用 UITextField 自定义UISearchBar 监听输入字符串改变的问题

用 UITextField 自定义的 UISearchBar 没有如下的 UISearchBar 中的协议方法

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText

UITextField 中只有协议方法：

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string
该方法只能监听将要改变之前的状态，不能监听当前 textfield 的字符串，监听的字符串总是慢一步。如果将要输入中文，则监听到的是中文拼音，并且拼音中间以空格隔开，
textField.text.length长度为英文字母加空格个数。

解决办法：

UITextFieldTextDidChangeNotification

[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(textChanged)
name:UITextFieldTextDidChangeNotification
object:_searchTF];

-(void)textChanged
{
BOOL isEqual = [_searchTF.text isEqualToString:_oldStr];

if ( isEqual || ((!isEqual) && (_oldStr.length > _searchTF.text.length))) {

NSLog(@"===////%@====////=====",_searchTF.text);

}

_oldStr = _searchTF.text;
}

//或者
-(void)textChanged
{

if ([_searchTF.text isEqualToString:_oldStr]) {

NSLog(@"===////%@====////=====",_searchTF.text);

}
if ((![_searchTF.text isEqualToString:_oldStr])&&(_oldStr.length > _searchTF.text.length)) {

NSLog(@"===////%@====////=====",_searchTF.text);

}
_oldStr = _searchTF.text;

}

更正：

-(void)textChanged
{

if ([_searchTF.text isEqualToString:_changeStr]) {

//        [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
//                [_doctorsArray removeAllObjects];
//                [self loadDoctorWithKeyword:_searchTF.text AndIsSearchType:YES AndPage:1];
_oldStr = _searchTF.text;
NSLog(@"===////%@====////=====",_searchTF.text);
}else if ((![_searchTF.text isEqualToString:_oldStr])&&(_oldStr.length > _searchTF.text.length)) {

//        [UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
//                [_doctorsArray removeAllObjects];
//                [self loadDoctorWithKeyword:_searchTF.text AndIsSearchType:YES AndPage:1];
_oldStr = _searchTF.text;
NSLog(@"===////%@====////=====",_searchTF.text);

}
_changeStr = _searchTF.text;

}

-(void)textChanged
{
BOOL isEqual = [_searchTF.text isEqualToString:_changeStr];

if ( isEqual || ((!isEqual) && (_oldStr.length > _searchTF.text.length))) {
_oldStr = _searchTF.text;
NSLog(@"===////%@====////=====",_searchTF.text);

[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
[_doctorsArray removeAllObjects];
[self loadDoctorWithKeyword:_searchTF.text AndIsSearchType:YES AndPage:1];
}

_changeStr = _searchTF.text;

}