当应用程序从后台进入前台时，如何显示特定活动？

Question

I have an application with several activities.One of them is Login activity and this activity defined as MAIN in my app in manifest:

<activity
        android:name="com.company.myapp.AuthorizationMainActivity"
        android:label="@string/app_name" 
        android:launchMode="singleTask" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

The problem when my app enters background (eg I press home button) and then I open the app again - the Login page is showed to me. How can I show activity which was active for user at the moment application enter background?

Answer 1

If you don't explicitly want to use it for a special requirement, remove "android:launchMode="singleTask".

A "singleTask" activity allows other activities to be part of its task. It's always at the root of its task, but other activities (necessarily "standard" and "singleTop" activities) can be launched into that task. (found here at Android Developes)

Answer 2

Use a dummy activity as your base activity that launches and in that activity check to see if you need to display the login activity or another one. Then start that specific activity you want to go to from the dummy activity.

make sure you set the dummy activity to noHistory in the manifest so the user cannot navigate back to it

if(needsLogIn){
    Intent i = new Intent(this,LoginActivity.class);
    startActivity(i);
}else{
    Intent i = new Intent(this,OtherActivity.class);
    startActivity(i);
}

Answer 3

Remove android:launchMode="singleTask" > singletask activity will be the root and when you press home button all the activities above it will be removed. when you remove android:launchMode="singleTask" then the default behaviour will take place ie when you press home button and then launch again it will open the activity from where you left. have a look at the link http://developer.android.com/guide/components/tasks-and-back-stack.html