一、PackageManager的resolveActivity
public abstract ResolveInfo resolveActivity(Intent intent, int flags);
getPackageManager().resolveActivity（）;
返回能够匹配的Intent，如果不能匹配就返回NULL，
二、PackageManager的queryIntentActivities
public abstract List<ResolveInfo> queryIntentActivities(Intent intent, int flags);
getPackageManager().queryIntentActivities(intent,PackageManager.MATCH_DEFAULT_ONLY);
返回所有成功匹配的Activity信息
三、Intent的resolveActivity
public ComponentName resolveActivity(PackageManager pm)
Intent intent = new Intent(); ComponentName componentName = intent.resolveActivity();
第一个参数代表Intent
第二个参数：设置PackageManager.MATCH_DEFAULT_ONLY
原文：http://www.cnblogs.com/liunanjava/p/5816393.html