Fire onSeek after seek completes on Android, document onSeek

README.md

@@ -295,6 +295,7 @@ var styles = StyleSheet.create({
 * [onLoad](#onload)
 * [onLoadStart](#onloadstart)
 * [onProgress](#onprogress)
+* [onSeek](#onseek)
 * [onTimedMetadata](#ontimedmetadata)
 
 ### Methods
@@ -848,6 +849,29 @@ Example:
 
 Platforms: all
 
+#### onSeek
+Callback function that is called when a seek completes.
+
+Payload:
+
+Property | Type | Description
+--- | --- | ---
+currentTime | number | The current time after the seek
+seekTime | number | The requested time
+
+Example:
+```
+{
+  currentTime: 100.5
+  seekTime: 100
+}
+```
+
+Both the currentTime & seekTime are reported because the video player may not seek to the exact requested position in order to improve seek performance.
+
+
+Platforms: Android ExoPlayer, Android MediaPlayer, iOS, Windows UWP
+
 #### onTimedMetadata
 Callback function that is called when timed metadata becomes available
 
@@ -941,7 +965,7 @@ Platforms: iOS
 
 Seek to the specified position represented by seconds. seconds is a float value.
 
-`seek()` can only be called after the `onLoad` event has fired.
+`seek()` can only be called after the `onLoad` event has fired. Once completed, the [onSeek](#onseek) event will be called.
 
 Example:
 ```

android-exoplayer/src/main/java/com/brentvatne/exoplayer/ReactExoplayerView.java

@@ -110,6 +110,7 @@ class ReactExoplayerView extends FrameLayout implements
     private boolean isBuffering;
     private float rate = 1f;
     private float audioVolume = 1f;
+    private long seekTime = C.TIME_UNSET;
 
     private int minBufferMs = DefaultLoadControl.DEFAULT_MIN_BUFFER_MS;
     private int maxBufferMs = DefaultLoadControl.DEFAULT_MAX_BUFFER_MS;
@@ -605,7 +606,8 @@ public void onTimelineChanged(Timeline timeline, Object manifest, int reason) {
 
     @Override
     public void onSeekProcessed() {
-        // Do nothing.
+        eventEmitter.seek(player.getCurrentPosition(), seekTime);
+        seekTime = C.TIME_UNSET;
     }
 
     @Override
@@ -892,7 +894,7 @@ public void setVolumeModifier(float volume) {
 
     public void seekTo(long positionMs) {
         if (player != null) {
-            eventEmitter.seek(player.getCurrentPosition(), positionMs);
+            seekTime = positionMs;
             player.seekTo(positionMs);
         }
     }

android/src/main/java/com/brentvatne/react/ReactVideoView.java

@@ -47,6 +47,7 @@ public class ReactVideoView extends ScalableVideoView implements
     MediaPlayer.OnPreparedListener,
     MediaPlayer.OnErrorListener,
     MediaPlayer.OnBufferingUpdateListener,
+    MediaPlayer.OnSeekCompleteListener,
     MediaPlayer.OnCompletionListener,
     MediaPlayer.OnInfoListener,
     LifecycleEventListener,
@@ -127,6 +128,7 @@ public String toString() {
     private float mProgressUpdateInterval = 250.0f;
     private float mRate = 1.0f;
     private float mActiveRate = 1.0f;
+    private long mSeekTime = 0;
     private boolean mPlayInBackground = false;
     private boolean mBackgroundPaused = false;
     private boolean mIsFullscreen = false;
@@ -213,6 +215,7 @@ private void initializeMediaPlayerIfNeeded() {
             mMediaPlayer.setOnErrorListener(this);
             mMediaPlayer.setOnPreparedListener(this);
             mMediaPlayer.setOnBufferingUpdateListener(this);
+            mMediaPlayer.setOnSeekCompleteListener(this);
             mMediaPlayer.setOnCompletionListener(this);
             mMediaPlayer.setOnInfoListener(this);
             if (Build.VERSION.SDK_INT >= 23) {
@@ -606,15 +609,18 @@ public void onBufferingUpdate(MediaPlayer mp, int percent) {
         mVideoBufferedDuration = (int) Math.round((double) (mVideoDuration * percent) / 100.0);
     }
 
+    public void onSeekComplete(MediaPlayer mp) {
+        WritableMap event = Arguments.createMap();
+        event.putDouble(EVENT_PROP_CURRENT_TIME, getCurrentPosition() / 1000.0);
+        event.putDouble(EVENT_PROP_SEEK_TIME, mSeekTime / 1000.0);
+        mEventEmitter.receiveEvent(getId(), Events.EVENT_SEEK.toString(), event);
+        mSeekTime = 0;
+    }
+
     @Override
     public void seekTo(int msec) {
-
         if (mMediaPlayerValid) {
-            WritableMap event = Arguments.createMap();
-            event.putDouble(EVENT_PROP_CURRENT_TIME, getCurrentPosition() / 1000.0);
-            event.putDouble(EVENT_PROP_SEEK_TIME, msec / 1000.0);
-            mEventEmitter.receiveEvent(getId(), Events.EVENT_SEEK.toString(), event);
-
+            mSeekTime = msec;
             super.seekTo(msec);
             if (isCompleted && mVideoDuration != 0 && msec < mVideoDuration) {
                 isCompleted = false;