在Android中难以将共享的首选项值存储到SQLIte并存储了空值

Question

我想我没有关于如何执行此操作的想法。 我正在构建具有注册和登录功能的TODO应用。 登录用户后，可以在SQLite（现在）中创建新的todos任务，稍后我也想删除并重命名todos。

这是我的SQliteHelper数据库类。

public class DatabaseHelper extends SQLiteOpenHelper {


// Database Version
private static final int DATABASE_VERSION = 1;

// Database Name
private static final String DATABASE_NAME = "UserManager.db";

// User table name
private static final String TABLE_USER = "user";

 // User Table Columns names
private static final String COLUMN_USER_ID = "user_id";
private static final String COLUMN_USER_NAME = "user_name";
private static final String COLUMN_USER_EMAIL = "user_email";
private static final String COLUMN_USER_PASSWORD = "user_password";

 //Table mToDo task name
private final static String mTODO = "Todos"; 

//Todos table columns names
private final static String TASK_ID = "task_Id"; //autoincrement
private final static String user_Id =  "userId";
private final static String TITLE = "title";
private final static String CONTENT = "content";

 // create table sql query
private String CREATE_USER_TABLE = "CREATE TABLE " + TABLE_USER + "("
        + COLUMN_USER_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + 
COLUMN_USER_NAME + " TEXT,"
        + COLUMN_USER_EMAIL + " TEXT," + COLUMN_USER_PASSWORD + " TEXT" + 
 ")";

private String CREATE_mTODO_TABLE = "CREATE TABLE " + mTODO + "("
        + TASK_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + user_Id + " TEXT NOT NULL,"
        + TITLE + " TEXT," + CONTENT + " TEXT" + ")";

// drop table sql query
private String DROP_USER_TABLE = "DROP TABLE IF EXISTS " + TABLE_USER;

public DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
 //        this.ctx = context;
}

 @Override
public void onCreate(SQLiteDatabase db) {
    db.execSQL(CREATE_USER_TABLE);
    db.execSQL(CREATE_mTODO_TABLE);

}

 @Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

    //Drop User Table if exist
    db.execSQL(DROP_USER_TABLE);


    // Create tables again
    onCreate(db);

}

将新任务添加到第二个表

 public void add(ToDo todoTask) {
    SQLiteDatabase db = this.getWritableDatabase();
 //        SharedPreferences sp = PreferenceManager
 //                .getDefaultSharedPreferences(ctx);
 //        String d = sp.toString();

 ContentValues values = new ContentValues();
    values.put(TITLE, todoTask.getTitle());
    values.put(CONTENT, todoTask.getContent());

 //        values.put(user_Id,todoTask.getUserID(d));


// Inserting Row
    db.insert(mTODO, null, values);
    db.close();
}

待办事项

public class ToDo {

private int id;
private String userID;
private String title;
private String content;

public ToDo(String content, int id, String title, String userID) {
    this.content = content;
    this.id = id;
    this.title = title;
    this.userID = userID;
}

public ToDo(String content, String title, String userID) {
    this.content = content;
    this.title = title;
    this.userID = userID;
}

public ToDo() {
}

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

public int getId(String name) {
    return id;
}

public void setId(int id) {
    this.id = id;
}

public String getTitle() {
    return title;
}

public void setTitle(String title) {
    this.title = title;
}

public String getUserID(String userID) {
    return userID;
}

public void setUserID(String userID) {
    this.userID = userID;
}
}

使用输入添加活动类并添加方法

public class addTask extends AppCompatActivity {


private EditText titleUser;
private EditText contentDesc;
private DatabaseHelper db;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_add_task);
    Button btnAdd = (Button) findViewById(R.id.addToDo);
    titleUser = (EditText) findViewById(R.id.titleID);
    contentDesc = (EditText) findViewById(R.id.contentDescId);
    db = new DatabaseHelper(this);
    btnAdd.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
                AddItem();
        }


    });

}



private void AddItem() {
    ToDo todo = new ToDo();
    todo.setTitle(titleUser.getText().toString().trim());
    todo.setContent(contentDesc.getText().toString().trim());
    db.add(todo);
    finish();
}

当前登录的用户，我将该用户ID设置为“共享的首选项”在第二个表中，我有类似的内容

task_Id user_id title   content
 1      null    Eat      go to Mc

这里的user_id为null，我不知道为什么

我想要这样的东西

task_Id user_id title   content
 1      2    Eat      go to Mc

user_id-应该是要执行任务的用户ID

Answer 1

假设您已经知道如何从共享首选项中存储和获取用户ID。

在您的addTask活动中，添加：

private String userId;
@Override
protected void onCreate(Bundle savedInstanceState) {
    ...
    userId = sharedPreference.getString("USER_ID",null);
    ...
}

在addItem()添加：

private void AddItem() {
    ...
    todo.setUserId(userId);
    ...
}

在数据库的add()使用以下命令：

public void add(ToDo todoTask) {
    ...
    values.put(USERID, todoTask.getUserId());
    ...
}

要么：

另一种方法是，如果您确定永远不会为其他用户插入任务，则直接从DB类获取值。

public void add(ToDo todoTask) {
    SQLiteDatabase db = this.getWritableDatabase();
    SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(ctx);
    String d = sp.toString();

    ContentValues values = new ContentValues();
    values.put(TITLE, todoTask.getTitle());
    values.put(CONTENT, todoTask.getContent());
    values.put(user_Id,todoTask.getUserID(d));

    db.insert(mTODO, null, values);
    db.close();
}

并在构造函数中保存上下文以备将来使用。

private Context ctx;

public DatabaseHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    this.ctx = context;
}

Answer 2

您正在使用user_id创建ToDo表。 而静态字符串refrenced是userid：因此在数据库中，输入时默认为null

   //Table mToDo task name
private final static String mTODO = "Todos"; 

//Todos table columns names
private final static String TASK_ID = "task_Id"; 
private final static String user_Id =  "userId"; //<----Wrong Here
private final static String TITLE = "title";
private final static String CONTENT = "content";

private String CREATE_mTODO_TABLE = "CREATE TABLE " + mTODO + "("
    + TASK_ID + " INTEGER PRIMARY KEY AUTOINCREMENT," + user_Id + " TEXT NOT NULL,"
    + TITLE + " TEXT," + CONTENT + " TEXT" + ")";

另外，这里还为您提供了更多功能，您只需向字段提供用户ID值即可。 以下是一些示例

 private static final String TAG = "DB_HANDLER";

private static final int DATABASE_VERSION = 15;
private static final String DATABASE_NAME = "ElmexContactsManager.db";

/*-------------------------------------------BIZ_SEGMENT----------------------------------------*/
private static final String TABLE_BIZ_SEGMENT = "BizSegment";

/*01*/private static final String KEY_LOCAL_BIZ_SEGMENT_ID = "LocalBizSegmentId";
/*02*/private static final String KEY_BIZ_SEGMENT_ID = "BizSegmentId";
/*03*/private static final String KEY_BIZ_SEGMENT = "BizSegment";
/*04*/private static final String KEY_ADDED_ON = "AddedOn";
/*05*/private static final String KEY_UPDATED_ON = "UpdatedOn";

  /*-------------------------------------------BIZ_SEGMENT----------------------------------------*/
    String CREATE_TABLE_BIZ_SEGMENT = "CREATE TABLE " + TABLE_BIZ_SEGMENT + "("
  /*01*/ + KEY_LOCAL_BIZ_SEGMENT_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
  /*02*/ + KEY_BIZ_SEGMENT_ID + " INTEGER,"
  /*03*/ + KEY_BIZ_SEGMENT + " TEXT,"
  /*04*/ + KEY_ADDED_ON + " TEXT,"
  /*05*/ + KEY_UPDATED_ON + " TEXT"
            + ")";

public ContactDatabaseHandler(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
    //3rd argument to be passed is CursorFactory instance
}


@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {  try {
        sqLiteDatabase.execSQL(CREATE_TABLE_BIZ_SEGMENT);
        sqLiteDatabase.execSQL(CREATE_TABLE_CONTACT_TYPE);
        sqLiteDatabase.execSQL(CREATE_TABLE_CONTACT_SOURCE);
        sqLiteDatabase.execSQL(CREATE_TABLE_CONT_INDUSTRY);
        sqLiteDatabase.execSQL(CREATE_TABLE_MARKETING_REGION);
        sqLiteDatabase.execSQL(CREATE_TABLE_MARKETING_REGION_BLOCK);
        sqLiteDatabase.execSQL(CREATE_TABLE_CONTACT_MASTER);
        sqLiteDatabase.execSQL(CREATE_TABLE_CONTACT_DET);
    } catch (SQLException e) {
        e.printStackTrace();
    }
    Log.d(TAG, "Table Craeted ");
}
@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
    // Drop older table if existed
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_BIZ_SEGMENT);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACT_TYPE);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACT_SOURCE);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_CONT_INDUSTRY);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_MARKETING_REGION);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_MARKETING_REGION_BLOCK);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACT_MASTER);
    sqLiteDatabase.execSQL("DROP TABLE IF EXISTS " + TABLE_CONTACT_DET);
    // Create tables again
    onCreate(sqLiteDatabase);
    Log.d(TAG, "Table Udgraded to Version :" + i1);
}

/*-------------------------------------------BIZ_SEGMENT----------------------------------------*/
public void addBizSegment(BizSegment bizSegment) {
    SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
    DateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    ContentValues values = new ContentValues();
    values.put(KEY_BIZ_SEGMENT_ID, bizSegment.getBizSegmentId());
    values.put(KEY_BIZ_SEGMENT, bizSegment.getBizSegment());
    values.put(KEY_ADDED_ON, df.format(bizSegment.getAddedOn()));
    values.put(KEY_UPDATED_ON, df.format(bizSegment.getUpdatedOn()));
    // Inserting Row
    sqLiteDatabase.insert(TABLE_BIZ_SEGMENT, null, values);
    //2nd argument is String containing nullColumnHack
    sqLiteDatabase.close(); // Closing database connection
}

public void updateBizSegment(BizSegment bizSegment) {
    SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
    DateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    ContentValues values = new ContentValues();
    //values.put(KEY_BIZ_SEGMENT_ID, bizSegment.getBizSegmentId());
    values.put(KEY_BIZ_SEGMENT, bizSegment.getBizSegment());
    values.put(KEY_ADDED_ON, df.format(bizSegment.getAddedOn()));
    values.put(KEY_UPDATED_ON, df.format(bizSegment.getUpdatedOn()));
    // Inserting Row
    sqLiteDatabase.update(TABLE_BIZ_SEGMENT, values, KEY_BIZ_SEGMENT_ID + " = ?", new String[]{String.valueOf(bizSegment.getBizSegmentId())});
    //2nd argument is String containing nullColumnHack
    sqLiteDatabase.close(); // Closing database connection
}

public List<BizSegment> getBizSegmentAll() {
    SQLiteDatabase sqLiteDatabase = this.getWritableDatabase();
    List<BizSegment> bizSegmentList = new ArrayList<BizSegment>();
    DateFormat df = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss");
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_BIZ_SEGMENT;

    Cursor cursor = sqLiteDatabase.rawQuery(selectQuery, null);

    if (cursor.moveToFirst()) {
        do {
            try {
                BizSegment bizSegment = new BizSegment(cursor.getInt(0),
                        cursor.getInt(1),
                        cursor.getString(2),
                        df.parse(cursor.getString(3)),
                        df.parse(cursor.getString(4)));
                bizSegmentList.add(bizSegment);
            } catch (ParseException e) {
                e.printStackTrace();
            }

        } while (cursor.moveToNext());
    }
    cursor.close();
    sqLiteDatabase.close();
    //2nd argument is String containing nullColumnHack
    return bizSegmentList;
}

public void deleteBizSegment(BizSegment bizSegment) {
    SQLiteDatabase db = this.getWritableDatabase();
    db.delete(TABLE_BIZ_SEGMENT, KEY_BIZ_SEGMENT_ID + " = ?",
            new String[]{String.valueOf(bizSegment.getBizSegmentId())});
    db.close();
}

其他方法是使用适用于有限数据的共享首选项。 它不提供任何关系。 我用它来存储基本的用户相关数据。 不适用于复杂/相关的大数据。 对于那个Sqlite是首选。

public class AppPreference {

SharedPreferences pref;
SharedPreferences.Editor edit;

/**
 * @param clientMaster object to set preference
 * @param context      Context of call
 */
public void putPreference(ClientMaster clientMaster, Context context) {

    pref = context.getSharedPreferences("AppPreference", Context.MODE_PRIVATE);
    edit = pref.edit();

    edit.putInt("ClientId", clientMaster.getClientId());
    edit.putString("FirstName", clientMaster.getFirstName());
    edit.putString("LastName", clientMaster.getLastName());
    edit.putString("Mobile", clientMaster.getMobile());
    edit.putInt("PincodeId", clientMaster.getPincodeId());
    edit.putString("Email", clientMaster.getEmail());
    edit.putString("Password", clientMaster.getPassword());
    edit.putString("MembershipCode", clientMaster.getMembershipCode());
    edit.putString("MembershipIssueDate", clientMaster.getMembershipIssueDate().toString());
    edit.putString("MembershipExpiryDate", clientMaster.getMembershipExpiryDate().toString());
    edit.putString("MemberShipUpdatedOn", clientMaster.getMemberShipUpdatedOn().toString());
    edit.putString("MemberShipQRCode", clientMaster.getMemberShipQRCode());
    edit.putInt("ReferredByTypeID", clientMaster.getReferredByTypeID());
    edit.putInt("ReferredByID", clientMaster.getReferredByID());
    //edit.putString("LastPasswordUpdatedOn", clientMaster.getLastPasswordUpdatedOn().toString());
    edit.putString("TempMembershipCode", clientMaster.getTempMembershipCode());
    edit.putString("AddedOn", clientMaster.getAddedOn().toString());
    //edit.putString("UpdatedOn", clientMaster.getUpdatedOn().toString());
    edit.putBoolean("Login", true);
    edit.putBoolean("Skip", false);
    edit.commit();
}

/**
 *
 * @param appLanguage
 * @param context
 */
public void putLanguagePreference(String appLanguage, Context context) {

    pref = context.getSharedPreferences("AppPreference", Context.MODE_PRIVATE);
    edit = pref.edit();
    edit.putString("AppLanguage", appLanguage);
    edit.commit();
}

/**
 * To clear All Object preference & Login False
 *
 * @param context Context call
 */
public void clearPreference(Context context) {
    pref = context.getSharedPreferences("AppPreference", Context.MODE_PRIVATE);
    edit = pref.edit();

    edit.clear();

    edit.putBoolean("Login", false);
    edit.commit();

}

/**
 * @param InstanceId Instance Id
 * @param context
 */
public void putPreferenceInstance(String InstanceId, Context context) {

    pref = context.getSharedPreferences("AppPreference", Context.MODE_PRIVATE);
    edit = pref.edit();
    edit.putString("InstanceId", InstanceId);
    edit.commit();
}

}