Question

我需要帮助，我试图在android studio上的TextView上显示数据库中的信息，这是学生姓名及其年龄的列表。我知道如何显示随机文本（注释掉的行），但是不知道何时使用数据库

 public void doList(View v){
        LinearLayout l = (LinearLayout)findViewById(R.id.mainView);
        Cursor c = myDB.doQuery("SELECT name, age from students");

        while (c.moveToNext()){
            TextView t = new TextView(this);

            //t.setText("Some text");
            //l.addView(t);

            System.out.println(c.getString(c.getColumnIndex("name")) + "," + c.getLong(c.getColumnIndex("age")));
        }

        c.close();
    }

完整代码（MainActivity.java）：

package com.example.databaseexample;

import android.app.Activity;
import android.database.Cursor;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;


public class MainActivity extends Activity {

    DatabaseHelper myDB;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        myDB=new DatabaseHelper(this, "app");
        setContentView(R.layout.activity_main);
    }

    public void doList(View v){
        LinearLayout l = (LinearLayout)findViewById(R.id.mainView);
        Cursor c = myDB.doQuery("SELECT name, age from students");

        while (c.moveToNext()){
            TextView t = new TextView(this);
            //t.setText("Some text");
            //l.addView(t);
            System.out.println(c.getString(c.getColumnIndex("name")) + "," + c.getLong(c.getColumnIndex("age")));
        }

        c.close();
    }

    public void doInsert(View v){
        String[] vals = {"Steve","23"};
        myDB.doUpdate("Insert into students(name, age) values (?,?);", vals);
    }

    public void doQuery(View v){
        Cursor c = myDB.doQuery("SELECT name, age from students");
        while (c.moveToNext()){
            System.out.println(c.getString(c.getColumnIndex("name")) + "," + c.getLong(c.getColumnIndex("age")));
        }
        c.close();
    }


}

Answer 1

要从数据库中获取某些东西，请使用：

   Cursor data
   data = mydatabasereference.showData();//Show the board database
   data.moveToFirst();//point the location to first instance of data
   String text_data = (data.getString(1)));//Gets the string data
   mytextbox.setText(text_data);

data.getstring（1）第二次进入数据库存储结构。请注意，它必须是字符串才能起作用。或者，您需要将该数据转换为字符串以进行打印。

在TextView Android Studio上显示数据库中的信息

1 个答案: