获取PackageManager对象

PackageManager packageManager = getActivity().getPackageManager();

ResolveInfo

Intent过滤器的返回值，通常记录了 AndroidManifest.xml 中的相关标签。

获取符合隐式Intent的最优Activity

resolveActivity返回的是ResolveInfo对象。

if (packageManager.resolveActivity(/* Intent */, PackageManager.MATCH_DEFAULT_ONLY) == null) {
    // 不存在与隐式Inten对应的Activity
}

获取所有符合隐式Intent的多个Activity

Intent startupIntent = new Intent(Intent.ACTION_MAIN);
startupIntent.addCategory(Intent.CATEGORY_LAUNCHER);
List<ResolveInfo> activities = packageManager.queryIntentActivities(startupIntent, PackageManager.MATCH_DEFAULT_ONLY);

载入ResolveInfo对象的标签

mResolveInfo是与符合过滤器Intent.ACTION_MAIN的Activity相对应的，所以此处的Label通常是应用名字。

PackageManager packageManager = getActivity().getPackageManager();
String appName = mResolveInfo.loadLabel(packageManager).toString();