Android app opening screen

How to detect Android application open and close: Background and Foreground events.

Dec 17, 2017 · 4 min read

This question seems to come up a lot. Especially if you are just starting out with Android developme n t. It’s simply because there is nothing obvious built into the Android SDK enabling developers to hook into application lifecycle events. Activities and Fragments have all the callbacks under the sun to detect lifecycle change, but there is nothing for the whole application. So how do you detect when a user backgrounds and foregrounds your app. This is an example of how your could detect Application lifecycle events. Feel free to adjust and enhance it to suit your needs, but this idea should be enough to work for most applications with one caveat, it will only work for Android API level 14+(IceCreamSandwich 🍦🥪).

Detecting App Lifecycle Evnts

Backgrounding

ComponentCallbacks2 — Looking at the documentation is not 100% clear on how you would use this. However, take a closer look and you will noticed the onTrimMemory method passes in a flag. These flags are typically to do with the memory availability but the one we care about is TRIM_MEMORY_UI_HIDDEN. By checking if the UI is hidden we can potentially make an assumption that the app is now in the background. Not exactly obvious but it should work.

Foregrounding

ActivityLifecycleCallbacks — We can use this to detect foreground by overriding onActivityResumed and keeping track of the current application state (Foreground/Background).

Implementing a Foreground and Background Handler

First, lets create our interface that will be implemented by a custom Application class. Something as simple as this:

Next, we need a class that is going to implement the ActivityLifecycleCallbacks and ComponentCallbacks2 we discussed earlier. So lets create an AppLifecycleHandler and implement those interfaces and override the methods required. And lets take an instance of the LifecycleDelegate as a constructor parameter so we can call the functions we defined on the interface when we detect a foreground or background event.

We outlined earlier that we could use onTrimMemory and the TRIM_MEMORY_UI_HIDDEN flag to detect background events. So lets do that now.

Add this into the onTrimMemory method callback body

So now we have the background event covered lets handle the foreground event. To do this we are going to use the onActivityResumed. This method gets called every time any Activity in your app is resumed, so this could be called multiple times if you have multiple Activities. What we will do is use a flag to mark it as resumed so subsequent calls are ignored, and then reset the flag when the the app is backgrounded. Lets do that now.

So here we create a Boolean to flag the application is in the foreground. Now, when the application onActivityResumed method is called we check if it is currently in the foreground. If not, we set the appInForeground to true and call back to our lifecycle delegate ( onAppForegrounded()). We just need to make one simple tweak to our onTrimMemory method to make sure that sets appInForeground to false.

Now we are ready to use our AppLifecycleHandler class.

AppLifecycleHandler

Now all we need to do is have our custom Application class implement our LifecycleDelegate interface and register.

And there you go. You now have a way of listening to your app going into the background and foreground.

This is only supposed to be used as an idea to adapt from. The core concept using onTrimMemory and onActivityResumed with some app state should be enough for most applications, but take the concept, expand it and break things out it to fit your requirements. For the sake of brevity I won’t go into how we might do multiple listeners in this post, but with a few tweaks you should easily be able to add a list of handlers or use some kind of observer pattern to dispatch lifecycle events to any number of observers. If anyone would like me to expand on this and provide a multi listener solution let me know in the comments and I can set something up in the example project on GitHub.

Update: Using Android Architecture Components

Thanks to Yurii Hladyshev for the comment.

If you are using the Android Architecture Components library you can use the ProcessLifecycleOwner to set up a listener to the whole application process for onStart and onStop events. To do this, make your application class implement the LifecycleObserver interface and add some annotations for onStop and onStart to your foreground and background methods. Like so:

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Implementing the Perfect Splash Screen in Android

Splash Screen is the first screen visible to the user when the application’s launched. It’s a vital screen that will allow the users to have first impressions of the application.

A Splash Screen is a screen that appears when you open an app on your mobile device. Sometimes it’s referred to as a launch screen or startup screen and shows up when your app is loading after you’ve just opened it.

When the loading is finished, you’ll be taken to a more functional screen where you can complete actions.

Splash screens appear on your screen for a fleeting moment — look away and you might miss them. The splash screen is one of the most vital screens in the application since it’s the user’s first experience with the application.

There are 2 common methods of implementing splash screens and will find the right way:

1. Using Timers (the bad)
2. Using a Launcher Theme (The Right way)

Using timer (Our 1st Method) into your activity to display splash, we create a splash activity and create a thread in onCreate() for shows up for 2/3 seconds, then go to our desired activity. Here, see the implementation of this easy method:

The above approach isn’t the correct approach. It’ll give rise to cold starts.

The purpose of a Splash Screen is to quickly display a beautiful screen while the application fetches the relevant content if any (from network calls/database). With the above approach, there’s an additional overhead that the SplashActivity uses to create its layout.

It’ll give rise to slow starts to the application which is bad for the user experience (wherein a blank black/white screen appears).

The cold start appears since the application takes time to load the layout file of the Splash Activity. So instead of creating the layout, we’ll use the power of the application theme to create our initial layout (Our 2nd Method).

Application theme is instantiated before the layout is created. We’ll set a drawable inside the theme that’ll comprise the Activity’s background and an icon using layer-list as shown below.

Do you know when an activity is called Android OS first see in the manifest is there any theme for that activity and load the theme from manifest?

So, we will set a custom theme in Manifest for our splash activity. To create the theme for the splash screen, follow the below process.

Step 1

Create Background for Splash Screen in drawable/splash_background.xml, the bitmap is the image we want to show.

Step 2

Create the gradient onto which your app logo will be placed in drawable/bg_gradient.xml, background can be a gradient or any colour depending on your app.

Step 3

Create Style for Splash Screen in res/values/themes.xml

Step 4

Create an empty Activity named SplashScreenActivity and set the style as the theme for it in AndroidManifest.xml

Step 5

Setting the Intent to your MainActivity.java from SplashScreenActivity.java

As we are loading the splash screen them from manifest, there is no need to setContentView() with any xml layout. If you want to show your splash screen for some amount of time (like five secs) you can create a Handler , also using a timer can help you fetch data from the cloud on your MainActivity which could be a better approach than to show a dialog on home screen.

Using the theme and removing the layout from the SplashScreenActivity is the correct way to create a splash screen 🙌.

Now that our splash is working, what size of the image should I put into a drawable folder?

Always put your app_logo.png into drawable-xxhdpi folder so that your logo automatically scales for all types of phone screens in most cases.

Also, make sure that image resolution is not more than 1000×1000 pixels . It can have less resolution depending on how you want it. Now there are diverse types of splash screen which has multiple logos on various parts of the screen. How that could be done?

From the above example, we implemented our method to create a splash like Twitter, and now to create one like Facebook we just make a slight change to our drawable/splash_background.xml.

Just add as many item to your layer-list you want to place in your splash screen.

Splash screen best practices

Splash screens are simple. They’re used to enhance a brand and give users something nice to look at as they wait. In this regard, here are some best practices for when you design your own splash screen:

• Keep it free from unnecessary distraction
• Don’t use multiple colours or logos
• Use animation sparingly

Hope it helped. Happy Coding 😀

BTW, I solve real-world problems by building useful apps. Have a look at my portfolio .

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New Splash Screen In Android

A better way to display Android Splash Screen. #Android12

🚣 Hi, In this article we learn to implement splash screen in android. From OLD traditional way to NEW modern way.

Introduction

Android Splash Screen usually the first screen that is displayed to the user when an app is not fully ready to display content.

How the splash screen works

When a user launches an app while the app’s process is not running (a cold start) or the Activity has not been created (a warm start), the following events occur. (The splash screen is never shown during a hot start.)

1. The system shows the splash screen using themes and any animations that you’ve defined.

2. When the app is ready, the splash screen is dismissed and the app is displayed.

Now let’s dive in,

Initializing Splash Activity

First, To launch the activity as splash screen we just need to add the action main and category launcher to your activity in AndroidManifest.xml

Traditional Approach

The old way,

We used to pause the user interaction for like 2–3 sec for a splash screen to load.

UI Holding was never an option. As in Activity we used to write these horrific code… and activity used to look like shi**.

This used to work well back then & now too, but we all knew there should be something more than just waiting.

Modern Approach

With a new approach, we don’t declare a time to wait.

Step 1

First, Gather all necessary elements for splash screen like colors & logo.

Then, Create drawable placing logo as bitmap/drawable.

Step 2

In style declare a any desired theme for splash screen and set android:windowBackground attribute value to drawable we created.

The android:windowBackground attribute will show our created drawable on activity transition.

And, In AndroidManifest.xml we add our theme as.

Final Step

To hide content of splash screen layout, in activity remove setContentView(),

As to show created drawable as a transition between these splash & another activity we won’t be needing splash layout.

Here’s the source code… if you need.

Done. The modern approach is more convincing than our traditional approach.

Continue to read more on Android 12 Splash Screen

— Recently,

Android 12 adds the SplashScreen API, which enables a new app launch animation for all apps. This includes an into-app motion at launch, a splash screen showing your app icon, and a transition to your app itself.

The new experience brings standard design elements to every app launch, but it’s also customizable so your app can maintain its unique branding.

This is similar to our modern approach.

Read more at the official website.

Let’s test Splash by Upgrading to — Android 12,

After upgrading, From NoWhere, Boom A error popups and your application installation failed.

Installation did not succeed.
The application could not be installed: INSTALL_FAILED_VERIFICATION_FAILURE
List of apks:
[0] ‘…/build/outputs/apk/debug/app-debug.apk’
Installation failed due to: ‘null’

INSTALL_PARSE_FAILED_MANIFEST_MALFORMED: Failed parse during installPackageLI:

Targeting S+ (version 10000 and above) requires that an explicit value for android:exported be defined when intent filters are present”

To Fix Installation failed ?👼

Now For Splash Screen,

For testing the effects & changes let’s observe with WHITE & BLACK color background first.

Create new styles.xml or theme.xml (v31).

As mentioned, It’s similar to our modern approach.

The only Difference is , we need to remove android:windowBackground for Android 12.

By default your launcher icon will act as a splash screen view.

No need to create drawable. Just add your launcher icon & Kaboom it’s a splash screen logo.

As documented, SplashScreen uses the windowBackground of your theme if it’s a single color and the launcher icon. The customization of the splash screen is done by adding attributes to the app theme.

But it can be customized in many ways. Amazing and simple right?

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