How to start an activity without calling another activity in Android?

Question

I have 2 activities, LoginActivity and MainActivity. In the first activity i'm logging in the user and redirect him to the MainActivity. I have also have created in the MainActivity a sign-out button which calls this sign-out method:

private void signOut() {
    Auth.GoogleSignInApi.signOut(googleApiClient).setResultCallback(new ResultCallback<Status>() {
        @Override
        public void onResult(Status status) {
            Intent intent = new Intent(MainActivity.this, LoginActivity.class);
            intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
            startActivity(intent);
        }
    });
}

Every time the app starts, i check if the user in logged in. If it's logged in, the user remains in the MainActivity and if not, it is redirected to the LoginActivity. The problem is, when the user is not logeed in, the app first of all starts the MainActivity and after that it starts the LoginActivity.

This is how my AndroidManifest looks like:

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

How can i start the app, when the user is not logged in, without opening the MainActivity?

you are doing wrong first start loginactivity and then check and login to main — JAAD, Jan 13 '17 at 19:41

score 2 · Answer 1 · edited May 23 '17 at 12:33

2

You create a third Activity which is your true launch activity. Then just this determines which should be the next one.

@Override
public void onCreate(Bundle si) {
   ...
   if (isLoggedIn()) {
      goToMain();
   } else {
      goToLogin();
   }

   finish();
}

This will open up an Activity which decides where to go after. You may see a slight flash on the screen when the Activity loads. Here's a discussion on styling a transparent activity. `

edited May 23 '17 at 12:33

Community

1
1

answered Jan 13 '17 at 17:52

DeeV

35,865
9
108
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I just tried this and in stead of starting first the `MainActivity`, it's starts `LaunchActivity`, which is a blank one. Do you have another idea? – Alex Mamo Jan 13 '17 at 18:10
That's how you do it. Android has no idea of know if your user is logged in. You have to make that decision. You can style the LaunchActivity to be transparent so it doesn't have that brief millisecond of flash. – DeeV Jan 13 '17 at 18:12
How to create a transparent activity. http://stackoverflow.com/questions/2176922/how-to-create-transparent-activity-in-android – DeeV Jan 13 '17 at 18:13

Bugs Buggy · Accepted Answer · 2017-01-13T20:31:47.847

2

I think at best what you can do is have two layouts in MainActivity, say MainLayout and LoginLayout, hide the MainLayout if the user is not logged in, and show LoginLayout in the same Activity, i.e. MainActivity, and make the user login, then again hide the LoginLayout and show the MainLayout. Or, rather than hiding the LoginLayout, restart the Activity.

Put these conditions at the start of onCreate() under if-else statements.

Somewhat like this (in your onCreate of MainActivity):

//Initially, have your LoginLayout GONE and MainLayout VISIBLE
if (!isUserLoggedIn) {
    MainLayout.setVisibility(View.GONE);
    LoginLayout.setVisibility(View.VISIBLE);
    /*
    Code to get user logged in,
    then restart activity, 
    or simply hide LoginLayout and show MainLayout
    */
}

edited Jan 13 '17 at 20:31

answered Jan 13 '17 at 18:16

Bugs Buggy

1,514
19
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This is the right answer for me. I get my app stared, when the user is not logged in, without opening any other activities. Thanks! – Alex Mamo Jan 13 '17 at 20:08
@AlexM. There is another way to go about this, that is starting a splash screen when the app starts and checking whether the user is logged in or not, and starting the appropriate activity. – Bugs Buggy Jan 13 '17 at 20:32

score 1 · Answer 3 · answered Jan 13 '17 at 18:06

1

Move the decision making code to a third activity and set it as the new launch activity.

     if (condition1) {
         startActivity(intent1);
     }
     else {
        startActivity(intent2);
     }

And change the theme of the new activity as below

    android:theme="@android:style/Theme.NoDisplay

answered Jan 13 '17 at 18:06

rabhis

440
2
5

I just tried this and in stead of starting first the MainActivity, it's starts LaunchActivity, which is a blank one. Do you have another idea? – Alex Mamo Jan 13 '17 at 18:12

How to start an activity without calling another activity in Android?

3 Answers3