Android开发——ListView的简单使用

一、自定义一个Friend类，用于对应ListView的每一基本数据项

Friend.java

public class Friend {
    
    

    private String name; //名称
    private int icon; //头像
    private String description; // 描述

    //初始花化数据
    public Friend(String n, int ic, String des){
    
    
        name = n;
        icon = ic;
        description = des;
    }

    //获取数据的三个函数
    public String getName() {
    
    
        return name;
    }
    public int getIcon() {
    
    
        return icon;
    }
    public String getDescription() {
    
    
        return description;
    }
}

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二、自定义一个布局文件来存储每一项数据的UI

item_friend_layout.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="wrap_content"
    android:padding="5dp"
    >
    <ImageView
        android:id="@+id/item_im_icon"
        android:layout_width="60dp"
        android:layout_height="60dp"
        android:src="@drawable/head_1"
        android:adjustViewBounds="true"
        android:scaleType="fitXY"
        />
    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="vertical"
        android:paddingLeft="10dp">
        <TextView
            android:id="@+id/item_tv_name"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:textColor="#000"
            android:text="张三"
            android:textSize="25sp"
            android:gravity="center_vertical"
            />
        <TextView
            android:id="@+id/item_tv_des"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:text="我是张三"
            android:textSize="20sp"
            android:gravity="center_vertical"/>
    </LinearLayout>

</LinearLayout>

效果显示

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三、自定义一个Adapter, 继承自BaseAdapter，并绑定item_friend_layout.xml布局

FreiendAdapter.java

public class FriendAdapter extends BaseAdapter {
    
    

    private List<Friend> data; //friend数据
    private Context context;
    private LayoutInflater layoutInflater;

    //初始化数据，并获取主窗口的context,获取friend数据，之后获取context的布局服务
    public FriendAdapter(Context context, List<Friend> data) {
    
    
        this.data = data;
        this.context = context;
        layoutInflater = LayoutInflater.from(context);
    }

    //获取friend的数目
    @Override
    public int getCount() {
    
    
        return data.size();
    }

    //获取第i个friend的数据
    @Override
    public Friend getItem(int i) {
    
    
        return data.get(i);
    }

    //获取第i个friend的id
    @Override
    public long getItemId(int i) {
    
    
        return i;
    }

    //设置每一项friend item的UI
    @Override
    public View getView(int position, View convertView, ViewGroup viewGroup) {
    
    
        convertView = layoutInflater.inflate(R.layout.item_friend_layout,null); //加载item布局

        //获取item布局的子控件，将friend的数据设置到控件上
        TextView textView = (TextView) convertView.findViewById(R.id.item_tv_name);
        textView.setText((String)data.get(position).getName()); //设置名称
        ImageView imageView = (ImageView)convertView.findViewById(R.id.item_im_icon);
        imageView.setImageResource(data.get(position).getIcon()); //设置图片
        TextView textView1 = (TextView)convertView.findViewById(R.id.item_tv_des);
        textView1.setText((String)data.get(position).getDescription()); //设置描述

        return  convertView;
    }
}

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四、在MainActivity.java设置ListView

1、在主布局里面添加ListView控件

activity_main.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="match_parent"
    android:orientation="vertical">

    <ListView
        android:id="@+id/lv_1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

2、设置ListView控件

MainActivit.java

public class MainActivity extends AppCompatActivity {
    
    

    private ListView listView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView)findViewById(R.id.lv_1);
        setListView();
    }

    //设置ListView
    private void setListView(){
    
    

        //设置ListView内容
        FriendAdapter friendAdapter = new FriendAdapter(this,getData());
        listView.setAdapter(friendAdapter);

        //设置ListView点击事件
        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    
    
            @Override
            public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
    
    
                Toast.makeText(MainActivity.this,((FriendAdapter)listView.getAdapter()).getItem(i).getName() + ": " +
                        ""+((FriendAdapter)listView.getAdapter()).getItem(i).getDescription(), Toast.LENGTH_SHORT).show();
            }
        });
    }

    //获取列表内部的friend数据
    private List<Friend> getData(){
    
    
        List<Friend> data = new ArrayList<Friend>();
        for(int i = 0; i<10;i++){
    
    
            //根据图片名称获取图片id
            int id = getResources().getIdentifier("head_"+i%4,"drawable",getPackageName());
            data.add(new Friend("用户"+i,id,"我是用户"+i));
        }
        return data;
    }

}

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五、效果显示