android自定义viewgroup之我也玩瀑布流

先看效果图吧，

继上一篇《android自定义viewgroup实现等分格子布局》中实现的布局效果，这里稍微有些区别，每个格子的高度不规则，就是传说的瀑布流布局，一般实现这种效果，要么用第三方控件，如果不是加载图片还可以直接写在xml中实现，不过代码会很多的；

下面我重写了viewgroup,实现 onMeasure,onLayout方法，动态设置每个布局的高度，这里有一个小的技巧，一般我们自定义的控件，嵌套在scrollview中显示不 全，这个问题也纠结我一小会，不过当你打开scrollview的源码，你会发现有一个地方，同时可以理解scrollview中嵌套 viewpager,gridview,listview时候会显示不全的问题

下面是自定义viewgroup的全部代码：

package com.allen.view;import com.allen.mygridlayout.R;import android.content.Context; import android.content.res.TypedArray; import android.util.AttributeSet; import android.view.View; import android.view.ViewGroup; import android.view.View.MeasureSpec;/*** @package：com.fumei.letao.views* @author：Allen* @email：jaylong1302@163.com* @data：2013年11月26日 下午8:39:51* @description：瀑布流视图*/ public class WaterfullLayout extends ViewGroup {final String tag = "balance";// 列数int columns = 2;// 行数int rows = 0;// 边距int margin = 10;// 子视图数量int count = 0;private int mMaxChildWidth = 0;private int mMaxChildHeight = 0;public WaterfullLayout(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);if (attrs != null) {TypedArray a = getContext().obtainStyledAttributes(attrs,R.styleable.MyGridLayout);columns = a.getInteger(R.styleable.MyGridLayout_numColumns, 2);margin = (int) a.getInteger(R.styleable.MyGridLayout_itemMargin, 2);}}public WaterfullLayout(Context context, AttributeSet attrs) {super(context, attrs, 0);// TODO Auto-generated constructor stub }public WaterfullLayout(Context context) {super(context);// TODO Auto-generated constructor stub }@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {mMaxChildWidth = 0;mMaxChildHeight = 0;count = getChildCount();if (count == 0) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);return;}rows = count % columns == 0 ? count / columns : count / columns + 1;// 行数int top[] = new int[columns];for (int i = 0; i < rows; i++) {// 遍历行for (int j = 0; j < columns; j++) {// 遍历每一行的元素View child = this.getChildAt(i * columns + j);if (child == null)break;ViewGroup.LayoutParams lp = child.getLayoutParams();if (child.getVisibility() == GONE) {continue;}child.measure(MeasureSpec.makeMeasureSpec(MeasureSpec.getSize(widthMeasureSpec),MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(lp.height, MeasureSpec.AT_MOST));top[j] += lp.height + margin;mMaxChildWidth = Math.max(mMaxChildWidth,child.getMeasuredWidth());}}setMeasuredDimension(resolveSize(mMaxChildWidth, widthMeasureSpec),resolveSize(getMax(top) + margin, heightMeasureSpec));}@Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {// TODO Auto-generated method stubint height = b - t;// 布局区域高度int width = r - l;// 布局区域宽度if (count == 0)return;int gridW = (width - margin * (columns + 1)) / columns;// 格子宽度int gridH = 0;// 格子高度int left = 0;int top[] = new int[columns];for (int i = 0; i < rows; i++) {// 遍历行for (int j = 0; j < columns; j++) {// 遍历每一行的元素View child = this.getChildAt(i * columns + j);if (child == null)return;ViewGroup.LayoutParams lp = child.getLayoutParams();child.measure(MeasureSpec.makeMeasureSpec(gridW,MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(lp.height, MeasureSpec.AT_MOST));// 如果最后有一个对其的标志，为了底部对其if (child.getTag() != null && child.getTag().equals(tag)) {child.measure(MeasureSpec.makeMeasureSpec(gridW,MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(getMax(top) - top[j], MeasureSpec.EXACTLY));gridH = getMax(top) - top[j];left = j * gridW + margin * (j + 1);child.layout(left, top[j] + margin, left + gridW, top[j]+ gridH);break;}gridH = lp.height;left = j * gridW + margin * (j + 1);top[j] += margin;child.layout(left, top[j], left + gridW, top[j] + gridH);top[j] += gridH;}}}/** 计算整体布局高度，为了在嵌套在scrollview中能显示出来 */private int getMax(int array[]) {int max = array[0];for (int i = 0; i < array.length; i++) {if (max < array[i])max = array[i];}return max;}}

转载于:https://www.cnblogs.com/Free-Thinker/p/3644292.html

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