【Android 控件使用及源码解析】 GridView规则显示图片仿微信朋友圈发图片

<com.view.SquareLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical" >
    <ImageView
        android:id="@+id/item_grida_image"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="fitXY"
        android:layout_margin="@dimen/tinyest_space">
    </ImageView>
</com.view.SquareLayout>

noScrollgridview = (GridView) findViewById(R.id.noScrollgridview);
        noScrollgridview.setNumColumns(3);  //默认设置在3列图片
        //上传成功传值给adapter
        picAdapter = new PictureAdapter(this, 1, appItem_file);
        noScrollgridview.setAdapter(picAdapter);

//根据图片数量设置图片的列
        int size = appItemFile.getFiles().split(",").length;
        if (size==1){
            noScrollgridview.setNumColumns(1);
        }
        else if (size==2){
            noScrollgridview.setNumColumns(2);
        }
        else if (size>2){
            noScrollgridview.setNumColumns(3);
        }
        picAdapter.notifyDataSetChanged();

/**
 * 方形布局
 */
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);
	}
}