【Android】ListView 控件的简单使用

1. 效果预览

2. 在布局文件中放置 ListView 控件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

3. 创建 ListView 的 item 布局

<?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:layout_width="match_parent"
    android:layout_height="wrap_content">

    <ImageView
        android:id="@+id/iv_interaction"
        android:layout_alignParentStart="true"
        android:padding="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:ignore="ContentDescription" />

    <TextView
        android:id="@+id/tv_interaction"
        android:layout_toEndOf="@+id/iv_interaction"
        android:layout_centerVertical="true"
        android:textSize="20sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:ignore="RelativeOverlap" />

    <ImageView
        android:id="@+id/messages_into"
        android:layout_alignParentEnd="true"
        android:padding="10dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        tools:ignore="ContentDescription" />

</RelativeLayout>

4. 创建实体类

public class InteractionBean {

    private final int iv_interaction;
    private final String tv_interaction;
    private final int messages_into;

    public InteractionBean(int iv_interaction, String tv_interaction, int messages_into){
        this.iv_interaction = iv_interaction;
        this.tv_interaction = tv_interaction;
        this.messages_into = messages_into;
    }

    public int getIv_interaction() {
        return iv_interaction;
    }

    public String getTv_interaction() {
        return tv_interaction;
    }

    public int getMessages_into() {
        return messages_into;
    }

}

5. 创建适配器继承自 BaseAdapter

public class InteractionAdapter extends BaseAdapter {

    private final Context context;
    private final List<InteractionBean> interactions;

    public InteractionAdapter(Context context, List<InteractionBean> interactions){
        this.context = context;
        this.interactions = interactions;
    }

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

    @Override
    public Object getItem(int i) {
        return interactions.get(i);
    }

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

    @Override
    public View getView(int i, View view, ViewGroup viewGroup) {

        ViewHolder holder;

        if (view == null){
            view = LayoutInflater.from(context).inflate(R.layout.interaction_item, viewGroup, false);
            holder = new ViewHolder();
            holder.iv_interaction = view.findViewById(R.id.iv_interaction);
            holder.tv_interaction = view.findViewById(R.id.tv_interaction);
            holder.messages_into = view.findViewById(R.id.messages_into);
            view.setTag(holder);
        }else {
            holder = (ViewHolder) view.getTag();
        }

        holder.iv_interaction.setImageResource(interactions.get(i).getIv_interaction());
        holder.tv_interaction.setText(interactions.get(i).getTv_interaction());
        holder.messages_into.setImageResource(interactions.get(i).getMessages_into());

        return view;

    }

    static class ViewHolder{
        ImageView iv_interaction;
        TextView tv_interaction;
        ImageView messages_into;
    }

}

6. 为 item 设置数据，为 ListView 设置适配器

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ListView listView = findViewById(R.id.listView);
        List<InteractionBean> interactions = new ArrayList<>();
        InteractionAdapter adapter = new InteractionAdapter(MainActivity.this, interactions);

        InteractionBean at = new InteractionBean(R.drawable.messages_at, "有人@你", R.drawable.messages_into);
        InteractionBean comment = new InteractionBean(R.drawable.messages_comment, "评论提醒", R.drawable.messages_into);
        InteractionBean like = new InteractionBean(R.drawable.messages_like, "点赞提醒", R.drawable.messages_into);

        interactions.add(at);
        interactions.add(comment);
        interactions.add(like);

        listView.setAdapter(adapter);

    }
}