问题
i have UILabel (cocoa touch framework) and i want to right and left justify its text. as a consequence it will stretch the text inside.
Example: like if i had this text "While the saved costs of physical manufacturing and shipping" it would appear like the following:
"While the saved"
"c o s t s o f"
"p h y s i c a l"
"manufacturing"
"a n d shipping"
as you can see left and right justification...
how can i achieve that ???
many thanks
- i'm sorry i had to put the double qoutations to post the question.
回答1:
You should use my OHAttributedLabel class.
It has everything needed to display an NSAttributedString, including justifying left, center, right… and justified, and is really simple to use.
You can find it here on github. See the sample code provided that also shows how to change text justification.
// suppose that label is an IBOutlet to an OHAttributedLabel (subclass oh UILabel)
label.textAlignment = UITextAlignmentJustify; // and that's all, OHAttributedLabel does everything needed for you!
(Note: UITextAlignmentJustify is a constant defined in OHAttributedLabel headers that matches corresponding CoreText constant for justify alignment. This constant does not exists in Apple's SDK)
[EDIT] iOS6 SDK
Since iOS6 SDK, the UITextAlignmentJustify does not work anymore and generate a crash at runtime. Now you should set the text alignment of your NSAttributedString itself instead of using the textAlignment property of the label.
回答2:
Using UIWebView can be slow, so if that's an issue CoreText is the way to go.
Here's some code that uses core text to display an attributed string on a view. It indents a bit like UILabel. I've left some other paragraph formatting options in to illustrate how you can set other paragraph properties and also set the attributed string to bold. Remember you'll need to add the CoreText framework otherwise you'll get build errors.
This code doesn't full justify the last line. Not sure you can get this for free in CoreText.
the .h file
//
// SmartLabel.h
//
#import <UIKit/UIKit.h>
#import <CoreText/CoreText.h> // needed for CTFontRef, CTFontCreateWithName
@interface SmartLabel : UIView
{
NSMutableAttributedString* _pgSmartString;
}
@property (nonatomic, retain) NSMutableAttributedString* smartString;
- (void) setText: (NSString*) string;
- (void) formatString;
@end
And the .m file
//
// SmartLabel.m
//
#import "SmartLabel.h"
@implementation SmartLabel
@synthesize smartString = _pgSmartString;
- (void)dealloc
{
[_pgSmartString release];
[super dealloc];
}
- (id)initWithFrame:(CGRect)frame;
{
if ((self = [super initWithFrame:frame]))
{
[self setBackgroundColor: [UIColor clearColor]];
}
return self;
}
- (void)drawRect:(CGRect)rect
{
CGContextRef graphicsContext = UIGraphicsGetCurrentContext();
CGContextSetTextMatrix(graphicsContext, CGAffineTransformIdentity);
// turns things right way up
CGContextTranslateCTM(graphicsContext, 0, self.bounds.size.height);
CGContextScaleCTM(graphicsContext, 1.0, -1.0);
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)[self smartString]);
CGRect bounds = [self bounds];
bounds.origin.x = bounds.origin.x + 8;
bounds.size.width = bounds.size.width - 16;
CGMutablePathRef path = CGPathCreateMutable();
CGPathAddRect(path, NULL, bounds);
CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(0, [[self smartString] length]), path, NULL);
CFRelease(path);
CTFrameDraw(frame, graphicsContext);
CFRelease(frame);
CFRelease(framesetter);
}
- (void) setText: (NSString*) string;
{
NSMutableAttributedString* attributedString = [[NSMutableAttributedString alloc] initWithString:string];
[self setSmartString:attributedString];
[attributedString release];
[self formatString];
}
- (void) formatString;
{
CTTextAlignment alignment = kCTJustifiedTextAlignment; // could put different alignments here
CGFloat paragraphSpacing = 11.0;
CGFloat paragraphSpacingBefore = 0.0;
CGFloat firstLineHeadIndent = 0.0;
CGFloat headIndent = 0.0;
CTParagraphStyleSetting altSettings[] =
{
{ kCTParagraphStyleSpecifierAlignment, sizeof(CTTextAlignment), &alignment},
{ kCTParagraphStyleSpecifierFirstLineHeadIndent, sizeof(CGFloat), &firstLineHeadIndent},
{ kCTParagraphStyleSpecifierHeadIndent, sizeof(CGFloat), &headIndent},
{ kCTParagraphStyleSpecifierParagraphSpacing, sizeof(CGFloat), ¶graphSpacing},
{ kCTParagraphStyleSpecifierParagraphSpacingBefore, sizeof(CGFloat), ¶graphSpacingBefore},
};
CTParagraphStyleRef style;
style = CTParagraphStyleCreate( altSettings, sizeof(altSettings) / sizeof(CTParagraphStyleSetting) );
if ( style == NULL )
{
NSLog(@"*** WARNING *** Unable To Create CTParagraphStyle in apply paragraph formatting" );
return;
}
[[self smartString] addAttributes:[NSDictionary dictionaryWithObjectsAndKeys:(NSObject*)style,(NSString*) kCTParagraphStyleAttributeName, nil] range:NSMakeRange(0,[[self smartString] length])];
CFRelease(style);
UIFont* boldFont = [UIFont boldSystemFontOfSize:12.0];
CTFontRef boldCoreTextFontReference = CTFontCreateWithName ((CFStringRef)[boldFont fontName],[boldFont pointSize], NULL);
[[self smartString] addAttributes:[NSDictionary dictionaryWithObjectsAndKeys:(NSObject*)boldCoreTextFontReference,(NSString*) kCTFontAttributeName, nil] range:NSMakeRange(0,[[self smartString] length])];
}
@end
And to put to use, something like this:
SmartLabel* smartLabel = [[SmartLabel alloc] initWithFrame:CGRectMake(20, 120, 90, 140.0)];
[[self window] addSubview:smartLabel];
[smartLabel setText:@"While the saved costs of physical manufacturing and shipping"];
[smartLabel release];
回答3:
Its very easy after the release of IOS 6. Use this
//build a style for justification
NSMutableParagraphStyle *stringStyle=[[NSMutableParagraphStyle alloc]init];
[stringStyle setAlignment:NSTextAlignmentJustified];
//build a string with the particular paragraph style
NSMutableAttributedString* yourString=[[NSMutableAttributedString alloc]init];
[yourString addAttribute:NSParagraphStyleAttributeName value:stringStyle range:NSMakeRange(0, [yourString length])];
//and here you go
UILabel *yourLabel;
yourlabel.attributedText=yourString;
回答4:
From iOS 6 you can use NSMutableAttributedString for this,
NSMutableAttributedString* attrStr = [[NSMutableAttributedString alloc] initWithData:[@"Your String value" dataUsingEncoding:NSUTF8StringEncoding] options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType, NSCharacterEncodingDocumentAttribute: [NSNumber numberWithInt:NSUTF8StringEncoding]} documentAttributes:nil error:nil];
NSRange rangeOfTitle = NSMakeRange(0,[attrStr length]);
[attrStr addAttribute: NSFontAttributeName value:[UIFont fontWithName:@"Calibri" size:19.0]range:rangeOfTitle];
myLabel.attributedText = attrStr;
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
[style setLineSpacing:10];
style.lineBreakMode = NSLineBreakByWordWrapping;
style.alignment = NSTextAlignmentJustified;
[attrStr addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, myLabel.text.length)];
myLabel.attributedText = attrStr;
回答5:
The perfect solution is to used NSMutableParagraphStyle
NSMutableParagraphStyle *paragraphStyles = [[NSMutableParagraphStyle alloc] init];
paragraphStyles.alignment = NSTextAlignmentJustified; //justified text
paragraphStyles.firstLineHeadIndent = 1.0;
NSDictionary *attributes = @{NSParagraphStyleAttributeName: paragraphStyles};
NSAttributedString *attributedString = [[NSAttributedString alloc] initWithString: YourString attributes: attributes];
YourLabel.attributedText = attributedString;
回答6:
This is so called "full justification", but isn't supported by the UILabel system (which only has "alignments" - left, right and centre). If you want this, you'll have to code it up yourself, building a control with CoreText or similar.
回答7:
Agree that this can only be done with a good bit of custom coding; which I would think will be some pretty heavy stuff. Before you get into that; and this is depending on your requirement; do consider having a UIWebView where I imagine you would be able to manage text styles and alignments with a bit more freedom using some HTML and CSS coding.
回答8:
The following works as a quick fix, but note that for anything more than black plain text you'll need some styling or css.
(From: Justified Alignment in UITextView - iPhone)
I have come to a solution that works. First of all, you will need to change your UITextView and use a UIWebView instead.
Details.h
@interface Details : UIViewController {
IBOutlet UIWebView *descripcion;
}
@property (nonatomic, retain) UITextView *descripcion;
Then, load your UIWebView as follows:
Details.m
[descripcion loadHTMLString:[NSString stringWithFormat:@"<div align='justify'>%@<div>",YOUR_TEXT] baseURL:nil];
来源：https://stackoverflow.com/questions/7378409/uilabel-justify-left-and-right