intent.resolveActivity != null but launching the i

问题:

I post this question here for educational purposes, since I couldn't find answers anywhere and eventually found the root cause the old way, i.e. by myself.

Here's the problematic code :

// initially getting the intent from polling the PackageManager about activities resolving Search intent.

ComponentName componentName = intent.resolveActivity(pm);

if (componentName != null) {
    context.startActivity(intent);
}

despite the check i get an ActivityNotFound exception.

EDIT: apparently the point wasn't obvious to everyone so : how come there's an activity resolving the intent, yet trying to launch it throws an ActivityNotFound exception - two facts apparently contradictory ?

回答1:

From what i could see, intent.resolveActivity() will return true if there is ANY activity resolving this intent. Even if this activity is not exported (which makes it unusable for all practical purposes in case it's not from your package). Android's API doesn't care to mention that, so you have to figure it out by yourself, and make sure that the activity you're trying to launch is indeed exported.

ActivityInfo activityInfo = intent.resolveActivityInfo(pm, intent.getFlags());
if (activityInfo.exported) {
    doSomething();
}

EDIT: the point of this question is that ResolveActivity will return a componentName even if activityInfo.exported==false AND it's not from your own package - which makes it unlaunchable, and surprised me cause the intent was resolved and yet unlaunchable.

回答2:

ActivityNotFound exception is thrown when a call to startActivity(Intent) or one of its variants fails because an Activity can not be found to execute the given Intent. For example, if you’re trying to send an email, but there is no app on your device that could process ACTION_SEND intent action, ActivityNotFound will be thrown.

A way to avoid the exception is to do the following:

final ComponentName componentName = intent.resolveActivity(pm);
if (componentName != null) {
  try {
    context.startActivity(intent);    
  } catch (ActivityNotFoundException ex) {
    // Notify the user?
  }
}