常用类继承自ViewGroup的写法

本文主要是介绍常用类继承自ViewGroup的写法，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

通常情况下要写一个自定义的类继承自ViewGroup，仅需重写OnLayout这个方法就可以了, 到时再需要再上来copy

public class MyViewGroup extends ViewGroup {

   private final static int VIEW_MARGIN = 2;//定义一个边界值
   private int maxWidth = 0;
   private int maxHeight = 60;

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

   protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

       for (int index = 0; index < getChildCount(); index++) {
           final View child = getChildAt(index);
           child.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
       }
       super.onMeasure(widthMeasureSpec, heightMeasureSpec);
   }

   protected void onLayout(boolean arg0, int arg1, int arg2, int arg3, int arg4) {

       final int count = getChildCount();
       int row = 0;// which row lay you view relative to parent
       int lengthX = arg1;    // right position of child relative to parent
       int lengthY = arg2;    // bottom position of child relative to parent
       for(int i = 0 ; i < count ; i++){

           final View child = this.getChildAt(i);
           int width = child.getMeasuredWidth();
           //            int height = child.getMeasuredHeight();
           int height = maxHeight; //限制子节点的高度
           lengthX += width + VIEW_MARGIN;

           lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height + arg2;
           if(width + VIEW_MARGIN > maxWidth){
               maxWidth = width + VIEW_MARGIN;
           }

           if(lengthX > arg3){
               lengthX = width + VIEW_MARGIN + arg1;
               row ++;
               lengthY = row * (height + VIEW_MARGIN) + VIEW_MARGIN + height + arg2;

           }
           child.layout(lengthX - width, lengthY - height, lengthX, lengthY);
       }
   }

}