Android開發——ListView的簡單使用

一、自定義一個Friend類，用于對應ListView的每一基本資料項

Friend.java

public class Friend {

    private String name; //名稱
    private int icon; //頭像
    private String description; // 描述

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

    //獲取資料的三個函式
    public String getName() {
        return name;
    }
    public int getIcon() {
        return icon;
    }
    public String getDescription() {
        return description;
    }
}

二、自定義一個布局檔案來存盤每一項資料的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="張三"
            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="我是張三"
            android:textSize="20sp"
            android:gravity="center_vertical"/>
    </LinearLayout>

</LinearLayout>

效果顯示

三、自定義一個Adapter, 繼承自BaseAdapter，并系結item_friend_layout.xml布局

FreiendAdapter.java

public class FriendAdapter extends BaseAdapter {

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

    //初始化資料，并獲取主視窗的context,獲取friend資料，之后獲取context的布局服務
    public FriendAdapter(Context context, List<Friend> data) {
        this.data = data;
        this.context = context;
        layoutInflater = LayoutInflater.from(context);
    }

    //獲取friend的數目
    @Override
    public int getCount() {
        return data.size();
    }

    //獲取第i個friend的資料
    @Override
    public Friend getItem(int i) {
        return data.get(i);
    }

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

    //設定每一項friend item的UI
    @Override
    public View getView(int position, View convertView, ViewGroup viewGroup) {
        convertView = layoutInflater.inflate(R.layout.item_friend_layout,null); //加載item布局

        //獲取item布局的子控制元件，將friend的資料設定到控制元件上
        TextView textView = (TextView) convertView.findViewById(R.id.item_tv_name);
        textView.setText((String)data.get(position).getName()); //設定名稱
        ImageView imageView = (ImageView)convertView.findViewById(R.id.item_im_icon);
        imageView.setImageResource(data.get(position).getIcon()); //設定圖片
        TextView textView1 = (TextView)convertView.findViewById(R.id.item_tv_des);
        textView1.setText((String)data.get(position).getDescription()); //設定描述

        return  convertView;
    }
}

四、在MainActivity.java設定ListView

1、在主布局里面添加ListView控制元件

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、設定ListView控制元件

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();
    }

    //設定ListView
    private void setListView(){

        //設定ListView內容
        FriendAdapter friendAdapter = new FriendAdapter(this,getData());
        listView.setAdapter(friendAdapter);

        //設定ListView點擊事件
        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();
            }
        });
    }

    //獲取串列內部的friend資料
    private List<Friend> getData(){
        List<Friend> data = new ArrayList<Friend>();
        for(int i = 0; i<10;i++){
            //根據圖片名稱獲取圖片id
            int id = getResources().getIdentifier("head_"+i%4,"drawable",getPackageName());
            data.add(new Friend("用戶"+i,id,"我是用戶"+i));
        }
        return data;
    }

}

五、效果顯示