GridLayout中addView方法报错的有关问题

GridLayout中addView方法报错的问题
今天尝试用了一下GridLayout，但是在使用addView的时候却报了个错
谁知道是 什么问题帮忙看一下，代码很简单如下

	GridLayout gridLayout = null;
	
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		gridLayout = (GridLayout) findViewById(R.layout.activity_main);
		View view = View.inflate(this, R.layout.item, null);
		ImageView image = (ImageView) view.findViewById(R.id.image);
		image.setBackgroundResource(R.drawable.ic_launcher);
		
		gridLayout.addView(view);
	}

配置文件如下

<GridLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/GridLayout1"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:rowCount="4"
    android:columnCount="4"
   >
 

</GridLayout>

日志信息如下：


------解决方案--------------------
gridLayout = (GridLayout) findViewById(R.layout.activity_main);

=》

gridLayout = (GridLayout) findViewById(R.id.GridLayout1);