android数据库的添加和查询

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主类

package com.zhl.test;import android.os.Bundle;import android.app.Activity;import android.content.ContentValues;import android.content.Intent;import android.database.sqlite.SQLiteDatabase;import android.view.Menu;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;public class MainActivity extends Activity {private EditText ed;private SQLiteDatabase db;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);// 通过传着四个参数创建数据库Sql sql = new Sql(MainActivity.this, "name", null, 1);db = sql.getWritableDatabase();ed = (EditText) findViewById(R.id.name);Button button = (Button) findViewById(R.id.button1);button.setOnClickListener(new OnClickListener() {public void onClick(View v) {// TODO Auto-generated method stub// 把从EditText中获取的值转成字符串String str = ed.getText().toString();// 同过ContentValues向数据库中添加数据ContentValues cv = new ContentValues();cv.put("name", str);// 把数据添加到数据裤中db.insert("name", null, cv);startActivity(new Intent(MainActivity.this, ZhanShi.class));}});}}

布局

<RelativeLayout xmlns:android="<a target=_blank href="http://schemas.android.com/apk/res/android">http://schemas.android.com/apk/res/android</a>"    xmlns:tools="<a target=_blank href="http://schemas.android.com/tools">http://schemas.android.com/tools</a>"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity" >

    <EditText        android:id="@+id/name"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerInParent="true"        android:layout_centerVertical="true"        android:hint="请输入要存储的名字" />

    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentBottom="true"        android:layout_centerHorizontal="true"        android:layout_marginBottom="71dp"        android:text="展示存储的名字" />

</RelativeLayout>

数据库类

package com.zhl.test;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;public class Sql extends SQLiteOpenHelper {public Sql(Context context, String name, CursorFactory factory, int version) {super(context, name, factory, version);// TODO Auto-generated constructor stub}/** * 创建数据库中的表 * */@Overridepublic void onCreate(SQLiteDatabase db) {// TODO Auto-generated method stub// 创建表时使用正常的sql语句进行创建db.execSQL("create table name(id integer primary key autoincrement,name char)");}/** * 数据库的版本发生改变时使用的方法 * */@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {// TODO Auto-generated method stub}}

展示类

package com.zhl.test;import java.util.ArrayList;import java.util.List;import android.os.Bundle;import android.app.Activity;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.view.Menu;import android.widget.ArrayAdapter;import android.widget.ListView;public class ZhanShi extends Activity {private SQLiteDatabase db;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_zhan_shi);Sql sql = new Sql(ZhanShi.this, "name", null, 1);db = sql.getReadableDatabase();// 创建查询语句Cursor cr = db.query("name", null, null, null, null, null, null);List<String> list = new ArrayList<String>();while (cr.moveToNext()) {// 查询表中摸个名字的值String name = cr.getString(cr.getColumnIndex("name"));// 放到集合中去list.add(name);}ListView listview = (ListView) findViewById(R.id.listview);// 使用listview展示出来listview.setAdapter(new ArrayAdapter<String>(ZhanShi.this,android.R.layout.simple_list_item_1, android.R.id.text1, list));}}

布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".ZhanShi" >    <ListView        android:id="@+id/listview"        android:layout_width="wrap_content"        android:layout_height="wrap_content" >    </ListView></RelativeLayout>

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