termux-vibrate: Do not vibrate when in silent mode

Do not vibrate when in silent mode unless the -f/--force option is
given.

app/src/main/java/com/termux/api/VibrateAPI.java

@@ -2,6 +2,7 @@
 
 import android.content.Context;
 import android.content.Intent;
+import android.media.AudioManager;
 import android.os.Vibrator;
 
 import com.termux.api.util.ResultReturner;
@@ -11,7 +12,15 @@ public class VibrateAPI {
 	static void onReceive(TermuxApiReceiver apiReceiver, Context context, Intent intent) {
 		Vibrator vibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
 		int milliseconds = intent.getIntExtra("duration_ms", 1000);
-		vibrator.vibrate(milliseconds);
+		boolean force = intent.getBooleanExtra("force", false);
+
+		AudioManager am = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);
+		if (am.getRingerMode() == AudioManager.RINGER_MODE_SILENT && !force) {
+			// Not vibrating since in silent mode and -f/--force option not used.
+		} else {
+			vibrator.vibrate(milliseconds);
+		}
+
 		ResultReturner.noteDone(apiReceiver, intent);
 	}