java - Android中如何全局访问SQl​​ite返回的数据？

Question

public class MainObj {
    private static final MainObj instance = new MainObj();

    public static MainObj getInstance() {
        return instance;
    }

    public static class User {
        public int account_id;
        public String user_id;
        public String sip_id;
        public String username;
        public String fullname;
        public boolean active;
        public boolean status;

        public int getAccount_id() {
            return account_id;
        }
        public void setAccount_id(int account_id) {
            Log.e("myphone", account_id+"");
            this.account_id = account_id;
        }
        public String getUser_id() {
            return user_id;
        }
        public void setUser_id(String user_id) {
            this.user_id = user_id;
        }
        public String getSip_id() {
            return sip_id;
        }
        public void setSip_id(String sip_id) {
            this.sip_id = sip_id;
        }
        public String getUsername() {
            return username;
        }
        public void setUsername(String username) {
            this.username = username;
        }
        public String getFullname() {
            return fullname;
        }
        public void setFullname(String fullname) {
            this.fullname = fullname;
        }
        public boolean isActive() {
            return active;
        }
        public void setActive(boolean active) {
            this.active = active;
        }
        public boolean isStatus() {
            return status;
        }
        public void setStatus(boolean status) {
            this.status = status;
        }
    }
}

我在Android上编写sip应用程序。我有一些有关用户登录的信息。我想做类似的事情。

1. 具有用户设置的用户对象(存储在 SQlite 中)
2. 从 SQlite 数据访问用户数据并存储在对象中
3. 直接使用来自对象的用户数据，例如(在 UI Activity 、 fragment 中......):

User user = new User();Log.i("TAG", user.sip_id);

or

Log.i("TAG", user.getSip_id());

// get user data from table
public HashMap<String, String> getUserDetails() {
    HashMap<String, String> user = new HashMap<String, String>();
    String selectQuery = "SELECT * FROM user";

    SQLiteDatabase db = this.getReadableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    cursor.moveToFirst();

    if (cursor.getCount() > 0) {
        MainObj.User user = new MainObj.User();
        user.setSip_id(cursor.getString(1));
        user.setAccount_id(cursor.getString(2));
        .... and so on
    }

    cursor.close();
    db.close();

    // return user
    return user;
}

我不知道如何正确地进行谷歌搜索，因为我已经搜索了大约 3 个小时。

Answer 1

只需像这样更改代码，您就可以在任何地方访问数据。

import android.util.Log;

public class User {
    private static final User instance = new User();

    public static User getInstance() {
        return instance;
    }

    private User() {
        super();
    }

    private int account_id;
    private String user_id;
    private String sip_id;
    private String username;
    private String fullname;
    private boolean active;
    private boolean status;

    public int getAccount_id() {
        return account_id;
    }

    public void setAccount_id(int account_id) {
        Log.e("myphone", account_id + "");
        this.account_id = account_id;
    }

    public String getUser_id() {
        return user_id;
    }

    public void setUser_id(String user_id) {
        this.user_id = user_id;
    }

    public String getSip_id() {
        return sip_id;
    }

    public void setSip_id(String sip_id) {
        this.sip_id = sip_id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getFullname() {
        return fullname;
    }

    public void setFullname(String fullname) {
        this.fullname = fullname;
    }

    public boolean isActive() {
        return active;
    }

    public void setActive(boolean active) {
        this.active = active;
    }

    public boolean isStatus() {
        return status;
    }

    public void setStatus(boolean status) {
        this.status = status;
    }

}

您可以通过像这样访问实例来向用户 obj 设置数据

//get user data from table
public void getUserDetails() {
 String selectQuery = "SELECT * FROM user";

 SQLiteDatabase db = this.getReadableDatabase();
 Cursor cursor = db.rawQuery(selectQuery, null);
 cursor.moveToFirst();

 if (cursor.getCount() > 0) {
     //If you want you can hold the reference in a User obj = User.getInstance(); just to write less code
     User.getInstance().setSip_id(cursor.getString(1));
     User.getInstance().setAccount_id(cursor.getString(2));
     .... and so on
 }

 cursor.close();
 db.close();
}

如果您在获取数据后需要某个地方的数据，只需执行以下操作:

mEditText.setText(User.getInstance().getUsername());