Conditionally set first activity in Android-ThrowExceptions

Exception or error:

Currently we have a splash screen that is displayed in our app. However, if there is no data to be gathered or processed that is waiting, we’d like to go straight into our first activity. Is there a way to do that without having the splash screen flash?

The AndroidManifest.XML of the splashscreen portion is as follows:

<activity android:name="com.example.SplashScreenActivity"
        android:label="@string/app_name"
        android:noHistory="true" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
How to solve:

What I have done successfully in the past is to create an invisible activity as the main activity. It never gets shown to the user, because it launches the “correct” activity in the constructor.

For this reason, there is no need to theme the activity as “invisible” as it does not load a view.

Inside I place some logic which determines which activity to show to the user first. This works perfectly for my use case – give it a try.


Manifest Declaration (note the noHistory="true" parameter):

    <activity
        android:name=".activity.EntryActivity"
        android:launchMode="singleInstance"
        android:noHistory="true" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

Note: As pointed out in comments below, the launchmode setting is unrelated to this question IIRC. This was related to the various ways that the EntryActivity was launched.


EntryActivity class:

public class EntryActivity extends Activity 
{ 

    @Override
    public void onCreate(Bundle savedInstanceState) 
    { 
        super.onCreate(savedInstanceState); 

        // launch a different activity 
        Intent launchIntent = new Intent(); 
        Class<?> launchActivity; 
        try
        { 
            String className = getScreenClassName(); 
            launchActivity = Class.forName(className); 
        } 
        catch (ClassNotFoundException e) 
        { 
            launchActivity = DefaultHomeActivity.class; 
        } 
        launchIntent.setClass(getApplicationContext(), launchActivity); 
        startActivity(launchIntent); 

        finish(); 
    } 

    /** return Class name of Activity to show **/
    private String getScreenClassName() 
    {       
        // NOTE - Place logic here to determine which screen to show next
        // Default is used in this demo code
        String activity = DefaultHomeActivity.class.getName(); 
        return activity; 
    } 

} 

###

Given that the launcher will start the activity you specify in your Manifest, it’s not possible to set conditions on whether that activity will be started (or another).

So you’re left with the options as Richard Le Mesurier and dors suggest:

  1. Start the main Activity, then launch the Splash Activity if needed
  2. Start a gui-less Activity (no layout file), then decide which Activity should be presented to the user

I’d prefer the second option, or if you’re planning to introduce Fragments anyway, use them here:

  1. Use Fragments. Start your main activity, which has a Fragment placeholder. If you need to show Splash Screen, load the SplashScreenFragment in that activity, otherwise, load the Fragment that constitutes the first useful screen to the user.

As an aside, the use of splash screens is discouraged; as a user, I’d prefer to see the main Activity with most of the static UI components loaded immediately, and some on-screen indication that something is loading/updating.

###

You can do something like this:

  1. Your Splash Screen is the main activity (Launcher-Category)
  2. If your splash screen can load data (or whatever your splashscreen does), do it. After finished, close the spalsh screen (call finish()) and start the real first activity and pass the data as intent extra.
  3. If your splashscreen can not load data or (or whatever your splashscreen does), start the next Activity by using an Intent and finish the spalsh screen activity by calling finish()

So the workflow of your app will be:

  1. Click on the launcher icon
  2. The Splash Screen Activity will always been started
  3. If spalsh screen can not load, than the activity will be finished immediately and the other activity will be started. Your app user will not notice that the splash screen activity if you finish() the splash screen activity immediately, because the activity is never shown on screen in this case

###

afaik you can only have 1 main activity.

What I did when I had this issue is always start the main activity (not splash), and in its onCreate() method I would start the splash screen if needed.

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