iOS巔峰之如何讓UISearchBar預留位置居左

解決方案:建立一個UISearchBar的category，我這裡建立的名字為UISearchBar+ZMSearchBarPlaceholder

代碼如下： UISearchBar+ZMSearchBarPlaceholder.h

#import <UIKit/UIKit.h>@interface UISearchBar (ZMSearchBarPlaceholder)-(void)changeLeftPlaceholder:(NSString *)placeholder;@end

UISearchB ar+ZMSearchBarPlaceholder.h

@implementation UISearchBar (ZMSearchBarPlaceholder)-(void)changeLeftPlaceholder:(NSString *)placeholder {    self.placeholder = placeholder;    SEL centerSelector = NSSelectorFromString([NSString stringWithFormat:@"%@%@", @"setCenter", @"Placeholder:"]);    if ([self respondsToSelector:centerSelector]) {        BOOL centeredPlaceholder = NO;         NSMethodSignature *signature = [[UISearchBar class] instanceMethodSignatureForSelector:centerSelector];        NSInvocation *invocation = [NSInvocation invocationWithMethodSignature:signature];        [invocation setTarget:self];        [invocation setSelector:centerSelector];        [invocation setArgument:&centeredPlaceholder atIndex:2];        [invocation invoke];    }}@end

然後調用該方法即可：

-(void)changeLeftPlaceholder:(NSString *)placeholder; 最後在工程中用到UISearchBar的類中匯入#UISearchBar+ZMSearchBarPlaceholder.h標頭檔，