ViewPager 高度自适应

public class ContentViewPager extends ViewPager {
    public ContentViewPager(Context context) {
        super(context);
    }
    public ContentViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        int index = getCurrentItem();
        int height = 0;
        View v = ((Fragment) getAdapter().instantiateItem(this, index)).getView();
        if (v != null) {
            v.measure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
            height = v.getMeasuredHeight();
        }
        heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }
}