diff options
| -rw-r--r-- | objective-c.html.markdown | 104 |
1 files changed, 89 insertions, 15 deletions
diff --git a/objective-c.html.markdown b/objective-c.html.markdown index 1ed0ed58..419c0475 100644 --- a/objective-c.html.markdown +++ b/objective-c.html.markdown @@ -50,52 +50,101 @@ int main (int argc, const char * argv[]) // String NSString *worldString = @"World"; - NSLog(@"Hello %@!", worldString); // Print "Hello World!" + NSLog(@"Hello %@!", worldString); // prints => "Hello World!" + // NSMutableString is a mutable version of the NSString object. + NSMutableString *mutableString = [NSMutableString stringWithString:@"Hello"]; + [mutableString appendString:@" World!"]; + NSLog(@"%@", mutableString); // prints => "Hello World!" // Character literals NSNumber *theLetterZNumber = @'Z'; - char theLetterZ = [theLetterZNumber charValue]; + char theLetterZ = [theLetterZNumber charValue]; // or 'Z' NSLog(@"%c", theLetterZ); // Integral literals NSNumber *fortyTwoNumber = @42; - int fortyTwo = [fortyTwoNumber intValue]; + int fortyTwo = [fortyTwoNumber intValue]; // or 42 NSLog(@"%i", fortyTwo); NSNumber *fortyTwoUnsignedNumber = @42U; - unsigned int fortyTwoUnsigned = [fortyTwoUnsignedNumber unsignedIntValue]; + unsigned int fortyTwoUnsigned = [fortyTwoUnsignedNumber unsignedIntValue]; // or 42 NSLog(@"%u", fortyTwoUnsigned); NSNumber *fortyTwoShortNumber = [NSNumber numberWithShort:42]; - short fortyTwoShort = [fortyTwoShortNumber shortValue]; + short fortyTwoShort = [fortyTwoShortNumber shortValue]; // or 42 NSLog(@"%hi", fortyTwoShort); + + NSNumber *fortyTwoShortNumber = [NSNumber numberWithShort:41]; + unsigned short fortyTwoUnsigned = [fortyTwoShortNumber unsignedShortValue]; // or 41 + NSLog(@"%hu", fortyTwoUnsigned); NSNumber *fortyTwoLongNumber = @42L; - long fortyTwoLong = [fortyTwoLongNumber longValue]; + long fortyTwoLong = [fortyTwoLongNumber longValue]; // or 42 NSLog(@"%li", fortyTwoLong); + NSNumber *fortyTwoLongNumber = @53L; + unsigned long fiftyThreeUnsigned = [fortyTwoLongNumber unsignedLongValue]; // or 53 + NSLog(@"%lu", fiftyThreeUnsigned); + // Floating point literals NSNumber *piFloatNumber = @3.141592654F; - float piFloat = [piFloatNumber floatValue]; - NSLog(@"%f", piFloat); + float piFloat = [piFloatNumber floatValue]; // or 3.141592654f + NSLog(@"%f", piFloat); // prints => 3.141592654 + NSLog(@"%5.2f", piFloat); // prints => " 3.14" NSNumber *piDoubleNumber = @3.1415926535; - double piDouble = [piDoubleNumber doubleValue]; + double piDouble = [piDoubleNumber doubleValue]; // or 3.1415926535 NSLog(@"%f", piDouble); + NSLog(@"%4.2f", piDouble); // prints => "3.14" + + // NSDecimalNumber is a fixed-point class that's more precise then float or double + NSDecimalNumber *oneDecNum = [NSDecimalNumber decimalNumberWithString:@"10.99"]; + NSDecimalNumber *twoDecNum = [NSDecimalNumber decimalNumberWithString:@"5.002"]; + // NSDecimalNumber isn't able to use standard +, -, *, / operators so it provides its own: + [oneDecNum decimalNumberByAdding:twoDecNum]; + [oneDecNum decimalNumberBySubtracting:twoDecNum]; + [oneDecNum decimalNumberByMultiplyingBy:twoDecNum]; + [oneDecNum decimalNumberByDividingBy:twoDecNum]; + NSLog(@"%@", oneDecNum); // prints => 10.99 as NSDecimalNumber is immutable. // BOOL literals NSNumber *yesNumber = @YES; NSNumber *noNumber = @NO; + // or + BOOL yesBool = YES; + BOOL noBool = NO; + NSLog(@"%i", yesBool); // prints => 1 // Array object NSArray *anArray = @[@1, @2, @3, @4]; NSNumber *thirdNumber = anArray[2]; NSLog(@"Third number = %@", thirdNumber); // Print "Third number = 3" + // NSMutableArray is mutable version of NSArray allowing to change items in array + // and extend or shrink array object. Convenient, but not as efficient as NSArray. + NSMutableArray *mutableArray = [NSMutableArray arrayWithCapacity:2]; + [mutableArray addObject:@"Hello"]; + [mutableArray addObject:@"World"]; + [mutableArray removeObjectAtIndex:0]; + NSLog(@"%@", [mutableArray objectAtIndex:0]); // prints => "World" // Dictionary object NSDictionary *aDictionary = @{ @"key1" : @"value1", @"key2" : @"value2" }; NSObject *valueObject = aDictionary[@"A Key"]; NSLog(@"Object = %@", valueObject); // Print "Object = (null)" + // NSMutableDictionary also available as a mutable dictionary object. + NSMutableDictionary *mutableDictionary = [NSMutableDictionary dictionaryWithCapacity:2]; + [mutableDictionary setObject:@"value1" forKey:@"key1"]; + [mutableDictionary setObject:@"value2" forKey:@"key2"]; + [mutableDictionary removeObjectForKey:@"key1"]; + + // Set object + NSSet *set = [NSSet setWithObjects:@"Hello", @"Hello", @"World", nil]; + NSLog(@"%@", set); // prints => {(Hello, World)} (may be in different order) + // NSMutableSet also available as a mutable set object. + NSMutableSet *mutableSet = [NSMutableSet setWithCapacity:2]; + [mutableSet addObject:@"Hello"]; + [mutableSet addObject:@"Hello"]; + NSLog(@"%@", mutableSet); // prints => {(Hello)} /////////////////////////////////////// // Operators @@ -176,6 +225,14 @@ int main (int argc, const char * argv[]) // "2," // "3," + // Object for loop statement. Can be used with any Objective-C object type. + for (id item in values) { + NSLog(@"%@,", item); + } // => prints "0," + // "1," + // "2," + // "3," + // Try-Catch-Finally statements @try { @@ -225,14 +282,30 @@ int main (int argc, const char * argv[]) // @end @interface MyClass : NSObject <MyProtocol> { - int count; - id data; - NSString *name; + // Instance variable declarations (can exist in either interface or implementation file) + int count; // Protected access by default. + @private id data; // Private access. (More convenient to declare in implementation file) + NSString *name; } -// Convenience notation to auto generate public getter and setter +// Convenient notation to auto generate public access getter and setter @property int count; @property (copy) NSString *name; // Copy the object during assignment. @property (readonly) id data; // Declare only a getter method. +// To access public variable in implementation file, use '_' followed by variable name: +_count = 5; +NSLog(@"%d", _count); // prints => 5 +// To access public variable outside implementation file, @property generates setter method +// automatically. Method name is 'set' followed by @property variable name: +MyClass *myClass = [[MyClass alloc] init]; // create MyClass object instance. +[myClass setCount:10]; +NSLog(@"%@", [myClass count]); // prints => 10 +// You can customize the getter and setter names instead of using default 'set' name: +@property (getter=countGet, setter=countSet:) int count; +[myClass countSet:32]; +NSLog(@"%i", [myClass countGet]); // prints => 32 +// For convenience, you may use dot notation to set object instance variables: +myClass.count = 45; +NSLog(@"%i", myClass.count); // prints => 45 // Methods +/- (return type)methodSignature:(Parameter Type *)parameterName; @@ -247,8 +320,9 @@ int main (int argc, const char * argv[]) @end // Implement the methods in an implementation (MyClass.m) file: - -@implementation MyClass +@implementation MyClass { + long count; // Private access instance variable. +} // Call when the object is releasing - (void)dealloc |