ListView

列表视图以垂直列表的方式列出需要显示的列表项。

android:dividerHeight="30dp"  间隔高度
android:divider="@color/colorPrimary"  间距背景色
android:fadingEdge="vertical"  设置上下方阴影,none为无
android:scrollbars="horizontal"  值为horizontallvertical时显示滚动条
android:drawSelectorOnTop="false"  点击某条记录,颜色成为背景色
android:fastScrollEnabled="true"  快速滚动效果
android:listSelector="@color/colorPrimary"  选中时的颜色
android:entries="@array/city"  设置列表填充的内容

基础的使用

<ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginStart="0dp"
        android:layout_marginTop="0dp"
        android:id="@+id/listview"
        android:dividerHeight="30dp"
        android:divider="@color/colorBlue"
        android:fadingEdge="vertical"
        android:fastScrollEnabled="true"
        android:listSelector="@color/colorPurple"
        android:entries="@array/name"/>

//arrays.xml
<?xml version="1.0" encoding="utf-8"?>
<resources>
    <array name="name">
        <item>贝贝</item>
        <item>晶晶</item>
        <item>欢欢</item>
        <item>迎迎</item>
        <item>妮妮</item>
    </array>
</resources>
public class MainActivity_Listview extends AppCompatActivity {

    private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main__listview);
        listView = (ListView)findViewById(R.id.listview);
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                TextView tv=(TextView)view;
                Toast.makeText(MainActivity_Listview.this,tv.getText(),Toast.LENGTH_SHORT).show();
            }
        });
    }
}

ListActivity类的使用:

//不需要设置布局
public class MainActivity_listact extends ListActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ArrayAdapter arrayAdapter = ArrayAdapter.createFromResource(
                this,R.array.name,android.R.layout.simple_list_item_1);
        setListAdapter(arrayAdapter);
    }

    @Override
    protected void onListItemClick(ListView l, View v,int position,long id){
        Toast.makeText(this,((TextView)v).getText(),Toast.LENGTH_SHORT).show();
    }
}

单选和多选的使用

public class MainActivity_lvch extends AppCompatActivity {

    private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_lvch);
        listView = (ListView)findViewById(R.id.listview);

        String[] arr = getResources().getStringArray(R.array.name);

        //单选模式
        ArrayAdapter<String> aa1 = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_single_choice,arr);
        listView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);

        //多选模式
        //ArrayAdapter<String> aa2 = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_multiple_choice,arr);
        //listView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

        listView.setAdapter(aa1);
    }
}

ListView实现图文列表

//list_item_sa.xml,作为每一项的布局使用,两个方式都需要
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical"
    android:padding="16dp">

    <ImageView
        android:id="@+id/imageView_icon"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:srcCompat="@android:drawable/btn_star_big_on" />

    <TextView
        android:id="@+id/textView_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="TextView"
        android:layout_marginLeft="10dp"/>
</LinearLayout>

1)SimpleAdapter的使用

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ListView;
import android.widget.SimpleAdapter;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public class MainActivity_sa extends AppCompatActivity {

    private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_sa);
        listView = (ListView)findViewById(R.id.listview);

        //准备数据,每一个HashMap是一条记录
        HashMap<String,Object> title1 = new HashMap<>();
        title1.put("title","title-1");
        title1.put("icon",android.R.drawable.star_big_off);
        HashMap<String,Object> title2 = new HashMap<>();
        title2.put("title","title-2");
        title2.put("icon",android.R.drawable.star_on);
        HashMap<String,Object> title3 = new HashMap<>();
        title3.put("title","title-3");
        title3.put("icon",android.R.drawable.star_big_on);

        ArrayList<Map<String,Object>> list = new ArrayList<>();
        list.add(title1);
        list.add(title2);
        list.add(title3);

        //把数据填充到Adapter
        SimpleAdapter sa = new SimpleAdapter(
                this,list,R.layout.list_item_sa,new String[]{"title","icon"},new int[]{R.id.textView_title,R.id.imageView_icon});
        listView.setAdapter(sa);
    }
}

2)自定义Adapter

import android.content.Context;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity_uda extends AppCompatActivity {

    private ListView listView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_uda);
        listView = (ListView)findViewById(R.id.listview);
        listView.setAdapter(new MyAdapter(this));
    }

    static class MyAdapter extends BaseAdapter{
        private String[] titles = {"title-1","title-2","title-3","title-4","title-5"};
        private int[] icons = {android.R.drawable.btn_star,android.R.drawable.star_big_on,
                android.R.drawable.btn_star_big_on,android.R.drawable.star_off,android.R.drawable.star_on};

        private Context context;
        public MyAdapter(Context context){
            this.context = context;
        }
        @Override
        public int getCount() {
            return titles.length;
        }

        @Override
        public Object getItem(int position) {
            return titles[position];
        }

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {

            LayoutInflater inflater = LayoutInflater.from(context);
            View view = inflater.inflate(R.layout.list_item_uda,null);

            TextView tv_title = (TextView) view.findViewById(R.id.textView_title);
            ImageView iv_icon = (ImageView) view.findViewById(R.id.imageView_icon);

            tv_title.setText(titles[position]);
            iv_icon.setImageResource(icons[position]);

            return view;
        }
    }
}

优化:

1.使用convertView减少对象组件

if(convertView==null) {
                LayoutInflater inflater = LayoutInflater.from(context);
                //实例化一个布局文件
                convertView = inflater.inflate(R.layout.list_item_uda,null);
            }
            System.out.println(position+"----"+convertView);
            TextView tv_title = (TextView) convertView.findViewById(R.id.textView_title);
            ImageView iv_icon = (ImageView) convertView.findViewById(R.id.imageView_icon);

            tv_title.setText(titles[position]);
            iv_icon.setImageResource(icons[position]);

            return convertView;

2.View Holder优化

static class MyAdapter extends BaseAdapter{
        private String[] titles = {"title-1","title-2","title-3","title-4","title-5",
                "title-6","title-7","title-8","title-9","title-10",
                "title-11","title-12","title-13"};
        private int[] icons = {android.R.drawable.btn_star,android.R.drawable.star_big_on,
                android.R.drawable.btn_star_big_on,android.R.drawable.star_off,
                android.R.drawable.star_on,android.R.drawable.btn_star,
                android.R.drawable.star_big_on, android.R.drawable.btn_star_big_on,
                android.R.drawable.star_off, android.R.drawable.star_on,
                android.R.drawable.btn_star,android.R.drawable.star_big_on,
                android.R.drawable.btn_star_big_on};

        private Context context;
        public MyAdapter(Context context){
            this.context = context;
        }
        @Override
        public int getCount() {
            return titles.length;
        }

        @Override
        public Object getItem(int position) {
            return titles[position];
        }

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder vh;
            if(convertView==null) {
                LayoutInflater inflater = LayoutInflater.from(context);
                //实例化一个布局文件
                convertView = inflater.inflate(R.layout.list_item_uda,null);
                vh = new ViewHolder();
                vh.iv_icon = (ImageView)convertView.findViewById(R.id.imageView_icon);
                TextView tv_title = (TextView)convertView.findViewById(R.id.textView_title);
                convertView.setTag(vh);
            }else {
                vh = (ViewHolder) convertView.getTag();
            }
            
            vh.tv_title.setText(titles[position]);
            vh.iv_icon.setImageResource(icons[position]);

            return convertView;
        }

        //用于保存第一次查找的组件,避免下次重复查找
        static class ViewHolder{
            ImageView iv_icon;
            TextView tv_title;
        }

listView刷新分页

1.当前 Activity implements OnScrollListener

2.实现接口的方法

3.listView注册滚动监听

4.Adapter中添加增加数据的函数

5.获得2页以后的数据后,adapter增加数据,并刷新notifyDateSetChanged();

<!--activity_main_fy.xml-->
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity_fy">

    <ListView
        android:id="@+id/listview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true"/>
</RelativeLayout>

<!--list_item.fy.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="wrap_content"
    android:gravity="center_vertical"
    android:padding="16px">

    <TextView
        android:id="@+id/textView_title"
        android:layout_width="64dp"
        android:layout_height="60dp"
        android:layout_marginLeft="10dp"
        android:text="title" />

    <TextView
        android:id="@+id/textView_content"
        android:layout_width="100dp"
        android:layout_height="60dp"
        android:layout_marginLeft="10dp"
        android:text="content" />
</LinearLayout>

<!--loading.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="wrap_content"
    android:orientation="horizontal"
    android:gravity="center">

    <ProgressBar
        android:id="@+id/progressBar"
        style="?android:attr/progressBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="正在玩命加载数据..." />
</LinearLayout>

//MainActivity_fy.java
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;

import java.util.Vector;

public class MainActivity_fy extends AppCompatActivity implements AbsListView.OnScrollListener {
    private ListView listView;
    private Vector<News> news = new Vector<>();
    private MyAdapter myAdapter;
    private static final int DATA_UPDATE = 0x1;//数据更新完成后的标记

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_fy);
        listView = (ListView) findViewById(R.id.listview);
        listView.setOnScrollListener(this);
        View footerView = getLayoutInflater().inflate(R.layout.loading,null);
        listView.addFooterView(footerView);
        initDate();
        myAdapter = new MyAdapter();
        listView.setAdapter(myAdapter);
    }

    private int index = 1;
    /***
     * 初始化数据
     */
    private void initDate(){
        for (int i=0;i<10;i++){
            News n = new News();
            n.title = "title--"+index;
            n.content = "content--"+index;
            index++;
            news.add(n);
        }
    }

    private int visibleLeastIndex;//用来可显示的最后一条数据d的索引
    //状态改变,三个状态,fling,idl,touch_scroll
    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        if(myAdapter.getCount() == visibleLeastIndex && scrollState == AbsListView.OnScrollListener.SCROLL_STATE_IDLE){
            new LoadDataThread().start();
        }
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        visibleLeastIndex = firstVisibleItem+visibleItemCount-1;
    }

    //线程之间通讯的机制
    private Handler handler = new Handler() {
        //处理消息
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {
                case DATA_UPDATE:
                    myAdapter.notifyDataSetChanged();
                    break;
            }
        }
    };

    //模拟加载数据的线程
    class LoadDataThread extends Thread{
        @Override
        public void run(){
            initDate();
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
//            myAdapter.notifyDataSetChanged();
            //通过handler给主线程发送一个消息标记
            handler.sendEmptyMessage(DATA_UPDATE);
        }
    }

    class MyAdapter extends BaseAdapter{

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

        @Override
        public Object getItem(int position) {
            return news.get(position);
        }

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

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ViewHolder vh;
            if(convertView==null){
                convertView = getLayoutInflater().inflate(R.layout.list_item_fy,null);
                vh = new ViewHolder();
                vh.tv_title = (TextView) convertView.findViewById(R.id.textView_title);
                vh.tv_content = (TextView) convertView.findViewById(R.id.textView_content);
                convertView.setTag(vh);
            }else {
                vh = (ViewHolder)convertView.getTag();
            }
            News n = news.get(position);
            vh.tv_title.setText(n.title);
            vh.tv_content.setText(n.content);
            return convertView;
        }

        class ViewHolder{
            TextView tv_title;
            TextView tv_content;
        }
    }
}

//news.java
public class News {
    String title;
    String content;
}


 

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