One point of confusion when developing across different languages is access modifiers. This time, as a smartphone application development edition, we will investigate each access modifier for Java / Kotlin used for Android development, Objective-C / Swift used for iOS development, and C # / F # used for Xamarin, and summarize it as a comparison table. I tried it.
| Access modifier | Java | Kotlin | Objective-C | Swift | C# | F# |
|---|---|---|---|---|---|---|
| open | (not exist) | (not exist) | (not exist) | Accessable from anywhere * Added in Swift3 |
(not exist) | (not exist) |
| public | Accessable from anywhere | Accessable from anywhere | Accessable from anywhere | Accessable from anywhere ※ただし別モジュールからの継承とオーバーライドは不可（Swift2まではAccessable from anywhere） |
Can be accessed from anywhere | Can be accessed from anywhere |
| package | (not exist) | (not exist) | Accessable from within the same framework * Private outside the framework |
(not exist) | (not exist) | (not exist) |
| protected | Accessable from class + derived class in the same package | 継承したAccessable from class + derived class in the same package | Accessable from the same class + derived class | (not exist) | Can be accessed from the same class + derived class | (not exist) |
| protected internal | (not exist) | (not exist) | (not exist) | (not exist) | Accessable from class + derived class in the same project | (not exist) |
| internal | (not exist) | Accessable within the same module | (not exist) | Accessable within the same module | Accessable within the same assembly | Accessable within the same assembly |
| fileprivate | (not exist) | (not exist) | (not exist) | Can be accessed within the same file * Added in Swift3 |
(not exist) | (not exist) |
| private | Accessable within the same scope * You can also refer to the private variable of the inner class. |
Accessable within the same scope | Accessable within the same scope | Accessable within the same scope * Up to Swift2 can be accessed in the same file |
Accessable within the same scope | Accessable within the same scope |
| Not specified | Accessable within the same package | Same as public | Same as protected | Same as internal | Same as private | Same as public * Let binding/do束縛ではSame as private |
It seems that you need to be careful because the movement when you do not specify anything is wonderfully different.
First time in Kotlin. I compared it with Java Access control from Swift 3 Objective-C access specifier