通过Intent.CATEGORY_LAUNCHER筛选出包含launcher的桌面应用列表，在所有的应用列表applicationInfos中匹配，成功，则放入appInfos中。

public List<AppInfo> queryFilterAppInfo() {
        pm = context.getPackageManager();

	// 创建一个类别为CATEGORY_LAUNCHER的该包名的Intent
	Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);
	resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);
	// 通过getPackageManager()的queryIntentActivities方法遍历,得到所有能打开的app的packageName
	List<ResolveInfo>  resolveinfoList = pm.queryIntentActivities(resolveIntent, 0);

	Set<String> allowPackages=new HashSet();
	for (ResolveInfo resolveInfo:resolveinfoList){
		allowPackages.add(resolveInfo.activityInfo.packageName);
	}
	debug("allowPackages = " + allowPackages);

	// 查询所有已经安装的应用程序,GET_UNINSTALLED_PACKAGES代表已删除，但还有安装目录的
	List<ApplicationInfo> applicationInfos　= pm.getInstalledApplications(PackageManager.GET_UNINSTALLED_PACKAGES);
	List<AppInfo> appInfos = new ArrayList<AppInfo>();

	for (ApplicationInfo info : applicationInfos) {
		if (allowPackages.contains(info.packageName)){
			AppInfo appInfo = new AppInfo();

			//获取应用的名称
			String app_name = info.loadLabel(pm).toString();
			appInfo.setApp_name(app_name);

			//获取应用的包名
			String packageName = info.packageName;
			appInfo.setPackagename(packageName);

			appInfos.add(appInfo);
		}
	}
	debug("appInfos = " + appInfos);
	return appInfos;
}