Gridview 显示成正方形

import android.content.Context;
import android.util.AttributeSet;
import android.widget.RelativeLayout;

public class SquareLayout extends RelativeLayout{
public SquareLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public SquareLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}

public SquareLayout(Context context) {
super(context);
}
@SuppressWarnings("unused")
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// For simple implementation, or internal size is always 0.
// We depend on the container to specify the layout size of
// our view. We can't really know what it is since we will be
// adding and removing different arbitrary views and do not
// want the layout to change as this happens.
setMeasuredDimension(getDefaultSize(0, widthMeasureSpec), getDefaultSize(0, heightMeasureSpec));

// Children are just made to fill our space.
int childWidthSize = getMeasuredWidth();
int childHeightSize = getMeasuredHeight();
//高度和宽度一样
heightMeasureSpec = widthMeasureSpec = MeasureSpec.makeMeasureSpec(childWidthSize, MeasureSpec.EXACTLY);
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}
}