bluetooth: android: register for adapter on/off events.

device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java

Index: device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
diff --git a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
index 0a54a0bdfe73f817a2cff9c0ee24783c91842eed..4e90503d0966795c195c6c2a62e8dac9af38d6fb 100644
--- a/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
+++ b/device/bluetooth/android/java/src/org/chromium/device/bluetooth/ChromeBluetoothAdapter.java
@@ -8,6 +8,10 @@ import android.Manifest;
 import android.annotation.TargetApi;
 import android.bluetooth.BluetoothAdapter;
 import android.bluetooth.le.ScanSettings;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.IntentFilter;
 import android.os.Build;
 import android.os.ParcelUuid;
 
@@ -26,7 +30,7 @@ import java.util.List;
  */
 @JNINamespace("device")
 @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-final class ChromeBluetoothAdapter {
+final class ChromeBluetoothAdapter extends BroadcastReceiver {
     private static final String TAG = "Bluetooth";
 
     private long mNativeBluetoothAdapterAndroid;
@@ -49,6 +53,7 @@ final class ChromeBluetoothAdapter {
             long nativeBluetoothAdapterAndroid, Wrappers.BluetoothAdapterWrapper adapterWrapper) {
         mNativeBluetoothAdapterAndroid = nativeBluetoothAdapterAndroid;
         mAdapter = adapterWrapper;
+        registerBroadcastReceiver();
         if (adapterWrapper == null) {
             Log.i(TAG, "ChromeBluetoothAdapter created with no adapterWrapper.");
         } else {
@@ -63,6 +68,7 @@ final class ChromeBluetoothAdapter {
     private void onBluetoothAdapterAndroidDestruction() {
         stopScan();
         mNativeBluetoothAdapterAndroid = 0;
+        unregisterBroadcastReceiver();
     }
 
     // ---------------------------------------------------------------------------------------------
@@ -187,6 +193,19 @@ final class ChromeBluetoothAdapter {
                 || context.checkPermission(Manifest.permission.ACCESS_FINE_LOCATION);
     }
 
+    private void registerBroadcastReceiver() {
+        if (mAdapter != null) {
+            mAdapter.getContext().registerReceiver(
+                    this, new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED));
+        }
+    }
+
+    private void unregisterBroadcastReceiver() {
+        if (mAdapter != null) {
+            mAdapter.getContext().unregisterReceiver(this);
+        }
+    }
+
     /**
      * Starts a Low Energy scan.
      * @return True on success.
@@ -275,6 +294,28 @@ final class ChromeBluetoothAdapter {
         }
     }
 
+    @Override
+    public void onReceive(Context context, Intent intent) {
+        String action = intent.getAction();
+
+        if (isPresent() && BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
+            int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);
+
+            Log.w(TAG, "BluetoothStateReceiver#onReceive action: %d", state);

[scheib, 2016/02/26 00:05:59]

This string doesn't mean much to me, would it be more direct as
"onReceive: BluetoothAdapter.ACTION_STATE_CHANGED: %d"
Would be nice to output string values for the 4 state values too, but that's
optional.

[perja, 2016/02/26 10:51:04]

Done.

+
+            switch (state) {
+                case BluetoothAdapter.STATE_ON:
+                    nativeOnAdapterStateChanged(mNativeBluetoothAdapterAndroid, true);
+                    break;
+                case BluetoothAdapter.STATE_OFF:
+                    nativeOnAdapterStateChanged(mNativeBluetoothAdapterAndroid, false);
+                    break;
+                default:
+                    // do nothing
+            }
+        }
+    }
+
     // ---------------------------------------------------------------------------------------------
     // BluetoothAdapterAndroid C++ methods declared for access from java:
 
@@ -287,4 +328,8 @@ final class ChromeBluetoothAdapter {
     // http://crbug.com/505554
     private native void nativeCreateOrUpdateDeviceOnScan(long nativeBluetoothAdapterAndroid,
             String address, Object bluetoothDeviceWrapper, List<ParcelUuid> advertisedUuids);
+
+    // Binds to BluetoothAdapterAndroid::nativeOnAdapterStateChanged
+    private native void nativeOnAdapterStateChanged(
+            long nativeBluetoothAdapterAndroid, boolean powered);
 }