自定义View-自动换行的标签控件

android自定义换行标签：最近项目中需要实现一个功能：

网上有很多可以用的开源控件，我自己也学习写了一个自定义换行标签，让一个View继承ViewGroup，重写onmeasure()和onlayout()方法，核心代码如下

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

        //最后测量宽度和高度
        int resultWidth = 0;
        int resultHeigh = 0;
        //临时测量宽度和高度
        int linewidth = 0;
        int lineHeight = 0;
        int childCount = getChildCount();
        //测量控件的宽高模式  在之前文章中有讲过这个用法，不懂的可以看下
        int heightSize = MeasureSpec.getSize(heightMeasureSpec);
        int widthSize = MeasureSpec.getSize(widthMeasureSpec);
        int heightMode = MeasureSpec.getMode(heightMeasureSpec);
        int widthMode = MeasureSpec.getMode(widthMeasureSpec);

        for (int i = 0; i < childCount; i++) {
            View childView = getChildAt(i);
            //测量每一个子view的宽和高
            measureChild(childView, widthMeasureSpec, heightMeasureSpec);
            //获取测量的高度
            int childWidth = childView.getMeasuredWidth();
            int childHeight = childView.getMeasuredHeight();
            //因为子View可能设置margin，这里要加上margin的距离
            MarginLayoutParams mlp = (MarginLayoutParams) childView.getLayoutParams();
            //子控件真实宽度和高度
            int realwidth = mlp.leftMargin + childWidth + mlp.rightMargin;
            int realHight = mlp.topMargin + childHeight + mlp.bottomMargin;

            //计算宽度
            if (linewidth + realwidth > widthSize) {
                //换行
                resultWidth = Math.max(linewidth, realwidth);
                resultHeigh = resultHeigh + realHight;
                //换行后高度和宽度重新计算
                linewidth = realwidth;
                lineHeight = realHight;
            } else {
                linewidth = linewidth + realwidth;
                lineHeight = Math.max(lineHeight, realHight);
            }
        }
        //保存测量完成后的宽度和高度
        setMeasuredDimension(widthMode == MeasureSpec.EXACTLY ? widthSize : resultWidth,
                heightMode == MeasureSpec.EXACTLY ? heightSize : resultHeigh);
    }

    @Override
    protected void onLayout(boolean changed, int l, int t, int r, int b) {
        //子控件左边距离和上边距离
        int childleft = 0;
        int childtop = 0;
        //为每个孩子布局
        int childCount = getChildCount();
        for (int i = 0; i < childCount; i++) {
            View childView = getChildAt(i);

            int measuredHeight = childView.getMeasuredHeight();
            int measuredWidth = childView.getMeasuredWidth();

            //因为子View可能设置margin，这里要加上margin的距离
            MarginLayoutParams mlp = (MarginLayoutParams) childView.getLayoutParams();
            if (childleft + mlp.leftMargin + mlp.rightMargin + measuredWidth > getWidth()) {
                //换行上边距离增加，左边距离为0
                childtop = childtop + mlp.topMargin + mlp.bottomMargin + measuredHeight;
                childleft = 0;
            }

	    //计算子控件
            int left = childleft + mlp.leftMargin;
            int top = childtop + mlp.topMargin;
            int right = childleft + mlp.leftMargin + mlp.rightMargin + measuredWidth;
            int bottom = childtop + mlp.topMargin + mlp.bottomMargin + measuredHeight;

	    //布局子控件
            childView.layout(left, top, right, bottom);
            //不换行左边距离是前面子控件宽度之和
            childleft = childleft + mlp.leftMargin + mlp.rightMargin + measuredWidth;

        }
    }

	这样我们基本完成了该控件的绘制，我们通过addview加入子控件，例如：	

	public void setTextviewRes(List<TextView> textviews) {
  	  //添加文字
  	  //先移除所有的子view
  	  removeAllViews();
  	  for (int i = 0; i < textviews.size(); i++) {
  	      TextView textView = textviews.get(i);
   	     addView(textView);
   	 }
   	 //重新布局
  	  requestLayout();
	}

	我们使用控件，调用控件的settextviewres()方法，以textview为例子，

	传入添加好的textview的集合（这里可以任意设置，功能需求是什么就可以按照自己的需求去更改）。

	这样就完成自定义换行标签