objective-c - UITextField rightView "WhileEditing"问题

Question

我尝试如下子类化 UITextField 以将自定义 rightView 实现为清除按钮:

-(void) drawRect:(CGRect)rect
{

    [self.layer setBackgroundColor:[[UIColor colorWithRed:20.0/255.0 green:20.0/255.0 blue:20.0/255.0 alpha:1] CGColor]];
    [self.layer setCornerRadius:15.0];

    UIImage  *imgClear = [UIImage imageNamed:@"btnClear"];
    CGSize iSize = [imgClear size];

    UIButton *clearButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, iSize.width, iSize.height)];

    [clearButton setImage:imgClear forState:UIControlStateNormal];
    [clearButton addTarget:self action:@selector(clearText:) forControlEvents:UIControlEventTouchUpInside];

    [self setRightViewMode:UITextFieldViewModeWhileEditing];
    [self setRightView:clearButton];

    [clearButton release];
}

但问题是:当文本字段刚刚成为焦点时，“清除”按钮也变得可见，并且在我开始点击键盘后它消失了。有什么想法吗？

Answer 1

我也遇到了同样的问题。我想这是一个 iOS 错误，但是，我尝试通过以下实现来解决这个问题，它对我来说很好用。希望这对您有所帮助。

- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
    ...
    [self addTarget:self action:@selector(onEditing:) forControlEvents: UIControlEventEditingChanged]
    ...
}

-(void) onEditing:(id)sender {
    if(![self.text isEqualToString:@""]){
        self.rightViewMode = UITextFieldViewModeAlways;
    }else{
        self.rightViewMode = UITextFieldViewModeNever;
    }
}
- (BOOL)becomeFirstResponder{
    BOOL ret = YES ;
    ret = [super becomeFirstResponder] ;
    if( ret & ![self.text isEqualToString:@""]){
        self.rightViewMode = UITextFieldViewModeAlways;
    }else{
        self.rightViewMode = UITextFieldViewModeNever;
    }

    return ret ;
}
- (BOOL)resignFirstResponder
{
    BOOL ret = YES ;
    ret = [super resignFirstResponder] ;
    if( ret )
        self.rightViewMode = UITextFieldViewModeNever;
    return ret ;
}
- (void) clearText:(id)sender
{
    self.text = @"";
    self.rightViewMode = UITextFieldViewModeNever;
}