Add a shake animation on a terminal bell

app/src/main/java/com/termux/app/TermuxActivity.java

@@ -49,6 +49,8 @@ import android.view.View.OnClickListener;
 import android.view.View.OnLongClickListener;
 import android.view.ViewGroup;
 import android.view.WindowManager;
+import android.view.animation.Animation;
+import android.view.animation.AnimationUtils;
 import android.view.inputmethod.InputMethodManager;
 import android.widget.AdapterView;
 import android.widget.AdapterView.OnItemClickListener;
@@ -139,6 +141,8 @@ public final class TermuxActivity extends Activity implements ServiceConnection
             .setUsage(AudioAttributes.USAGE_ASSISTANCE_SONIFICATION).build()).build();
     int mBellSoundId;
 
+    Animation mOnBellAnimation;
+
     private final BroadcastReceiver mBroadcastReceiever = new BroadcastReceiver() {
         @Override
         public void onReceive(Context context, Intent intent) {
@@ -209,6 +213,8 @@ public final class TermuxActivity extends Activity implements ServiceConnection
     public void onCreate(Bundle bundle) {
         super.onCreate(bundle);
 
+        mOnBellAnimation = AnimationUtils.loadAnimation(this, R.anim.on_bell);
+
         mSettings = new TermuxPreferences(this);
 
         setContentView(R.layout.drawer_layout);
@@ -402,7 +408,10 @@ public final class TermuxActivity extends Activity implements ServiceConnection
 
             @Override
             public void onBell(TerminalSession session) {
-                if (mIsVisible) {
+                if (!mIsVisible) return;
+
+                mTerminalView.startAnimation(mOnBellAnimation);
+
                 switch (mSettings.mBellBehaviour) {
                     case TermuxPreferences.BELL_BEEP:
                         mBellSoundPool.play(mBellSoundId, 1.f, 1.f, 1, 0, 1.f);
@@ -416,7 +425,6 @@ public final class TermuxActivity extends Activity implements ServiceConnection
                 }
 
             }
-            }
 
             @Override
             public void onColorsChanged(TerminalSession changedSession) {

app/src/main/res/anim/on_bell.xml

@@ -0,0 +1,7 @@
+<set xmlns:android="http://schemas.android.com/apk/res/android">
+    <translate android:duration="30"
+               android:fromXDelta="-1%"
+               android:repeatCount="1"
+               android:repeatMode="reverse"
+               android:toXDelta="1%"/>
+</set>