);
return item;
}

其中mPages是动态添加到PagerAdapter的PageInfo结构的内部列表，而CustomImageView只是常规的ImageView，带有重写的onMeasure()方法，该方法根据指定的宽度设置其高度并保持图像纵横比。

你可以在setPrimaryItem()方法中强制ViewPager高度:

@Override
public void setPrimaryItem(ViewGroup container, int position, Object object) {
super.setPrimaryItem(container, position, object);


PageInfo item = (PageInfo) object;
ViewPager pager = (ViewPager) container;
int width = item.mImageView.getMeasuredWidth();
int height = item.mImageView.getMeasuredHeight();
pager.setLayoutParams(new FrameLayout.LayoutParams(width, Math.max(height, 1)));
}

注意Math.max(height, 1)。这修复了ViewPager不更新显示页面(显示为空白)的恼人错误，当前一页的高度为零(即在CustomImageView中可绘制null)，每次在两页之间来回滑动。

小开

另一个更通用的解决方案是让wrap_content正常工作。

我扩展了ViewPager来覆盖onMeasure()。高度被包裹在第一个子视图周围。如果子视图的高度不完全相同，这可能会导致意想不到的结果。因此，类可以很容易地扩展，让我们说动画到当前视图/页面的大小。但我不需要。

你可以在yout XML布局中使用这个ViewPager，就像原来的ViewPager一样:

<view
android:layout_width="match_parent"
android:layout_height="wrap_content"
class="de.cybergen.ui.layout.WrapContentHeightViewPager"
android:id="@+id/wrapContentHeightViewPager"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"/>

优点:这种方法允许在任何布局(包括RelativeLayout)中使用ViewPager来覆盖其他ui元素。

还有一个缺点:如果你想使用页边距，你必须创建两个嵌套的布局，并给内部的一个指定所需的页边距。

代码如下:

public class WrapContentHeightViewPager extends ViewPager {


/**
* Constructor
*
* @param context the context
*/
public WrapContentHeightViewPager(Context context) {
super(context);
}


/**
* Constructor
*
* @param context the context
* @param attrs the attribute set
*/
public WrapContentHeightViewPager(Context context, AttributeSet attrs) {
super(context, attrs);
}


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);


// find the first child view
View view = getChildAt(0);
if (view != null) {
// measure the first child view with the specified measure spec
view.measure(widthMeasureSpec, heightMeasureSpec);
}


setMeasuredDimension(getMeasuredWidth(), measureHeight(heightMeasureSpec, view));
}


/**
* Determines the height of this view
*
* @param measureSpec A measureSpec packed into an int
* @param view the base view with already measured height
*
* @return The height of the view, honoring constraints from measureSpec
*/
private int measureHeight(int measureSpec, View view) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);


if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
} else {
// set the height from the base view if available
if (view != null) {
result = view.getMeasuredHeight();
}
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return result;
}


}

小开

我遇到了同样的问题，当用户在页面之间滚动时，我还必须让ViewPager环绕其内容。使用cybergen上面的答案，我定义onMeasure方法如下:

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);


if (getCurrentItem() < getChildCount()) {
View child = getChildAt(getCurrentItem());
if (child.getVisibility() != GONE) {
heightMeasureSpec = MeasureSpec.makeMeasureSpec(MeasureSpec.getSize(heightMeasureSpec),
MeasureSpec.UNSPECIFIED);
child.measure(widthMeasureSpec, heightMeasureSpec);
}


setMeasuredDimension(getMeasuredWidth(), measureHeight(heightMeasureSpec, getChildAt(getCurrentItem())));
}
}

这样，onMeasure方法设置ViewPager显示的当前页面的高度。

小开

重写ViewPager的onMeasure将使它获得当前拥有的最大子结点的高度。

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);


int height = 0;
int childWidthSpec = MeasureSpec.makeMeasureSpec(
Math.max(0, MeasureSpec.getSize(widthMeasureSpec) -
getPaddingLeft() - getPaddingRight()),
MeasureSpec.getMode(widthMeasureSpec)
);
for (int i = 0; i < getChildCount(); i++) {
View child = getChildAt(i);
child.measure(childWidthSpec, MeasureSpec.UNSPECIFIED);
int h = child.getMeasuredHeight();
if (h > height) height = h;
}
    

if (height != 0) {
heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
}


super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

小开

我也遇到了这个问题，但在我的例子中，我有一个FragmentPagerAdapter，它向ViewPager提供它的页面。我遇到的问题是ViewPager的onMeasure()在任何Fragments被创建之前被调用(因此不能正确地调整自己的大小)。

经过一些尝试和错误，我发现FragmentPagerAdapter的finishUpdate()方法在Fragments被初始化之后(从FragmentPagerAdapter中的instantiateItem()开始)被调用，并且在页面滚动之后/期间被调用。我做了一个小界面:

public interface AdapterFinishUpdateCallbacks
{
void onFinishUpdate();
}

我把它传递给我的FragmentPagerAdapter并调用:

@Override
public void finishUpdate(ViewGroup container)
{
super.finishUpdate(container);


if (this.listener != null)
{
this.listener.onFinishUpdate();
}
}

这反过来允许我在我的CustomViewPager实现上调用setVariableHeight():

public void setVariableHeight()
{
// super.measure() calls finishUpdate() in adapter, so need this to stop infinite loop
if (!this.isSettingHeight)
{
this.isSettingHeight = true;


int maxChildHeight = 0;
int widthMeasureSpec = MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY);
for (int i = 0; i < getChildCount(); i++)
{
View child = getChildAt(i);
child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(ViewGroup.LayoutParams.WRAP_CONTENT, MeasureSpec.UNSPECIFIED));
maxChildHeight = child.getMeasuredHeight() > maxChildHeight ? child.getMeasuredHeight() : maxChildHeight;
}


int height = maxChildHeight + getPaddingTop() + getPaddingBottom();
int heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);


super.measure(widthMeasureSpec, heightMeasureSpec);
requestLayout();


this.isSettingHeight = false;
}
}

我不确定这是最好的方法，如果你认为它是好的/坏的/邪恶的，我会喜欢评论，但它似乎在我的实现中工作得很好:)

希望这能帮助到一些人!

我忘记在调用super.measure()后添加requestLayout()(否则它不会重绘视图)。

我还忘记在最终高度中添加父元素的填充。

我还放弃了保留原来的宽度/高度度量，以便根据需要创建一个新的度量。已更新相应的代码。

我遇到的另一个问题是，它不会在ScrollView中正确地大小自己，并发现罪魁祸首是用MeasureSpec.EXACTLY而不是MeasureSpec.UNSPECIFIED来测量孩子。更新以反映这一点。

这些更改都已添加到代码中。如果需要，您可以检查历史记录以查看旧的(不正确的)版本。

小开

我的答案基于Daniel López Lacalle和这篇文章http://www.henning.ms/2013/09/09/viewpager-that-simply-dont-measure-up/。丹尼尔回答的问题是，在某些情况下，我的孩子的身高为零。不幸的是，解决办法是测量两次。

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int mode = MeasureSpec.getMode(heightMeasureSpec);
// Unspecified means that the ViewPager is in a ScrollView WRAP_CONTENT.
// At Most means that the ViewPager is not in a ScrollView WRAP_CONTENT.
if (mode == MeasureSpec.UNSPECIFIED || mode == MeasureSpec.AT_MOST) {
// super has to be called in the beginning so the child views can be initialized.
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int height = 0;
for (int i = 0; i < getChildCount(); i++) {
View child = getChildAt(i);
child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
int h = child.getMeasuredHeight();
if (h > height) height = h;
}
heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
}
// super has to be called again so the new specs are treated as exact measurements
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

这也允许你在ViewPager上设置一个高度，如果你想要的话，或者只是wrap_content。

小开

以上建议对我都没用。我的用例是在ScrollView中有4个自定义ViewPagers。顶部是基于纵横比测量的，其余部分只有layout_height=wrap_content。我已经尝试过cybergen，丹尼尔López拉卡勒解决方案。没有一个是完全适合我的。

我猜为什么cybergen不能在页面> 1上工作是因为它基于第1页计算页面的高度，如果你进一步滚动，这是隐藏的。

在我的例子中，cybergen和丹尼尔López拉卡勒的建议都有奇怪的行为:3个中的2个加载ok, 1个随机高度为0。似乎onMeasure在子节点被填充之前被调用。所以我想出了这两个答案加上我自己的修正:

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (getLayoutParams().height == ViewGroup.LayoutParams.WRAP_CONTENT) {
// find the first child view
View view = getChildAt(0);
if (view != null) {
// measure the first child view with the specified measure spec
view.measure(widthMeasureSpec, heightMeasureSpec);
int h = view.getMeasuredHeight();
setMeasuredDimension(getMeasuredWidth(), h);
//do not recalculate height anymore
getLayoutParams().height = h;
}
}
}

思想是让ViewPager计算子尺寸，并在ViewPager的布局参数中保存第一页的计算高度。不要忘记将fragment的布局高度设置为wrap_content，否则你可以得到height=0。我用过这个:

<?xml version="1.0" encoding="utf-8"?>


<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content">
<!-- Childs are populated in fragment -->
</LinearLayout>

请注意，如果所有页面都具有相同的高度，则此解决方案非常有效。否则，你需要基于当前的子活动重新计算ViewPager的高度。我不需要它，但如果你提出解决方案，我很乐意更新答案。

小开

public CustomPager (Context context) {
super(context);
}


public CustomPager (Context context, AttributeSet attrs) {
super(context, attrs);
}


int getMeasureExactly(View child, int widthMeasureSpec) {
child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
int height = child.getMeasuredHeight();
return MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
}


@Override
public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
boolean wrapHeight = MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST;


final View tab = getChildAt(0);
if (tab == null) {
return;
}


int width = getMeasuredWidth();
if (wrapHeight) {
// Keep the current measured width.
widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
}
Fragment fragment = ((Fragment) getAdapter().instantiateItem(this, getCurrentItem()));
heightMeasureSpec = getMeasureExactly(fragment.getView(), widthMeasureSpec);


//Log.i(Constants.TAG, "item :" + getCurrentItem() + "|height" + heightMeasureSpec);
// super has to be called again so the new specs are treated as
// exact measurements.
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

小开

对于有此问题并使用c#编写Xamarin Android代码的人来说，这可能也是一个快速解决方案:

pager.ChildViewAdded += (sender, e) => {
e.Child.Measure ((int)MeasureSpecMode.Unspecified, (int)MeasureSpecMode.Unspecified);
e.Parent.LayoutParameters.Height = e.Child.MeasuredHeight;
};

如果您的子视图具有相同的高度，这主要是有用的。否则，您将被要求在您检查的所有子视图上存储某种“minimumHeight”值，即使这样，您可能也不希望在较小的子视图下显示空白区域。

虽然解决方案本身对我来说是不够的，但这是因为我的子项目是listViews，他们的MeasuredHeight似乎没有正确计算。

小开

我已经在几个项目中遇到过这个问题，从来没有一个完整的解决方案。所以我创建了一个WrapContentViewPager github项目作为ViewPager的替代。

https://github.com/rnevet/WCViewPager

解决方案的灵感来自这里的一些答案，但改进了:

根据当前视图(包括滚动时)动态更改ViewPager高度。
考虑像PagerTabStrip这样的“装饰”视图的高度。
考虑所有填充。

为支持库版本24更新，打破了以前的实现

小开

如果你正在使用的ViewPager是ScrollView的子函数，和有一个PagerTitleStrip子函数，你将需要对已经提供的答案进行轻微修改。作为参考，我的XML看起来像这样:

<ScrollView android:id="@+id/match_scroll_view" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@color/white"> <LinearLayout android:id="@+id/match_and_graphs_wrapper" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <view android:id="@+id/pager" class="com.printandpixel.lolhistory.util.WrapContentHeightViewPager" android:layout_width="match_parent" android:layout_height="wrap_content"> <android.support.v4.view.PagerTitleStrip android:id="@+id/pager_title_strip" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_gravity="top" android:background="#33b5e5" android:paddingBottom="4dp" android:paddingTop="4dp" android:textColor="#fff" /> </view> </LinearLayout> </ScrollView>

在你的onMeasure中，你必须添加 PagerTitleStrip的measuredHeight(如果找到的话)。否则，即使它占用了额外的空间，它的高度也不会被认为是所有子结点的最大高度。

希望这能帮助到其他人。很抱歉，这有点黑…

public class WrapContentHeightViewPager extends ViewPager { public WrapContentHeightViewPager(Context context) { super(context); } public WrapContentHeightViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int pagerTitleStripHeight = 0; int height = 0; for(int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); int h = child.getMeasuredHeight(); if (h > height) { // get the measuredHeight of the tallest fragment height = h; } if (child.getClass() == PagerTitleStrip.class) { // store the measured height of the pagerTitleStrip if one is found. This will only // happen if you have a android.support.v4.view.PagerTitleStrip as a direct child // of this class in your XML. pagerTitleStripHeight = h; } } heightMeasureSpec = MeasureSpec.makeMeasureSpec(height+pagerTitleStripHeight, MeasureSpec.EXACTLY); super.onMeasure(widthMeasureSpec, heightMeasureSpec); } }

小开

从爆米花时间安卓应用程序的源代码，我发现这个解决方案，动态调整大小的viewpager与漂亮的动画取决于当前的孩子的大小。

https://git.popcorntime.io/popcorntime/android/blob/5934f8d0c8fed39af213af4512272d12d2efb6a6/mobile/src/main/java/pct/droid/widget/WrappingViewPager.java

public class WrappingViewPager extends ViewPager { private Boolean mAnimStarted = false; public WrappingViewPager(Context context) { super(context); } public WrappingViewPager(Context context, AttributeSet attrs){ super(context, attrs); } @TargetApi(Build.VERSION_CODES.JELLY_BEAN) @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if(!mAnimStarted && null != getAdapter()) { int height = 0; View child = ((FragmentPagerAdapter) getAdapter()).getItem(getCurrentItem()).getView(); if (child != null) { child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); height = child.getMeasuredHeight(); if (VersionUtils.isJellyBean() && height < getMinimumHeight()) { height = getMinimumHeight(); } } // Not the best place to put this animation, but it works pretty good. int newHeight = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY); if (getLayoutParams().height != 0 && heightMeasureSpec != newHeight) { final int targetHeight = height; final int currentHeight = getLayoutParams().height; final int heightChange = targetHeight - currentHeight; Animation a = new Animation() { @Override protected void applyTransformation(float interpolatedTime, Transformation t) { if (interpolatedTime >= 1) { getLayoutParams().height = targetHeight; } else { int stepHeight = (int) (heightChange * interpolatedTime); getLayoutParams().height = currentHeight + stepHeight; } requestLayout(); } @Override public boolean willChangeBounds() { return true; } }; a.setAnimationListener(new Animation.AnimationListener() { @Override public void onAnimationStart(Animation animation) { mAnimStarted = true; } @Override public void onAnimationEnd(Animation animation) { mAnimStarted = false; } @Override public void onAnimationRepeat(Animation animation) { } }); a.setDuration(1000); startAnimation(a); mAnimStarted = true; } else { heightMeasureSpec = newHeight; } } super.onMeasure(widthMeasureSpec, heightMeasureSpec); } }

小开

当在viewpager中使用静态内容时，你不希望有花哨的动画，你可以使用下面的viewpager

public class HeightWrappingViewPager extends ViewPager { public HeightWrappingViewPager(Context context) { super(context); } public HeightWrappingViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); View firstChild = getChildAt(0); firstChild.measure(widthMeasureSpec, heightMeasureSpec); super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(firstChild.getMeasuredHeight(), MeasureSpec.EXACTLY)); } }

小开

我有一个版本的WrapContentHeightViewPager是在API 23之前正确工作的，它将根据当前选定的子视图调整父视图的高度。

在升级到API 23后，它停止工作。原来旧的解决方案是使用getChildAt(getCurrentItem())来获取当前的子视图来测量哪个是无效的。参见解决方案:https://stackoverflow.com/a/16512217/1265583

下面是API 23的工作原理:

@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); int height = 0; ViewPagerAdapter adapter = (ViewPagerAdapter)getAdapter(); View child = adapter.getItem(getCurrentItem()).getView(); if(child != null) { child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); height = child.getMeasuredHeight(); } heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY); super.onMeasure(widthMeasureSpec, heightMeasureSpec); }

小开

我有一个类似的(但更复杂的场景)。我有一个对话框，其中包含一个ViewPager.
其中一个子页面是短的，具有静态高度另一个子页面应该总是尽可能高另一个子页面包含一个ScrollView，如果ScrollView内容不需要对话框的完整高度，那么该页面(以及整个对话框)应该WRAP_CONTENT
现有的答案都不完全适用于这个特定的场景。坚持住，这是一段颠簸的旅程。

void setupView() { final ViewPager.SimpleOnPageChangeListener pageChangeListener = new ViewPager.SimpleOnPageChangeListener() { @Override public void onPageSelected(int position) { currentPagePosition = position; // Update the viewPager height for the current view /* Borrowed from https://github.com/rnevet/WCViewPager/blob/master/wcviewpager/src/main/java/nevet/me/wcviewpager/WrapContentViewPager.java Gather the height of the "decor" views, since this height isn't included when measuring each page's view height. */ int decorHeight = 0; for (int i = 0; i < viewPager.getChildCount(); i++) { View child = viewPager.getChildAt(i); ViewPager.LayoutParams lp = (ViewPager.LayoutParams) child.getLayoutParams(); if (lp != null && lp.isDecor) { int vgrav = lp.gravity & Gravity.VERTICAL_GRAVITY_MASK; boolean consumeVertical = vgrav == Gravity.TOP || vgrav == Gravity.BOTTOM; if (consumeVertical) { decorHeight += child.getMeasuredHeight(); } } } int newHeight = decorHeight; switch (position) { case PAGE_WITH_SHORT_AND_STATIC_CONTENT: newHeight += measureViewHeight(thePageView1); break; case PAGE_TO_FILL_PARENT: newHeight = ViewGroup.LayoutParams.MATCH_PARENT; break; case PAGE_TO_WRAP_CONTENT: // newHeight = ViewGroup.LayoutParams.WRAP_CONTENT; // Works same as MATCH_PARENT because...reasons... // newHeight += measureViewHeight(thePageView2); // Doesn't allow scrolling when sideways and height is clipped /* Only option that allows the ScrollView content to scroll fully. Just doing this might be way too tall, especially on tablets. (Will shrink it down below) */ newHeight = ViewGroup.LayoutParams.MATCH_PARENT; break; } // Update the height ViewGroup.LayoutParams layoutParams = viewPager.getLayoutParams(); layoutParams.height = newHeight; viewPager.setLayoutParams(layoutParams); if (position == PAGE_TO_WRAP_CONTENT) { // This page should wrap content // Measure height of the scrollview child View scrollViewChild = ...; // (generally this is a LinearLayout) int scrollViewChildHeight = scrollViewChild.getHeight(); // full height (even portion which can't be shown) // ^ doesn't need measureViewHeight() because... reasons... if (viewPager.getHeight() > scrollViewChildHeight) { // View pager too tall? // Wrap view pager height down to child height newHeight = scrollViewChildHeight + decorHeight; ViewGroup.LayoutParams layoutParams2 = viewPager.getLayoutParams(); layoutParams2.height = newHeight; viewPager.setLayoutParams(layoutParams2); } } // Bonus goodies :) // Show or hide the keyboard as appropriate. (Some pages have EditTexts, some don't) switch (position) { // This case takes a little bit more aggressive code than usual if (position needs keyboard shown){ showKeyboardForEditText(); } else if { hideKeyboard(); } } } }; viewPager.addOnPageChangeListener(pageChangeListener); viewPager.getViewTreeObserver().addOnGlobalLayoutListener( new ViewTreeObserver.OnGlobalLayoutListener() { @Override public void onGlobalLayout() { // http://stackoverflow.com/a/4406090/4176104 // Do things which require the views to have their height populated here pageChangeListener.onPageSelected(currentPagePosition); // fix the height of the first page if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) { viewPager.getViewTreeObserver().removeOnGlobalLayoutListener(this); } else { viewPager.getViewTreeObserver().removeGlobalOnLayoutListener(this); } } } ); } ... private void showKeyboardForEditText() { // Make the keyboard appear. getDialog().getWindow().clearFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE | WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM); getDialog().getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_VISIBLE | WindowManager.LayoutParams.SOFT_INPUT_ADJUST_PAN); inputViewToFocus.requestFocus(); // http://stackoverflow.com/a/5617130/4176104 InputMethodManager inputMethodManager = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE); inputMethodManager.toggleSoftInputFromWindow( inputViewToFocus.getApplicationWindowToken(), InputMethodManager.SHOW_IMPLICIT, 0); } ... /** * Hide the keyboard - http://stackoverflow.com/a/8785471 */ private void hideKeyboard() { InputMethodManager inputManager = (InputMethodManager) getActivity().getSystemService(Context.INPUT_METHOD_SERVICE); inputManager.hideSoftInputFromWindow(inputBibleBookStart.getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS); } ... //https://github.com/rnevet/WCViewPager/blob/master/wcviewpager/src/main/java/nevet/me/wcviewpager/WrapContentViewPager.java private int measureViewHeight(View view) { view.measure(ViewGroup.getChildMeasureSpec(-1, -1, view.getLayoutParams().width), View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)); return view.getMeasuredHeight(); }

非常感谢@Raanan提供的代码来测量视图和测量装饰高度。我在他的库中遇到了一些问题——动画结结巴，我认为当对话框的高度足够短时，我的ScrollView无法滚动。

小开

我发现了一个解决方案，它有点像这里提到的一些解决方案的合并。

其思想是测量ViewPager的当前视图。

以下是完整的代码:

MainActivity.kt

class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) viewPager.adapter = WrapHeightViewPager.CustomPagerAdapter(this) } }

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity"> <com.android.myapplication.WrapHeightViewPager android:layout_width="match_parent" android:id="@+id/viewPager" android:background="#33ff0000" android:layout_height="wrap_content"/> </FrameLayout>

view_pager_page.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:gravity="center" android:layout_width="match_parent" android:layout_height="wrap_content"> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@android:drawable/sym_def_app_icon"/> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/textView"/> </LinearLayout>

WrapHeightViewPager.kt

class WrapHeightViewPager : ViewPager { constructor(context: Context) : super(context) {} constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) {} override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { super.onMeasure(widthMeasureSpec, heightMeasureSpec) val adapter = adapter as CustomPagerAdapter? val currentView = adapter?.currentView if (currentView != null) { currentView.measure(widthMeasureSpec, heightMeasureSpec) super.onMeasure( widthMeasureSpec, View.MeasureSpec.makeMeasureSpec(currentView.measuredHeight, View.MeasureSpec.EXACTLY) ) return } super.onMeasure(widthMeasureSpec, heightMeasureSpec) } class CustomPagerAdapter(private val context: Context) : PagerAdapter() { var currentView: View? = null override fun instantiateItem(parent: ViewGroup, position: Int): Any { val inflater = LayoutInflater.from(context) val view = inflater.inflate(R.layout.view_pager_page, parent, false) view.textView.text = "item$position" parent.addView(view) return view } override fun setPrimaryItem(container: ViewGroup, position: Int, obj: Any) { super.setPrimaryItem(container, position, obj) currentView = obj as View } override fun destroyItem(collection: ViewGroup, position: Int, view: Any) = collection.removeView(view as View) override fun getCount(): Int = 3 override fun isViewFromObject(view: View, obj: Any) = view === obj override fun getPageTitle(position: Int): CharSequence? = "item $position" } }

如果你使用< >强RecyclerPagerAdapter图书馆< / >强，获取"currentView"的方法是从你设置的pager-view-holder中获取:

val item = obj as PagerViewHolder currentView = item.itemView

小开

在我的例子中，添加clipToPadding解决了这个问题。

<android.support.v4.view.ViewPager ... android:clipToPadding="false" ... />

干杯!

小开

使用Daniel López Localle answer，我在Kotlin中创建了这个类。希望能节省你更多的时间

class DynamicHeightViewPager @JvmOverloads constructor(context: Context, attrs: AttributeSet? = null) : ViewPager(context, attrs) { override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { var heightMeasureSpec = heightMeasureSpec var height = 0 for (i in 0 until childCount) { val child = getChildAt(i) child.measure(widthMeasureSpec, View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED)) val h = child.measuredHeight if (h > height) height = h } if (height != 0) { heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(height, View.MeasureSpec.EXACTLY) } super.onMeasure(widthMeasureSpec, heightMeasureSpec) }}

小开

如果你需要ViewPager 为每个孩子调整大小，不仅仅是最大的一个，我写了一段代码来做它。注意，在这个变化上没有动画(在我的例子中没有必要)

还支持android: minHeight标志。

public class ChildWrappingAdjustableViewPager extends ViewPager { List<Integer> childHeights = new ArrayList<>(getChildCount()); int minHeight = 0; int currentPos = 0; public ChildWrappingAdjustableViewPager(@NonNull Context context) { super(context); setOnPageChangeListener(); } public ChildWrappingAdjustableViewPager(@NonNull Context context, @Nullable AttributeSet attrs) { super(context, attrs); obtainMinHeightAttribute(context, attrs); setOnPageChangeListener(); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { childHeights.clear(); //calculate child views for (int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); int h = child.getMeasuredHeight(); if (h < minHeight) { h = minHeight; } childHeights.add(i, h); } if (childHeights.size() - 1 >= currentPos) { heightMeasureSpec = MeasureSpec.makeMeasureSpec(childHeights.get(currentPos), MeasureSpec.EXACTLY); } super.onMeasure(widthMeasureSpec, heightMeasureSpec); } private void obtainMinHeightAttribute(@NonNull Context context, @Nullable AttributeSet attrs) { int[] heightAttr = new int[]{android.R.attr.minHeight}; TypedArray typedArray = context.obtainStyledAttributes(attrs, heightAttr); minHeight = typedArray.getDimensionPixelOffset(0, -666); typedArray.recycle(); } private void setOnPageChangeListener() { this.addOnPageChangeListener(new SimpleOnPageChangeListener() { @Override public void onPageSelected(int position) { currentPos = position; ViewGroup.LayoutParams layoutParams = ChildWrappingAdjustableViewPager.this.getLayoutParams(); layoutParams.height = childHeights.get(position); ChildWrappingAdjustableViewPager.this.setLayoutParams(layoutParams); ChildWrappingAdjustableViewPager.this.invalidate(); } }); } }

小开

我的情况下添加android:fillViewport="true"解决了这个问题

小开

我在这里看到的大多数解决方案似乎都在做双重测量:首先测量子视图，然后调用super.onMeasure()

我提出了一个自定义的WrapContentViewPager是更有效的，与RecyclerView和Fragment工作得很好

你可以在这里查看演示:

github/ssynhtn/WrapContentViewPager .

和这里类的代码: WrapContentViewPager.java < / p >

小开

在我的例子中，当应用大小时，我需要一个带有wrap_content的viewpager来显示当前选择的元素和动画。下面您可以看到我的实现。有人能派上用场吗?

package one.xcorp.widget import android.animation.ValueAnimator import android.content.Context import android.util.AttributeSet import android.view.View import android.view.ViewGroup.LayoutParams.MATCH_PARENT import android.view.ViewGroup.LayoutParams.WRAP_CONTENT import one.xcorp.widget.R import kotlin.properties.Delegates.observable class ViewPager : android.support.v4.view.ViewPager { var enableAnimation by observable(false) { _, _, enable -> if (enable) { addOnPageChangeListener(onPageChangeListener) } else { removeOnPageChangeListener(onPageChangeListener) } } private var animationDuration = 0L private var animator: ValueAnimator? = null constructor (context: Context) : super(context) { init(context, null) } constructor (context: Context, attrs: AttributeSet?) : super(context, attrs) { init(context, attrs) } private fun init(context: Context, attrs: AttributeSet?) { context.theme.obtainStyledAttributes( attrs, R.styleable.ViewPager, 0, 0 ).apply { try { enableAnimation = getBoolean( R.styleable.ViewPager_enableAnimation, enableAnimation ) animationDuration = getInteger( R.styleable.ViewPager_animationDuration, resources.getInteger(android.R.integer.config_shortAnimTime) ).toLong() } finally { recycle() } } } override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { val heightMode = MeasureSpec.getMode(heightMeasureSpec) val measuredHeight = if (heightMode == MeasureSpec.EXACTLY) { MeasureSpec.getSize(heightMeasureSpec) } else { val currentViewHeight = findViewByPosition(currentItem)?.also { measureView(it) }?.measuredHeight ?: 0 if (heightMode != MeasureSpec.AT_MOST) { currentViewHeight } else { Math.min( currentViewHeight, MeasureSpec.getSize(heightMeasureSpec) ) } } super.onMeasure( widthMeasureSpec, MeasureSpec.makeMeasureSpec(measuredHeight, MeasureSpec.EXACTLY) ) } private fun measureView(view: View) = with(view) { val horizontalMode: Int val horizontalSize: Int when (layoutParams.width) { MATCH_PARENT -> { horizontalMode = MeasureSpec.EXACTLY horizontalSize = this@ViewPager.measuredWidth } WRAP_CONTENT -> { horizontalMode = MeasureSpec.UNSPECIFIED horizontalSize = 0 } else -> { horizontalMode = MeasureSpec.EXACTLY horizontalSize = layoutParams.width } } val verticalMode: Int val verticalSize: Int when (layoutParams.height) { MATCH_PARENT -> { verticalMode = MeasureSpec.EXACTLY verticalSize = this@ViewPager.measuredHeight } WRAP_CONTENT -> { verticalMode = MeasureSpec.UNSPECIFIED verticalSize = 0 } else -> { verticalMode = MeasureSpec.EXACTLY verticalSize = layoutParams.height } } val horizontalMeasureSpec = MeasureSpec.makeMeasureSpec(horizontalSize, horizontalMode) val verticalMeasureSpec = MeasureSpec.makeMeasureSpec(verticalSize, verticalMode) measure(horizontalMeasureSpec, verticalMeasureSpec) } private fun findViewByPosition(position: Int): View? { for (i in 0 until childCount) { val childView = getChildAt(i) val childLayoutParams = childView.layoutParams as LayoutParams val childPosition by lazy { val field = childLayoutParams.javaClass.getDeclaredField("position") field.isAccessible = true field.get(childLayoutParams) as Int } if (!childLayoutParams.isDecor && position == childPosition) { return childView } } return null } private fun animateContentHeight(childView: View, fromHeight: Int, toHeight: Int) { animator?.cancel() if (fromHeight == toHeight) { return } animator = ValueAnimator.ofInt(fromHeight, toHeight).apply { addUpdateListener { measureView(childView) if (childView.measuredHeight != toHeight) { animateContentHeight(childView, height, childView.measuredHeight) } else { layoutParams.height = animatedValue as Int requestLayout() } } duration = animationDuration start() } } private val onPageChangeListener = object : OnPageChangeListener { override fun onPageScrollStateChanged(state: Int) { /* do nothing */ } override fun onPageScrolled( position: Int, positionOffset: Float, positionOffsetPixels: Int ) { /* do nothing */ } override fun onPageSelected(position: Int) { if (!isAttachedToWindow) { return } findViewByPosition(position)?.let { childView -> measureView(childView) animateContentHeight(childView, height, childView.measuredHeight) } } } }

在项目中添加attrs.xml:

<?xml version="1.0" encoding="utf-8"?> <resources> <declare-styleable name="ViewPager"> <attr name="enableAnimation" format="boolean" /> <attr name="animationDuration" format="integer" /> </declare-styleable> </resources>

和使用:

<one.xcorp.widget.ViewPager android:id="@+id/wt_content" android:layout_width="match_parent" android:layout_height="wrap_content" app:enableAnimation="true" />

小开

下面的代码是唯一对我有用的东西

1. 使用这个类来声明一个hightwrappingviewpager:

public class HeightWrappingViewPager extends ViewPager { public HeightWrappingViewPager(Context context) { super(context); } public HeightWrappingViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int mode = MeasureSpec.getMode(heightMeasureSpec); // Unspecified means that the ViewPager is in a ScrollView WRAP_CONTENT. // At Most means that the ViewPager is not in a ScrollView WRAP_CONTENT. if (mode == MeasureSpec.UNSPECIFIED || mode == MeasureSpec.AT_MOST) { // super has to be called in the beginning so the child views can be initialized. super.onMeasure(widthMeasureSpec, heightMeasureSpec); int height = 0; for (int i = 0; i < getChildCount(); i++) { View child = getChildAt(i); child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); int h = child.getMeasuredHeight(); if (h > height) height = h; } heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY); } // super has to be called again so the new specs are treated as exact measurements super.onMeasure(widthMeasureSpec, heightMeasureSpec); } }

2. 在xml文件中插入高度包装视图分页器:

<com.project.test.HeightWrappingViewPager android:id="@+id/pager" android:layout_width="match_parent" android:layout_height="match_parent"> </com.project.test.HeightWrappingViewPager>

3.声明您的视图分页:

HeightWrappingViewPager mViewPager; mViewPager = (HeightWrappingViewPager) itemView.findViewById(R.id.pager); CustomAdapter adapter = new CustomAdapter(context); mViewPager.setAdapter(adapter); mViewPager.measure(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

小开

这个ViewPager只调整到当前可见的子节点(不是它实际的最大子节点)

这个想法来自https://stackoverflow.com/a/56325869/4718406

public class DynamicHeightViewPager extends ViewPager { public DynamicHeightViewPager (Context context) { super(context); initPageChangeListener(); } public DynamicHeightViewPager (Context context, AttributeSet attrs) { super(context, attrs); initPageChangeListener(); } private void initPageChangeListener() { addOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { @Override public void onPageSelected(int position) { requestLayout(); } }); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { //View child = getChildAt(getCurrentItem()); View child = getCurrentView(this); if (child != null) { child.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED)); int h = child.getMeasuredHeight(); heightMeasureSpec = MeasureSpec.makeMeasureSpec(h, MeasureSpec.EXACTLY); } super.onMeasure(widthMeasureSpec, heightMeasureSpec); } View getCurrentView(ViewPager viewPager) { try { final int currentItem = viewPager.getCurrentItem(); for (int i = 0; i < viewPager.getChildCount(); i++) { final View child = viewPager.getChildAt(i); final ViewPager.LayoutParams layoutParams = (ViewPager.LayoutParams) child.getLayoutParams(); Field f = layoutParams.getClass().getDeclaredField("position"); //NoSuchFieldException f.setAccessible(true); int position = (Integer) f.get(layoutParams); //IllegalAccessException if (!layoutParams.isDecor && currentItem == position) { return child; } } } catch (NoSuchFieldException e) { e.fillInStackTrace(); } catch (IllegalArgumentException e) { e.fillInStackTrace(); } catch (IllegalAccessException e) { e.fillInStackTrace(); } return null; }

｝

小开

测量ViewPager的高度:

public class WrapViewPager extends ViewPager { View primaryView; public WrapViewPager(Context context, AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); if (primaryView != null) { int height = 0; for (int i = 0; i < getChildCount(); i++) { if (primaryView == getChildAt(i)) { int childHeightSpec = MeasureSpec.makeMeasureSpec(0x1 << 30 - 1, MeasureSpec.AT_MOST); getChildAt(i).measure(widthMeasureSpec, childHeightSpec); height = getChildAt(i).getMeasuredHeight(); } } setMeasuredDimension(widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY)); } } public void setPrimaryView(View view) { primaryView = view; } }

调用setPrimaryView(视图):

public class ZGAdapter extends PagerAdapter { @Override public void setPrimaryItem(@NonNull ViewGroup container, int position, @NonNull Object object) { super.setPrimaryItem(container, position, object); ((WrapViewPager)container).setPrimaryView((View)object); } }

小开

改进的丹尼尔López拉卡勒答案，在芬兰湾的科特林中重写:

class MyViewPager(context: Context, attrs: AttributeSet): ViewPager(context, attrs) { override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { val zeroHeight = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED) val maxHeight = children .map { it.measure(widthMeasureSpec, zeroHeight); it.measuredHeight } .max() ?: 0 if (maxHeight > 0) { val maxHeightSpec = MeasureSpec.makeMeasureSpec(maxHeight, MeasureSpec.EXACTLY) super.onMeasure(widthMeasureSpec, maxHeightSpec) return } super.onMeasure(widthMeasureSpec, heightMeasureSpec) } }

小开

给ViewPager的父布局NestedScrollView

<androidx.core.widget.NestedScrollView android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="5dp" android:paddingRight="5dp" android:fillViewport="true"> <androidx.viewpager.widget.ViewPager android:id="@+id/viewPager" android:layout_width="match_parent" android:layout_height="wrap_content"> </androidx.viewpager.widget.ViewPager> </androidx.core.widget.NestedScrollView>

不要忘记设置android:fillViewport="true"

这将拉伸滚动视图及其子内容以填充视口。

https://developer.android.com/reference/android/widget/ScrollView.html#attr_android:fillViewport

小开

我编辑cybergen答案使viewpager改变高度取决于选定的项目类是cybergen的相同，但我添加了一个整数向量，这是所有viewpager的子视图高度，我们可以在页面更改为更新高度
时访问它
这是这个类:

import android.content.Context; import android.util.AttributeSet; import android.view.View; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.viewpager.widget.ViewPager; import java.util.Vector; public class WrapContentHeightViewPager extends ViewPager { private Vector<Integer> heights = new Vector<>(); public WrapContentHeightViewPager(@NonNull Context context) { super(context); } public WrapContentHeightViewPager(@NonNull Context context, @Nullable AttributeSet attrs) { super(context, attrs); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); for(int i=0;i<getChildCount();i++) { View view = getChildAt(i); if (view != null) { view.measure(widthMeasureSpec, heightMeasureSpec); heights.add(measureHeight(heightMeasureSpec, view)); } } setMeasuredDimension(getMeasuredWidth(), measureHeight(heightMeasureSpec, getChildAt(0))); } public int getHeightAt(int position){ return heights.get(position); } private int measureHeight(int measureSpec, View view) { int result = 0; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { result = specSize; } else { if (view != null) { result = view.getMeasuredHeight(); } if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return result; } }

然后在你的活动中添加一个OnPageChangeListener

WrapContentHeightViewPager viewPager = findViewById(R.id.my_viewpager); viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() { @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {} @Override public void onPageSelected(int position) { LinearLayout.LayoutParams params = (LinearLayout.LayoutParams) viewPager.getLayoutParams(); params.height = viewPager.getHeightAt(position); viewPager.setLayoutParams(params); } @Override public void onPageScrollStateChanged(int state) {} });

这里是xml:

<com.example.example.WrapContentHeightViewPager android:id="@+id/my_viewpager" android:fillViewport="true" android:layout_width="match_parent" android:layout_height="wrap_content"/>

如有必要请纠正我的英语

小开

并非所有答案都完美无缺。所以我创建了一个。当选择一个新页面以使viewPager的高度为当前子视图的高度时，下面的类将请求布局。

class WrapContentViewPager : ViewPager { constructor(context: Context) : super(context) constructor(context: Context, attrs: AttributeSet?) : super(context, attrs) private var curPos = 0 init { addOnPageChangeListener(object : ViewPager.OnPageChangeListener { override fun onPageScrollStateChanged(state: Int) {} override fun onPageScrolled( position: Int, positionOffset: Float, positionOffsetPixels: Int ) {} override fun onPageSelected(position: Int) { curPos = position requestLayout() } }) } override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { if (childCount == 0) { super.onMeasure(widthMeasureSpec, heightMeasureSpec) return } measureChildren(widthMeasureSpec, heightMeasureSpec) setMeasuredDimension(measuredWidth, getChildAt(curPos).measuredHeight) } }

小开

另一个Kotlin代码

class DynamicViewPager @JvmOverloads constructor( context: Context, attrs: AttributeSet? = null ) : ViewPager(context, attrs) { override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) { var height = 0 (0 until childCount).forEach { val child = getChildAt(it) child.measure( widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED) ) height = max(height, child.measuredHeight) } if (height > 0) { super.onMeasure( widthMeasureSpec, MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY) ) } else { super.onMeasure(widthMeasureSpec, heightMeasureSpec) } } }

小开

对于那些想要ViewPager2的解决方案，将ViewPager2具有与所有页面的最大高度相同的高度，遗憾的是，我只找到了这个解决方案:

viewPager.doOnPreDraw { //workaround to set the viewPagerheight the same as its children var height = 0 for (i in 0 until featuresViewPager.adapter!!.itemCount) { val viewHolder = viewPager.adapter!!.createViewHolder(viewPager, 0) viewPager.adapter!!.bindViewHolder(viewHolder, i) val child: View = viewHolder.itemView child.layoutParams.height = ViewGroup.LayoutParams.WRAP_CONTENT val widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(viewPager.width, View.MeasureSpec.EXACTLY) val heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED) child.measure(widthMeasureSpec, heightMeasureSpec) val childHeight = child.measuredHeight child.layoutParams.height = ViewGroup.LayoutParams.MATCH_PARENT if (childHeight > height) height = childHeight } viewPager.layoutParams.height = height }

我说“悲伤”;因为它遍历所有的页面，创建它们的视图，度量它们，并调用用于其他目的的函数。

应该在大多数情况下工作良好。

如果你知道更好的解决办法，请告诉我。