Android onConfigurationChanged not called for Landscape and Reverselandscape

當螢幕方向改變時，我們通常會在Activity中Override function : onConfigurationChanged 的方式來接收變化。

但目前只有當 Landscape 與 Portrait 之間互轉時才會收到event.
所以landscape轉成reverse landscape並不會由onConfigurationChanged收到變化.

onConfigurationChanged

onConfigurationChanged接收orientation變化的方式如下

在AndroidManifest.xml的填入android:configChanges

AndroidManifest.xml

<application ... >
    <activity
        android:name=".MainActivity"
        android:screenOrientation="sensorLandscape"
        android:configChanges="orientation|screenSize|keyboardHidden"/>
</application>

在MainActivity.java中增加Override function : onConfigurationChanged 。

AndroidManifest.xml

override fun onConfigurationChanged(newConfig: Configuration?) {
    super.onConfigurationChanged(newConfig)
}

以上的方式無法得知 landscape轉成reverse landscape的訊息。

我們可監聽Ratation的變化來實現此功能。

Rotation Changed Listener

Step 1: 建立callback : RotationCallback

新增kotlin interface : RotationCallback

RotationCallback.kt

interface RotationCallback {
  fun onRotationChanged(lastRotation: Int, newRotation: Int)
}

Step 2: 建立Listerner : RotationListener

新增kotlin class : RotationListener
其中mOrientationEventListener監聽Rotation的變化，並透過mCallback傳遞給上層

RotationListener.kt

class RotationListener {
  private var mOrientationEventListener: OrientationEventListener? = null
  private var mCallback: RotationCallback? = null

  private var lastRotation: Int = 0

  constructor(callback: RotationCallback) {
    mCallback = callback
  }

  fun listen(context: Context) {
    mOrientationEventListener = object : OrientationEventListener(context, SensorManager.SENSOR_DELAY_NORMAL) {
      override fun onOrientationChanged(orientation: Int) {
        val localWindowManager = context.getSystemService(Context.WINDOW_SERVICE) as WindowManager
        if (null != localWindowManager && null != mCallback) {
          val newRotation = localWindowManager.defaultDisplay.rotation
          if (newRotation != lastRotation) {
            mCallback!!.onRotationChanged(lastRotation, newRotation)
            lastRotation = newRotation
          }
        }
      }
    }
    mOrientationEventListener!!.enable()

    lastRotation = (context.getSystemService(Context.WINDOW_SERVICE) as WindowManager).defaultDisplay.rotation
  }

  fun stop() {
    if (null != mOrientationEventListener) {
      mOrientationEventListener!!.disable()
    }
    mOrientationEventListener = null
    mCallback = null
  }
}

Step 3: MainActivity監聽與解除接聽

MainActivity繼承RotationCallback且實現其onRotationChanged function，並在onCreate時建立監聽Rotation變化, 而在onDestroy時取消監聽

MainActivity.kt

class MainActivity : AppCompatActivity(), RotationCallback {
  private val TAG = "MainActivity "
  
  private var mRotationListener : RotationListener? = null

  override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    setContentView(R.layout.activity_main)

    mRotationListener = RotationListener(this)
    mRotationListener!!.listen(this.applicationContext)
  }
  
  override fun onDestroy() {
    super.onDestroy()
    Log.e(TAG, "onDestroy()")
    
    mRotationListener!!.stop()
    mRotationListener = null
  }

  //RotationCallback
  override fun onRotationChanged(lastRotation: Int, newRotation: Int) {
    Log.d(TAG, "onRotationChanged: last " + (lastRotation) +"  new " + (newRotation));
  }
}

這樣就可以得知landscape與reverse landscape的變化了。