Confirm deleting signatures

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

@@ -392,12 +392,27 @@ public class ActivitySignature extends ActivityBase {
     }
 
     private void delete() {
-        Intent result = getIntent();
+        new AlertDialog.Builder(this)
-        if (result == null)
+                .setIcon(R.drawable.twotone_gesture_24)
-            result = new Intent();
+                .setTitle(R.string.title_edit_signature_delete)
-        result.putExtra("html", (String) null);
+                .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
-        setResult(RESULT_OK, result);
+                    @Override
-        finish();
+                    public void onClick(DialogInterface dialog, int which) {
+                        Intent result = getIntent();
+                        if (result == null)
+                            result = new Intent();
+                        result.putExtra("html", (String) null);
+                        setResult(RESULT_OK, result);
+                        finish();
+                    }
+                })
+                .setNegativeButton(android.R.string.cancel, new DialogInterface.OnClickListener() {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        // Do nothing
+                    }
+                })
+                .show();
     }
 
     private void save() {

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

@@ -2040,6 +2040,7 @@
         When sending a message, the image is copied into the message from the selected location.
         So, don\'t delete the image file!
     </string>
+    <string name="title_edit_signature_delete">Delete signature?</string>
 
     <string name="title_answer_define_name">Name</string>
     <string name="title_answer_define_value">Value</string>