如何從 BackupAgentHelper 中獲取 PpreferencesManager

Question

在我的BackupAgentHelper中，我需要知道标准首选项文件的名称。我认为"getPreferenceManager（）.getSharedPreferencesName（）"是个好主意，但似乎我无法获得上下文。

如何获取标准首选项文件的名称和/或首选项管理器的方法？

public class MyBackupAgentHelper extends BackupAgentHelper {
    private static final String TAG_PREFERENCES = "preferences";
    @Override
    public void onCreate() {
        SharedPreferencesBackupHelper helper = new SharedPreferencesBackupHelper(this, this
                .getPreferenceManager().getSharedPreferencesName());
        addHelper(TAG_PREFERENCES, helper);
    }
}

Answer 1

API缺乏简单的方法。我这样做是为了避免硬编码任何东西。

final public class BackupAgent extends BackupAgentHelper
{
    // A key to uniquely identify the set of backup data
    static final String PREFS_BACKUP_KEY = "prefs";
    public void onCreate()
    {
        String packageName = "???";
        try {
            // read current version information about this package
            Context context = getApplicationContext();
            PackageManager manager = context.getPackageManager();
            PackageInfo info = manager.getPackageInfo(context.getPackageName(), 0);
            packageName = info.packageName;
            // preference file name is <package_name>_preferences
            packageName += "_preferences";
            SharedPreferencesBackupHelper helper = 
                            new SharedPreferencesBackupHelper(this, packageName);
            addHelper(PREFS_BACKUP_KEY, helper);
        } catch (Exception e) {
                  e.printStackTrace();
        }   
    }
}