tests/WindowAnimationJank/src/android/windowanimationjank/FlowLayout.java

/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */
package android.windowanimationjank;

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

/**
 * Custom layout that place all elements in flows with and automatically wraps them.
 */
public class FlowLayout extends ViewGroup {
    private int mLineHeight;

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

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        final int width =
                MeasureSpec.getSize(widthMeasureSpec) - getPaddingLeft() -getPaddingRight();
        int height =
                MeasureSpec.getSize(heightMeasureSpec) - getPaddingTop() - getPaddingBottom();
        final int count = getChildCount();

        int x = getPaddingLeft();
        int y = getPaddingTop();
        int lineHeight = 0;

        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) {
                child.measure(MeasureSpec.makeMeasureSpec(width, MeasureSpec.AT_MOST),
                        childHeightMeasureSpec);
                final int childWidth = child.getMeasuredWidth();
                lineHeight = Math.max(lineHeight, child.getMeasuredHeight());

                if (x + childWidth > width) {
                    x = getPaddingLeft();
                    y += lineHeight;
                }

                x += childWidth;
            }
        }
        mLineHeight = lineHeight;

        if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.UNSPECIFIED) {
            height = y + lineHeight;
        } else if (MeasureSpec.getMode(heightMeasureSpec) == MeasureSpec.AT_MOST) {
            if (y + lineHeight < height) {
                height = y + lineHeight;
            }
        }
        setMeasuredDimension(width, height);
    }

    @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 x = getPaddingLeft();
        int y = getPaddingTop();

        for (int i = 0; i < count; i++) {
            final View child = getChildAt(i);
            if (child.getVisibility() != GONE) {
                final int childWidth = child.getMeasuredWidth();
                final int childHeight = child.getMeasuredHeight();
                if (x + childWidth > width) {
                    x = getPaddingLeft();
                    y += mLineHeight;
                }
                child.layout(x, y, x + childWidth, y + childHeight);
                x += childWidth;
            }
        }
    }
}