回收视图展开/折叠项

不是说这是最好的方法，但对我来说似乎很有效。

完整代码可在以下网址找到: 示例代码位于: < a href = “ https://github.com/dbleicher/迴收视图-网格-快速返回”> https://github.com/dbleicher/recyclerview-grid-quickreturn

首先，将展开的区域添加到单元格/项布局中，并使封闭的单元格布局 animateLayoutChanges = “ true”。这将确保扩张/崩溃是活跃的:

<LinearLayout
android:id="@+id/llCardBack"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="@android:color/white"
android:animateLayoutChanges="true"
android:padding="4dp"
android:orientation="vertical">


<TextView
android:id="@+id/tvTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center|fill_horizontal"
android:padding="10dp"
android:gravity="center"
android:background="@android:color/holo_green_dark"
android:text="This is a long title to show wrapping of text in the view."
android:textColor="@android:color/white"
android:textSize="16sp" />


<TextView
android:id="@+id/tvSubTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center|fill_horizontal"
android:background="@android:color/holo_purple"
android:padding="6dp"
android:text="My subtitle..."
android:textColor="@android:color/white"
android:textSize="12sp" />


<LinearLayout
android:id="@+id/llExpandArea"
android:visibility="gone"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:orientation="horizontal">


<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="6dp"
android:text="Item One" />


<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="6dp"
android:text="Item Two" />


</LinearLayout>
</LinearLayout>

然后，让 RV Adapter 类实现 View.OnClickListener，这样就可以对被单击的项进行操作。添加一个 int 字段以保持一个展开视图的位置，并将其初始化为负值:

private int expandedPosition = -1;

最后，实现 ViewHolder、 onBindViewHolder ()方法并重写 onClick ()方法。如果 onBindViewHolder 中的视图的位置等于“  展開位置”，您可以展開它，如果不等于，您可以隐藏它。您可以在 onClick 侦听器中设置 expandposition 的值:

@Override
public void onBindViewHolder(RVAdapter.ViewHolder holder, int position) {


int colorIndex = randy.nextInt(bgColors.length);
holder.tvTitle.setText(mDataset.get(position));
holder.tvTitle.setBackgroundColor(bgColors[colorIndex]);
holder.tvSubTitle.setBackgroundColor(sbgColors[colorIndex]);


if (position == expandedPosition) {
holder.llExpandArea.setVisibility(View.VISIBLE);
} else {
holder.llExpandArea.setVisibility(View.GONE);
}
}


@Override
public void onClick(View view) {
ViewHolder holder = (ViewHolder) view.getTag();
String theString = mDataset.get(holder.getPosition());


// Check for an expanded view, collapse if you find one
if (expandedPosition >= 0) {
int prev = expandedPosition;
notifyItemChanged(prev);
}
// Set the current position to "expanded"
expandedPosition = holder.getPosition();
notifyItemChanged(expandedPosition);


Toast.makeText(mContext, "Clicked: "+theString, Toast.LENGTH_SHORT).show();
}


/**
* Create a ViewHolder to represent your cell layout
* and data element structure
*/
public static class ViewHolder extends RecyclerView.ViewHolder {
TextView tvTitle;
TextView tvSubTitle;
LinearLayout llExpandArea;


public ViewHolder(View itemView) {
super(itemView);


tvTitle = (TextView) itemView.findViewById(R.id.tvTitle);
tvSubTitle = (TextView) itemView.findViewById(R.id.tvSubTitle);
llExpandArea = (LinearLayout) itemView.findViewById(R.id.llExpandArea);
}
}

这应该一次只展开一个项目，使用系统默认的动画进行布局更改。至少对我有用。希望能有帮助。

将 onClick 侦听器设置为 ViewHolder 类之后执行以下操作:

@Override
public void onClick(View v) {
final int originalHeight = yourLinearLayout.getHeight();
animationDown(YourLinearLayout, originalHeight);//here put the name of you layout that have the options to expand.
}


//Animation for devices with kitkat and below
public void animationDown(LinearLayout billChoices, int originalHeight){


// Declare a ValueAnimator object
ValueAnimator valueAnimator;
if (!billChoices.isShown()) {
billChoices.setVisibility(View.VISIBLE);
billChoices.setEnabled(true);
valueAnimator = ValueAnimator.ofInt(0, originalHeight+originalHeight); // These values in this method can be changed to expand however much you like
} else {
valueAnimator = ValueAnimator.ofInt(originalHeight+originalHeight, 0);


Animation a = new AlphaAnimation(1.00f, 0.00f); // Fade out


a.setDuration(200);
// Set a listener to the animation and configure onAnimationEnd
a.setAnimationListener(new Animation.AnimationListener() {
@Override
public void onAnimationStart(Animation animation) {


}


@Override
public void onAnimationEnd(Animation animation) {
billChoices.setVisibility(View.INVISIBLE);
billChoices.setEnabled(false);
}


@Override
public void onAnimationRepeat(Animation animation) {


}
});
// Set the animation on the custom view
billChoices.startAnimation(a);
}
valueAnimator.setDuration(200);
valueAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
valueAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
Integer value = (Integer) animation.getAnimatedValue();
billChoices.getLayoutParams().height = value.intValue();
billChoices.requestLayout();
}
});




valueAnimator.start();
}
}

我认为这应该有所帮助，这就是我如何实现和做同样的谷歌在最近的呼叫视图。

有一个非常简单的使用图书馆与梯度支持: https://github.com/cachapa/ExpandableLayout。

来自图书馆的文件:

<net.cachapa.expandablelayout.ExpandableLinearLayout
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:el_duration="1000"
app:el_expanded="true">


<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Click here to toggle expansion" />


<TextView
android:layout_width="match_parent"
android:layout_height="50dp"
android:text="Fixed height"
app:layout_expandable="true" />


</net.cachapa.expandablelayout.ExpandableLinearLayout>

在标记了 可扩展的视图之后，只需在容器上调用以下任何一个方法: expand()、 collapse()或 toggle()

请不要使用任何库来达到这个效果，而是按照 Google I/O 推荐的方法来做。在回收站的 OnBindViewHolder方法中这样做:

final boolean isExpanded = position==mExpandedPosition;
holder.details.setVisibility(isExpanded?View.VISIBLE:View.GONE);
holder.itemView.setActivated(isExpanded);
holder.itemView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
mExpandedPosition = isExpanded ? -1:position;
TransitionManager.beginDelayedTransition(recyclerView);
notifyDataSetChanged();
}
});

• 其中 详情是我的视图，将显示在触摸(呼叫细节在您的情况下。默认可见性 GONE)。
• 是一个初始化为 -1的 int 变量

android:background="@drawable/comment_background"
android:stateListAnimator="@animator/comment_selection"

<selector
xmlns:android="http://schemas.android.com/apk/res/android"
android:constantSize="true"
android:enterFadeDuration="@android:integer/config_shortAnimTime"
android:exitFadeDuration="@android:integer/config_shortAnimTime">


<item android:state_activated="true" android:drawable="@color/selected_comment_background" />
<item android:drawable="@color/comment_background" />
</selector>

<selector xmlns:android="http://schemas.android.com/apk/res/android">


<item android:state_activated="true">
<objectAnimator
android:propertyName="translationZ"
android:valueTo="@dimen/z_card"
android:duration="2000"
android:interpolator="@android:interpolator/fast_out_slow_in" />
</item>


<item>
<objectAnimator
android:propertyName="translationZ"
android:valueTo="0dp"
android:duration="2000"
android:interpolator="@android:interpolator/fast_out_slow_in" />
</item>
</selector>