ListView（优化），自定义Layout和adapter，entity，ViewHolder，ConvertView用法案例（phone）

来源：互联网发布：蓝光软件编辑：程序博客网时间：2024/05/21 15:02

自定义实体类：PhoneEntity.java

package com.example.entity;/** * Created by Administrator on 2017/2/16. */public class PhoneEntity {    private int img;    private String name,price,countNum;    public int getImg() {        return img;    }    public String getName() {        return name;    }    public String getPrice() {        return price;    }    public String getCountNum() {        return countNum;    }    public void setImg(int img) {        this.img = img;    }    public void setName(String name) {        this.name = name;    }    public void setPrice(String price) {        this.price = price;    }    public void setCountNum(String countNum) {        this.countNum = countNum;    }}

自定义布局（Layout） acvitity_phone_list.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="horizontal"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:layout_margin="5dp">    <ImageView        android:src="@drawable/ihone7plus"        android:id="@+id/img_phone"        android:layout_width="150dp"        android:layout_height="150dp"        android:layout_margin="10dp"/>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="vertical">        <TextView            android:id="@+id/phone_name"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="ihone7Plus玫瑰金"            android:textSize="20dp"            android:layout_marginTop="50sp"/>        <TextView            android:id="@+id/phone_price"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="￥7188"            android:textSize="20dp"            android:textColor="#f45959" />        <TextView            android:id="@+id/phone_counter"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="50353条评价"            android:textSize="15dp"            android:textColor="@android:color/darker_gray"/>    </LinearLayout></LinearLayout>

自定义acvitity_phone.xml(定义ListView)

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/activity_phone"    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="com.example.jump.PhoneActivity">    <ListView        android:id="@+id/lv_phone"        android:layout_width="wrap_content"        android:layout_height="wrap_content"></ListView></RelativeLayout>

自定义PhoneAcvitity

package com.example.jump;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.widget.ListView;import com.example.adapter.PhoneAdapter;import com.example.entity.PhoneEntity;import java.util.ArrayList;import java.util.List;public class PhoneActivity extends AppCompatActivity {    private ListView lv;    private int[] ids=new int[]{R.drawable.ihone7plus,R.drawable.mi5s,R.drawable.leshi2,R.drawable.rongyao8};     private String[] phonenames=new String[]{"苹果7Plus,128G玫瑰金","小米5S全网通版，32G亚光金","乐视2原力金32GB内存","荣耀8全网通4GB32G珠光白"};    private String[] phoneprice=new String[]{"￥7188","￥1899","￥1099","￥2229"};    private String[] phonecounter=new String[]{"50353条评价","20353条评价","34553条评价","65053条评价"};    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_phone);        lv= (ListView) findViewById(R.id.lv_phone);        intiCustomPhoneAdapter();    }    private void intiCustomPhoneAdapter(){        List<PhoneEntity> list =new ArrayList<PhoneEntity>();        for (int i = 0; i < phonenames.length; i++) {            PhoneEntity phone=new PhoneEntity();            phone.setImg(ids[i]);            phone.setName(phonenames[i]);            phone.setPrice(phoneprice[i]);            phone.setCountNum(phonecounter[i]);            list.add(phone);        }        PhoneAdapter phoneada=new PhoneAdapter(list,this);        lv.setAdapter(phoneada);    }}

自定义adapter（PhoneAdapter）复用convertview,减少item的数量：节省内存，运行更流畅使用ViewHolder类，减少findviewbyid的次数，好处就是运行更流畅

package com.example.adapter;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;import com.example.entity.PhoneEntity;import com.example.jump.R;import java.util.List;/** * Created by Administrator on 2017/2/16. */public class PhoneAdapter extends BaseAdapter {    private List<PhoneEntity> list;//数据源    private Context context;//上下文对象    private LayoutInflater inflater;    public PhoneAdapter(List<PhoneEntity> list, Context context) {        this.list = list;        this.context = context;        inflater=LayoutInflater.from(context);    }    //有参的构造函数，为数据源，上下文对象复制，同时实例化布局加载器    //有多少条数据，需要创建多少个item布局    @Override    public int getCount() {        return list.size();    }    //返回position对应位置的数据    @Override    public Object getItem(int position) {        return list.get(position);    }    //返回position对应位置item的id    @Override    public long getItemId(int position) {        return position;    }    /**     * 具体定义加载item布局，并将数据显示到item布局上的方法。     * @param position     * @param convertView     * @param parent     * @return     */    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder holder=null;        //加载item布局 将xml布局加载到内存中，形成一个view        if(convertView==null){ //被复用后的convertview类依然包含tag            holder=new ViewHolder();            convertView=inflater.inflate(R.layout.activity_phone_list,null);            holder.iv= (ImageView) convertView.findViewById(R.id.img_phone);            holder.tv_phonename= (TextView) convertView.findViewById(R.id.phone_name);            holder.tv_phoneprice= (TextView) convertView.findViewById(R.id.phone_price);            holder.tv_phonecounter= (TextView) convertView.findViewById(R.id.phone_counter);            convertView.setTag(holder);        }else {//convertview不为空，不为空则说明convertview包含tag           holder= (ViewHolder) convertView.getTag();        }//        View view=inflater.inflate(R.layout.activity_phone_list,null);        //实例化item布局上的控件//          ImageView iv= (ImageView) view.findViewById(R.id.img_phone);//          TextView tv_phonename= (TextView) view.findViewById(R.id.phone_name);//          TextView tv_phoneprice= (TextView) view.findViewById(R.id.phone_price);//          TextView tv_phonecounter= (TextView) view.findViewById(R.id.phone_counter);        //往控件上显示数据        //获取position对应位置的数据        PhoneEntity phonety= (PhoneEntity) getItem(position);        holder.iv.setImageResource(phonety.getImg());        holder.tv_phonename.setText(phonety.getName());        holder.tv_phoneprice.setText(phonety.getPrice());        holder.tv_phonecounter.setText(phonety.getCountNum());        return convertView;    }    class ViewHolder{        public ImageView iv;        public  TextView tv_phonename;        public  TextView tv_phoneprice;        public TextView tv_phonecounter;    }}

MainAcvitity

package com.example.jump;import android.content.Intent;import android.net.Uri;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.CheckBox;import android.widget.CompoundButton;import com.example.adapter.MyAdapter;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private Button textButton, tv_btn, btn_edit, btn_cb, btn_imgsca, work_activity, rg_btn, timedatepick_btn, arrayadapter, btn_myadapter, btn_phone;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    private void initView() {        tv_btn = (Button) findViewById(R.id.btn_test);        tv_btn.setOnClickListener(this);        btn_edit = (Button) findViewById(R.id.btn_edit);        btn_edit.setOnClickListener(this);        btn_cb = (Button) findViewById(R.id.btn_cb);        btn_cb.setOnClickListener(this);        btn_imgsca = (Button) findViewById(R.id.btn_imgsca);        btn_imgsca.setOnClickListener(this);        work_activity = (Button) findViewById(R.id.work_activity);        work_activity.setOnClickListener(this);        rg_btn = (Button) findViewById(R.id.rg_btn);        rg_btn.setOnClickListener(this);        timedatepick_btn = (Button) findViewById(R.id.datetimepick_btn);        timedatepick_btn.setOnClickListener(this);        arrayadapter = (Button) findViewById(R.id.lv_arrayadapter);        arrayadapter.setOnClickListener(this);        btn_myadapter = (Button) findViewById(R.id.btn_myadapter);        btn_myadapter.setOnClickListener(this);        btn_phone = (Button) findViewById(R.id.btn_phone);        btn_phone.setOnClickListener(this);    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.btn_edit:                startNewApplication(EditTestActivity.class);                break;            case R.id.btn_cb:                startNewApplication(CheckBoxActivity.class);            case R.id.btn_imgsca:                startNewApplication(ImageScaleActivity.class);            case R.id.work_activity:                startNewApplication(WorkActivity.class);                break;            case R.id.rg_btn:                startNewApplication(RadioGroupActivity.class);                break;            case R.id.datetimepick_btn:                startNewApplication(TimeDatePickerActivity.class);                break;            case R.id.btn_myadapter:                startNewApplication(ArrayAdapterActivity.class);                break;            case R.id.btn_phone:                startNewApplication(PhoneActivity.class);                break;        }    }    private void startNewApplication(Class<?> cls) {        Intent intent = new Intent(this, cls);        startActivity(intent);    }}

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