Fixed bug 2415 - Message Boxes aren't implemented on Android

Philipp Wiesemann

I attached a patch for an incomplete implementation of the messagebox parts.

It was not tested on lots of devices yet and features a very fragile workaround to block the calling SDL thread while the dialog is handled on Android's UI thread. Although it works for testmessage.c I assume there are lot of situations were it may fail (standby, device rotation and other changes). Also not all flags and colors are implemented.

On the other hand most uses of the messagebox are to show an error on start and fragility (or working at all) may not matter there.

src/core/android/SDL_android.c

@@ -1342,6 +1342,85 @@ void Android_JNI_HideTextInput()
     Android_JNI_SendMessage(COMMAND_TEXTEDIT_HIDE, 0);
 }
 
+int Android_JNI_ShowMessageBox(const SDL_MessageBoxData *messageboxdata, int *buttonid)
+{
+    JNIEnv *env;
+    jmethodID mid;
+    jobject context;
+    jstring title;
+    jstring message;
+    jintArray button_flags;
+    jintArray button_ids;
+    jobjectArray button_texts;
+    jintArray colors;
+    jint temp;
+    int i;
+
+    env = Android_JNI_GetEnv();
+
+    /* convert parameters */
+
+    title = (*env)->NewStringUTF(env, messageboxdata->title);
+    message = (*env)->NewStringUTF(env, messageboxdata->message);
+
+    button_flags = (*env)->NewIntArray(env, messageboxdata->numbuttons);
+    button_ids = (*env)->NewIntArray(env, messageboxdata->numbuttons);
+    button_texts = (*env)->NewObjectArray(env, messageboxdata->numbuttons,
+        (*env)->FindClass(env, "java/lang/String"), NULL);
+    for (i = 0; i < messageboxdata->numbuttons; ++i) {
+        temp = messageboxdata->buttons[i].flags;
+        (*env)->SetIntArrayRegion(env, button_flags, i, 1, &temp);
+        temp = messageboxdata->buttons[i].buttonid;
+        (*env)->SetIntArrayRegion(env, button_ids, i, 1, &temp);
+        (*env)->SetObjectArrayElement(env, button_texts, i, (*env)->NewStringUTF(env, messageboxdata->buttons[i].text));
+    }
+
+    if (messageboxdata->colorScheme) {
+        colors = (*env)->NewIntArray(env, SDL_MESSAGEBOX_COLOR_MAX);
+        for (i = 0; i < SDL_MESSAGEBOX_COLOR_MAX; ++i) {
+            temp = (0xFF << 24) |
+                   (messageboxdata->colorScheme->colors[i].r << 16) |
+                   (messageboxdata->colorScheme->colors[i].g << 8) |
+                   (messageboxdata->colorScheme->colors[i].b << 0);
+            (*env)->SetIntArrayRegion(env, colors, i, 1, &temp);
+        }
+    } else {
+        colors = NULL;
+    }
+
+    /* call function */
+
+    mid = (*env)->GetStaticMethodID(env, mActivityClass, "getContext","()Landroid/content/Context;");
+
+    context = (*env)->CallStaticObjectMethod(env, mActivityClass, mid);
+
+    mid = (*env)->GetMethodID(env, (*env)->GetObjectClass(env, context),
+        "messageboxShowMessageBox", "(ILjava/lang/String;Ljava/lang/String;[I[I[Ljava/lang/String;[I)I");
+    *buttonid = (*env)->CallIntMethod(env, context, mid,
+        messageboxdata->flags,
+        title,
+        message,
+        button_flags,
+        button_ids,
+        button_texts,
+        colors);
+
+    /* delete parameters */
+
+    (*env)->DeleteLocalRef(env, title);
+    (*env)->DeleteLocalRef(env, message);
+    (*env)->DeleteLocalRef(env, button_flags);
+    (*env)->DeleteLocalRef(env, button_ids);
+    for (i = 0; i < messageboxdata->numbuttons; ++i) {
+        (*env)->DeleteLocalRef(env, (*env)->GetObjectArrayElement(env, button_texts, i));
+        (*env)->SetObjectArrayElement(env, button_texts, i, NULL);
+    }
+    (*env)->DeleteLocalRef(env, button_texts);
+    (*env)->DeleteLocalRef(env, colors);
+
+    return 0;
+}
+
 /*
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 //