總結iOS 開發的幾個常用代碼

近期總結了一些常用的ios代碼。

1、iOS中不定參數（可變參數）的方法

常見於NSArray初始化方法中，如：

@interface NSArray (NSArrayCreation)+ (id)arrayWithObjects:(id)firstObj, ... NS_REQUIRES_NIL_TERMINATION;- (id)initWithObjects:(id)firstObj, ... NS_REQUIRES_NIL_TERMINATION;//...@end

NS_REQUIRES_NIL_TERMINATION 是一個宏，用於編譯時間非nil結尾的檢查。自訂不定參數的方法與C/C++一樣，樣本如下：

- (id)initWithColumns: (NSString*)firstColumnName, ... {if (self = [self init]) {NSMutableArray* arrays = [NSMutableArray array];va_list argList;if (firstColumnName) {[arrays addObject:firstColumnName];va_start(argList, firstColumnName);id arg;while ((arg = va_arg(argList, id))) {[arrays addObject:arg];}}self.columnNames = [NSArray arrayWithArray:arrays];}return self;}

2、iOS中URL編碼

NSString* escapedURLString = [unescapedStringstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]或NSString * encodedString = (NSString *)CFURLCreateStringByAddingPercentEscapes(NULL, (CFStringRef)yourtext, NULL, (CFStringRef)@”!*’();:@&=+$,/?%#[]“, kCFStringEncodingUTF8);

3、判斷iOS裝置是否是iPad

#define IS_IPAD ([[UIDevice currentDevice] respondsToSelector:@selector(userInterfaceIdiom)] && [[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad)