iOS 使用UITextField自定义搜索框 实现用户输入完之后“实时搜索”功能

- (void)textFieldDidChange{
 if (self.searchDelegate && [self.searchDelegate respondsToSelector:@selector(customSearchBar:textDidChange:)]) {
 [self.searchDelegate customSearchBar:self textDidChange:self.text];
 }
}

@property (nonatomic, strong) LGCustomSearchBar *searchBar;
@property (nonatomic, assign) NSInteger inputCount; 记录输入次数

- (void)viewDidLoad {
 [super viewDidLoad];
 self.searchBar = [[LGCustomSearchBar alloc] initWithFrame:CGRectMake(20, 10, kScreenWidth-40, 36)];
 self.searchBar.searchDelegate = self;
 [self.view addSubview:self.searchBar];
}
- (void)customSearchBar:(LGCustomSearchBar *)searchBar textDidChange:(NSString *)searchText{
 if (searchText.length == 0) {
 [self searchKeyword:@(self.inputCount)];
 }
 else{
 self.inputCount++;
 [self performSelector:@selector(searchKeyword:) withObject:@(self.inputCount) afterDelay:1.5f];
 }
}
- (void)searchKeyword:(NSNumber *)inputCount{
	// 判断不等于0是为了防止用户输入完直接点击搜索，延时结束之后又搜索一次
 if (inputCount.integerValue == self.inputCount && self.inputCount != 0) {
 [self loadData];
 }
}
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
 [self loadData];
 return NO;
}
- (void)loadData{
 self.inputCount = 0;
	// 本地查询 或者 请求数据
	...
 [self.tableView reloadData];
}

[self performSelector:@selector(searchKeyword:) withObject:@(self.inputCount) 
afterDelay:1.5f];