Develop Reference

What is the expected startup experience for a Progressive Web Application?

Testing a Progressive Web Application.
When I start the app in airplane mode, I get an unexpected startup/splash experience (Android/Chrome).
Launch from Home Screen Experience
I see a white screen, followed by a brief flash of the "offline dinosaur" before the app successfully starts and all is well. The startup time is longer than I expected, especially after testing with Chrome Devtools on a laptop, where startup is near instant.
Since it is a little tricky to debug where this time is being spent (especially in the “service-worker-not-running” case), it would be helpful to have some baseline knowledge:
Launch from Browser Experience
Just a brief flash of the "offline dinosaur" before the app successfully starts. Starts much faster.
Questions
What is the expected startup time and experience on Android/Chrome?
Is the experience described above just the current state of things (11/2015)?
Is there any way to specify the startup (splash) experience for Chrome? (I'm aware of background color and 144x144 icon in app manifest for splash, but for Opera only)
First time PWA for me, so any information on this would be helpful.
My platform:
Samsung GS 5,
Android 5.0,
Chrome 46.0.2490.76

The reason for the existence of the splash screen is because on mobile it can take over a second to start the render process so we paint something (the background colour and icons) util you have a first paint generated by your app.
If you are seeing a white screen on startup it might be because you added to the homescreen prior to Chrome landing (46) the splash screen feature. Some things to lookout for:
Ensure your manifest has a short_name and name
Ensure your start_url is in the same scope as a SW that is registered on the page
Have good icons in the manifest ideally > 192px
Set background_color in the manifest to the color of your background on the page (ideally.) This will ensure that the splash screen is the expected colour of your site.
You shouldn't see the offline dinosaur at all, even when you are in aeroplane mode. Airhorner should represent the ideal experience: Blue splash screen with an icon that morphs into the display of the app.
re: Icons - I recommend actually 192px icon or higher.

Regarding the offline-dino flash:
I was using sw-toolbox and performing asynchronous work to setup route handlers at worker startup. This caused an offline dino flash when the application was offline and starting up.
To avoid that, set a sw-toolbox default handler that waits for the asynchronous route handler setup to complete.
var toolbox = require('sw-toolbox');
var setupPromise = someAsyncHandlerSetup()
.then(function () {
// make default handler temporary, allows other fetch handlers (like sw-precache, for example)
toolbox.router.default = null;
});
// until the async handler setup is done, provide a default handler
// to avoid an offline-dino flash when starting up while offline.
toolbox.router.default = function defaultHandler (request) {
return setupPromise.then(function () {
var handler = toolbox.router.match(request);
if (handler) {
return handler(request);
}
throw new Error('default handler could not handle ' + request.url);
});
};

Recent Apps on UiAutomator

I am now working with Android UiAutomator on for UI Test on my Android app. My app has a function that requires the user to verify the email to continue, so I try to do it like this: after reach to that function -> getUiDevice.pressHome -> Browser -> try to log in email -> PressHome again -> Press RecentApps then I stuck here, I cannot press on my Apps to return to it again. I try another way by clicking on my App icon but it starts my app again, not at the state before. Can anyone suggest me a solution for this? Any help is appreciate.
Thanks in advance.

Try this :
UiObject appBackground = new UiObject(new UiSelector().description("ABC"));
appBackground.click();
It did not show any description through 'uiautomatorviewer' command but this worked for me.

I could manage to create this behavior with:
fun backgroundAndForeground() {
val device = UiDevice.getInstance(getInstrumentation())
device.pressHome()
// Pressing app switch two times makes the last app put on background come to foreground.
device.pressKeyCode(KeyEvent.KEYCODE_APP_SWITCH)
device.pressKeyCode(KeyEvent.KEYCODE_APP_SWITCH)
}

In this case, I think that android only resume app when clicking the recent app image. It does not work on clicking display text or app icon. So, we need to click image of your app in recent app list. At that time you need to write as below. I always do that for similar case.
// Take all image view by class type and click by instance no.
new UiObject(new UiSelector().className("android.widget.ImageView").instance(3)).click();
You need to count instance no of your recent app image view. Not app icon image in recent app scroll view. Please try this. Thanks.

I've spent half a day on this and concluded I needed to issue a device.click(). Since my use-case is that my app was the last one running (not switching to the browser like you), I can safely click the middle of the screen and it'll always work.
If you're the 2nd to last running app, you can probably do x: 0 and y: device.displayHeight/2.
I've not tested this on many operating systems, only 9.

How to hide bottom system bar in android tablet

I am developing an application for tablet only, where the requirement is to run the app on the full screen of the tablet.
For this I have used following code in my main activity:
getWindow().requestFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
This code snippet only removes the title bar and action bar. But in tablets, there is a bottom system bar (having home and back button). I also want to remove or hide this system bar too.
I have searched but there is only following solution:
There is no API to remove or hide the system bar.
You can use some android app to hide system bar. (for example:
surelock, hidebar, etc)
My question is :
Is it really not possible in android?
Above available app (i.e surelock, hide bar, etc) also hiding bar.
It means they are using something to do so. Can be use this
something in our app so the user will not require to download these
app seperatly.
Please guide me.
I know this is not a good idea. But My app is only for tablet having Android 4.0 or greater and that tablet will run only this single app so we do not need to go back and use home button. That's why my requirement is to use the app in full screen.

If you have root access you can use this code other wise it is not allowed
try{
//REQUIRES ROOT
Build.VERSION_CODES vc = new Build.VERSION_CODES();
Build.VERSION vr = new Build.VERSION();
String ProcID = "79"; //HONEYCOMB AND OLDER
//v.RELEASE //4.0.3
if(vr.SDK_INT >= vc.ICE_CREAM_SANDWICH){
ProcID = "42"; //ICS AND NEWER
}
//REQUIRES ROOT
Process proc = Runtime.getRuntime().exec(new String[]{"su","-c","service call activity "+ ProcID +" s16 com.android.systemui"}); //WAS 79
proc.waitFor();
}catch(Exception ex){
Toast.makeText(getApplicationContext(), ex.getMessage(), Toast.LENGTH_LONG).show();
}
See this

From Android API 4.0 and later you can use the following code to hide the bottom system bar.
View decorView = getWindow().getDecorView();
int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN;
decorView.setSystemUiVisibility(uiOptions);

This is not possible unless you've root access. Alternatively, you can create a launcher application.
Otherwise it will be beyond the scope of your Application to Hide System/Navigation bar.

After a lot of searching on the internet, I managed to get the System Bar to hide and appear in a 4.2 device using:
To Hide:
Runtime.getRuntime().exec("service call activity 42 s16 com.android.systemui");
Or use 79 instead of 42 for API less than 14. You may also need to include the SET_DEBUG_APP permission, in which case you need to have the application signed with the system key or installed in the /system/app/ directory.
To Show:
Runtime.getRuntime().exec("am startservice --user 0 -n com.android.systemui/.SystemUIService");
Alternatively some people have used the -a (instead of -n) option, though this was causing an error on my device:
Error: Not found; no service started.

Honeycomb 3.1 / Mono for Android persist 'LightsOut'

I developed my app using Mono for Android. I have the latest version 4.0.3. My AndroidManifest.xml specifies:
<uses-sdk android:targetSdkVersion="11" android:minSdkVersion="8" />
The app runs on tablets, so in Honeycomb I need to hide the status bar at the bottom of the screen. This is how I do that (with a simple extension method):
internal static void LightsOut(this View view)
{
try
{
IntPtr view_setSystemUiVisibility = JNIEnv.GetMethodID(view.Class.Handle, "setSystemUiVisibility", "(I)V");
JNIEnv.CallVoidMethod(view.Handle, view_setSystemUiVisibility, new JValue(1));
}
catch
{ }
}
I call this on every view that I instantiate. On my Motorola Xoom, running 3.0.1, this works great.
On my Samsung Galaxy Tab running 3.1, it works; but the status bar comes back after some short period of time. In the Android Log I see that LightsOn() is getting called...
How can I prevent the status bar from coming back in 3.1? I saw this event:
http://developer.android.com/reference/android/view/View.OnSystemUiVisibilityChangeListener.html
And thought I could use it to hide the status bar, if it comes back. But I don't see how I can subscribe to it (it doesn't show in Intellisense).

Does something specific happen before the status bar comes back, or is it solely time related? A quick search of the ICS source suggests that the status bar status will be reset when the top App Window changes. Are you calling StartActivity() or moving to another app when you see this behavior?
The View.OnSystemUiVisibilityChangeListener interface has been bound as the View.IOnSystemUiVisibilityChangeListener interface and through the View.SystemUiVisibilityChange event. However, both of these mechanisms require that your $(TargetFrameworkVersion) target Android v3.1 or later, which would set your //uses-sdk/#android:minSdkVersion attribute to 12, and is thus something you (presumably) don't want to do.
I see two plausible solutions here:
Figure out why LightsOn() is being invoked and try to work around it (call LightsOut() within every Activity.OnCreate() method?).
Provide two versions of your app, one with a minSdkVersion of 8, and one of (at least) 12, and then use Multiple APK Support to include both in your program. The device will then run the appropriate package, permitting access to the View.SystemUiVisibilityChange event.

Hide Status bar on Android Ice Cream Sandwich

I'm working in a launcher for Android ICS but I have a problem with tablets.
I can't hide the status bar. I have try it in Android 2.3.X and it's ok. The problem appears only with Android 4.0.
How can I hide it?

You can not get 100% true full screen in Android 4.0.
Use the following to dim the notification bar (aka. status bar, system bar)
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LOW_PROFILE);
And use this to hide it
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);
And, if I guess right, you are trying to achieve a "kiosk mode". You can get a little help with an app named "surelock". This blocks all the "home" and "back" actions.
It is still not perfect but this may be the best we can achieve with Android ICS.

It is possible to hide the statusbar on a rooted android device. The program Hidebar does this by killing the systemui process. The program is open source, so you can read all about it in the source code.
See http://ppareit.github.com/HideBar/.

You cannot get rid of the system bar on tablets. You may be able to get rid of the navigation bar and status bar on phones. Please read the "Controls for system UI visibility" section of the Android 4.0 SDK release notes.

I know my answer comes a bit late, but after assembling info from various places, I came up with this, which works ONLY ON ROOTED DEVICES:
private void KillStatusBar()
{
Process proc = null;
String ProcID = "79"; //HONEYCOMB AND OLDER
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH){
ProcID = "42"; //ICS AND NEWER
}
try {
proc = Runtime
.getRuntime()
.exec(new String[] { "su", "-c",
"service call activity "+ProcID+" s16 com.android.systemui" });
} catch (IOException e) {
Log.w(TAG,"Failed to kill task bar (1).");
e.printStackTrace();
}
try {
proc.waitFor();
} catch (InterruptedException e) {
Log.w(TAG,"Failed to kill task bar (2).");
e.printStackTrace();
}
}
This should eliminate the bottom bar on any rooted device and turn it into "kiosk" mode.

To hide status bar and navigation bar in android 4.0, we should use code below:
LinearLayout layout = (LinearLayout)findViewById(R.id.layout);
layout.setSystemUiVisibility(View.SYSTEM_UI_FLAG_HIDE_NAVIGATION);

Building upon ppareit's answer.
You can not hide the navigation bar on most stock devices. However, there is a work around if you rooting the device is an option. Here are the steps for one solution:
Root device
Install and run Busybox (required for taking full advantage of rooted device)
Install HideBar from resource
In HideBar there is an option to run in 'Kiosk' mode, in which there is no way to re-display the navigation bar. Needless to say, you really need to be careful with this.