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Android Question Use global function
- Thread starter devmobile
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I guess you could create a class containing the function, then compile it to a library.
- Colin.
- Colin.
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I know but it need to Initialize library,
I need use it without declare it.
Example when i enable library MyCamera then i use MyCamera.Take
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Well in that case I don't think you can do it. As far as I know, the only ways are:
1) Create a class, compile it to a library then initialize an instance of the library to call the sub (eg: library.sub);
2) Create a class & declare a Public Sub, then initialize an instance of the class to call the sub (eg:class.sub);
3) Create a code module & declare a Public Sub, then call the sub from another module, activity or service (eg: module.sub);
4) Create an activity or service & declare a Public Sub, then call it from another module, activity or service (eg: CallSub(activity/service, "sub").
I don't think there's any way to create a globally visible sub & access it without a reference to the class, module, service or activity that it resides in. In fact, I can't think of a way of doing that in any of the languages I code in. Eg: even if you create an extension or singleton in Swift, you still have to use a reference to the class or type that it's declared in to access it.
Why do you need to access it like a built-in function?
- Colin.
1) Create a class, compile it to a library then initialize an instance of the library to call the sub (eg: library.sub);
2) Create a class & declare a Public Sub, then initialize an instance of the class to call the sub (eg:class.sub);
3) Create a code module & declare a Public Sub, then call the sub from another module, activity or service (eg: module.sub);
4) Create an activity or service & declare a Public Sub, then call it from another module, activity or service (eg: CallSub(activity/service, "sub").
I don't think there's any way to create a globally visible sub & access it without a reference to the class, module, service or activity that it resides in. In fact, I can't think of a way of doing that in any of the languages I code in. Eg: even if you create an extension or singleton in Swift, you still have to use a reference to the class or type that it's declared in to access it.
Why do you need to access it like a built-in function?
- Colin.
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I love built-in function.
I dont want to use module.sub
Actually I want to use sub directly,maybe?
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The only way to do that is to declare the sub in the same module as you are calling it from - but you would still need to use module.sub to call it from outside that module (as far as I know).
- Colin.
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Code modules can not have events. Code modules is most probably not the right place.
Service, Activity or Classes. I would like to suggest to create a class.
Add the sub to your activity if you want to use it directly. If you want to use the sub from another activity; add the code to this acivity TOO.
If you want to get rid of not using all the code multiple times: WRITE A CLASS and use this Class in all your activities or Services.
There is no way to make it a build-in method.
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I think you mean code modules can't handle events - but devmobile was talking about functions, the equivalent of which are subs in B4X. A class may or may not be the right place for this, depending on what he actually wants to do. If it's simply calling a utility function that will do some processing, then a code module is probably better. If he wants to also encapsulate data (member variables, etc...) &/or have multiple instances, then a class would be the way to go.
- Colin.
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Probably it is treated differently, but the Core library allows what @devmobile would like to do.
The author of Core lib could say this: who is he?
The author of Core lib could say this: who is he?
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Yes Yes it is good solution.Who is author of Core lib?Probably it is treated differently, but the Core library allows what @devmobile would like to do.
The author of Core lib could say this: who is he?
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I was kidding: he is Erel
My post was to ask him some suggestions about your question (but mainly to have confirmation that the Core library is handled differently).
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Maybe this was another my dream but...
Sometimes I seemed to see libraries that did not need initialization and that you could call their routines directly.
But most likely I'm wrong, because you usually have to create a class, turn it into a library (if you want) and use a variable followed by dot and the routine name
Sometimes I seemed to see libraries that did not need initialization and that you could call their routines directly.
But most likely I'm wrong, because you usually have to create a class, turn it into a library (if you want) and use a variable followed by dot and the routine name
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Yes, "Anywhere Software" is a more correct answer.
There are so many Erel working in Anywhere Software, I think
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There was a similar question some months ago but now I can't find it.
As said here, there is no direct way (that I know of) to "extend" language without a "." in the call. But there is no need to instantiate/initialize a variable if you compile a library with a code module.
For instance, you name your code module "myUtils", and add some functions to it "function1" and "function2". Then compile it into a library.
In your other project just reference the library, and can directly use
B4X:
Dim a as int=3
Dim b as int=4
myUtils.function1(a,b) '<-- no need to instantiate (nor initialize) anything before.
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Using a routine directly can also be a problem: you do not know which library contains that routine!
In the case of a code module compiled as library you do not know the name of the code module.
Have to write something like:
MyLibrary.DoSomething
lets you know (when you will read your source code after years) which library exposes DoSomething.
In the case of a code module compiled as library you do not know the name of the code module.
Have to write something like:
MyLibrary.DoSomething
lets you know (when you will read your source code after years) which library exposes DoSomething.
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If you have / need a single code moduleThat's right. The trick is to compile the library with the same name as the code module
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