Android usa SimpleCursorAdapter para mostrar datos de SQLite en ListView

Android usa SimpleCursorAdapter para mostrar datos de SQLite en ListView

Sabemos que cuando usa ListView, necesita un origen de datos, que puede ser datos locales o datos de red. Esta publicación de blog utiliza SQLite para proporcionar una fuente de datos para ListView.

一、首先我们需要创建一个数据库表格。

    a、建立一个类 DBHelper 继承 SQLiteOpenHelper .

public class DBHelper extends SQLiteOpenHelper {

    public DBHelper(Context context) {
        super(context, "test2.db", null, 1);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        String sql = "create table class(_id integer primary key autoincrement,name varchar(64),number varchar(64))"; 
        //要使用游标适配器，SQLite表格必须包含一栏“_id”
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

}

Sobre el uso de SQLite, visite mi otra publicación de blog http://blog.csdn.net/q296264785/article/details/53155739

用单元测试的方法给数据库添加一些数据，方便看到效果。

public void add() {
        DBHelper dbHelper = new DBHelper(getContext());
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        ContentValues values = new ContentValues();
        values.put("name", "张利利");
        values.put("number", "12345");
        database.insert("class", null, values);
        values.put("name", "李提莫");
        values.put("number", "43455");
        database.insert("class", null, values);
        values.put("name", "王石说");
        values.put("number", "42345");
        database.insert("class", null, values);
        values.put("name", "赵六壳");
        values.put("number", "14215");
        database.insert("class", null, values);
        values.put("name", "郭撒大");
        values.put("number", "45234");
        database.insert("class", null, values);
        values.put("name", "刘䮻明");
        values.put("number", "23445");
        database.insert("class", null, values);
    }

    c、在XML文件中编辑一个布局界面，下面是效果图：

Archivo de diseño XML:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#cccccc"
        android:paddingBottom="10sp" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="编号"
            android:textColor="#2828ff"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="姓名"
            android:textColor="#2828ff"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="工号"
            android:textColor="#2828ff"
            android:textSize="20sp" />
    </LinearLayout>

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

    d、在Activity中创建一个SimpleCursorAdapter，并且设置给ListView。

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends Activity {
    private DBHelper dbHelper;
    private SQLiteDatabase database;
    private SimpleCursorAdapter adapter;// 简单的游标适配器
    private ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView1);
        dbHelper = new DBHelper(this);
        database = dbHelper.getReadableDatabase();
        Cursor c = database.query("class", null, null, null, null, null, null);
        String[] from = { "_id", "name", "number" };
        int[] to = { R.id.textView1, R.id.textView2, R.id.textView3 };
        adapter = new SimpleCursorAdapter(this, R.layout.activity_main, c,
                from, to);//改方法在搞版本已经过时，因为如果读取数据库时间过长是系统会报错，新的方法将数据库读取操作放在另外的线程中。
        listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Directorio de archivos:

————————————————— Línea de división ——————————————————
Código fuente:

Archivo de diseño:

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="#cccccc"
        android:paddingBottom="10sp" >

        <TextView
            android:id="@+id/textView1"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="编号"
            android:textColor="#2828ff"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/textView2"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="姓名"
            android:textColor="#2828ff"
            android:textSize="20sp" />

        <TextView
            android:id="@+id/textView3"
            android:layout_width="0sp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:paddingTop="10dp"
            android:text="工号"
            android:textColor="#2828ff"
            android:textSize="20sp" />
    </LinearLayout>

    <ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

Clase DBHelper:

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class DBHelper extends SQLiteOpenHelper {

    public DBHelper(Context context) {
        super(context, "test2.db", null, 1);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        // TODO Auto-generated method stub
        String sql = "create table class(_id integer primary key autoincrement,name varchar(64),number varchar(64))";
        db.execSQL(sql);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

    }

}

Actividad principal:

import android.app.Activity;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ListView;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends Activity {
    private DBHelper dbHelper;
    private SQLiteDatabase database;
    private SimpleCursorAdapter adapter;// 简单的游标适配器
    private ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView1);
        dbHelper = new DBHelper(this);
        database = dbHelper.getReadableDatabase();
        Cursor c = database.query("class", null, null, null, null, null, null);
        String[] from = { "_id", "name", "number" };
        int[] to = { R.id.textView1, R.id.textView2, R.id.textView3 };
        adapter = new SimpleCursorAdapter(this, R.layout.activity_main, c,
                from, to);//该方法在高的版本中已经过时，因为在如果读取数据库时间过长系统会报错，新的版本中将数据库读取操作放在另外的线程中。
        listView.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

}

Prueba clase prueba

import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.test.AndroidTestCase;

public class test extends AndroidTestCase {
    public void create() {
        DBHelper dbHelper = new DBHelper(getContext());
        SQLiteDatabase database = dbHelper.getReadableDatabase();
    }

    public void add() {
        DBHelper dbHelper = new DBHelper(getContext());
        SQLiteDatabase database = dbHelper.getReadableDatabase();
        ContentValues values = new ContentValues();
        values.put("name", "张利利");
        values.put("number", "12345");
        database.insert("class", null, values);
        values.put("name", "李提莫");
        values.put("number", "43455");
        database.insert("class", null, values);
        values.put("name", "王石说");
        values.put("number", "42345");
        database.insert("class", null, values);
        values.put("name", "赵六壳");
        values.put("number", "14215");
        database.insert("class", null, values);
        values.put("name", "郭撒大");
        values.put("number", "45234");
        database.insert("class", null, values);
        values.put("name", "刘䮻明");
        values.put("number", "23445");
        database.insert("class", null, values);
    }
}