Conditionally set first activity in Android

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

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.

Tags:

Android