Android使用ListView将数据显示到手机屏幕上

下面是一个LinearLayout，里面的内容超级简单，就是一个ListView

<LinearLayout 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=".MainActivity" >

<ListView
android:id="@+id/Lv"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</ListView>

</LinearLayout>

为了使程序更有扩展性，我这里创建了一个model包，里面包含一个Person类，就是数据库的信息名称

package com.neusoft.ListView.model;

public class Person {
private String _id;
private String name;
private String salary;
private String phone;

public Person(String _id, String name, String salary, String phone) {
super();
this._id = _id;
this.name = name;
this.salary = salary;
this.phone = phone;
}

@Override
public String toString() {
return _id + "," + name + "," + salary+ "," + phone;
}

public String get_id() {
return _id;
}

public void set_id(String _id) {
this._id = _id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public String getSalary() {
return salary;
}

public void setSalary(String salary) {
this.salary = salary;
}

public String getPhone() {
return phone;
}

public void setPhone(String phone) {
this.phone = phone;
}

}

下面的这个MyOpenHelper类就是老套路了，大家都知道。他是为了创建数据库和升级数据库等等对数据库的操作的类

package com.neusoft.ListView;

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

public class MyOpenHelper extends SQLiteOpenHelper {

public MyOpenHelper(Context context) {
super(context, "people.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table person(_id integer primary key autoincrement,name char(20),salary char(20),phone char(20))");
}
@Override
public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
System.out.print("数据库升级了");

}

}

这是MainActivity,

package com.neusoft.ListView;

import java.util.ArrayList;
import java.util.List;
import java.util.zip.Inflater;

import android.os.Bundle;
import android.R.integer;
import android.app.Activity;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

import com.neusoft.ListView.model.*;

public class MainActivity extends Activity {
private ListView Lv;
List<Person> personList;//创建一个List集合，将所有数据库中每个person加入到此集合中
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//insert();

//从数据库中取出数据
personList=new ArrayList<Person>();
MyOpenHelper oh=new MyOpenHelper(this);
SQLiteDatabase db=oh.getWritableDatabase();

Cursor cursor=db.query("person",null, null, null, null, null,null);
while(cursor.moveToNext())
{
//循环取出每个person的值
String _id=cursor.getString(cursor.getColumnIndex("_id"));
String name=cursor.getString(cursor.getColumnIndex("name"));
String salary=cursor.getString(cursor.getColumnIndex("salary"));
String phone=cursor.getString(cursor.getColumnIndex("phone"));
Person p=new Person(_id, name, salary, phone);
personList.add(p);//将值加入到集合中
}
Lv=(ListView) findViewById(R.id.Lv);
//将数据显示到屏幕
Lv.setAdapter(new MyAdapter());

}
//创建一个内部类MyAdapter，适配器，就是将数据显示到屏幕的工具。
class MyAdapter extends BaseAdapter
{

@Override
public int getCount() {
return personList.size();
}

@Override
public Object getItem(int arg0) {
// TODO Auto-generated method stub
return null;
}

@Override
public long getItemId(int arg0) {
// TODO Auto-generated method stub
return 0;
}

@Override
public View getView(int arg0, View arg1, ViewGroup arg2) {
Person p=personList.get(arg0);
//第一种写法
//			View view=View.inflate(MainActivity.this,R.layout.item_activity, null);
//第二种写法
//			LayoutInflater inflater=LayoutInflater.from(MainActivity.this);
//			View view=inflater.inflate(R.layout.item_activity, null);

//第三种写法
//			LayoutInflater inflater2=(LayoutInflater) getSystemService(LAYOUT_INFLATER_SERVICE);
//			View view2=inflater2.inflate(R.layout.item_activity, null);

//ListView优化
View view=null;
if(arg1==null)//这里是ListView的优化，有了这就话话后，我们就可以把用过了的存入缓存，避免浪费资源
{
view=View.inflate(MainActivity.this, R.layout.item_activity, null);
}
else
{
view=arg1;
}
TextView tv_name=(TextView) view.findViewById(R.id.tv_name);
tv_name.setText(p.getName());
TextView tv_salary=(TextView) view.findViewById(R.id.tv_salary);
tv_salary.setText(p.getSalary());
TextView tv_phone=(TextView) view.findViewById(R.id.tv_phone);
tv_phone.setText(p.getPhone());
return view;
}

}
//刚开始插入的数据
public void insert()
{
MyOpenHelper oh=new MyOpenHelper(this);
SQLiteDatabase db=oh.getWritableDatabase();
for(int i=0;i<100;i++)
{
ContentValues values=new ContentValues();
values.put("name", "张宇翔"+i);
values.put("salary", "1500"+i);
values.put("phone","13408"+i);
db.insert("person", null, values);
}
}
}

源码