Android：SharedPreferences布尔值

Question

does someone know where the mistake is? There is an error in Android Studio.

The following is the code for now.

final String keyFirstTime = "keyFirstTime";

prefsEditor.putBoolean(keyFirstTime, false);

if (keyFirstTime = false) {

Thanks in advance.

Answer 1

1. keyFirstTime is a string (see comment)
2. you are PUTTING a value not getting a value
3. You are using an assignment in an if statement
4. You are comparing a STRING to a BOOLEAN

In Activity 1 you should have:

final String keyFirstTime = "keyFirstTime";
prefsEditor.putBoolean(keyFirstTime, false);

In Activity 2 you should have:

boolean firstTime = prefs.getBoolean(keyFirstTime, false); //you don't need the editor
if (firstTime) {
    ...
}

Please go here for a tutorial: https://developer.android.com/training/basics/data-storage/shared-preferences.html

EDIT Try doing this (stolen from here )

private static final String FIRST_RUN = "FIRST_RUN";
SharedPreferences prefs = null;

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

    prefs = getSharedPreferences(getApplicationContext().getPackageName(), MODE_PRIVATE);
}

@Override
protected void onResume() {
    super.onResume();

    if (prefs.getBoolean(FIRST_RUN, true)) {           
        prefs.edit().putBoolean(FIRST_RUN, false).commit();
        //call relevant function for first run
    } else {
        //call relevant function for every other run
    }
}

Answer 2

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences();  prefs.edit().putBoolean("keyFirstTime", true).commit();

Now to get Boolean value you have to use

Boolean check = prefs.getBoolean("keyFirstTime", false);

Now you can check this way

if(check){ your code here }