Note about NSUserDefault in version update: nsuserdefault

Note about NSUserDefault in version update: nsuserdefault
Notes about NSUserDefault in version update
When updating the version, you need to prevent this situation, that is, whether the key you set in NSUserDefault has the corresponding value, and whether the ket in the new NSUserDefault version has the same name as the key in the previous version, and whether the same name will affect the program! Blues_zhou was published at: ---> app updates are binary files and data is not upgraded, so this is why we need to implement data compatibility during updates, if the data can be automatically upgraded, I think those database migration operations are unnecessary. Haha! Obviously, this is impossible. So the question is: Is UserDefault part of the binary data file or the data part?

Obviously, it is similar to the initialization parameter of the app. Without it, the app may run normally, but it only needs to be set again. It should belong to the data part.

One sentence: blueseaineye is published at: ---> Update retains the Document and Lib directories and replaces the. app directories.
Is the NSUserDefault of the iPhone a database or a plist? Apple does not disclose the NSUserDefault implementation method, but NSUserDefault is saved using Key-Value.
The items to be prepared for cycling and traveling are also worth noting. For details, you should carry a loose jacket, shorts, travel shoes, sun hats, sunglasses, and carrying shoulder-and-shoulder dual-purpose backpacks, a canvas bag can be hashed on the rear frame of a bicycle. A basket is installed in front of the handlebar to bring food and drinks, we also need to bring bicycle parts and car repair tools, maps, compass, rain gear, gloves, flashlights, matches, candles, lunch boxes, water cups, fruit knives, spoons, toiletries, ropes, and photographic products. When a car crashes, the front and back of the foot can take turns to force each part of the leg muscles to take turns to rest, extend endurance. At the beginning, I don't know much about my endurance. I can ride slowly first. After I adapt, I can accelerate it as appropriate. However, it generally does not exceed 15 kilometers per hour. Pay attention to the regular adjustment of the foot position and the two-arm handlebar posture when the car is parked. Every two or three hours, you can take a rest, drink some water, wipe the sweat, and then go on the road.