ListView详解5

五、本次要讲的是一个listview的进阶效果，主要实现的功能是，单击显示的item时，会显示出一个大图，以突出效果，即抽屉效果的ListView。效果如下所示：

其主要实现思路是：在getView的时候，动态修改布局，将选中的item添加新的View，这样就做到了点击的时候，与其他的item不同的效果。

代码如下：

public class MainActivity extends ListActivity {

	DrawListAdapter adapter;
	int[] imgs={R.drawable.image,R.drawable.packed,R.drawable.paste,R.drawable.text,R.drawable.delete};
	String[] text={"第一抽屉","第二抽屉","第三抽屉","第四抽屉","第五抽屉"};
	int currentItem=0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        adapter = new DrawListAdapter(this);
        //setListAdapter和getListView方法是ListActivity的方法，分别用于设置adapter和获得一个listview
        this.setListAdapter(adapter);
        this.getListView().setOnItemClickListener(new OnItemClickListener(){

			public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
					long arg3) {
				// TODO Auto-generated method stub
				currentItem=arg2;
				//notifyDataSetChanged()可以在修改适配器绑定的数组后，不用重新刷新Activity，通知Activity更新ListView
				adapter.notifyDataSetChanged();
			}
        });
    }

    public class DrawListAdapter extends BaseAdapter{

    	Activity activity;
    	LayoutInflater inflater;

    	public DrawListAdapter(Activity a){
    		activity=a;
    		inflater=activity.getLayoutInflater();
    	}

		public int getCount() {
			// TODO Auto-generated method stub
			return imgs.length;
		}

		public Object getItem(int arg0) {
			// TODO Auto-generated method stub
			return null;
		}

		public long getItemId(int position) {
			// TODO Auto-generated method stub
			return position;
		}

		public View getView(int position, View convertView, ViewGroup arg2) {
			// TODO Auto-generated method stub
			LinearLayout layout=new LinearLayout(activity);
			layout.setOrientation(LinearLayout.VERTICAL);
			layout.addView(addTitleView(position));
			if(currentItem==position){
				layout.addView(addCustomView(position));
			}
			return layout;
		}

		//获取选中项的内容
		private View addCustomView(int i) {
			// TODO Auto-generated method stub
			View view=new View(activity);
			ImageView iv=new ImageView(activity);
			//根据点击的position设置相应要显示的图片
			switch (i) {
			case 0:
				iv.setImageResource(R.drawable.ic_launcher);
				view=iv;
				break;
			case 1:
				iv.setImageResource(R.drawable.ic_launcher);
				view=iv;
				break;
			case 2:
				iv.setImageResource(R.drawable.ic_launcher);
				view=iv;
				break;
			case 3:
				iv.setImageResource(R.drawable.ic_launcher);
				view=iv;
				break;
			case 4:
				iv.setImageResource(R.drawable.ic_launcher);
				view=iv;
				break;
			}
			return view;
		}

		//获取list的标题内容
		private View addTitleView(int i) {
			// TODO Auto-generated method stub
			LinearLayout layout=new LinearLayout(activity);
			layout.setOrientation(LinearLayout.HORIZONTAL);
			ImageView iv=new ImageView(activity);
			iv.setImageResource(imgs[i]);
			layout.addView(iv,new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT));
			TextView tv=new TextView(activity);
			tv.setText(text[i]);
			layout.addView(tv,new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT));
			layout.setGravity(Gravity.CENTER);
			return layout;
		}

    }
}