1 files changed, 47 insertions, 7 deletions

diff --git a/src/com/android/calculator2/AlertDialogFragment.java b/src/com/android/calculator2/AlertDialogFragment.java
index bb7a50b..49f9549 100644
--- a/src/com/android/calculator2/AlertDialogFragment.java
+++ b/src/com/android/calculator2/AlertDialogFragment.java
@@ -21,22 +21,50 @@ import android.app.AlertDialog;
 import android.app.Dialog;
 import android.app.DialogFragment;
 import android.content.Context;
+import android.content.DialogInterface;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 import android.view.LayoutInflater;
 import android.widget.TextView;
 
-public class AlertDialogFragment extends DialogFragment {
+/**
+ * Display a message with a dismiss putton, and optionally a second button.
+ */
+public class AlertDialogFragment extends DialogFragment implements DialogInterface.OnClickListener {
+
+    public interface OnClickListener {
+        /**
+         * This method will be invoked when a button in the dialog is clicked.
+         *
+         * @param fragment the AlertDialogFragment that received the click
+         * @param which the button that was clicked (e.g.
+         *            {@link DialogInterface#BUTTON_POSITIVE}) or the position
+         *            of the item clicked
+         */
+        public void onClick(AlertDialogFragment fragment, int which);
+    }
 
     private static final String NAME = AlertDialogFragment.class.getName();
     private static final String KEY_MESSAGE = NAME + "_message";
     private static final String KEY_BUTTON_NEGATIVE = NAME + "_button_negative";
+    private static final String KEY_BUTTON_POSITIVE = NAME + "_button_positive";
 
-    public static void showMessageDialog(Activity activity, CharSequence message) {
+    /**
+     * Create and show a DialogFragment with the given message.
+     * @param activity originating Activity
+     * @param message displayed message
+     * @param positiveButtonLabel label for second button, if any.  If non-null, activity must
+     * implement AlertDialogFragment.OnClickListener to respond.
+     */
+    public static void showMessageDialog(Activity activity, CharSequence message,
+            @Nullable CharSequence positiveButtonLabel) {
+        final AlertDialogFragment dialogFragment = new AlertDialogFragment();
         final Bundle args = new Bundle();
         args.putCharSequence(KEY_MESSAGE, message);
         args.putCharSequence(KEY_BUTTON_NEGATIVE, activity.getString(R.string.dismiss));
-
-        final AlertDialogFragment dialogFragment = new AlertDialogFragment();
+        if (positiveButtonLabel != null) {
+            args.putCharSequence(KEY_BUTTON_POSITIVE, positiveButtonLabel);
+        }
         dialogFragment.setArguments(args);
         dialogFragment.show(activity.getFragmentManager(), null /* tag */);
     }
@@ -53,9 +81,21 @@ public class AlertDialogFragment extends DialogFragment {
         final TextView textView = (TextView) inflater.inflate(R.layout.dialog_message,
                 null /* root */);
         textView.setText(args.getCharSequence(KEY_MESSAGE));
-        return new AlertDialog.Builder(context)
+        final AlertDialog.Builder builder = new AlertDialog.Builder(context)
                 .setView(textView)
-                .setNegativeButton(args.getCharSequence(KEY_BUTTON_NEGATIVE), null /* listener */)
-                .create();
+                .setNegativeButton(args.getCharSequence(KEY_BUTTON_NEGATIVE), null /* listener */);
+        final CharSequence positiveButtonLabel = args.getCharSequence(KEY_BUTTON_POSITIVE);
+        if (positiveButtonLabel != null) {
+            builder.setPositiveButton(positiveButtonLabel, this);
+        }
+        return builder.create();
+    }
+
+    @Override
+    public void onClick(DialogInterface dialog, int which) {
+        final Activity activity = getActivity();
+        if (activity instanceof AlertDialogFragment.OnClickListener /* always true */) {
+            ((AlertDialogFragment.OnClickListener) activity).onClick(this, which);
+        }
     }
 }