change to use displaymanager listener for refresh rate updating

library/core/src/main/java/com/google/android/exoplayer2/video/MediaCodecVideoRenderer.java

@@ -236,7 +236,7 @@ public class MediaCodecVideoRenderer extends MediaCodecRenderer {
     tunnelingAudioSessionId = getConfiguration().tunnelingAudioSessionId;
     tunnelingAudioSessionId = getConfiguration().tunnelingAudioSessionId;
     tunneling = tunnelingAudioSessionId != C.AUDIO_SESSION_ID_UNSET;
     tunneling = tunnelingAudioSessionId != C.AUDIO_SESSION_ID_UNSET;
     eventDispatcher.enabled(decoderCounters);
     eventDispatcher.enabled(decoderCounters);
-    frameReleaseTimeHelper.enable(context);
+    frameReleaseTimeHelper.enable();
   }
   }
 
 
   @Override
   @Override

library/core/src/main/java/com/google/android/exoplayer2/video/VideoFrameReleaseTimeHelper.java

@@ -17,6 +17,8 @@ package com.google.android.exoplayer2.video;
 
 
 import android.annotation.TargetApi;
 import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.Context;
+import android.hardware.display.DisplayManager;
+import android.os.Build;
 import android.os.Handler;
 import android.os.Handler;
 import android.os.HandlerThread;
 import android.os.HandlerThread;
 import android.os.Message;
 import android.os.Message;
@@ -31,6 +33,7 @@ import com.google.android.exoplayer2.C;
 @TargetApi(16)
 @TargetApi(16)
 public final class VideoFrameReleaseTimeHelper {
 public final class VideoFrameReleaseTimeHelper {
 
 
+  private static final int DISPLAY_ID_UNKNOWN = -1;
   private static final double DISPLAY_REFRESH_RATE_UNKNOWN = -1;
   private static final double DISPLAY_REFRESH_RATE_UNKNOWN = -1;
   private static final long CHOREOGRAPHER_SAMPLE_DELAY_MILLIS = 500;
   private static final long CHOREOGRAPHER_SAMPLE_DELAY_MILLIS = 500;
   private static final long MAX_ALLOWED_DRIFT_NS = 20000000;
   private static final long MAX_ALLOWED_DRIFT_NS = 20000000;
@@ -38,6 +41,9 @@ public final class VideoFrameReleaseTimeHelper {
   private static final long VSYNC_OFFSET_PERCENTAGE = 80;
   private static final long VSYNC_OFFSET_PERCENTAGE = 80;
   private static final int MIN_FRAMES_FOR_ADJUSTMENT = 6;
   private static final int MIN_FRAMES_FOR_ADJUSTMENT = 6;
 
 
+  private DisplayManager.DisplayListener displayListener = null;
+  private Context context = null;
+
   private VSyncSampler vsyncSampler;
   private VSyncSampler vsyncSampler;
   private boolean useDefaultDisplayVsync;
   private boolean useDefaultDisplayVsync;
   private long vsyncDurationNs;
   private long vsyncDurationNs;
@@ -68,6 +74,8 @@ public final class VideoFrameReleaseTimeHelper {
    */
    */
   public VideoFrameReleaseTimeHelper(Context context) {
   public VideoFrameReleaseTimeHelper(Context context) {
     this(getDefaultDisplayRefreshRate(context));
     this(getDefaultDisplayRefreshRate(context));
+    this.context = context;
+    registerDisplayListener();
   }
   }
 
 
   private VideoFrameReleaseTimeHelper(double defaultDisplayRefreshRate) {
   private VideoFrameReleaseTimeHelper(double defaultDisplayRefreshRate) {
@@ -77,12 +85,12 @@ public final class VideoFrameReleaseTimeHelper {
   /**
   /**
    * Enables the helper.
    * Enables the helper.
    */
    */
-  public void enable(Context context) {
+  public void enable() {
     haveSync = false;
     haveSync = false;
     if (useDefaultDisplayVsync) {
     if (useDefaultDisplayVsync) {
-      setSync(getDefaultDisplayRefreshRate(context));
       vsyncSampler.addObserver();
       vsyncSampler.addObserver();
     }
     }
+    registerDisplayListener();
   }
   }
 
 
   /**
   /**
@@ -92,6 +100,29 @@ public final class VideoFrameReleaseTimeHelper {
     if (useDefaultDisplayVsync) {
     if (useDefaultDisplayVsync) {
       vsyncSampler.removeObserver();
       vsyncSampler.removeObserver();
     }
     }
+    unregisterDisplayListener();
+  }
+
+  private void registerDisplayListener() {
+    if (displayListener == null && context != null &&
+     Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      DisplayManager displayManager = context.getSystemService(DisplayManager.class);
+      if (displayManager != null) {
+        displayListener = new DefaultDisplayListener(context);
+        displayManager.registerDisplayListener(displayListener, null);
+      }
+    }
+  }
+
+  private void unregisterDisplayListener() {
+    if (context != null && displayListener != null &&
+     Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
+      DisplayManager displayManager = context.getSystemService(DisplayManager.class);
+      if (displayManager != null) {
+        displayManager.unregisterDisplayListener(displayListener);
+        displayListener = null;
+      }
+    }
   }
   }
 
 
   private void setSync(double defaultDisplayRefreshRate) {
   private void setSync(double defaultDisplayRefreshRate) {
@@ -206,10 +237,16 @@ public final class VideoFrameReleaseTimeHelper {
     return snappedAfterDiff < snappedBeforeDiff ? snappedAfterNs : snappedBeforeNs;
     return snappedAfterDiff < snappedBeforeDiff ? snappedAfterNs : snappedBeforeNs;
   }
   }
 
 
+  private static int getDefaultDisplayId(Context context) {
+    WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
+    return manager != null && manager.getDefaultDisplay() != null ?
+     manager.getDefaultDisplay().getDisplayId() : DISPLAY_ID_UNKNOWN;
+  }
+
   private static double getDefaultDisplayRefreshRate(Context context) {
   private static double getDefaultDisplayRefreshRate(Context context) {
     WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
     WindowManager manager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
-    return manager.getDefaultDisplay() != null ? manager.getDefaultDisplay().getRefreshRate()
-        : DISPLAY_REFRESH_RATE_UNKNOWN;
+    return manager != null && manager.getDefaultDisplay() != null ?
+     manager.getDefaultDisplay().getRefreshRate() : DISPLAY_REFRESH_RATE_UNKNOWN;
   }
   }
 
 
   /**
   /**
@@ -307,4 +344,30 @@ public final class VideoFrameReleaseTimeHelper {
 
 
   }
   }
 
 
+  @TargetApi(17)
+  private class DefaultDisplayListener implements DisplayManager.DisplayListener {
+
+    private final Context context;
+    DefaultDisplayListener(Context context) {
+      this.context = context;
+    }
+
+    @Override
+    public void onDisplayAdded(int displayId) {
+    }
+
+    @Override
+    public void onDisplayRemoved(int displayId) {
+    }
+
+    @Override
+    public void onDisplayChanged(int displayId) {
+      final int defaultDisplayId = getDefaultDisplayId(context);
+      if (displayId == defaultDisplayId || defaultDisplayId == DISPLAY_ID_UNKNOWN) {
+        setSync(getDefaultDisplayRefreshRate(context));
+      }
+    }
+
+  }
+
 }
 }