Notes on changes from iOS 8 to iOS 9

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Here we will introduce some changes and solutions brought about by the transition from iOS8 to iOS9 in our daily development.

Information Collection

language: zh-Hans(iOS8) ——> zh-Hans-CN(iOS9)

All process lists cannot be obtained

App Transport Security

App Transport Security is a new feature of iOS9 and OS X El Capitan. Its purpose is to improve the security of Apple operating systems and any applications running on them. ATS is an encapsulation of NSURL made by Apple. After iOS9, ATS is enabled by default, which means that network transmission needs to use HTTPS. If you want to continue to use HTTP after iOS9, there are two ways to go:

Add a Dictionary of type NSAppTransportSecurity in Info.plist, and under NSAppTransportSecurity, add NSAllowsArbitraryLoads, with Boolean set to YES.

Directly use CFNetwork to make network requests. ASIHTTPRequest is a wrapper based on CFNetwotk. If you have any needs, you can look at the source code in ASI. If you want to use HTTPS at a certain time, ASI has some problems with SSL/TSL certificate verification, and you have to wrap the certificate verification yourself. I just said that ATS is an encapsulation made by Apple for the NSURL layer, so if we use CFNetwork or lower-level network requests, we are not restricted by ATS.

Removed the discoveryd DNS resolution service

After upgrading iPhone to iOS8, WiFi sometimes has problems. Especially after upgrading Mac to OS X Yosemite, sometimes the computer cannot connect to WiFi after waking up from sleep mode, and sometimes it suddenly drops the connection. You often have to manually turn off WiFi and reconnect. This is because Apple replaced the previous mDNSResponder with discoveryd DNS in OS X Yosemite. mDNSResponder is back after iOS9 and OS X Yosemite10.4.

mDNSResponder: Apple has previously used a process to control DNS and Bonjour services.

discoveryd: A new process released by Apple after OS X Yosemite.

App Thinning

App Thinning is a feature that saves storage space on iOS devices. It allows iOS devices to download only the required resources when installing, updating, and running apps, reducing the space occupied by apps and thus saving device storage space.

App Thinning has three main mechanisms:

Slicing: After the developer uploads the App installation package to the AppStore, the Apple service will automatically cut the installation package into different application variants (App variant). When the user downloads the installation package, the system will download and install the corresponding single application variant according to the device model.

On-Demand Resources: ORD (on-demand resources) means that after the developer adds tags to the resources and uploads them, the system will dynamically download and load the required resources based on the running status of the App, and automatically delete such resources when the storage space is insufficient.

Bitcode: After turning on Bitcode compilation, developers only need to upload Intermediate Representation (middleware) instead of the final executable binary file when uploading the App. Before users download the App, the AppStore will automatically compile the middleware and generate the executable file required by the device for users to download and install.

Among them, the Bitcode mechanism can support dynamic App Slicing, and for Apple's future hardware upgrade measures, this mechanism can ensure compatibility with new devices without developers re-releasing versions. Xcode7 starts Bitcode by default, if you don't want to use it, you can manually turn off Bitcode:

Select the project -> click Target -> click Build Settings -> search bitcode in the search bar -> change Yes to No for Enable Bitcode.

When enabling the Bitcode compilation mechanism, you need to pay attention to the following points:

If Bitcode is enabled for an application, then other third-party libraries integrated into it must also be Bitcode-compiled packages in order to be truly Bitcode-compiled

After turning on Bitcode compilation, the size of the compiled .app will become larger (intermediate code, not the package downloaded by the user), and the .dSYM file cannot be used to symbolize the crash log (the package downloaded by the user is recompiled by Apple services, and new symbol files are generated). Students who use dSYM to collect Crash logs should pay attention.

When you upload the AppStore package via Archive, you can download the new symbol file of the corresponding installation package in the Organizer tool of Xcode.

Background positioning

After iOS9, Apple has set permissions for apps to request background location in order to protect the privacy of users' geographic locations, so you need to add some more code. If you are not compatible with iOS9, you cannot secretly locate in the background. If you do not have the permission for background location, you can still locate in the background, but a blue bar will appear.

Enable background location function: locationManager.allowsBackgroundLocationUpdates = YES;

locationManager is the object of CLLocationManager, which is used to manage the entire positioning.

Key points:

Configure info.plist, add a Required background modes of Array type, and then set the Value corresponding to Item 0 in Required background modes to App registers for location updates. This will solve the problem of blue bar appearing in background positioning in iOS9.

UI Testing

Apple introduced a new way to test apps in Xcode7 - UI Testing. UI Testing allows us to find UI elements to interact with, and check properties and states. UI Testing has been fully integrated into the test report of Xcode7 and can be executed together with unit tests. It is similar to XCTest in Xcode5. Xcode bots provide support for this, and the command line supports immediate notification when UI tests fail.

You can refer to the Demo on Github, steps:

Create a method starting with test in DemoTests.m

Start the application XCUIApplication().launch() in setUp()

Create a new method starting with test and get the application in it let app = XCUIApplication()

Let app = XCUIApplication(), app.buttons["View Detail"].tap()?. buttons is a collection of all buttons in the current interface. The button name is written in []. tap() is to execute the method corresponding to this button, which can be a network request, interface jump, etc.

URL scheme

In iOS9, if you use URL scheme, you must whitelist the URL scheme you want to call externally in "Info.plist", otherwise it cannot be used.

Configure info.plist, add a LSApplicationQueriesSchemes of Array type, and then add urlscheme in the Item of LSApplicationQueriesSchemes. URLscheme is an arbitrary string, which is the urlscheme you need to use. The iOS9 URL scheme whitelist adaptation is completed.

Lots of warnings

After running the previous project in Xcode7, a lot of warnings appeared, such as:

(null): warning: /var/folders/p4/z7zy68r92hd3p5ry5g2v3k_8rlwzzr/C/org.llvm.clang.dalmo/ModuleCache/1TXZDLI9N2EMV/Foundation-3DFYNEBRQSXST.pcm: No such file or directory.

As a person with mysophobia, I can't stand it anyway. The general reason for the warning is related to the above-mentioned turning on Bitcode. The .dSYM file cannot be used for symbolication. Xcode tries to create a dSYM file, but you don't need it.

Workaround

Build Settings ——>Build Options ——>Debug Information Format

Change DWARF with dsYM File under Debug to DWARF

The default DWARF with dsYM File remains unchanged under Release