Map annotation Visibility

- 



MKMapRectContainsPoint will tell you if it is visible.






visibleCount = 0;
for (MyAnnotation *annotation in mapView.annotations) {
    if (MKMapRectContainsPoint(mapView.visibleMapRect, MKMapPointForCoordinate(annotation.coordinate)))
    {
        visibleCount++;
    }
}

Comments

Post a Comment

Popular posts from this blog

iOS Architecture

-
Image
I am pretty sure that even a few experienced iOS developers would have a hard time defining the iOS SDK in one sentence. The acronym  SDK  stands for  Software Development Kit . The iOS SDK contains the tools and resources to develop native iOS applications, which means that the SDK enables developers to develop, install, run, and test applications in the simulator and on physical devices. The two driving forces powering native iOS applications are Swift (or Objective-C) and the native iOS system frameworks. In the previous articles, we explored the Swift programming language. In this article, I want to explore the frameworks that power native iOS applications. You now know what the iOS SDK is, but what makes an application qualify as a native iOS application? The simple answer is that an iOS application is an application that runs on an iOS device. That's only half the truth, though. What about web applications that run in Safari? An iOS application is...
Read more

Performance Tips for IOS Application

-
Performance Tips for IOS Application At each step in the development of your app, consider the implications of your design choices on the overall performance of your app. Power usage and memory consumption are extremely important considerations for iOS apps, and there are many other considerations as well. The following sections describe the factors you should consider throughout the development process. 1. Reduce Your App’s Power Consumption Power consumption on mobile devices is always an issue. The power management system in iOS conserves power by shutting down any hardware features that are not currently being used. You can help improve battery life by optimizing your use of the following features: The CPU Wi-Fi, Bluetooth, and baseband (EDGE, 3G) radios The Core Location framework The accelerometers The disk The goal of your optimizations should be to do the most work you can in the most efficient way possible. You should always optimize your app’...
Read more

setNeedsLayout vs layoutIfNeeded Explained

-
Let’s take a look at the difference between  setNeedsLayout  and  layoutIfNeeded . As part of the normal startup process,  UIApplication  in iOS starts the main run loop for an app, which runs on the main thread. The main run loop processes events (such as user touches) and handles updates to view-based interfaces. As events occur, such as touch, location updates, motion, and multimedia control, the run loop finds the appropriate handler for the events, calling appropriate methods, which call other methods, and so on. At some moment in time, all events will have been handled and control will return to the run loop. Let’s label this point where control is returned to the run loop as the  update cycle , since this is how Apple refers to it in some of their documentation. You could use other terminology to conceptualize it, such as a break in the action, the redraw cycle, or a free moment. While events are being processed and dispatched, and as...
Read more