重写 ViewGroup 的 addView 方法

Viewgroup.addView()有5个重载方法：

void	addView(View child, int index, ViewGroup.LayoutParams params)

void	addView(View child, ViewGroup.LayoutParams params)

void	addView(View child, int index)

void	addView(View child)

void	addView(View child, int width, int height)

如果需要想重写addView()实际只需要重写**addView(View child, int index, ViewGroup.LayoutParams params)**即可。

看一下addView的源码：

    public void addView(View child) {
        addView(child, -1);
    }
    
    public void addView(View child, int index) {
        LayoutParams params = child.getLayoutParams();
        if (params == null) {
            params = generateDefaultLayoutParams();
            if (params == null) {
                throw new IllegalArgumentException("generateDefaultLayoutParams() cannot return null");
            }
        }
        addView(child, index, params);
    }


    public void addView(View child, int width, int height) {
        final LayoutParams params = generateDefaultLayoutParams();
        params.width = width;
        params.height = height;
        addView(child, -1, params);
    }
    
    public void addView(View child, LayoutParams params) {
        addView(child, -1, params);
    }

    /**
     * Adds a child view with the specified layout parameters.
     *
     * @param child the child view to add
     * @param index the position at which to add the child
     * @param params the layout parameters to set on the child
     */
    public void addView(View child, int index, LayoutParams params) {
        // addViewInner() will call child.requestLayout() when setting the new LayoutParams
        // therefore, we call requestLayout() on ourselves before, so that the child's request
        // will be blocked at our level
        requestLayout();
        invalidate();
        addViewInner(child, index, params, false);
    }