Thanks for clearing this up for me,
Now i understand what i did, and offcourse i did send null to context
and that will not work. now i do like this:
if (isProInstalled(this)
and then it will be PackageManager manager =
this.getPackageManager();
I have to say that your answer was very good, thanks for the time it
took you.
On 19 Maj, 21:47, "Jason Teagle" <teagle.ja...@gmail.com> wrote:
> >Well the problem is that iam trying to make somthing happen that iam
> >not really understand (iam trying to learn)
>
> >So what i wanna do is to "grabb" the "return true" or the "return
> >false" so that i could create my if statement.
>
> In that respect - using the static function call to grab the result for an if
> statement - you were using it correctly.
>
> What you must understand, though, is that in order to get through that static
> method and return an answer to you, it must execute the code within the
> method. That means that you must pass it valid data to work with (or code to
> *expect* null references as an acceptable condition), otherwise at run time
> it will do exactly what it did to you - throw an exception.
>
> An exception is the Java mechanism for alerting you to the fact that
> something bad happened at run time, and it exits out to the nearest catch
> handler it can as soon as possible - but not exactly gracefully (it may
> unwind the stack for you, but it won't return the value you intended -
> because code never gets that far). If you don’t explicitly add a try / catch
> block higher up the call chain, then your app will die.
>
> For defending against exceptions you could use a try / catch block around the
> code in your isProInstalled() method - but in your case I advise against that
> for now, as it's likely going to hide a lot of problems you will encounter
> until your understanding improves.
>
> If your method is asking for a context and trying to use it, ask yourself why
> you are not passing it any valid context. Can you get a valid context to pass
> to it?
>
> If you *want* to be able to get a quick answer without passing a valid
> context, then you need to code your method to check the context reference
> before you use it - and return an appropriate response if it is null. For
> example:
>
> protected static boolean isProInstalled(Context context) {
> if (context == null)
> return false ; // No valid context - can't tell if it's installed.
> PackageManager manager = context.getPackageManager();
> ...
>
> Since your method requires the context to be able to do its job, you need to
> try and get a valid context to pass to the method.
>
> If you are calling this code somewhere from an Activity, then the activity
> itself is a context you can pass (as ‘this’).
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