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How can I do something like a FlowLayout in Android?

Posted by: admin March 11, 2020 Leave a comment

Questions:

How can I do something like a FlowLayout in Android?

How to&Answers:

If you watch the talk I gave at the Devoxx University day (available on parleys.com) you will learn how to do it yourself. During the talk I wrote a FlowLayout implementation live on stage to show how simple it is to write custom layouts.

The implementation is hosted here.

Answer:

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.

visual representation of FlexboxLayout
More about this – https://android-developers.googleblog.com/2017/02/build-flexible-layouts-with.html

Answer:

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));
}

Answer:

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

Answer:

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!

Answer:

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

enter image description here

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"));
                    }
                }
            });

        }
    }
}

Answer:

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);
        }
    }
}

Answer:

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;
}