Android开发自定义控件View应对wrap_content

直接修改onMeasure()方法即可

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);


    // 获取宽-测量规则的模式和大小
    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    int widthSize = MeasureSpec.getSize(widthMeasureSpec);

    // 获取高-测量规则的模式和大小
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    // 设置wrap_content的默认宽 / 高值
    // 默认宽/高的设定并无固定依据,根据需要灵活设置
    // 类似TextView,ImageView等针对wrap_content均在onMeasure()对设置默认宽 / 高值有特殊处理,具体读者可以自行查看
    int mWidth = 400;
    int mHeight = 400;

  
    if (getLayoutParams().width == ViewGroup.LayoutParams.WRAP_CONTENT && getLayoutParams().height == ViewGroup.LayoutParams.WRAP_CONTENT) {
        setMeasuredDimension(mWidth, mHeight);
    // 宽 / 高任意一个布局参数为= wrap_content时，都设置默认值
    } else if (getLayoutParams().width == ViewGroup.LayoutParams.WRAP_CONTENT) {
        setMeasuredDimension(mWidth, heightSize);
    } else if (getLayoutParams().height == ViewGroup.LayoutParams.WRAP_CONTENT) {
        setMeasuredDimension(widthSize, mHeight);
}