个人项目实践

Using a BaseAdapter with ListVie

2017-07-03  本文已影响0人  不知鸟

item.java:

public class Item {
    private String itemName;
    private String itemDescription;
        
    public Items(String name, String description) {
    this.itemName = name;
    this.itemDescription = description;
    }
        
    public String getItemName() {
        return this.itemName;
    }
        
    public String getItemDescription() {
        return itemDescription;
    }   
}

layout_list_view_row_items.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">

    <TextView
        android:id="@+id/text_view_item_name"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/text_view_item_description"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>

CustomListAdapter.java:

public class CustomListAdapter extends BaseAdapter {
    private Context context; //context
    private ArrayList<Item> items; //data source of the list adapter
    
    //public constructor 
    public CustomListAdapter(Context context, ArrayList<Item> items) {
        this.context = context;
        this.items = items;
    }

    @Override
    public int getCount() {
        return items.size(); //returns total of items in the list
    }

    @Override
    public Object getItem(int position) {
        return items.get(position); //returns list item at the specified position
    }

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

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

    if (convertView == null) {
        convertView = LayoutInflater.from(context).inflate(R.layout.layout_list_view_row_items, parent, false);
        viewHolder = new ViewHolder(convertView);
        convertView.setTag(viewHolder);
    } else {
        viewHolder = (ViewHolder) convertView.getTag();
    }

    Item currentItem = (Item) getItem(position);
    viewHolder.itemName.setText(currentItem.getItemName());
    viewHolder.itemDescription.setText(currentItem.getItemDescription());

    return convertView;
}

private class ViewHolder {
    TextView itemName;
    TextView itemDescription;

    public ViewHolder(View view) {
        itemName = (TextView)view.findViewById(R.id.text_view_item_name);
        itemDescription = (TextView) view.findViewById(R.id.text_view_item_description);
    }

}

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        // Setup the data source
        ArrayList<Item> itemsArrayList = new ArrayList<Item>(); // calls function to get items list

        Item item = new Item("...","...");
        Item item1 = new Item("...", "......");
        itemsArrayList.add(item);
        itemsArrayList.add(item1);
        // instantiate the custom list adapter
        CustomListAdapter adapter = new CustomListAdapter(this, itemsArrayList);

        // get the ListView and attach the adapter
        ListView itemsListView  = (ListView) findViewById(R.id.list_view);
        itemsListView.setAdapter(adapter);
    }
}

出处:https://guides.codepath.com/android/Using-a-BaseAdapter-with-ListView

上一篇 下一篇

猜你喜欢

热点阅读