Added show undo send option

app/src/main/java/eu/faircode/email/ActivityView.java

@@ -2540,8 +2540,10 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
         String to = intent.getStringExtra("to");
 
         SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
+        boolean send_undo = prefs.getBoolean("send_undo", false);
         int send_delayed = prefs.getInt("send_delayed", 0) * 1000;
-        if (send_delayed == 0)
+
+        if (!send_undo || send_delayed == 0)
             return;
 
         long timeout = at - new Date().getTime();
@@ -2563,7 +2565,7 @@ public class ActivityView extends ActivityBilling implements FragmentManager.OnB
             }
 
             @Override
-            protected Long onExecute(Context context, Bundle args) throws Throwable {
+            protected Long onExecute(Context context, Bundle args) {
                 long id = args.getLong("id");
                 return ActivityCompose.undoSend(id, context);
             }

app/src/main/java/eu/faircode/email/FragmentOptionsSend.java

@@ -91,6 +91,7 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
     private SwitchCompat swAutoSaveDot;
     private SwitchCompat swDiscardDelete;
     private Spinner spSendDelayed;
+    private SwitchCompat swSendUndo;
     private Spinner spAnswerActionSingle;
     private Spinner spAnswerActionLong;
     private Button btnSound;
@@ -142,7 +143,7 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
             "purge_contact_age", "purge_contact_freq",
             "send_reminders", "send_chips", "send_nav_color", "send_pending",
             "save_revisions", "auto_save_paragraph", "auto_save_dot", "discard_delete",
-            "send_delayed",
+            "send_delayed", "send_undo",
             "answer_single", "answer_action",
             "sound_sent",
             "compose_color", "compose_font", "compose_monospaced",
@@ -189,6 +190,7 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
         swAutoSaveDot = view.findViewById(R.id.swAutoSaveDot);
         swDiscardDelete = view.findViewById(R.id.swDiscardDelete);
         spSendDelayed = view.findViewById(R.id.spSendDelayed);
+        swSendUndo = view.findViewById(R.id.swSendUndo);
         spAnswerActionSingle = view.findViewById(R.id.spAnswerActionSingle);
         spAnswerActionLong = view.findViewById(R.id.spAnswerActionLong);
         btnSound = view.findViewById(R.id.btnSound);
@@ -436,7 +438,9 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
             @Override
             public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
                 int[] values = getResources().getIntArray(R.array.sendDelayedValues);
-                prefs.edit().putInt("send_delayed", values[position]).apply();
+                int send_delayed = values[position];
+                prefs.edit().putInt("send_delayed", send_delayed).apply();
+                swSendUndo.setEnabled(send_delayed > 0);
             }
 
             @Override
@@ -445,6 +449,13 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
             }
         });
 
+        swSendUndo.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
+            @Override
+            public void onCheckedChanged(CompoundButton compoundButton, boolean checked) {
+                prefs.edit().putBoolean("send_undo", checked).apply();
+            }
+        });
+
         spAnswerActionSingle.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
             @Override
             public void onItemSelected(AdapterView<?> adapterView, View view, int position, long id) {
@@ -966,6 +977,9 @@ public class FragmentOptionsSend extends FragmentBase implements SharedPreferenc
                     break;
                 }
 
+            swSendUndo.setChecked(prefs.getBoolean("send_undo", false));
+            swSendUndo.setEnabled(send_delayed > 0);
+
             String[] answerValues = getResources().getStringArray(R.array.answerValues);
 
             String answer_default = prefs.getString("answer_single", "menu");

app/src/main/res/layout/fragment_options_send.xml

@@ -433,6 +433,18 @@
                     app:layout_constraintStart_toStartOf="parent"
                     app:layout_constraintTop_toBottomOf="@id/tvSendDelayed" />
 
+                <androidx.appcompat.widget.SwitchCompat
+                    android:id="@+id/swSendUndo"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_marginStart="12dp"
+                    android:layout_marginTop="12dp"
+                    android:text="@string/title_advanced_send_undo"
+                    app:layout_constraintEnd_toEndOf="parent"
+                    app:layout_constraintStart_toStartOf="parent"
+                    app:layout_constraintTop_toBottomOf="@id/spSendDelayed"
+                    app:switchPadding="12dp" />
+
                 <TextView
                     android:id="@+id/tvAnswerActionSingle"
                     android:layout_width="0dp"
@@ -444,7 +456,7 @@
                     android:textColor="?android:attr/textColorPrimary"
                     app:layout_constraintEnd_toEndOf="parent"
                     app:layout_constraintStart_toStartOf="parent"
-                    app:layout_constraintTop_toBottomOf="@id/spSendDelayed" />
+                    app:layout_constraintTop_toBottomOf="@id/swSendUndo" />
 
                 <eu.faircode.email.SpinnerEx
                     android:id="@+id/spAnswerActionSingle"

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

@@ -477,6 +477,7 @@
     <string name="title_advanced_send_nav_color">Use the identity color for the bottom action bar</string>
     <string name="title_advanced_send_reminders">Show reminders</string>
     <string name="title_advanced_send_delayed">Delay sending messages</string>
+    <string name="title_advanced_send_undo">Show undo send option</string>
     <string name="title_advanced_send_top">Show send button at the top</string>
     <string name="title_advanced_attach_new">Create a new draft message for shared addresses and files</string>
     <string name="title_advanced_answer_caption">Answer button settings</string>