UITextField placeholder string is always Top aligned in ios7

假如想象 提交于 2019-12-04 00:30:58

drawInRect methods seem to behave differently in iOS7, you can try adding the following line and use that as the rect to draw instead. It's also backwards compatible with pre-iOS7.

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

The code bellow works on 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

I have fixed this problem by subclassing UITextFieldClass and override drawPlaceholderInRect function.

 - (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];
    }
}

A slight update

- (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/

Why not just shift the drawing rect and then invoke the super method implementation call? Swift code ensues...

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

Because you have set yourTextField.borderStyle = UITextBorderStyle....

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