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android - 获取适配器中的 sharedpreference 数据

问题描述

谷歌搜索并尝试了一整天在我的适配器中获取共享首选项数据。我有一SharedPreferenceManager堂课

public class SharedPrefManager {
static SharedPreferences sharedPreferences;
static Context mContext;

static int PRIVATE_MODE = 0;

private static final String PREF_NAME = "sessionPref";

static SharedPreferences.Editor editor;

public SharedPrefManager (Context context) {
    mContext = context;
    sharedPreferences = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    editor = sharedPreferences.edit();
}

public void saveUID(Context context,String uid){
    mContext = context;
    sharedPreferences = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString("UID", uid);
    editor.commit();
}
public String getUID(){
    sharedPreferences = mContext.getSharedPreferences(PREF_NAME, PRIVATE_MODE);
    return sharedPreferences.getString("UID", "");
}
public void clear(){
    editor.clear();
    editor.apply();
}
}

我SharedPrefManager在任何这样的活动中调用

public SharedPrefManager sharedPrefManager;
public String uid

并且在onCreate()

sharedPrefManager = new SharedPrefManager(mContext);
uid = sharedPrefManager.getUID();

现在，如何在适配器中获取相同的数据，因为下面的代码在任何适配器中都会出错

SharedPrefManager sharedPrefManager = new SharedPrefManager(context);
public String uid = sharedPrefManager.getUID();

这是我的Adapter Class

public class MyCommentAdapter extends RecyclerView.Adapter<MyCommentAdapter.MyCommentHolder> {
Context context;
private List<MyComment> commentList;

//Here I get the null pointer error
SharedPrefManager sharedPrefManager = new SharedPrefManager(context);
public String uid = sharedPrefManager.getUID();
private DatabaseReference mDatabaseReference1=FirebaseDatabase.getInstance().getReference().child("User").child(uid).child("Comment");

int 最后一行代码我想使用 uid 访问数据库，这就是为什么我需要共享首选项中的 uid 值

public MyCommentAdapter(Context context, List<MyComment> commentList) {
    this.context = context;
    this.commentList = commentList;
}

标签： androidsharedpreferencesadapter

解决方案

public class SP {
    /**
     * @param mContext
     * @param key
     * @param value
     */
    public static void savePreferences(Context mContext, String key, String value) {
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.putString(key, value).apply();
    }

    /**
     * @param context
     * @param keyValue
     * @return
     */
    public static String getPreferences(Context context, String keyValue) {
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
        return sharedPreferences.getString(keyValue, "");
    }

    /**
     * @param mContext
     */
    public static void removeAllSharedPreferences(Context mContext) {
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
        SharedPreferences.Editor editor = sharedPreferences.edit();
        editor.clear().apply();
    }
}

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