以横向模式返回（android.hardware.Camera）

Question

I am building an app that contains a video capture from a custom camera with a surface view. It works fine in portrait mode, but when I change to landscape mode the camera preview goes to a blank screen.

Here's the code I'm using:

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    setContentView(R.layout.camera_activity);

        camera1 = Camera.open(camId);
        try {
            camera1.setPreviewDisplay(surfaceHolder);
            camera1.startPreview();
        } catch (IOException e) {
            e.printStackTrace();
        }

}

In the ConfigurationChanged function I'm not getting the camera1 Object.

How can I solve this?

Answer 1

You need to override onSaveInstanceState(Bundle savedInstanceState) and write the application state values you want to change to the Bundle parameter like this:

You can saved instance of each variable like this

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
  super.onSaveInstanceState(savedInstanceState);
  // Save UI state changes to the savedInstanceState.
  // This bundle will be passed to onCreate if the process is
  // killed and restarted.
  savedInstanceState.putBoolean("myBoolean", false);
  savedInstanceState.putDouble("myDouble", 1.121);
  savedInstanceState.putInt("myInt", 0);
  savedInstanceState.putString("myString", "Your String");
  // etc.
}

and That changes you can retrive like this

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
  super.onRestoreInstanceState(savedInstanceState);
  // Restore UI state from the savedInstanceState.
  // This bundle has also been passed to onCreate.
  boolean myBoolean = savedInstanceState.getBoolean("myBoolean");
  double myDouble = savedInstanceState.getDouble("myDouble");
  int myInt = savedInstanceState.getInt("myInt");
  String myString = savedInstanceState.getString("myString");
}

Hope this will help you .cheers!

UPDATE:

if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT)
        {   
            p.set("orientation", "portrait");
            p.set("rotation",90);
        }
        if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE)
        {                               
            p.set("orientation", "landscape");          
            p.set("rotation", 90);
        }

and set Property Like THis:

Camera.Parameters parameters = camera.getParameters();
parameters.set("orientation", "portrait");
camera.setParameters(parameters);

Answer 2

您可以让camera1对象幸免于Activity的死活和复活，或者（效率较低）销毁相机onStop（）或（更高效）在配置更改时保留Activity实例。