转屏的处理

出自http://eigo.co.uk/News-Article.aspx?NewsArticleID=103

How to lock the orientation

In the onCreateDialog(int) event of the activity use the setRequestedOrientation(int) method to set the screen orientation to your chosen setting. The activity will stay in this orientation regardless of if the device is tilted or not.

[Code sample – How to lock the orientation]

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    this.setRequestedOrientation(
ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}

 

How to detect the current orientation

To programmatically detect the current orientation of the activity use the following code snippet. The orientation property of the Configuration class returns three possible values corresponding to Landscape, Portrait and Square.

[Code sample – How to detect the current orientation]

switch (this.getResources().getConfiguration().orientation)
{
case Configuration.ORIENTATION_PORTRAIT:
  // Do something here
  break;
case Configuration.ORIENTATION_LANDSCAPE:
  // Do something here
  break;
case Configuration.ORIENTATION_SQUARE:
  // Do something here
  break;
default:
  throw new Exception("Unexpected orientation enumeration returned");
  break;
}

 

Example : Locking rotation while performing an action.

You might wish to disable the screen rotation whilst performing an action or by user command, to do this you need to combine the above samples to detect the current orientation and lock the display to that orientation.

[Code sample – Locking rotation while performing an action]

// Sets screen rotation as fixed to current rotation setting
private void mLockScreenRotation()
{
  // Stop the screen orientation changing during an event
    switch (this.getResources().getConfiguration().orientation)
    {
  case Configuration.ORIENTATION_PORTRAIT:
    this.setRequestedOrientation(
ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    break;
  case Configuration.ORIENTATION_LANDSCAPE:
    this.setRequestedOrientation(
ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    break;
    }
}

Once your action has completed you may wish to enable screen rotation again, see the next section for an example on how to do this.

 

How to re-enable screen rotation

To enable the orientation to be automatically changed on device tilt simply pass thesetRequestedOrientation(int) method the enumeration value for an unspecified orientation.

[Code sample – How to re-enable screen rotation]

// allow screen rotations again
this.setRequestedOrientation(
ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);

异步处理 的时候如果转屏 异步处理就会停止，附件就是防止这种情况发生