CODEWITHSUNDEEP
javaandroidsharedpreferencescontains
RexYuan
RexYuan

Reputation: 300

Why does a shared preference contains something I haven't put?

Problem solved.

The shared preference should contains anything before I close it for the first time but the error says IndexOutOfBoundsExceptions. How come?

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    SharedPreferences pref = getSharedPreferences("myfile", MODE_PRIVATE);
    SharedPreferences.Editor editor = pref.edit();
    editor.commit();
    if(pref.contains("key")){
    List.addAll(pref.getStringSet("key", null));
    };         
}

@Override
public void onStop(){
    super.onStop();
    if(size>0){
    Set<String> set1 = new HashSet<String>();
    set1.addAll(List);
    SharedPreferences pref = getSharedPreferences("myfile", MODE_PRIVATE);
    SharedPreferences.Editor editor = pref.edit();
    editor.putStringSet("key", set1);
    editor.commit();
    };
}

I'm not sure what to look for at logcat so I just paste it all.

06-05 13:05:30.023: E/AndroidRuntime(1625): FATAL EXCEPTION: main 06-05 13:05:30.023: E/AndroidRuntime(1625): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.vocabulary/com.example.vocabulary.MainActivity}: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread.access$600(ActivityThread.java:130) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.os.Handler.dispatchMessage(Handler.java:99) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.os.Looper.loop(Looper.java:137) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread.main(ActivityThread.java:4745) 06-05 13:05:30.023: E/AndroidRuntime(1625): at java.lang.reflect.Method.invokeNative(Native Method) 06-05 13:05:30.023: E/AndroidRuntime(1625): at java.lang.reflect.Method.invoke(Method.java:511) 06-05 13:05:30.023: E/AndroidRuntime(1625): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 06-05 13:05:30.023: E/AndroidRuntime(1625): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 06-05 13:05:30.023: E/AndroidRuntime(1625): at dalvik.system.NativeStart.main(Native Method) 06-05 13:05:30.023: E/AndroidRuntime(1625): Caused by: java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0 06-05 13:05:30.023: E/AndroidRuntime(1625): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:251) 06-05 13:05:30.023: E/AndroidRuntime(1625): at java.util.ArrayList.get(ArrayList.java:304) 06-05 13:05:30.023: E/AndroidRuntime(1625): at com.example.vocabulary.MainActivity.PrintWords(MainActivity.java:70) 06-05 13:05:30.023: E/AndroidRuntime(1625): at com.example.vocabulary.MainActivity.ShitsToDoWhenCodeSucks(MainActivity.java:118) 06-05 13:05:30.023: E/AndroidRuntime(1625): at com.example.vocabulary.MainActivity.onCreate(MainActivity.java:145) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.Activity.performCreate(Activity.java:5008) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 06-05 13:05:30.023: E/AndroidRuntime(1625): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 06-05 13:05:30.023: E/AndroidRuntime(1625): ... 11 more

Upvotes: 0

Views: 219

Answers (1)

Nizam
Nizam

Reputation: 5731

Do you have a preferences file named 'myfile' there?

If a preferences file by this name does not exist, it will be created when you retrieve an editor (SharedPreferences.edit()) and then commit changes (Editor.commit()).

Upvotes: 0

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