ScreenShotView.java类
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Rect;
import android.util.Log;
import android.view.View;

public class ScreenShotView {
	// 获取指定Activity的截屏,保存到png文件  
    private static Bitmap takeScreenShot(Activity activity) {  
        // View是你需要截图的View  
        View view = activity.getWindow().getDecorView();  
        view.setDrawingCacheEnabled(true);  
        view.buildDrawingCache();  
        Bitmap b1 = view.getDrawingCache();  
  
        // 获取状态栏高度  
        Rect frame = new Rect();  
        activity.getWindow().getDecorView().getWindowVisibleDisplayFrame(frame);  
        int statusBarHeight = frame.top;  
        Log.i("TAG", "" + statusBarHeight);  
  
        // 获取屏幕长和高  
        int width = activity.getWindowManager().getDefaultDisplay().getWidth();  
        int height = activity.getWindowManager().getDefaultDisplay()  
                .getHeight();  
        // 去掉标题栏  
        // Bitmap b = Bitmap.createBitmap(b1, 0, 25, 320, 455);  
        Bitmap b = Bitmap.createBitmap(b1, 0, statusBarHeight, width, height  
                - statusBarHeight);  
        view.destroyDrawingCache();  
        return b;  
    }  
  
    // 保存到sdcard  
    private static void savePic(Bitmap b, String strFileName) {  
        FileOutputStream fos = null;  
        try {  
            fos = new FileOutputStream(strFileName);  
            if (null != fos) {  
                b.compress(Bitmap.CompressFormat.PNG, 90, fos);  
                fos.flush();  
                fos.close();  
            }  
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
  
    // 程序入口  
    public static void shootview(Activity a) {  
    	ScreenShotView.savePic(ScreenShotView.takeScreenShot(a), "sdcard/jietu.png");  
    }  
}

  

MainActivity.java类 
public class MainActivity extends Activity {
	Button btn;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}
	
	 public void onWindowFocusChanged(boolean hasFocus) {  
	        // TODO Auto-generated method stub  
	        super.onWindowFocusChanged(hasFocus);  
	        ScreenShotView.shootview(MainActivity.this);
	    }

	

}

  

 

需要注意的是,shoot方法只能在view已经被加载后方可调用。
或者在    

@Override
    public void onWindowFocusChanged(boolean hasFocus) {
        // TODO Auto-generated method stub
        super.onWindowFocusChanged(hasFocus);
        ScreenShot.shoot(this);
    }中调用