安卓入门学习之ListView

在安卓的数据列表显示的时候，通常会用到ListView,所以列出下学习时候遇到的

1，用系统自定义的ListView

首先在xml文件中建立listview

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

private String[] data = { "Apple" , "Banana" , "Orange" , "Watermelon",
                 "Pear", "Grape", "Pineapple", "Strawberry", "Cherry", "Mango" };
@Override
     protected void onCreate(Bundle savedInstanceState) {
            super.onCreate( savedInstanceState);
           requestWindowFeature(Window. FEATURE_NO_TITLE);
           setContentView(R.layout. activity_main);

           ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                      MainActivity.this, android.R.layout.simple_list_item_1 , data );
           ListView listview = (ListView) findViewById(R.id.list_view );
            listview.setAdapter( adapter);
     }

<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"
    android:layout_marginLeft="10dp"
    />

建立一个类，继承适配器类

public class FruitAdapter extends ArrayAdapter<Fruit> {
private int resourceId ;
     public FruitAdapter(Context context, int resource, List<Fruit> objects) {
            super( context, resource, objects);
            // TODO Auto-generated constructor stub
            resourceId= resource;
     }

     @Override
            public View getView(int position, View convertView, ViewGroup parent) {
                 // TODO Auto-generated method stub
                 /*return super.getView(position, convertView, parent);*/
            //获取当前的fruit实例
           Fruit fruit= getItem( position);
        View view=  LayoutInflater.from(getContext()).inflate(resourceId , null);
        
         ImageView fruitImage= (ImageView) view.findViewById(R.id. fruit_image);
           TextView fruitNmae=(TextView) view.findViewById(R.id. fruit_name);
           
            fruitImage.setImageResource( fruit.getImageId());
            fruitNmae.setText( fruit.getName());
            return view;        
     }

public class MainActivity extends Activity {
      /*private String[] data = { "Apple", "Banana", "Orange", "Watermelon",
                "Pear", "Grape", "Pineapple", "Strawberry", "Cherry", "Mango" };*/
private List<Fruit> fruitList = new ArrayList<Fruit>();
      @Override
      protected void onCreate(Bundle savedInstanceState) {
            super.onCreate( savedInstanceState);
            /*requestWindowFeature(Window.FEATURE_NO_TITLE);*/
           setContentView(R.layout. activity_main );

            /*ArrayAdapter<String> adapter = new ArrayAdapter<String>(
                     MainActivity.this, android.R.layout.simple_list_item_1, data);
           ListView listview = (ListView) findViewById(R.id.list_view);
           listview.setAdapter(adapter);*/
      //初始化水果
           initFruit();
       FruitAdapter adapter= new FruitAdapter(MainActivity. this, R.layout.fruit_item , fruitList );
       ListView listView=(ListView) findViewById(R.id.list_view );
       listView.setAdapter( adapter);
      
     }

      private void initFruit() {
            // TODO Auto-generated method stub
           Fruit apple = new Fruit( "Apple", R.drawable.apple_pic );
            fruitList.add( apple);
           Fruit banana = new Fruit( "Banana", R.drawable.banana_pic );
            fruitList.add( banana);
           Fruit orange = new Fruit( "Orange", R.drawable.orange_pic );
            fruitList.add( orange);
           Fruit watermelon = new Fruit( "Watermelon", R.drawable.watermelon_pic );
            fruitList.add( watermelon);
           Fruit pear = new Fruit( "Pear", R.drawable. pear_pic);
            fruitList.add( pear);
           Fruit grape = new Fruit( "Grape", R.drawable.grape_pic );
            fruitList.add( grape);
           Fruit pineapple = new Fruit( "Pineapple", R.drawable.pineapple_pic );
            fruitList.add( pineapple);
           Fruit strawberry = new Fruit( "Strawberry", R.drawable.strawberry_pic );
            fruitList.add( strawberry);
           Fruit cherry = new Fruit( "Cherry", R.drawable.cherry_pic );
            fruitList.add( cherry);
           Fruit mango = new Fruit( "Mango", R.drawable.mango_pic );
            fruitList.add( mango);
     }

public class FruitAdapter extends ArrayAdapter<Fruit> {
private int resourceId;
	public FruitAdapter(Context context, int resource, List<Fruit> objects) {
		super(context, resource, objects);
		// TODO Auto-generated constructor stub
		resourceId=resource;
	}

	@Override
		public View getView(int position, View convertView, ViewGroup parent) {
			// TODO Auto-generated method stub
			/*return super.getView(position, convertView, parent);*/
		//获取当前的fruit实例
		Fruit fruit= getItem(position);
		/*
		 * convertView主要是将之前加载好的布局进行缓存
		 */
		View view;
		ViewHolder viewHolder; 
		if(convertView==null)	
		{
			view=  LayoutInflater.from(getContext()).inflate(resourceId, null);
             viewHolder=new ViewHolder();
             viewHolder.fruitImage=(ImageView) view.findViewById(R.id.fruit_image);
             viewHolder.fruitName=(TextView) view.findViewById(R.id.fruit_name);
 		}
		else
			{
			view =convertView;
			viewHolder=(ViewHolder) view.getTag();
			}
		
	   /* ImageView fruitImage= (ImageView) view.findViewById(R.id.fruit_image);
		TextView fruitNmae=(TextView) view.findViewById(R.id.fruit_name);
		
		fruitImage.setImageResource(fruit.getImageId());
		fruitNmae.setText(fruit.getName());*/
		viewHolder.fruitImage.setImageResource(fruit.getImageId());
		viewHolder.fruitName.setText(fruit.getName());
		return view;
		
	}
class ViewHolder{
	ImageView fruitImage;
	TextView fruitName;
}
}