ListView展示数据库中的数据 并利用菜单简单添加固定数据

1.布局文件 activity_main.xml

主要view对象为listView  必须设置width  height :matchParent 优化性能

<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"

    android:paddingBottom="@dimen/activity_vertical_margin"

    android:paddingLeft="@dimen/activity_horizontal_margin"

    android:paddingRight="@dimen/activity_horizontal_margin"

    android:paddingTop="@dimen/activity_vertical_margin"

    tools:context=".MainActivity" >

    <ListView

        android:id="@+id/lv"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

         />

</RelativeLayout>

2.数据显示的样式文件item.xml

分为两个TextView 并列显示name 和 age

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="horizontal" >

    <TextView 

        android:id="@+id/tv_name"

        android:layout_height="wrap_content"

        android:layout_width="wrap_content"

        />

     <TextView 

        android:id="@+id/tv_age"

        android:layout_height="wrap_content"

        android:layout_width="wrap_content"

        />

</LinearLayout>

3.DBHelper.java  继承SQLiteOpenHelper 创建数据库和表

package com.example.day13_ex_sqlite;

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,"test.db", null,1);

    }

public DBHelper(Context context, String name, CursorFactory factory,

int version) {

super(context, name, factory, version);

// TODO Auto-generated constructor stub

}

@Override

public void onCreate(SQLiteDatabase arg0) {

// TODO Auto-generated method stub

      //创建表user

  String sql="create table user(_id integer primary key autoincrement,name text,age integer)";

  arg0.execSQL(sql);

}

@Override

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

// TODO Auto-generated method stub

}

}

4.main.xml菜单文件  用于在菜单上添加固定数据

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item

        android:id="@+id/action_settings"

        android:orderInCategory="100"

        android:showAsAction="always"

        android:title="添加固定数据"/>

</menu>

5.MainActivity.java

package com.example.day13_ex_sqlite;

import java.util.Currency;

import android.os.Bundle;

import android.app.Activity;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.support.v4.widget.SimpleCursorAdapter;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.AdapterView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.ListView;

import android.widget.TextView;

import android.widget.Toast;

public class MainActivity extends Activity {

    DBHelper db;

    SQLiteDatabase sd;

SimpleCursorAdapter adapter;

    @Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

    db=new DBHelper(this);

    sd=db.getWritableDatabase();

    //insert();插入成功

    ListView lv=(ListView) findViewById(R.id.lv);

    Cursor cs=query();

    adapter=new SimpleCursorAdapter(this,R.layout.item, cs,new String[]{"name","age"},new int[]{R.id.tv_name,R.id.tv_age},0);

    lv.setAdapter(adapter);

    //listView 设置点击事件

    lv.setOnItemClickListener(new OnItemClickListener() {

@Override

public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,

long arg3) {

// TODO Auto-generated method stub

       Toast.makeText(MainActivity.this,"您点击了位置"+arg2, 0).show();

}

});

}

@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;

}

//菜单点击事件

@Override

public boolean onOptionsItemSelected(MenuItem item) {

// TODO Auto-generated method stub

if(item.getItemId()==R.id.action_settings){

String name="乔峰";

int age=34;

String sql="insert into user(name,age) values('"+name+"','"+age+"')";

sd.execSQL(sql);

Toast.makeText(this,"添加数据成功!",0).show();

adapter.changeCursor(query());

adapter.notifyDataSetChanged();

return true;

}

return super.onOptionsItemSelected(item);

}

    //插入数据

public void insert(){

         for(int i=0;i<10;i++){

          String name="张"+i+"丰";

          int age=i;

          String sql="insert into user(name,age)values('"+name+"','"+i+"')";

          sd.execSQL(sql);

         }

}

//查询数据  返回游标对象

public Cursor query(){

 String sql="select * from user";

 Cursor cs = sd.rawQuery(sql,null);

 return cs;

}

}

原文链接：http://www.apkbus.com/blog-813041-61173.html