自定义ListView

我们在进行Android方面的开发时，追求的是个性化，自由化，所以一些控件都有自定义类型，ListView的三要素是listview控件本身，数据，适配器，下面展示ListView的使用方法还有在使用的时候出现的一些问题（本案例中使用的是web方式存储数据）：

首先在你需要使用ListView的xml页面加入该控件：

  <ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/mlistView"
    android:layout_gravity="center_horizontal" />

第二，我们需要做数据，本案例使用web存储数据，所以接下来展示web方向的代码（因为web只是获取数据，所以不过多注解）：

1.链接数据库的类在这里省略（DbUtils）

2添加Java bean 对象

public class Hospital {

private int id,age;

private String name,birthplace;

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public int getAge() {

return age;

}

public void setAge(int age) {

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getBirthplace() {

return birthplace;

}

public void setBirthplace(String birthplace) {

this.birthplace = birthplace;

}

3.接下来在做一些逻辑层代码

package com.scme.dao;

import java.sql.Connection;

import java.sql.PreparedStatement;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.util.ArrayList;

import java.util.List;

import com.scme.pojo.Hospital;

import com.scme.utils.DbUtils;

public class HostpitalDao {

private static Connection conn;

private static PreparedStatement ps;

private static ResultSet rs;

private static List<Hospital> cList;

public List<Hospital> queryAll(){

cList = new ArrayList<Hospital>();

try {

conn = DbUtils.getConnection();

String sql = "select * from demo";

ps = conn.prepareStatement(sql);

rs = ps.executeQuery();

while(rs.next()){

Hospital n = new Hospital();

n.setId(rs.getInt(1));

n.setName(rs.getString(2));

n.setBirthplace(rs.getString(3));

n.setAge(rs.getInt(4));

cList.add(n);

}

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

} catch (SQLException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return cList;

}

4.最后在servlet 操作

public void doPost(HttpServletRequest request, HttpServletResponse response)

throws ServletException, IOException {

request.setCharacterEncoding("utf-8");

response.setCharacterEncoding("utf-8");

response.setContentType("text/html");

PrintWriter out = response.getWriter();

HostpitalDao dao = new HostpitalDao();

List<Hospital> mlist = dao.queryAll();

Gson gson = new Gson();

String str = gson.toJson(mlist);

System.out.println(str);

out.write(str);

out.flush();

out.close();

}

在添加数据后，需要在Android端获取数据

package com.example.haichao.listviewdemo;

import android.app.Activity;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.widget.ListView;

import android.widget.Toast;

import org.json.JSONArray;

import org.json.JSONException;

import org.json.JSONObject;

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.net.HttpURLConnection;

import java.net.URL;

import java.util.ArrayList;

import java.util.List;

/**

* Created by Administrator on 2017/3/31.

*/

public class ShowHostpital extends Activity {

private ListView listView ;

@Override

protected
void onCreate(Bundle
savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main_doctor);

//绑定控件

listView = (ListView) findViewById(R.id.mlistView);

//从web端接受数据。

getURLJsonData();

}

//使用Handler做异步任务

Handler mHandler
= new Handler(){

public void handleMessage(Message msg) {

if(msg.what == 99) {

String jsonStr = String.valueOf(msg.obj);

List <Hostptial>
list = new ArrayList<Hostptial>();

try {

JSONArray array = new JSONArray(jsonStr);

for(int i=0; i<array.length(); i++) {

JSONObject json =
new JSONObject(array.getJSONObject(i).toString());

//在获取数据后添加到实体类中

Hostptial info = new Hostptial();

info.setId(Integer.parseInt(json.getString("id")));

info.setName(json.getString("name"));

info.setBirthplace(json.getString("birthplace"));

info.setAge(Integer.parseInt(json.getString("age")));

list.add(info);

}

//
Toast.makeText(ShowHostpital.this, "共有" + list.size() + "行", Toast.LENGTH_SHORT).show();

listView.setAdapter(new
Adptor( ShowHostpital.this,list));

} catch (JSONException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

};

/**

* 使用URL方式从web端取json数据

private void getURLJsonData() {

new Thread(new Runnable() {

@Override

public void run() {

// TODO Auto-generated method stub

try {

URL url = new URL("http://192.168.155.7:8080/DoctorApp/HospitalServlet");

HttpURLConnection
conn = (HttpURLConnection) url.openConnection();

if(conn.getResponseCode()
== 200) {

BufferedReader br
= new BufferedReader(new InputStreamReader(conn.getInputStream()));

String
responseText = br.readLine();

Message msg = new Message();

msg.what = 99;

msg.obj = responseText;

mHandler.sendMessage(msg);

}

} catch (IOException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}).start();

}

还需要在你的另一个xml页面设置其中的子布局，使用布局可以按照所需要的布局进行罗列，这个布局在listview显示的只是其中的一行。（为了方便每一行的图片定义死了）

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

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="horizontal"

<ImageView

android:id="@+id/mpic"

android:layout_width="wrap_content"