listView进阶，更改listView的界面

最新推荐文章于 2021-09-14 15:42:26 发布

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#listview

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本文通过一个完整的Android应用示例，展示了如何使用SQLite进行数据存储及基本的CRUD操作，并结合ListView实现了数据展示。

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MainActivity.java

package com.demo.introductiontothedb;

import java.util.List;

import com.demo.introductiontothedb.dao.PersonDao;
import com.demo.introductiontothedb.domain.PersonInfo;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;


public class MainActivity extends Activity {
	public static final String TAG = "MainActivity";
	private PersonDao personDao;
	private List<PersonInfo> personInfos;
	private ListView lv;
	private MyAdapter adapter;
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		
		//1.得到listview
		lv = (ListView) findViewById(R.id.lv);
		personDao = new PersonDao(this);
		personInfos = personDao.findAll();
		//2.设置listview的数据适配器
		adapter = new MyAdapter();
		lv.setAdapter(adapter);
		
		
	}
	
	//控制器  数据适配器
	private class MyAdapter extends BaseAdapter{

		//数据适配器里面有多少条数据
		@Override
		public int getCount() {
			return personInfos.size();
		}

		@Override
		public Object getItem(int position) {
			return null;
		}

		@Override
		public long getItemId(int position) {
			return 0;
		}

		//返回当前位置对应的view对象  显示的内容
		/**
		 * 与传统写listview比，该方法优势在于，用户
		 * 在界面上翻看多少listview的内容，
		 * 该方法就会执行多少次，大大的提高了效率节省了资源。
		 * 不会像传统的不管看还是不看，一次性把personInfos
		 * 里面的全部内容加载到界面上
		 */
		@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			//position 代表的是位置
//			Log.i(TAG, "getView" + position);
//			TextView tv = new TextView(MainActivity.this);
//			PersonInfo personInfo = personInfos.get(position);
//			tv.setText(personInfo.toString());
//			tv.setTextSize(16);
//			tv.setTextColor(Color.BLUE);
//			return tv;
			// 将xml文件创建成一个独立的view对象.
			View view = View.inflate(MainActivity.this, R.layout.list_view, null);
			// 从刚才转化出来的view对象里面寻找name
			//注意，一定从刚刚转换的view里面找,MainActivity里面可没有这textview
			TextView name = (TextView)view.findViewById(R.id.name);	
			// 从刚才转化出来的view对象里面寻找phone
			TextView phone = (TextView)view.findViewById(R.id.phone);	
			// 从刚才转化出来的view对象里面寻找address
			TextView address = (TextView)view.findViewById(R.id.address);	
			//从刚才转化出来的view对象里面寻找money
			TextView money = (TextView)view.findViewById(R.id.money);
			//得到该positiion位置的一个personinfo对象
			PersonInfo personInfo = personInfos.get(position);
			//绑定每个条目控件的信息
			name.setText(personInfo.getName());
			phone.setText(personInfo.getPhone());
			address.setText(personInfo.getAddress());
			money.setText("$:"+personInfo.getMoney());
			return view;
		}
		
	}
}

PersonDBOpenHelper.java

package com.demo.introductiontothedb;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;


/**
 * 1 .写一个类 继承 SQLiteOpenHelper 帮助创建数据库 版本的控制
 * @author Administrator
 *
 */
public class PersonDBOpenHelper extends SQLiteOpenHelper {

	
	/**
	 * 数据库创建帮助类的构造方法 
	 * @param context
	 */
	public PersonDBOpenHelper(Context context) {
		//name 数据库文件的名称
		//factory 访问数据库一个数据库的游标工厂
		// version 数据库的版本
		super(context, "person.db", null, 2);
	}
	/**
	 * 当数据库第一次被创建的是 调用的方法.
	 * 适合做数据库表结构的初始化
	 * 注意：数据库被创建后，onCreate不会再被调用
	 * 如果想更改数据库，比如更改表结构，更新版本等
	 * 使用下面的onUpgrade()方法,这里要想添加money列，
	 * 还必须先改数据库版本，onUpgrade()才会执行
	 */
	@Override
	public void onCreate(SQLiteDatabase db) {
		db.execSQL("create table personInfo (id integer primary key autoincrement, name varchar(20), phone varchar(20),address varchar(50)) ");
	}

	
	
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		db.execSQL("alter table personInfo add money varchar(20)");
		Log.i("TiShi", "数据库被更改啦");
	}

}

PersonDao.java

package com.demo.introductiontothedb.dao;

import java.util.ArrayList;
import java.util.List;

import com.demo.introductiontothedb.PersonDBOpenHelper;
import com.demo.introductiontothedb.domain.PersonInfo;

import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.text.TextUtils;


public class PersonDao {
	//增删改查
	//javaweb 1.加载jdbc驱动.连接 2.准备sql 3.查询

	private PersonDBOpenHelper helper;

	//任何人使用 dao 都要传递一个上下文
	public PersonDao(Context context) {
		helper = new PersonDBOpenHelper(context);
	}
	/**
	 * 添加一条记录
	 */
	public boolean add(String name,String phone,String address){
		SQLiteDatabase db = helper.getWritableDatabase();
		//	db.execSQL("insert into personInfo (name,phone,address) values (?,?,?)",
		//		new Object[]{name,phone,address});
		ContentValues values = new ContentValues();	//map集合
		values.put("name", name);
		values.put("phone", phone);
		values.put("address", address);
		long result = db.insert("personInfo", null, values);
		db.close();
		if(result != -1){
			return true;
		}else{
			return false;
		}


	}



	/**
	 * 根据名字查找一条记录
	 */
	public int find(String name){
		int id = -1;
		SQLiteDatabase db = helper.getReadableDatabase();
		//		Cursor cursor = db.rawQuery("select id from personInfo where name=?", 
		//				new String[]{name});
		Cursor cursor = db.query("personInfo", new String[]{"id"}, "name=?", new String[]{name}, null, null, null);
		if(cursor.moveToFirst()){
			id = cursor.getInt(0);
		}
		cursor.close();
		db.close();
		return id;
	}

	/**
	 * 删除一条记录
	 */
	public boolean delete(int id){
		SQLiteDatabase db = helper.getWritableDatabase();
		//db.execSQL("delete from personInfo where id=?", new Object[]{id});
		int result = db.delete("personInfo", "id=?", new String[]{id + ""});
		db.close();
		if(result > 0){
			return true;
		}else{
			return false;
		}
	}

	/**
	 * 更改一条记录
	 */
	public boolean update(String name,String phone,int id){
		SQLiteDatabase db = helper.getWritableDatabase();
//		db.execSQL("update personInfo set name=?,phone=? where id=?",
//				new Object[]{name,phone,id});
		//String table, ContentValues values, String whereClause, String[] whereArgs)
		ContentValues values = new ContentValues();
		values.put("name", name);
		values.put("phone", phone);
		int result = db.update("personInfo", values, "id=?", new String[]{id + ""});
		db.close();
		if(result > 0){
			return true;
		}else{
			return false;
		}
		
	}

	//查找全部
	public List<PersonInfo> findAll(){
		int money = 0;
		List<PersonInfo> personInfos = new ArrayList<PersonInfo>();
		SQLiteDatabase db = helper.getWritableDatabase();
		Cursor cursor = db.query("personInfo", new String[]{"id","name","phone","address","money"}, 
				null, null, null, null, null);
		while(cursor.moveToNext()){
			int id = cursor.getInt(cursor.getColumnIndex("id"));
			String name = cursor.getString(cursor.getColumnIndex("name"));
			String phone = cursor.getString(cursor.getColumnIndex("phone"));
			String address = cursor.getString(cursor.getColumnIndex("address"));
			String moneyStr = cursor.getString(cursor.getColumnIndex("money"));
			if(TextUtils.isEmpty(moneyStr)){
				money = 0;
			}else{
				money = Integer.parseInt(moneyStr);
			}
			PersonInfo personInfo = new PersonInfo(id, name, phone, address, money);
			personInfos.add(personInfo);
		}
		cursor.close();
		db.close();
		return personInfos;
	}

}

PersonInfo.java

package com.demo.introductiontothedb.domain;

public class PersonInfo {
	private int id;
	private String name;
	private String phone;
	private String address;
	private int money;
	
	
	public PersonInfo(int id, String name, String phone, String address,
			int money) {
		this.id = id;
		this.name = name;
		this.phone = phone;
		this.address = address;
		this.money = money;
	}
	
	@Override
	public String toString() {
		return "id=" + id + ", name=" + name + ", phone=" + phone
				+ ", address=" + address + ", money=" + money ;
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPhone() {
		return phone;
	}
	public void setPhone(String phone) {
		this.phone = phone;
	}
	public String getAddress() {
		return address;
	}
	public void setAddress(String address) {
		this.address = address;
	}
	public int getMoney() {
		return money;
	}
	public void setMoney(int money) {
		this.money = money;
	}
	
	
}

TestPerson.java

package com.demo.introductiontothedb.test;

import com.demo.introductiontothedb.dao.PersonDao;
import android.test.AndroidTestCase;

public class TestPerson extends AndroidTestCase {
	private PersonDao dao;
	@Override
	protected void setUp() throws Exception {
		dao = new PersonDao(getContext());
		super.setUp();
	}
	
	public void testAdd(){
		for(int i=1; i<=100; i++){
			dao.add("美女"+i,"7777"+i, "中国北京"+i);
		}
		
	}
	
	public void testDelete(){
		int id = dao.find("yangmi");
		//dao.delete(id);
		assertEquals(true, dao.delete(id));
	}

	public void testUpdate(){
		//dao.update("景甜", "888888", 10);
		assertEquals(true, dao.update("景甜", "888888", 10));
	}
	
	public void testFind(){
		//dao.find("麻生希");
		assertEquals(8, dao.find("麻生希"));
	}
	
}

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/ll_root"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="horizontal" >

        <TextView
            android:layout_width="0dip"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:text="姓名"
            android:textColor="#828282"
            android:textSize="18sp" />

        <TextView
            android:layout_width="0dip"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:text="电话"
            android:textColor="#CD8500"
            android:textSize="18sp" />

        <TextView
            android:layout_width="0dip"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:text="住址"
            android:textColor="#698B22"
            android:textSize="18sp" />

        <TextView
            android:layout_width="0dip"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center_horizontal"
            android:text="财产"
            android:textColor="#ff0000"
            android:textSize="18sp" />
    </LinearLayout>

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

</LinearLayout>

list_view.xml

<?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/name"
        android:text="姓名"
        android:layout_width="0dip"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="18sp"
        android:textColor="#828282"
        android:gravity="center_horizontal"
        />
    <TextView 
        android:id="@+id/phone"
        android:text="电话"
        android:layout_width="0dip"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="18sp"
        android:textColor="#CD8500"
        android:gravity="center_horizontal"
        />
    <TextView 
        android:id="@+id/address"
        android:text="住址"
        android:layout_width="0dip"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="18sp"
        android:textColor="#698B22"
        android:gravity="center_horizontal"
        />
    <TextView 
        android:id="@+id/money"
        android:text="财产"
        android:layout_width="0dip"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="18sp"
        android:textColor="#ff0000"
        android:gravity="center_horizontal"
        />

</LinearLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.demo.introductiontothedb"
    android:versionCode="1"
    android:versionName="1.0" >

    <instrumentation
        android:name="android.test.InstrumentationTestRunner"
        android:label="Tests for My App"
        android:targetPackage="com.demo.introductiontothedb" />

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >

        <!-- 在application节点下添加 使用的测试library -->
        <uses-library android:name="android.test.runner" />

        <activity
            android:name="com.demo.introductiontothedb.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

效果图：