在ListActivity中显示图标

在ListActivity中显示图标，好像并不复杂，实现起来却不轻松。

首先，定义列表中的每一行，这里不是用xml文件定义，而是用一个类定义，CheckBox、ImageView、TextView等控件以addView的方法添加。

//apk列表的一行

class item_apk extends LinearLayout{

	

	public CheckBox chk_apk;

	public TextView txt_name;  

	public TextView txt_flag;

	public ImageView img_apk; 

	 

	public item_apk(Context ctx, String item_name, String item_flag, Drawable item_draw)

	{

		 

		super(ctx);

		this.setOrientation(HORIZONTAL);

		

		chk_apk = new CheckBox(ctx);

		addView(chk_apk,

				new LinearLayout.LayoutParams((int)(MainActivity.wid_scr*0.2),60));		

		 

		img_apk = new ImageView(ctx);

		img_apk.setImageDrawable(item_draw);

		addView(img_apk,

				new LinearLayout.LayoutParams((int)(MainActivity.wid_scr*0.2),60));

		 

		txt_name = new TextView(ctx);

		txt_name.setText(item_name);

		addView(txt_name,

				new LinearLayout.LayoutParams((int)(MainActivity.wid_scr*0.4),60));

		 

		txt_flag = new TextView(ctx);

		txt_flag.setText(item_flag);

		addView(txt_flag,

				new LinearLayout.LayoutParams((int)(MainActivity.wid_scr*0.2),60));

		 

	 }



}

然后，是定义适配器，继承自BaseAdapter。

// apk列表

class list_apk extends BaseAdapter{

	

	 private Context ctx;

            private List<item_apk> list_data;

	

	public list_apk(Context context){

		

		ctx = context;

		list_data = new ArrayList<item_apk>();

		

	}



	@Override

	public int getCount() {

		// TODO Auto-generated method stub

		return list_data.size();

	}



	@Override

	public Object getItem(int arg0) {

		// TODO Auto-generated method stub

		return list_data.get(arg0);

	}



	@Override

	public long getItemId(int arg0) {

		// TODO Auto-generated method stub

		return list_data.indexOf(arg0);

	}



	@Override

	public View getView(int position, View convertView, ViewGroup parent) {



        item_apk my_item; 

        

        if (convertView==null) 

        {  

        	my_item = new item_apk(ctx,

        			(String)list_data.get(position).txt_name.getText(),

        			(String)list_data.get(position).txt_flag.getText(),

            		list_data.get(position).img_apk.getDrawable());  

        }

        else 

        {  

        	my_item = (item_apk)convertView;  

        	my_item.txt_name = list_data.get(position).txt_name;  

        	my_item.txt_flag = list_data.get(position).txt_flag; 

        	my_item.img_apk = list_data.get(position).img_apk;  

        }  

        return my_item; 

	

	}

	

    public void addItem(String txt_name, String txt_flag, Drawable ico_apk)

    {  

    	list_data.add(new item_apk(ctx,txt_name,txt_flag,ico_apk));	            	

    }

    

}

最后，是Activity的类，这里的Activity类的onCreate(Bundle savedInstanceState)里面没有setContentView()方法，取而代之的是setListAdapter()方法。

public class apk extends ListActivity{

	

	@Override

	protected void onCreate(Bundle savedInstanceState) {

		

		super.onCreate(savedInstanceState);

		

        list_apk list_ada =  new list_apk(this);

        

		// 包管理器

		PackageManager pm = getPackageManager();

		//获取手机内所有应用

		List<PackageInfo> pi = pm.getInstalledPackages(0); 

		

		list_ada.addItem("应用名称",

				"是否系统应用", 

				null);	

		

		for (int i=0; i<pi.size(); i++){

			

			PackageInfo pii = (PackageInfo) pi.get(i);

			String is_sys;

			Drawable icon;

			

			if ((pii.applicationInfo.flags & pii.applicationInfo.FLAG_SYSTEM) <= 0)

				is_sys = "否";

			else

				is_sys = "是";



			if (pii.applicationInfo.loadIcon(pm)!=null)

				icon = (Drawable)pii.applicationInfo.loadIcon(pm);

			else

				icon = (Drawable) getResources().getDrawable(R.drawable.ic_launcher);



			

			list_ada.addItem(String.valueOf(pii.applicationInfo.loadLabel(pm)),

					is_sys, 

					icon);			

			

		}

        

        setListAdapter(list_ada);



	}

	

	@Override

	public boolean onCreateOptionsMenu(Menu menu) {

		// Inflate the menu; this adds items to the action bar if it is present.

		getMenuInflater().inflate(R.menu.main, menu);

		return true;

	}



}

整个Activity都是由类构成，没有用到一个xml布局文件。

运行效果如下。