Fixes: #236: Double back press to exit.

Author: saketkumar

app/src/main/java/com/zulip/android/activities/ZulipActivity.java

@@ -129,6 +129,7 @@ public class ZulipActivity extends BaseActivity implements
     private ZulipApp app;
 
     private boolean logged_in = false;
+    private boolean backPressedOnce = false;
 
     private ZulipActivity that = this; // self-ref
 
@@ -146,6 +147,7 @@ public class ZulipActivity extends BaseActivity implements
     private AsyncGetEvents event_poll;
 
     private Handler statusUpdateHandler;
+    private Runnable statusUpdateRunnable;
 
     public MessageListFragment currentList;
     private MessageListFragment narrowedList;
@@ -406,7 +408,7 @@ public void onItemClick(AdapterView<?> parent, View view,
 
         // send status update and check again every couple minutes
         statusUpdateHandler = new Handler();
-        Runnable statusUpdateRunnable = new Runnable() {
+        statusUpdateRunnable = new Runnable() {
             @Override
             public void run() {
                 AsyncStatusUpdate task = new AsyncStatusUpdate(
@@ -1433,12 +1435,28 @@ public void clearChatBox() {
     }
 
     public void onBackPressed() {
-        if (narrowedList != null) {
-            narrowedList = null;
-            getSupportFragmentManager().popBackStack(NARROW,
+        if (narrowedList == null) {
+
+            if (backPressedOnce) {
+                finish();
+            }
+
+            backPressedOnce = true;
+            Toast.makeText(this, R.string.press_again_to_exit, Toast.LENGTH_SHORT).show();
+            statusUpdateRunnable = new Runnable() {
+                @Override
+                public void run() {
+                    backPressedOnce = false;
+                }
+            };
+
+            statusUpdateHandler.postDelayed(statusUpdateRunnable, 2000);
+
+
+        }   else {
+              narrowedList = null;
+              getSupportFragmentManager().popBackStack(NARROW,
                     FragmentManager.POP_BACK_STACK_INCLUSIVE);
-        } else {
-            super.onBackPressed();
         }
     }
 
@@ -1804,6 +1822,7 @@ protected void onDestroy() {
         super.onDestroy();
         if (statusUpdateHandler != null) {
             statusUpdateHandler.removeMessages(0);
+            statusUpdateHandler.removeCallbacks(statusUpdateRunnable);
         }
     }
 

app/src/main/res/values/strings.xml

@@ -18,6 +18,7 @@
     <string name="title_activity_legal">Legal</string>
     <string name="streams_open">Open stream sidebar</string>
     <string name="streams_close">Close stream sidebar</string>
+    <string name="press_again_to_exit">Press again to exit</string>
 
     <!-- Used on the indicator when loading messages -->
     <string name="loading_messages">Loading messages</string>