最常用的組件ListView

最常用的組件之一ListView

1. 最簡單的使用方法–只顯示文本數據

在Strings.xml中添加一組String-array 列表

  <string-array name="items"> //定義數據列表名爲items
    <item >第一條數據</item>
    <item >我是第二條 </item>
    <item >我叫黃幹</item>
    <item >ListView列表</item>              
</string-array>

Layout頁面插入一個ListView

<ListView
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:id="@+id/list_view" 
  android:entries="@array/items"  /> //引用名爲items的數據列表

效果圖

2. 設置ListView的點擊事件

給ListView設置setOnItemClickListener

  listView = (ListView)findViewById(R.id.listView1);
   listView.setOnItemClickListener(new OnItemClickListener() {
    public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,long arg3) {

        //上面的arg2參數比較常用，用來獲取點擊的是哪一個Item,0是第一個
       Toast.makeText(getApplicationContext(), "點擊了第"+arg2+"條", Toast.LENGTH_SHORT).show();

        }
      }
    });

效果圖

重點：ListView ,適配器 和java Bean 結

使用ArrayAdapter,共三個Class類Animals.java, AnimalAdapter.java, MainActivity.java

• 模型層 Animals.java

  public class Animals {
  private String name;
  private int imageId;
  
  public Animals(String name, int imageId) {
  this.name = name;
  this.imageId = imageId;
  }
  public String getName() {
  return name;
  }
  public int getImageId() {
  return imageId;
  }   }
  

• 適配器類AnimalAdapter.java

  public class AnimalAdapter extends ArrayAdapter<Animals> {
    private int resourceId;
   public AnimalAdapter(Context context, int resource,List<Animals> objects) {
   super(context, resource,objects);
   resourceId = resource;
   }
   //ArrayAdapter需要重寫的方法
   public View getView(int position,View convertView,ViewGroup parent){
   //給模型層提供ListView的位置
   Animals animals = getItem(position);
   //************
   //☆☆ListView的優化
   View view; 
   if(convertView == null){
   //設置視圖接口
   view = LayoutInflater.from(getContext()).inflate(resourceId, null);        
   }else{ view = convertView;}
   ImageView animalImage = (ImageView) view.findViewById(R.id.animals_image);
   TextView animalName = (TextView) view.findViewById(R.id.aniamls_name);
  animalImage.setImageResource(animals.getImageId());
  animalName.setText(animals.getName());
  //************
  //☆☆☆設置列表內的點擊事件
  animalImage.setOnClickListener(new OnClickListener() {  
  public void onClick(View v) {
      Toast.makeText(getContext(), "阿里符合貸款來開發的", Toast.LENGTH_SHORT).show();
  }
  });
  return view;    
  }
  }
  

• MainActivity.java

  public class MainActivity extends Activity {
  private List<Animals> animalList = new ArrayList<Animals>();
  
  protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  initAnimals();
  AnimalAdapter adapter = new AnimalAdapter(MainActivity.this, R.layout.animals_item,animalList);
  ListView listview = (ListView)findViewById(R.id.list_view);
  listview.setAdapter(adapter);
  listview.setOnItemClickListener(new OnItemClickListener() {
      @Override
      public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
              long arg3) {
          //☆ 獲取點擊的位置，並從位置獲取其數據        
          Animals animals = animalList.get(arg2);
          Toast.makeText(MainActivity.this, animals.getName(),
          Toast.LENGTH_SHORT).show();
      }
  });         
  }  
  //給數據層提供數據
  private void initAnimals() {
  Animals Tiger = new Animals("Tiger", R.drawable.ddd);
  animalList.add(Tiger);
  Animals Lion = new Animals("Lion", R.drawable.fff);
  animalList.add(Lion);
  Animals Dog = new Animals("Dog", R.drawable.ggg);
  animalList.add(Dog);
  }   }
  

示例：點擊列表條

點擊單條列表左側的圖片