Question

我有UITextField类的子类并执行以下代码

- (void)drawPlaceholderInRect:(CGRect)rect
{

    [self.placeHolderTextColor setFill];
    [self.placeholder drawInRect:rect
                        withFont:self.placeHolderFont
                   lineBreakMode:NSLineBreakByTruncatingTail
                       alignment:NSTextAlignmentLeft];

}

我也写过 self.contentVerticalAlignment = UIControlContentVerticalAlignmentTop; 代码行

此占位符文本在ios6中正确居中对齐，但在ios7中未显示在顶部对齐。

虽然我输入的文字显示为居中。它只有占位符字符串问题。

我已尝试使用xib设置占位符字符串。在XIB中它显示正常，但是当我运行代码时，textfield占位符是顶部对齐的。

对此有何解决方法？

Vadoff的回答对我有用。这仍然是完整的实施，可以帮助任何有同样问题的人。

ios7中不推荐使用

drawInRect方法，drawInRectWithAttributes正常工作

- (void)drawPlaceholderInRect:(CGRect)rect
{

    [self.placeHolderTextColor setFill];

    CGRect placeholderRect = CGRectMake(rect.origin.x, (rect.size.height- self.placeHolderFont.pointSize)/2 - 2, rect.size.width, self.placeHolderFont.pointSize);
    rect = placeholderRect;

    if(iOS7) {

        NSMutableParagraphStyle* style = [[NSMutableParagraphStyle alloc] init];
        style.lineBreakMode = NSLineBreakByTruncatingTail;
        style.alignment = self.placeHolderTextAlignment;


        NSDictionary *attr = [NSDictionary dictionaryWithObjectsAndKeys:style,NSParagraphStyleAttributeName, self.placeHolderFont, NSFontAttributeName, self.placeHolderTextColor, NSForegroundColorAttributeName, nil];

        [self.placeholder drawInRect:rect withAttributes:attr];


    }
    else {
        [self.placeholder drawInRect:rect
                            withFont:self.placeHolderFont
                       lineBreakMode:NSLineBreakByTruncatingTail
                           alignment:self.placeHolderTextAlignment];
    }

}

Answer 1

drawInRect方法在iOS7中的行为似乎不同，您可以尝试添加以下行并将其用作矩形来代替。它也向后兼容iOS7之前。

  CGRect placeholderRect = CGRectMake(rect.origin.x, (rect.size.height- self.font.pointSize)/2, rect.size.width, self.font.pointSize);

Answer 2

代码bellow适用于iOS 5/6/7

@implementation PlaceholderTextField

- (void)drawPlaceholderInRect:(CGRect)rect
{
    // Placeholder text color, the same like default
    UIColor *placeholderColor = [UIColor colorWithWhite:0.70 alpha:1];
    [placeholderColor setFill];

    // Get the size of placeholder text. We will use height to calculate frame Y position
    CGSize size = [self.placeholder sizeWithFont:self.font];

    // Vertically centered frame
    CGRect placeholderRect = CGRectMake(rect.origin.x, (rect.size.height - size.height)/2, rect.size.width, size.height);

    // Check if OS version is 7.0+ and draw placeholder a bit differently
    if (IS_IOS7) {

        NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
        style.lineBreakMode = NSLineBreakByTruncatingTail;
        style.alignment = self.textAlignment;
        NSDictionary *attr = [NSDictionary dictionaryWithObjectsAndKeys:style,NSParagraphStyleAttributeName, self.font, NSFontAttributeName, placeholderColor, NSForegroundColorAttributeName, nil];

        [self.placeholder drawInRect:placeholderRect withAttributes:attr];


    } else {
        [self.placeholder drawInRect:placeholderRect
                            withFont:self.font
                       lineBreakMode:NSLineBreakByTruncatingTail
                           alignment:self.textAlignment];
    }

}

@end

Answer 3

我通过继承UITextFieldClass并覆盖drawPlaceholderInRect函数来解决这个问题。

 - (void)drawPlaceholderInRect:(CGRect)rect
{

    if(IS_IOS7)
    {
        [[self placeholder] drawInRect:CGRectMake(rect.origin.x, rect.origin.y+10, rect.size.width, rect.size.height) withFont:self.font];
    }
    else {

        [[self placeholder] drawInRect:rect withFont:self.font];
    }
}

Answer 4

稍作更新

- (void) drawPlaceholderInRect:(CGRect)rect {
    if (self.useSmallPlaceholder) {
        NSDictionary *attributes = @{
                                 NSForegroundColorAttributeName : kInputPlaceholderTextColor,
                                 NSFontAttributeName : [UIFont fontWithName:kInputPlaceholderFontName size:kInputPlaceholderFontSize]
                                 };

        //center vertically
        CGSize textSize = [self.placeholder sizeWithAttributes:attributes];
        CGFloat hdif = rect.size.height - textSize.height;
        hdif = MAX(0, hdif);
        rect.origin.y += ceil(hdif/2.0);

        [[self placeholder] drawInRect:rect withAttributes:attributes];
    }
    else {
        [super drawPlaceholderInRect:rect];
    }
}

http://www.veltema.jp/2014/09/15/Changing-UITextField-placeholder-font-and-color/

Answer 5

为什么不直接移动绘图rect然后调用super方法实现调用？ Swift代码接着......

override func drawPlaceholderInRect(rect: CGRect) {
    var newRect = CGRectInset(rect, 0, 2)
    newRect.origin.y += 2
    super.drawPlaceholderInRect(newRect)
}

UITextField占位符字符串在ios7中始终是顶部对齐的

5 个答案: