Android Device onConfigurationChanged event does n

问题:

i have an activity and on startup of the activity i need to change the orientation in lanscape and then later on i want to handle both orientation changes as user rotates device , but it once changes the orientation and later on does not change the orientation. here is my code please help

    public class Hls extends Activity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_hls);

    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);


}



@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);

    Log.v("new orientation", "yes");

    if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT)
    {
        Toast.makeText(this, "portrait", Toast.LENGTH_LONG).show();
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    }
    if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
    {
        Toast.makeText(this, "landscape", Toast.LENGTH_LONG).show();
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    } 

}

回答1:

Using setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) in onCreate will fix your orientation permanently to landscape and will avoid any change in orientation. That is why your orientation gets fixed and doesn't respond to the rotations.

Here is an alternative you can use :-

1> Create two views in your layout. i.e one for landscape and one for portrait views.Lets say activity_hls_land and activity_hls_port.

2> Use setContentView(R.layout.activity_hls) in onConfigurationChanged(Configuration newConfig) instead of setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE) or setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT)

Here is the sample code:-

 public class MainActivity extends Activity {
boolean isLaunched=true;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);


        if(isLaunched){
        Toast.makeText(this, "1 st launch " , Toast.LENGTH_SHORT).show(); 
        setContentView(R.layout.activity_hls_land);
        }

    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);

    if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT)
    {
        Toast.makeText(this, "portrait", Toast.LENGTH_SHORT).show();
        setContentView(R.layout.activity_hls_port);
    }
     if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
    {
        Toast.makeText(this, "landscape", Toast.LENGTH_SHORT).show();
        setContentView(R.layout.activity_hls_land );
    } 
    }

}

and in the manifest add android:configChanges="orientation" in activity :-

<activity
            android:name=".MainActivity"
            android:label="@string/title_activity_main" 
            android:configChanges="orientation"
            >

            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
          </activity>

Sample layout for activity_hls_port :-

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
 <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
  <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
</LinearLayout>

Sample for landscape mode:-

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" 
    android:orientation="vertical"
    android:rotation="90">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
 <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
  <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world"
        tools:context=".MainActivity" />
</LinearLayout>

回答2:

On this statement

if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT)
    {
        Toast.makeText(this, "portrait", Toast.LENGTH_LONG).show();
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    }
    if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE)
    {
        Toast.makeText(this, "landscape", Toast.LENGTH_LONG).show();
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
    } 

also in onCreate(Bundle bundle);

You called

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

or

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);

It means that your activity is in landscape/portrait orientation and never rotate again

removing it will trigger the onConfigurationChanged(Configuration) again

回答3:

I'm not clear about your requirement. If you don't mind restarting your activity, you can just skip overriding onConfigurationChanged. System will handle Orientation changes for you. In case you don't want it to be restarted on orientation changes, just mention <activity android:configChanges="keyboardHidden|orientation|screenSize"/>, and override onConfigurationChanged and call setContentView()

public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    setContentview(R.layout.activity_hls);
    initializeViews();//here you can initialize all your memberVariables using findViewbyID()
}