Use of @ encode in Objective-C, objective-c @ encode

Use of @ encode in Objective-C, objective-c @ encode

Today, when I read Mansonry's code, I came across a rare keyword (maybe I have never used it myself ). :-)

 

@ Encode => encode a given type as an internal string.

In order to make it easier for you to check it out, you can also write a small example here to learn how to use it.

 

NSLog (@ "UIViewController: % s", @ encode (UIViewController ));

NSLog (@ "CGRect: % s", @ encode (CGRect ));

NSLog (@ "int: % s", @ encode (int ));

NSLog (@ "float: % s", @ encode (float ));

NSLog (@ "double: % s", @ encode (double ));

NSLog (@ "BOOL: % s", @ encode (BOOL ));

NSLog (@ "long: % s", @ encode (long ));

NSLog (@ "short: % s", @ encode (short ));

 

NSDictionary * numberDic ={ @ "double": [NSNumber numberWithDouble: 1.00f],

@ "Float": [NSNumber numberWithFloat: 2.0f],

@ "Int": [NSNumber numberWithInt: 2],

@ "Long": [NSNumber numberWithLong: 2],

@ "Bool": [NSNumber numberWithBool: YES],

@ "Short": [NSNumber numberWithShort: 2],

};

For (NSString * key in numberDic ){

NSNumber * value = [numberDic valueForKey: key];

Const char * pObjCType = [value objCType];

If (strcmp (pObjCType, @ encode (double) = 0 ){

NSLog (@ "double: % @", value );

}

If (strcmp (pObjCType, @ encode (float) = 0 ){

NSLog (@ "float: % @", value );

}

If (strcmp (pObjCType, @ encode (int) = 0 ){

NSLog (@ "int: % @", value );

}

If (strcmp (pObjCType, @ encode (long) = 0 ){

NSLog (@ "long: % @", value );

}

If (strcmp (pObjCType, @ encode (bool) = 0 ){

NSLog (@ "bool: % @", value );

}

If (strcmp (pObjCType, @ encode (short) = 0 ){

NSLog (@ "short: % @", value );

}

}

 

The output of this Code is as follows:

16:18:56. 316 test [1000:251554] UIViewController: {UIViewController = #}

16:18:56. 316 test [1000:251554] CGRect: {CGRect = {CGPoint = dd} {CGSize = dd }}

16:18:56. 316 test [1000:251554] int: I

16:18:56. 316 test [1000:251554] float: f

16:18:56. 316 test [1000:251554] double: d

16:18:56. 317 test [1000:251554] BOOL: B

16:18:56. 317 test [1000:251554] long: q

16:18:56. 317 test [1000:251554] short: s

16:18:57. 268 test [1000:251554] double: 1

16:18:57. 268 test [1000:251554] float: 2

16:18:57. 268 test [1000:251554] int: 2

16:18:57. 268 test [1000:251554] long: 2

16:18:57. 269 test [1000:251554] short: 2

 

From the above we can see that int is encoded as I; float is f; and so on.

Here is a problem: [NSNumber numberWithBool: YES] When the objCType method is called, "c" instead of "B" is returned ", therefore, the if judgment below does not print the bool-related output. To solve this problem, I made a search. "B" indicates a C ++ bool. In Ojbective-C, BOOL is actually a singned char, therefore, "c" is returned when objCType is called ".