很多App在搜索页时都有对热门标签的一个排列，而Android官方没有对应的布局控件，所以自己写了一个流式布局(也称标签布局)--FlowLayout。
为了大家使用的方便，没有添加自定义属性，所以需要在代码中设置下列两个属性值：
/*** 上下行间距*/public int veticalSpace = 30;/*** Item间距*/public int horSpace = 30;
其它的只需关注填充数据方法setAdapter，及设置点击事件setOnItemClick即可。
先上个效果图：
贴出完整代码，复制即用：
package com.custom.widget;import android.content.Context;import android.database.DataSetObserver;import android.util.AttributeSet;import android.util.SparseIntArray;import android.view.View;import android.widget.AdapterView;import android.widget.ListAdapter;public class FlowLayout extends AdapterView<ListAdapter> implementsView.OnClickListener {private ListAdapter mAdapter;/*** 上下行间距*/public int veticalSpace = 30;/*** Item间距*/public int horSpace = 30;/*** 每一行有多少个view*/private SparseIntArray mLineViews = new SparseIntArray();private AdapterDataSetObserver mDataSetObserver;/*** 一行的高度由最高的item决定*/private int lineHeight;public FlowLayout(Context context, AttributeSet attrs) {super(context, attrs);}@Overridepublic ListAdapter getAdapter() {return mAdapter;}@Overridepublic void setAdapter(ListAdapter adapter) {if (mAdapter != null && mDataSetObserver != null) {mAdapter.unregisterDataSetObserver(mDataSetObserver);}mAdapter = adapter;if (mAdapter != null) {mDataSetObserver = new AdapterDataSetObserver();mAdapter.registerDataSetObserver(mDataSetObserver);makeView();} else {removeAllViewsInLayout();invalidate();}}private void makeView() {removeAllViewsInLayout();int count = mAdapter.getCount();for (int i = 0; i < count; i++) {View child = mAdapter.getView(i, null, this);LayoutParams params = child.getLayoutParams();if (params == null)params = generateDefaultLayoutParams();addViewInLayout(child, i, params);}
<span style="white-space:pre"></span>requestLayout();}private class AdapterDataSetObserver extends DataSetObserver {@Overridepublic void onChanged() {super.onChanged();makeView();requestLayout();}}@Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);int widthSize = MeasureSpec.getSize(widthMeasureSpec);int heightSize = MeasureSpec.getSize(heightMeasureSpec);int modeWidth = MeasureSpec.getMode(widthMeasureSpec);int modeHeight = MeasureSpec.getMode(heightMeasureSpec);int layoutWidth = 0;int layoutHeight = 0;int lineWidth = getPaddingLeft() + getPaddingRight();if (mAdapter == null)return;int count = getChildCount();mLineViews.clear();int lineCount = 0;int line = 0;for (int i = 0; i < count; i++) {View child = getChildAt(i);measureChild(child, widthMeasureSpec, heightMeasureSpec);lineHeight = Math.max(lineHeight, child.getMeasuredHeight());int childWidth = child.getMeasuredWidth();if (lineWidth + childWidth > widthSize) {mLineViews.put(line, lineCount);lineWidth -= horSpace;layoutWidth = Math.max(layoutWidth, lineWidth);line++;lineWidth = getPaddingLeft() + getPaddingRight();lineCount = 0;}lineCount++;lineWidth += childWidth + horSpace;if (i == count - 1) {mLineViews.put(line, lineCount);lineWidth -= horSpace;layoutWidth = Math.max(layoutWidth, lineWidth);lineCount = 0;}}if (modeWidth == MeasureSpec.EXACTLY) {layoutWidth = widthSize;}if (modeHeight == MeasureSpec.EXACTLY) {layoutHeight = heightSize;} else {int lines = mLineViews.size();layoutHeight = getPaddingTop() + getPaddingBottom() + lines* lineHeight + (lines - 1) * veticalSpace;} setMeasuredDimension(layoutWidth, layoutHeight);}@Overrideprotected void onLayout(boolean changed, int left, int top, int right,int bottom) {int leftPos = 0;int topPos = 0;int lines = mLineViews.size();int lineCount;int position = 0;for (int i = 0; i < lines; i++) {lineCount = mLineViews.get(i);View child;topPos = getPaddingTop() + i * veticalSpace + i * lineHeight;leftPos = getPaddingLeft();for (int j = 0; j < lineCount; j++) {child = getChildAt(position);if (child == null)return;position++;child.setOnClickListener(this);int childWidth = child.getMeasuredWidth();child.layout(leftPos, topPos, leftPos + childWidth, topPos+ lineHeight);leftPos += childWidth + horSpace;}}}@Overridepublic void onClick(View v) {int pos = indexOfChild(v);performItemClick(v, pos, 0);}@Overridepublic void setSelection(int position) {// TODO Auto-generated method stub}@Overridepublic View getSelectedView() {// TODO Auto-generated method stubreturn null;}}
