自定义ListView

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2024-09-14 04:00:03 217人阅读

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"
            android:layout_height="wrap_content"
            android:background="@mipmap/hospital_img"
            />
    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_weight="3"
        >
            <TextView
                android:id="@+id/a"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"/>
            <TextView
                android:id="@+id/b"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"/>
            <TextView
                android:id="@+id/c"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_weight="1"/>
    </LinearLayout>
</LinearLayout>

接下来就是使用适配器进行绑定了：

package com.example.haichao.listviewdemo;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.TextView;

import java.util.List;

/**
* Created by haichao on 2017/4/5.
*/

public class Adptor extends BaseAdapter {
    private Context context;
    private List<Hostptial> list;
    public Adptor(Context context, List<Hostptial> mlist){
        this.context = context;
        this.list = mlist;
    }
    @Override
    public int getCount() {
        return list.size();
    }

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

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

    @Override
    public View getView(int i, View v, ViewGroup viewGroup) {
        v = LayoutInflater.from(context).inflate(R.layout.bottom_bar2,null);

        ((TextView)v.findViewById(R.id.c)).setText(String.valueOf(list.get(i).getAge()));
        ((TextView)v.findViewById(R.id.a)).setText(list.get(i).getName());
        ((TextView)v.findViewById(R.id.b)).setText(list.get(i).getBirthplace());
        return v;
    }
}