应用重新启动时android sharedpreferences不保存数据

Question

我有一个sharedpreference ，可以很好地保存数据直到应用程序关闭。 当应用重启时， sharedpreferences中的数据消失了，请告诉我解决方案。 我想在应用关闭或重新启动或电话重新启动时保存我的preferences中的数据。

public static final String MyPREF_MOB = "MyPref_mob";
public static final String WALLPAPER_MOB = "wallpaper_mob";

if(encodedImagee!=null) {
    // shre1 = PreferenceManager.getDefaultSharedPreferences(context);
    SharedPreferences.Editor edit = shre1.edit();
    edit.putString(WALLPAPER_MOB, encodedImagee);
    edit.apply();
    //  Toast.makeText(Profile1Activity.this, "new same image in prefrences", Toast.LENGTH_SHORT).show();
}
shre1 = getSharedPreferences(MyPREF_MOB, Context.MODE_PRIVATE);
final String image_save =shre1.getString(WALLPAPER_MOB, "");

我也尝试过

 if(encodedImagee!=null)
        {
           // shre1 = PreferenceManager.getDefaultSharedPreferences(context);
            SharedPreferences.Editor edit = shre1.edit();
            edit.putString("mob_wallpaper", encodedImagee);
            edit.commit();
            //  Toast.makeText(Profile1Activity.this, "new same image in prefrences", Toast.LENGTH_SHORT).show();
        }
        shre1 = PreferenceManager.getDefaultSharedPreferences(context);
        final String image_save =shre1.getString("mob_wallpaper", "");

我已使用此代码保存数据，当应用重启时我也可以获取数据，但是当手机重启数据再次消失时

if(encodedImagee!=null)
        {
           // shre1 = PreferenceManager.getDefaultSharedPreferences(context);
            SharedPreferences.Editor edit = shre1.edit();
            edit.remove("mob_wallpaper");
            edit.apply();
            edit.putString("mob_wallpaper", encodedImagee);
            edit.apply();
            //  Toast.makeText(Profile1Activity.this, "new same image in prefrences", Toast.LENGTH_SHORT).show();
        }
        shre1 = PreferenceManager.getDefaultSharedPreferences(context);
        final String image_save =shre1.getString("mob_wallpaper", "");

Answer 1

尝试这个，

        SharedPreferences sharedPreferences = getSharedPreferences("preference_name", Context.MODE_PRIVATE);
        if (encodedImagee != null){
            SharedPreferences.Editor edit = sharedPreferences.edit();
            edit.putString("mob_wallpaper", encodedImagee);
            edit.commit();
        }else{
            final String image_save = sharedPreferences.getString("mob_wallpaper","");
            // put your logic over here
        }

Answer 2

我从您的示例代码中假设您使用了

• PreferenceManager.getDefaultSharedPreferences用于读取
• getSharedPreferences(MyPREF_MOB, Context.MODE_PRIVATE)用于编写

我认为您在两种情况下都应使用相同的内容。

尝试更换

shre1 = getSharedPreferences(MyPREF_MOB, Context.MODE_PRIVATE);

通过

shre1 = PreferenceManager.getDefaultSharedPreferences(context);

Answer 3

//get the preference instance with this
SharedPreferences mPrefs = PreferenceManager.getDefaultSharedPreferences(this);
// acccess a saved key value
mPrefs.getString("key", "default_value");
//save a key-value
mPrefs.edit().putString("key", "new_value").apply();

Answer 4

以这种方式修改您的代码：

@Override
public void onCreate(.....){
    super.onCreate(......);
setContentView(R.layout.your_layout_xml);
shre1 = getSharedPreferences(MyPREF_MOB, Context.MODE_PRIVATE);

final String image_save =shre1.getString(WALLPAPER_MOB, "");

以及何时要更新图像

if(encodedImagee!=null) {
// shre1 = PreferenceManager.getDefaultSharedPreferences(context);
SharedPreferences.Editor edit = shre1.edit();
edit.putString(WALLPAPER_MOB, encodedImagee);
edit.commit(); //make use of commit
//  Toast.makeText(Profile1Activity.this, "new same image in prefrences", Toast.LENGTH_SHORT).show();
}