如何在 Android 中做类似 FlowLayout 的事情？

小开

I don't have enough reputation to post a comment to Romain Guy's answer but that's where this answer should be (I created an account just to share my edit).

Anyway, I see other people have found out his pretty cool FlowLayout solution has some issues. I could find one myself and I saw, as others, that some children were clipped. Looking in details at the algorithm it seems to be a very simple mistake in the calculation of the height. When the very last child is the one being put on a new line, then the height was not properly computed. I cleaned up a bit the computation (there was a weird use of "height" vs. currentHeight).

The following change fixes the problem of "last child is clipped if on a new line":

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
int widthLimit = MeasureSpec.getSize(widthMeasureSpec) - getPaddingRight();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);


boolean growHeight = widthMode != MeasureSpec.UNSPECIFIED;


int width = 0;


int currentWidth = getPaddingLeft();
int currentHeight = getPaddingTop();


int maxChildHeight = 0;


boolean breakLine = false;
boolean newLine = false;
int spacing = 0;


final int count = getChildCount();
for (int i = 0; i < count; i++)
{
View child = getChildAt(i);
measureChild(child, widthMeasureSpec, heightMeasureSpec);


LayoutParams lp = (LayoutParams) child.getLayoutParams();
spacing = mHorizontalSpacing;


if (lp.horizontalSpacing >= 0)
{
spacing = lp.horizontalSpacing;
}


if (growHeight && (breakLine || ((currentWidth + child.getMeasuredWidth()) > widthLimit)))
{
newLine = true;
currentHeight += maxChildHeight + mVerticalSpacing;


width = Math.max(width, currentWidth - spacing);


currentWidth = getPaddingLeft();
maxChildHeight = 0;
}
else
{
newLine = false;
}


maxChildHeight = Math.max(maxChildHeight, child.getMeasuredHeight());


lp.x = currentWidth;
lp.y = currentHeight;


currentWidth += child.getMeasuredWidth() + spacing;


breakLine = lp.breakLine;
}


if (newLine == false)
{
width = Math.max(width, currentWidth - spacing);
}


width += getPaddingRight();
int height = currentHeight + maxChildHeight + getPaddingBottom();


setMeasuredDimension(resolveSize(width, widthMeasureSpec),
resolveSize(height, heightMeasureSpec));
}

小开

Nice simple self-contained FlowLayout code here (just a few concise gist.github files):

http://hzqtc.github.io/2013/12/android-custom-layout-flowlayout.html

However, the activity there out of the box didn't work for me to load the custom layout.

I found this work-around [ using the 2-param .inflate() call from this example ]:

@Override
protected void onCreate(Bundle savedInstanceState)
{
// ..


setContentView(R.layout.main_res_layout_activity_main);


ViewGroup flowContainer = getFlowLayoutView();


// ..
}


ViewGroup getFlowLayoutView()
{
LayoutInflater inflater = getLayoutInflater();


ViewGroup flowLayout =
(ViewGroup)
inflater.inflate(
R.layout.main_res_layout_activity_main,
(FlowLayout) findViewById(R.id.flow_container)
);


return flowLayout;
}

小开

Like one of the previous answers, I started with the solution here: http://hzqtc.github.io/2013/12/android-custom-layout-flowlayout.html

I extended it to account for varying heights of children as below.

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;


// Custom layout that wraps child views to a new line
public class FlowLayout extends ViewGroup {


private int marginHorizontal;
private int marginVertical;


public FlowLayout(Context context) {
super(context);
init();
}


public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}


public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}


private void init() { // Specify the margins for the children
marginHorizontal = getResources().getDimensionPixelSize(R.dimen.activity_half_horizontal_margin);
marginVertical = getResources().getDimensionPixelSize(R.dimen.activity_half_vertical_margin);
}


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int lineHeight = 0;
int myWidth = resolveSize(100, widthMeasureSpec);
int wantedHeight = 0;


for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}


child.measure(getChildMeasureSpec(widthMeasureSpec, 0, child.getLayoutParams().width),
getChildMeasureSpec(heightMeasureSpec, 0, child.getLayoutParams().height));
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
lineHeight = Math.max(childHeight, lineHeight);


if (childWidth + childLeft + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft();
childTop = marginVertical + lowestBottom; // Spaced below the previous lowest point
lineHeight = childHeight;
}
childLeft += childWidth + marginHorizontal;


if (childHeight + childTop > lowestBottom) { // New lowest point
lowestBottom = childHeight + childTop;
}
}


wantedHeight += childTop + lineHeight + getPaddingBottom();
setMeasuredDimension(myWidth, resolveSize(wantedHeight, heightMeasureSpec));
}


@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int myWidth = right - left;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();


if (childWidth + childLeft + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft();
childTop = marginVertical + lowestBottom; // Spaced below the previous lowest point
}
child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childLeft += childWidth + marginHorizontal;


if (childHeight + childTop > lowestBottom) { // New lowest point
lowestBottom = childHeight + childTop;
}
}
}
}

I used this as a solution for wrapping multi-line TextEdits. Hope it helps!

小开

Here is the custom class where you can achive layout like following with adding dynamicaly view (Also called FlowLayout).

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;


/*
Created By Dhavalkumar Solanki
* */
public class FlowLayout extends ViewGroup {


private int line_height_space;


public static class LayoutParams extends ViewGroup.LayoutParams {


public int horizontal_spacing;
public int vertical_spacing;


/**
* @param horizontal_spacing Pixels between items, horizontally
* @param vertical_spacing   Pixels between items, vertically
*/
public LayoutParams(int horizontal_spacing, int vertical_spacing) {
super(0, 0);
this.horizontal_spacing = horizontal_spacing;
this.vertical_spacing = vertical_spacing;
}
}


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


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


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
assert (MeasureSpec.getMode(widthMeasureSpec) != MeasureSpec.UNSPECIFIED);


final int width = MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() - getPaddingRight();
int height = MeasureSpec.getSize(heightMeasureSpec) - getPaddingTop() - getPaddingBottom();
final int count = getChildCount();
int line_height_space = 0;


int xpos = getPaddingLeft();
int ypos = getPaddingTop();


int childHeightMeasureSpec;
if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.AT_MOST);
} else {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
}




for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
child.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.AT_MOST), childHeightMeasureSpec);
final int childw = child.getMeasuredWidth();
line_height_space = Math.max(line_height_space, child.getMeasuredHeight() + lp.vertical_spacing);


if (xpos + childw > width) {
xpos = getPaddingLeft();
ypos += line_height_space;
}


xpos += childw + lp.horizontal_spacing;
}
}
this.line_height_space = line_height_space;


if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED) {
height = ypos + line_height_space;


} else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
if (ypos + line_height_space < height) {
height = ypos + line_height_space;
}
}
setMeasuredDimension(width, height);
}


@Override
protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(1, 1); // default of 1px spacing
}


@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
if (p instanceof LayoutParams) {
return true;
}
return false;
}


@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
final int count = getChildCount();
final int width = r - l;
int xpos = getPaddingLeft();
int ypos = getPaddingTop();


for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != GONE) {
final int childw = child.getMeasuredWidth();
final int childh = child.getMeasuredHeight();
final LayoutParams lp = (LayoutParams) child.getLayoutParams();
if (xpos + childw > width) {
xpos = getPaddingLeft();
ypos += line_height_space;
}
child.layout(xpos, ypos, xpos + childw, ypos + childh);
xpos += childw + lp.horizontal_spacing;
}
}
}
}

Example :

text_view.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tool="http://schemas.android.com/tools"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="5dp">


<TextView
android:id="@+id/tvText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="19sp"
android:background="@drawable/unselected_tag"
android:textColor="@color/colorPrimary"
tool:text="Temp" />
</RelativeLayout>

activity_flow_layou_demo.xml

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


>
<ScrollView
android:layout_width="match_parent"
android:layout_height="wrap_content">


<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">


<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">


<TextView
android:id="@+id/tvTitleBusiness"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Business Interest "
android:textColor="@color/colorPrimary"
android:textSize="25sp" />


<com.example.tristateandroid2.radardemo.FlowLayout
android:id="@+id/flowBusiness"
android:layout_width="match_parent"
android:layout_height="wrap_content">


</com.example.tristateandroid2.radardemo.FlowLayout>
</LinearLayout>


<LinearLayout
android:layout_marginTop="@dimen/activity_horizontal_margin"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">


<TextView
android:id="@+id/tvTitlePrivate"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Private Interest "
android:textColor="@color/colorPrimary"
android:textSize="25sp" />


<com.example.tristateandroid2.radardemo.FlowLayout
android:id="@+id/flowPrivate"
android:layout_width="match_parent"
android:layout_height="wrap_content">


</com.example.tristateandroid2.radardemo.FlowLayout>
</LinearLayout>
</LinearLayout>
</ScrollView>
</RelativeLayout>

FlowLayouDemo.java

import android.graphics.Color;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;


import java.util.ArrayList;


public class FlowLayouDemo extends AppCompatActivity {
private TextView tvTitleBusiness;
private FlowLayout flowBusiness;
private TextView tvTitlePrivate;
private FlowLayout flowPrivate;
private ArrayList<TagModel> arrayList;


private void findViews() {
tvTitleBusiness = (TextView) findViewById(R.id.tvTitleBusiness);
flowBusiness = (FlowLayout) findViewById(R.id.flowBusiness);
tvTitlePrivate = (TextView) findViewById(R.id.tvTitlePrivate);
flowPrivate = (FlowLayout) findViewById(R.id.flowPrivate);
}


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_flow_layou_demo);
findViews();
addLayouts();
}


private void addLayouts() {
if (arrayList == null) {
arrayList = new ArrayList<>();
}
flowBusiness.removeAllViews();
flowPrivate.removeAllViews();
for (int i = 0; i < 75; i++) {


final boolean[] selected = {false};
View view = this.getLayoutInflater().inflate(R.layout.text_view, null);
final TextView textView = (TextView) view.findViewById(R.id.tvText);
if (i % 5 == 0) {
arrayList.add(new TagModel(i, false, "Business VIEW : " + i));
textView.setText("Busi VIEW To  IS : " + i);
} else {
arrayList.add(new TagModel(i, false, "TEXT IS : " + i));
textView.setText("Busi IS : " + i);
}
textView.setBackgroundResource(R.drawable.unselected_tag);
textView.setTextColor(Color.parseColor("#3F51B5"));
textView.setTag(i);
if(i<=50){
flowBusiness.addView(view);
}else {
textView.setText("Priv View : "+i);
flowPrivate.addView(view);
}


textView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
if (selected[0]) {
selected[0] = false;
textView.setBackgroundResource(R.drawable.unselected_tag);
textView.setTextColor(Color.parseColor("#3F51B5"));
} else {
selected[0] = true;
textView.setBackgroundResource(R.drawable.selected_tag);
textView.setTextColor(Color.parseColor("#FFFFFF"));
}
}
});


}
}
}

小开

You should use FlexboxLayout with flexWrap="wrap" attribute.

<com.google.android.flexbox.FlexboxLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:flexWrap="wrap">


<!-- contents go here -->


</com.google.android.flexbox.FlexboxLayout>

For build instructions, see the github repo.

implementation 'com.google.android:flexbox:2.0.1'

More about this - https://android-developers.googleblog.com/2017/02/build-flexible-layouts-with.html

小开

A revision to @MattNotEquals() FlowLayout that supports MarginLayoutParams.

This is just a minimalist implementation of MarginLayoutParms to support left, right, top, and bottom margins.

import android.content.Context;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;


/**
*  Original version courtesy of MattNotEquals() at http://stackoverflow.com/a/34169798/4515489 - 4/13/17.
*  7/15/17 Revised to support MarginLayoutParams.
*/
public class FlowLayout extends ViewGroup {
// Custom layout that wraps child views to a new line.


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


public FlowLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}


public FlowLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}


@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int lineHeight = 0;
int myWidth = resolveSize(100, widthMeasureSpec);
int wantedHeight = 0;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
child.measure(getChildMeasureSpec(widthMeasureSpec, 0, child.getLayoutParams().width),
getChildMeasureSpec(heightMeasureSpec, 0, child.getLayoutParams().height));
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
lineHeight = Math.max(childHeight, lineHeight);


final LayoutParams lp = (LayoutParams) child.getLayoutParams();
childLeft += lp.leftMargin;
childTop += lp.topMargin;
if (childLeft + childWidth + lp.rightMargin + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft() + lp.leftMargin;
childTop = lowestBottom + lp.topMargin; // Spaced below the previous lowest point
lineHeight = childHeight;
}
childLeft += childWidth + lp.rightMargin;


if (childTop + childHeight + lp.bottomMargin > lowestBottom) { // New lowest point
lowestBottom = childTop + childHeight + lp.bottomMargin;
}
}
wantedHeight += lowestBottom + getPaddingBottom(); // childTop + lineHeight + getPaddingBottom();
setMeasuredDimension(myWidth, resolveSize(wantedHeight, heightMeasureSpec));
}


@Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
int childLeft = getPaddingLeft();
int childTop = getPaddingTop();
int lowestBottom = 0;
int myWidth = right - left;
for (int i = 0; i < getChildCount(); i++) {
final View child = getChildAt(i);
if (child.getVisibility() == View.GONE) {
continue;
}
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();


final LayoutParams lp = (LayoutParams) child.getLayoutParams();
childLeft += lp.leftMargin;
childTop += lp.topMargin;
if (childLeft + childWidth + lp.rightMargin + getPaddingRight() > myWidth) { // Wrap this line
childLeft = getPaddingLeft() + lp.leftMargin;
childTop = lowestBottom + lp.topMargin; // Spaced below the previous lowest point
}
child.layout(childLeft, childTop, childLeft + childWidth, childTop + childHeight);
childLeft += childWidth + lp.rightMargin;


if (childTop + childHeight + lp.bottomMargin > lowestBottom) { // New lowest point
lowestBottom = childTop + childHeight + lp.bottomMargin;
}
}
}


@Override
public boolean shouldDelayChildPressedState() {
return false;
}


@Override
protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
return p instanceof LayoutParams;
}


@Override
protected LayoutParams generateDefaultLayoutParams() {
return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
}


@Override
public LayoutParams generateLayoutParams(AttributeSet attrs) {
return new FlowLayout.LayoutParams(getContext(), attrs);
}


@Override
protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams lp) {
if (lp instanceof LayoutParams) {
return new LayoutParams((LayoutParams) lp);
}
else if (lp instanceof MarginLayoutParams) {
return new LayoutParams((MarginLayoutParams) lp);
}
else
return super.generateLayoutParams(lp);
}


/**
* Per-child layout information for layouts that support margins.
*/
public static class LayoutParams extends MarginLayoutParams {
public LayoutParams(@NonNull Context c, @Nullable AttributeSet attrs) {
super(c, attrs);
}
public LayoutParams(int width, int height) {
super(width, height);
}
public LayoutParams(@NonNull ViewGroup.LayoutParams source) {
super(source);
}
public LayoutParams(@NonNull ViewGroup.MarginLayoutParams source) {
super(source);
}
public LayoutParams(@NonNull LayoutParams source) {
super(source);
}
}
}

小开

There is a library from Google, called "flexbox-layout". You should check it out.

To use it in RecyclerView, you can use something like that:

val layoutManager = FlexboxLayoutManager(activity)
layoutManager.flexDirection = FlexDirection.ROW
layoutManager.flexWrap = FlexWrap.WRAP
layoutManager.justifyContent = JustifyContent.FLEX_START
layoutManager.alignItems = AlignItems.FLEX_START
recyclerView.layoutManager=layoutManager

小开

There is now built in support in ConstraintLayout using a Flow widget. It has many options that can be used to achieve many type of flows.

Example:

<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">


<androidx.constraintlayout.helper.widget.Flow
android:layout_width="0dp"
android:layout_height="wrap_content"
app:constraint_referenced_ids="item_1,item_2,item_3"
app:flow_horizontalBias="0"
app:flow_horizontalGap="10dp"
app:flow_horizontalStyle="packed"
app:flow_verticalGap="8dp"
app:flow_wrapMode="aligned"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />


<View
android:id="@+id/item_1"
android:layout_width="50dp"
android:layout_height="50dp" />


<View
android:id="@+id/item_2"
android:layout_width="50dp"
android:layout_height="50dp" />


<View
android:id="@+id/item_3"
android:layout_width="50dp"
android:layout_height="50dp" />
</androidx.constraintlayout.widget.ConstraintLayout>

Take a look in this post: https://medium.com/@tapanrgohil/constraintlayout-flow-bye-bye-to-linerlayout-78fd7fa9b679

And here: https://www.bignerdranch.com/blog/constraintlayout-flow-simple-grid-building-without-nested-layouts/