Android: Activity with android:launchMode="singleTask" is blank after returning from background

[grebulon]

I have searched and made sure there are no existing issues for the issue I am filing

• I have searched the existing issues

Description

Can't use a singleTask activity by adding android:launchMode="singleTask" to the activity's manifest definition in tiapp.xml.

Expected Behavior

singleTask activity is a must when using Chrome Tab for OAuth login. These tabs open on top of the opening activity and can only be removed by returning to the app with a Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP launch intent.

Actual behavior

With Titanium, when the app returns to foreground, it will be blank.
I suspect it's because of some fault in handling of onNewIntent in TiBaseActivity, TiRootActivity and other activity subsclasses. It may also be related to the implementation of TiRootActivity.onCreate which I don't understand at all...

Reproducible sample

1. Download the test
2. All I did was to explicitly add android:launchMode="singleTask" to the activity in the manifest (see: steps to reproduce)
3. Build and run: ti build -p android
4. Move the app to background and then click the launch icon to return to foreground
   -> The app will be blank.

Steps to reproduce

1. Create a new test application for Android (ti create) - call it TestApp
2. open tiapp.xml and inside <android><manifest> replace the default empty <application> tag with:

<application android:icon="@mipmap/ic_launcher">
	<activity android:launchMode="singleTask" android:label="@string/app_name" android:name=".TestappActivity">
		<intent-filter>
			<action android:name="android.intent.action.MAIN"/>
			<category android:name="android.intent.category.LAUNCHER"/>
		</intent-filter>
	</activity>
</application>

3. This activity definition only actually adds android:launchMode="singleTask" to the default manifest that Titanium will create if we left the default <application/>
4. Build: ti build -p android
5. When the application starts, put it to background and then click the launch icon to return to foreground
6. The app will be blank.

Platform

Android

SDK version you are using

13.0.1.GA

Alloy version you are using

No response

[grebulon]

Note that this can happen even without a android:launchMode="singleTask" activity.
If you launch the app with Intent.FLAG_ACTIVITY_NEW_TASK flag like this:

Intent launchIntent = getPackageManager().getLaunchIntentForPackage(packageName);
launchIntent.addCategory(Intent.CATEGORY_LAUNCHER);
launchIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(launchIntent);

You also get a blank activity.

[m1ga]

According to #10519:

Dropped support for for "tiapp.xml" property intent-filter-new-task.
No longer needed now that Android singleTask like support via "newintent" is always enabled.

And I'm currently working on an app when I need to scan NFC tags and at first I had the issue that it was creating a new blank activity when I was scanning a code but I was able to fix that with different <intent-filter>. Maybe that works in your case too?

Not tested it with chrome tabs

[m1ga]

Two follow up questions:

• did you create a custom module for the Chrome Auth Tabs?
• did you try it without singleTask and check for the newintent event?

var act = Ti.Android.currentActivity;
act.addEventListener("newintent", function(e) {});

[grebulon]

1. I launch the ChromeTab from a module. Pasting the code below
2. It won't work. The only way to close a chrome tab is to launch an intent with Intent.FLAG_ACTIVITY_CLEAR_TOP

Note that you also can't use Intent.FLAG_ACTIVITY_NEW_TASK because it will do the blank activity bug again.

@Kroll.method
public boolean openChromeTab(String url, String topColor, boolean isDarkTheme) {
	try {
		Context ctx = TiApplication.getInstance();
		String browserPackage = getBrowserWithChromeTab(ctx);
		if (browserPackage == null)
			return false;

		CustomTabColorSchemeParams colorSchemeParams = new CustomTabColorSchemeParams.Builder()
				.setToolbarColor(TiColorHelper.parseColor(topColor))
				.build();
		CustomTabsIntent tabIntent = new CustomTabsIntent.Builder()
				.setColorScheme(isDarkTheme ? CustomTabsIntent.COLOR_SCHEME_DARK : CustomTabsIntent.COLOR_SCHEME_LIGHT)
				.setColorSchemeParams(CustomTabsIntent.COLOR_SCHEME_LIGHT, colorSchemeParams)
				.setColorSchemeParams(CustomTabsIntent.COLOR_SCHEME_DARK, colorSchemeParams)
				.setShowTitle(true)
				.build();

		tabIntent.intent.setPackage(browserPackage);
		tabIntent.intent.setFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
		Log.d(TAG, "openChromeTab - use browser: " + browserPackage);

		tabIntent.launchUrl(ctx, Uri.parse(url));
		// Note: on Android CustomTabs browser can't be closed. The only way to close it is to send an intent
		// useing startActivity(intent), with a FLAG_ACTIVITY_CLEAR_TOP flag.
		return true;
	} catch (Throwable e) {
		Log.e(TAG, "openChromeTab: failed to launch browser at: " + e.getMessage(), e);
	}
	return false;
}

private String getBrowserWithChromeTab(Context ctx) {
	List<String> chromeTabPackages = new ArrayList<>(2);
	Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("https://www.grebulon.com"));
	boolean hasChrome = false;
	List<ResolveInfo> browsersList = (Build.VERSION.SDK_INT >= 33) ?
                ctx.getPackageManager().queryIntentActivities(intent, PackageManager.ResolveInfoFlags.of(0)) :
                ctx.getPackageManager().queryIntentActivities(intent, 0);
	for (ResolveInfo info : browsersList) {
		String packageName = info.activityInfo.packageName;
		intent = new Intent();
		intent.setAction(CustomTabsService.ACTION_CUSTOM_TABS_CONNECTION);
		intent.setPackage(packageName);
		ResolveInfo service = (Build.VERSION.SDK_INT >= 33) ?
                ctx.getPackageManager().resolveService(intent, PackageManager.ResolveInfoFlags.of(0)) :
                ctx.getPackageManager().resolveService(intent, 0);
		if (service != null) {
			if ("com.android.chrome".equals(packageName)) {
				hasChrome = true;
				chromeTabPackages.add(0, packageName); // Prefer Chrome (always first)
			} else if ("org.mozilla.firefox".equals(packageName)) {
				chromeTabPackages.add(hasChrome ? 1 : 0, packageName); // Prefer Firefox (second if Chrome is detected)
			} else {
				chromeTabPackages.add(packageName);
			}
		}
	}
	return chromeTabPackages.size() > 0 ? chromeTabPackages.get(0) : null;
}

[m1ga]

ah ok, so basically a pimped https://github.com/tidev/titanium-web-dialog
It's not using the Auth Tabs you've posted above.

[m1ga]

wouldn't the Auth Tabs solve your issue?

Auth Tab, data is received using a callback, with direct data transfer between the Android API and the client app.

But it's the first time I hear about it so not really sure how and where that callback is triggered. But when you can get the data from the tab to the app you could close the chrome auth tab from the app.

[grebulon]

I didn't actually use AuthTabIntent. I call directly with CustomTabsIntent to our server which redirects back when the auth is done. But you have a point - I will test how this works with AuthTabIntent. It will probably require changes to the backend (which I don't want to touch).
I also use ChromeTab just for browsing instead of Ti.Platform.openURL(url)
But in any case, I don't see why there should be a problem with singleTask. Also, remember that it's enough to launch any Titanium app with Intent.FLAG_ACTIVITY_NEW_TASK to cause this to happen.

[m1ga]

I sadly don't know that much native parts to really understand the different launch flags in combination with Titanium.

Tried to build the webdialog module with browser 1.9.0 for Auth Tabs, but they only work with compile SDK 36 which will cause other issues with the app.

[grebulon]

The reason for this problem is that when the app is started, Titanium creates a TiRootActivity which shows the splash screen, then loads the javascript and runs it. This root activity is the main activity of the app, the one that is defined as: <category android:name="android.intent.category.LAUNCHER"/>.
When the javascript code creates a window (win=Ti.UI.createWindow) and opens it (win.open), Titanium starts a second activity (TiTranslucentActivity in my case) on top of the spalsh screen's TiRootActivity (WindowProxy.handleOpen). So a single window app, actually has 2 activities, where the main UI is in the second activity.
Now if the app goes to background and then to front, the TiRootActivity activity (which is the launcher activity), is started. If it is marked as singleTop, Android clears the activity stack, which destroys the activity that holds all the UI.

In my opinion this behavior is not good. If it was up to me, I'd change the code so that when the first window is opened, it would reuse the root activity - replacing the splash screen background with the main view of the window. This will remove a lot of the complication in handling onNewIntent and all the complicated double-start protection in the TiRootActivity code. However, this is not tirivial and will require some work.