Android之自定义ListView

步骤：

一、xml 自定义listview中包含的控件

<?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">    <ImageView        android:id="@+id/fruit_image"        android:layout_width="wrap_content"        android:layout_height="wrap_content" />    <TextView        android:id="@+id/fruit_name"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_gravity="center_vertical"        android:layout_marginLeft="10dp"/></LinearLayout>

二、定义一个实体类，作为ListView适配器的适配类型

public class Fruit {    private String name;    private int imageID;    public Fruit(String name, int imageID) {        this.name = name;        this.imageID = imageID;    }    public String getName() {        return name;    }    public int getImageID() {        return imageID;    }}

三、自定义适配器，需要继承于ArrayAdapter，并将泛型指定为Fruit类，新建FruitAdapter

public class FruitAdapter extends ArrayAdapter<Fruit> {    private int resourceID;    public FruitAdapter(Context context, int textViewResourceID, List<Fruit> objects) {        super(context, textViewResourceID, objects);        resourceID = textViewResourceID;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        Fruit fruit = getItem(position); // 获取当前项的Fruit实例        // 普通创建：滚动时会每次都重新加载一遍        // View view = LayoutInflater.from(getContext()).inflate(resourceID, parent, false);        // listview优化创建        /**         * getView()方法中的的convertView参数，这个参数用于将之前的加载好的布局进行缓存，以便以后复用         */        /*        View view;        if (convertView == null){            view = LayoutInflater.from(getContext()).inflate(resourceID, parent, false);        }else {            view = convertView;        }               ImageView fruitImage = (ImageView) view.findViewById(R.id.fruit_image);        TextView fruitName = (TextView) view.findViewById(R.id.fruit_name);        fruitImage.setImageResource(fruit.getImageID());        fruitName.setText(fruit.getName());                return view;        */        // 控件优化创建        View view;        ViewHolder viewHolder;        if (convertView == null) {            view = LayoutInflater.from(getContext()).inflate(resourceID, parent, false);            viewHolder = new ViewHolder();            viewHolder.fruitImage = (ImageView) view.findViewById(R.id.fruit_image);            viewHolder.fruitName = (TextView) view.findViewById(R.id.fruit_name);            // 将ViewHodler 存储在View中            view.setTag(viewHolder);        } else {            view = convertView;            viewHolder = (ViewHolder) view.getTag();        }        viewHolder.fruitImage.setImageResource(fruit.getImageID());        viewHolder.fruitName.setText(fruit.getName());        return view;    }        class ViewHolder {        ImageView fruitImage;        TextView fruitName;    }}
       

四、在需要的页面添加

public class MainActivity extends AppCompatActivity {        // 测试数据2 定制listView    private List<Fruit> fruitList = new ArrayList<>();    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);                // 自定义ListView的界面        // 初始化水果数据        initFruits();        FruitAdapter adapterF = new FruitAdapter(MainActivity.this, R.layout.fruit_item, fruitList);        ListView listView = (ListView) findViewById(R.id.list_view);        listView.setAdapter(adapterF);    }    private void initFruits() {        for (int i = 0; i<2; i++) {            Fruit apple = new Fruit("Apple", R.drawable.apple_pic);            fruitList.add(apple);        }    }}