CODEWITHSUNDEEP
androidfileandroid-layout
Steven Hammons
Steven Hammons

Reputation: 118

How to hide Android Application Layout if file exists?

I want to show a layout if a certain file does not exist. So how do I hide the layout if the file exists? I want my application to run in the background after the first layout is shown.

File myFile = new File("/LoggedIn.txt");
if(myFile.exists()) {
    /* do something */
} else {
    setContentView(R.layout.activity_main); 
}

I have tried this code alone to see if I could even hide the layout...

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    layoutLogin = (LinearLayout) findViewById(R.id.activity_main_id);
    layoutLogin.setVisibility(View.GONE);
}

But it causes my application to crash when it starts.

activity_main

<LinearLayout android:id="@+id/activity_main_id"
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
</LinearLayout>

LogCat:

08-12 00:37:29.145  30151-30151/? I/SELinux﹕ Function: selinux_android_load_priority [0], There is no sepolicy file.
08-12 00:37:29.145  30151-30151/? I/SELinux﹕ Function: selinux_android_load_priority [1], There is no sepolicy version file.
08-12 00:37:29.145  30151-30151/? I/SELinux﹕ Function: selinux_android_load_priority , priority is 3. priority version is VE=GOOGLE_POLICY
08-12 00:37:29.155  30151-30151/? D/dalvikvm﹕ Late-enabling CheckJNI
08-12 00:37:29.425  30151-30151/? D/ActivityThread﹕ handleBindApplication:com.example.steven.myapplication
08-12 00:37:29.685  30151-30151/? W/ApplicationPackageManager﹕ getCSCPackageItemText()
08-12 00:37:29.705  30151-30151/? D/DisplayManager﹕ DisplayManager()
08-12 00:37:29.835  30151-30151/? D/AndroidRuntime﹕ Shutting down VM
08-12 00:37:29.835  30151-30151/? W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41d0ad58)
08-12 00:37:29.855  30151-30151/? E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.steven.myapplication, PID: 30151
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.steven.myapplication/com.example.steven.myapplication.MainActivity}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2429)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)
            at android.app.ActivityThread.access$800(ActivityThread.java:166)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5584)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.example.steven.myapplication.MainActivity.onCreate(MainActivity.java:105)
            at android.app.Activity.performCreate(Activity.java:5442)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2393)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2493)
            at android.app.ActivityThread.access$800(ActivityThread.java:166)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1283)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5584)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1268)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1084)
            at dalvik.system.NativeStart.main(Native Method)

Upvotes: 0

Views: 129

Answers (1)

vaishnavi ramesh
vaishnavi ramesh

Reputation: 143

You can have an empty activity with may be a logo of your app in the middle and check if file exists in this activity. If file exists you can start your service and kill this empty activity else you can start the activity you want to display.

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);

/*activity_main can have a logo of your app or 
      can show progress circle in the middle*/

setContentView(R.layout.activity_main);

File myFile = new File("/LoggedIn.txt");
if(myFile.exists()) {
   /* Call service to do something */
  finish();
} else {
    /* Call another activity using intent */
  finish();
}
}

Upvotes: 1

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