我创建了一个Android的动态壁纸，我试图让用户选择自己的手机的图像，并将其应用为背景图像，但是当我启动的活动，开始有意挑选的图像，我共享preferences似乎并不正确保存。

下面是我开始时的用户presses的preference按钮活性的它获取设备上的图像的路径的onActivityResult（所有似乎工作）我onCreate方法，和。之后，我犯了preferences中的println打印出什么。

  @覆盖
公共无效的onCreate（包savedInstanceState）{
    super.onCreate（savedInstanceState）;

    意图photoPickerIntent =新的意图（Intent.ACTION_PICK）;
    photoPickerIntent.setType（图像/ *）;
    startActivityForResult（photoPickerIntent，SELECT_PICTURE）;
}

@覆盖
公共无效onActivityResult（INT申请code，INT结果code，意图数据）{
    super.onActivityResult（要求code，因此code，数据）;

    如果（结果code == RESULT_OK）{
        如果（要求code == SELECT_PICTURE）{
            乌里selectedImageUri = data.getData（）;
            selectedImagePath = getPath（selectedImageUri）;

            。preferences = getApplicationContext（）getShared preferences（preFERENCES_NAME，0）;
            。preferences.edit（）putString（SETTINGS_BACKGROUND_IMAGE，OKOK）;
            preferences.edit（）提交（）。

            的System.out.println（图像+ preferences.getString（SETTINGS_BACKGROUND_IMAGE，））;
        }
    }

    完（）;
}
 

解决方案

在documentation:

创建这些preferences一个新的编辑器，通过它可以使   修改数据在preferences和原子犯   这些更改回共享preferences对象。

由于这是一个新的编辑器的实例，你的code应该更多这样的：

  preferences = getApplicationContext（）getShared preferences（preFERENCES_NAME，0）;
共享preferences.Editor编辑器= preferences.edit（）;
editor.putString（SETTINGS_BACKGROUND_IMAGE奥科克）;
editor.commit（）;
 

I've created an Android live wallpaper and i'm trying to let a user choose an image from their phone and apply it as a background image, but when I launch the activity that start the intent to pick the images, my shared preferences don't seem to save properly.

Below is my onCreate method of the activity I start when the users presses the preference button, and the onActivityResult which gets the path of the image on the device (all that seems to work). The println after I commit the preferences prints out nothing.

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

    Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
    photoPickerIntent.setType("image/*");
    startActivityForResult(photoPickerIntent, SELECT_PICTURE);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {
            Uri selectedImageUri = data.getData();
            selectedImagePath = getPath(selectedImageUri);

            preferences = getApplicationContext().getSharedPreferences(PREFERENCES_NAME, 0);
            preferences.edit().putString(SETTINGS_BACKGROUND_IMAGE, "okok");
            preferences.edit().commit();

            System.out.println("Image" + preferences.getString(SETTINGS_BACKGROUND_IMAGE, ""));
        }
    }

    finish();
}

From the documentation:

Create a new Editor for these preferences, through which you can make modifications to the data in the preferences and atomically commit those changes back to the SharedPreferences object.

Since that's a new Editor instance, your code should be more like this:

preferences = getApplicationContext().getSharedPreferences(PREFERENCES_NAME, 0);
SharedPreferences.Editor editor = preferences.edit();
editor.putString(SETTINGS_BACKGROUND_IMAGE, "okok");
editor.commit();