- Swift share array between threads how to#
- Swift share array between threads code#
- Swift share array between threads download#
Open ViewController.swift and navigate to the viewDidLoad() method. With the user interface in place, we can focus on downloading an image and displaying it in the image view. Select the image view, open the Attributes Inspector on the right, and set Content Mode to Aspect Fit. Connect the imageView outlet to the image view in the View Controller scene.īefore we move on, we need to configure the image view. Select the view controller in the storyboard and open the Connections Inspector on the right. Pin the image view to the edges of the view controller's view. Open Main.storyboard, click the Library button in the top right, and add an image view to the View Controller scene.
The view controller downloads an image from a URL and displays it in its image view. Open ViewController.swift and create an outlet with name imageView of type UIImageView!, an implicitly unwrapped optional. Tell Xcode where you would like to save the project and click the Create button. Leave the checkboxes at the bottom unchecked. Name the project Images and set User Interface to Storyboard. from Xcode's File menu and choose the Single View App template from the iOS > Application section.
Swift share array between threads download#
This post focuses on the basics, that is, How does an application download an image from a URL in Swift? Let's start with a blank Xcode project. I show you the pros and cons of each solution and, most importantly, which pitfalls to avoid.
Swift share array between threads how to#
In this series, I show you how to download images using Swift.
Mse::TAsyncSharedReadWriteAccessRequester to safely share an object between threads.Most applications need to fetch data from a remote server and downloading images is a very common task applications need to perform. * This block contains a simple example demonstrating the use of Std::uniform_int_distribution udist_0_9( 0, 9) Ĭonst size_t num_digits_per_task = 10000 Ĭonst size_t num_digits = num_tasks * num_digits_per_task Std::default_random_engine rand_generator1 #include " mseasyncshared.h" #include #include #include #include #include #include #include int main() For these scenarios, you can use mse::TAsyncSharedReadWriteAccessRequester as demonstrated in the following example: So first let's consider the general scenario where the programmer wants to allow for the shared object to be modified, and for the possibility that the shared object has unprotected mutable members. (Particularly in older code.) So extra vigilance may be called for when determining whether or not an object could be modified. Sometimes those mutable members are "protected" (by a mutex or equivalent) making them "thread safe". Note that in C++, the fact that an object is declared const does not guarantee that it won't actually be modified due to the possibility of the object having "mutable" members. Scenarios in the non-read-only category are going to require an access control mechanism. The scenarios when an object is shared between threads in C++ can be divided into two categories - a "read-only" one where the object is never modified, and a "non-read-only" one. That said, when you do share objects between threads you're going to want to do it as safely as possible.
Swift share array between threads code#
Generally, when designing concurrent code we recommend favoring the " isolation + asynchronous messages" paradigm when practical. Indeed, we view the sharing of objects between threads as an often problematic but sometimes unavoidable practice.
First, this article should not be construed to be encouraging the sharing of objects between asynchronous threads.
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