Andorid 流式布局 热门标签解决方案

// 流式布局 话不多说，比较简单，注释都写的很清楚


import java.util.ArrayList;
import java.util.List;

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

/**
 * 
 * @author Mr.Himan
 * @version 1.0<br>
 *          2015年11月4日 11:12:06 <br>
 *          流式布局 设置MarginTop 和MarginLeft有效 MarginRight 暂未实现
 */
public class FlowLayout extends ViewGroup {

	/**
	 * 存储所有的子View
	 */
	private List<List<View>> mAllChildViews = new ArrayList<List<View>>();

	/**
	 * 存储每一行的高度
	 */
	private List<Integer> mLineHeight = new ArrayList<Integer>();

	public FlowLayout(Context context) {
		this(context, null);
	}

	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 onLayout(boolean changed, int l, int t, int r, int b) {
		mAllChildViews.clear();
		mLineHeight.clear();
		// 获取当前ViewGroup的宽度
		int width = getWidth();

		int lineWidth = 0;
		int lineHeight = 0;
		// 记录当前行的view
		List<View> lineViews = new ArrayList<View>();
		int childCount = getChildCount();
		for (int i = 0; i < childCount; i++) {
			View child = getChildAt(i);
			MarginLayoutParams lp = (MarginLayoutParams) child
					.getLayoutParams();
			int childWidth = child.getMeasuredWidth();
			int childHeight = child.getMeasuredHeight();

			// 如果需要换行
			if (childWidth + lineWidth + lp.leftMargin + lp.rightMargin > width) {
				// 记录LineHeight
				mLineHeight.add(lineHeight);
				// 记录当前行的Views
				mAllChildViews.add(lineViews);
				// 重置行的宽高
				lineWidth = 0;
				lineHeight = childHeight + lp.topMargin + lp.bottomMargin;
				// 重置view的集合
				lineViews = new ArrayList();
			}
			lineWidth += childWidth + lp.leftMargin + lp.rightMargin;
			lineHeight = Math.max(lineHeight, childHeight + lp.topMargin
					+ lp.bottomMargin);
			lineViews.add(child);
		}
		// 处理最后一行
		mLineHeight.add(lineHeight);
		mAllChildViews.add(lineViews);

		MarginLayoutParams params = (MarginLayoutParams) this.getLayoutParams();

		// 设置子View的位置
		int left = 0;
		// 添加marginTop
		int top = 0 + params.topMargin;
		// 获取行数
		int lineCount = mAllChildViews.size();
		for (int i = 0; i < lineCount; i++) {
			// 当前行的views和高度
			lineViews = mAllChildViews.get(i);
			lineHeight = mLineHeight.get(i);
			for (int j = 0; j < lineViews.size(); j++) {
				// 为每一列设置marginLeft
				if (j == 0) {
					left = 0 + params.leftMargin;
				}
				View child = lineViews.get(j);
				// 判断是否显示
				if (child.getVisibility() == View.GONE) {
					continue;
				}
				MarginLayoutParams lp = (MarginLayoutParams) child
						.getLayoutParams();
				int cLeft = left + lp.leftMargin;
				int cTop = top + lp.topMargin;
				int cRight = cLeft + child.getMeasuredWidth();
				int cBottom = cTop + child.getMeasuredHeight();
				// 进行子View进行布局
				child.layout(cLeft, cTop, cRight, cBottom);
				left += child.getMeasuredWidth() + lp.leftMargin
						+ lp.rightMargin;
			}
			left = 0;
			top += lineHeight;
		}
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

		// 父控件传进来的宽度和高度以及对应的测量模式
		int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
		int modeWidth = MeasureSpec.getMode(widthMeasureSpec);
		int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);
		int modeHeight = MeasureSpec.getMode(heightMeasureSpec);

		// 如果当前ViewGroup的宽高为wrap_content的情况
		int width = 0;// 自己测量的 宽度
		int height = 0;// 自己测量的高度
		// 记录每一行的宽度和高度
		int lineWidth = 0;
		int lineHeight = 0;

		// 获取子view的个数
		int childCount = getChildCount();
		 
		for (int i = 0; i < childCount; i++) {
			View child = getChildAt(i);
			// 测量子View的宽和高
			measureChild(child, widthMeasureSpec, heightMeasureSpec);
			// 得到LayoutParams

			MarginLayoutParams params = (MarginLayoutParams) child
					.getLayoutParams();
			// 子View占据的宽度
			int childWidth = child.getMeasuredWidth() + params.leftMargin
					+ params.rightMargin;
			// 子View占据的高度
			int childHeight = child.getMeasuredHeight() + params.bottomMargin
					+ params.topMargin;
			// 换行时候
			if (lineWidth + childWidth > sizeWidth) {
				// 对比得到最大的宽度
				width = Math.max(width, lineWidth);
				// 重置lineWidth
				lineWidth = childWidth;
				// 记录行高
				height += lineHeight;
				lineHeight = childHeight;
			} else {
				// 不换行情况
				// 叠加行宽
				lineWidth += childWidth;
				// 得到最大行高
				lineHeight = Math.max(lineHeight, childHeight);
			}
			// 处理最后一个子View的情况
			if (i == childCount - 1) {
				width = Math.max(width, lineWidth);
				height += lineHeight;
			}
		}
		setMeasuredDimension(modeWidth == MeasureSpec.EXACTLY ? sizeWidth
				: width, modeHeight == MeasureSpec.EXACTLY ? sizeHeight
				: height);

	}

	/**
	 * 与当前ViewGroup对应的LayoutParams
	 */
	@Override
	public LayoutParams generateLayoutParams(AttributeSet attrs) {
		return new MarginLayoutParams(getContext(), attrs);
	}
}