评估NSString大小来填充UITextView

Question

我有一个不可滚动的UITextView，我想用动态文本填充这个框架。

这是我的类代码：

#import "ViewController.h" 

#define FONT_SIZE 17.0f 

@interface ViewController()<UITextViewDelegate> 

@property (nonatomic, weak) IBOutlet UITextView * textview; 
-(IBAction)changeText:(UIButton*)sender; 

@end 

@implementation ViewController 

- (void)viewDidLoad { 
    [super viewDidLoad]; 

    self.automaticallyAdjustsScrollViewInsets = NO; 

    NSString * plainText = @"Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda."; 

    [self applyText:plainText]; 
} 

- (void)didReceiveMemoryWarning { 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 

} 

- (void)applyText: (NSString*) plainText 
{ 
    self.textview.frame = CGRectMake(0,0,self.view.frame.size.width,self.view.frame.size.height-47); 
    self.textview.contentSize = self.textview.frame.size; 

    self.textview.attributedText = [[NSAttributedString alloc] initWithString:plainText]; 
    [self.textview setFont:[UIFont fontWithName:@"HelveticaNeue" size:FONT_SIZE]]; 
    [self.textview setTextAlignment:NSTextAlignmentCenter]; 


    //first method 
    CGSize maximumLabelSize = self.textview.frame.size; 
    maximumLabelSize.height = 9999; 
    CGSize expectSize = [self.textview sizeThatFits:maximumLabelSize]; 

    NSLog(@"expected height %f",expectSize.height); 

    //second method 
    expectSize = [plainText boundingRectWithSize:CGSizeMake(self.textview.frame.size.width,MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:self.textview.font} context:nil].size; 

    NSLog(@"expected height 2 %f",expectSize.height); 

    //third method 
    expectSize = [self attributedSizeWithFont:self.textview.font maxWidth:self.textview.frame.size.width string:plainText]; 

    NSLog(@"expected height 3 %f",expectSize.height); 



    if (expectSize.height <= self.textview.frame.size.height) { 

     float fontSize = (FONT_SIZE * expectSize.height)/self.textview.frame.size.height; 
     NSLog(@">> font: %.2f",fontSize); 

     [self.textview setFont:[UIFont fontWithName:@"HelveticaNeue" size:fontSize]]; 

    } 
    else if (expectSize.height > self.textview.frame.size.height) { 

     float fontSize = (FONT_SIZE * self.textview.frame.size.height)/expectSize.height; 

     NSLog(@"<< font: %.2f",fontSize); 

     [self.textview setFont:[UIFont fontWithName:@"HelveticaNeue" size:fontSize]]; 

    } 
} 


- (CGSize) attributedSizeWithFont:(UIFont*) font maxWidth:(CGFloat) width string:(NSString*) string{ 

    NSMutableParagraphStyle* style = [[NSMutableParagraphStyle alloc] init]; 
    style.lineBreakMode = NSLineBreakByWordWrapping; 
    NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:string 
                     attributes:@{ NSFontAttributeName:font, 
                         NSForegroundColorAttributeName:[UIColor blackColor], 
                         NSParagraphStyleAttributeName:style }]; 

    CGRect textRect = [attributedText boundingRectWithSize:CGSizeMake(width, MAXFLOAT) 
                options:(NSStringDrawingUsesLineFragmentOrigin) 
                context:nil]; 
    CGSize size = textRect.size; 
    size.height = ceilf(size.height); 
    size.width = ceilf(size.width); 

    return size; 
} 


-(IBAction)changeText:(UIButton*)sender 
{ 
    NSString * plainText = @"Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Nam liber te conscient to factor tum poen legum odioque civiuda.Lorem ipsum dolor sit er elit lamet, consectetaur cillium adipisicing pecu, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat."; 

    [self applyText:plainText]; 

} 
@end 

但如果applyText功能评估的文字高度小于框的高度，它运作良好，否则测量的高度是错误的。

TextView的尺寸是300x620

什么想法？谢谢在提前

Answer 1

sizeThatFits:从未增加了在传入的大小要精确测量将被所需的最小尺寸，改变高度一些大的号码之前，它被称为：

CGSize maximumLabelSize = self.textview.frame.size; 
maximumLabelSize.height = 9999. 
CGSize expectSize = [self.textview sizeThatFits:maximumLabelSize]; 

Answer 2

UITextView* dummyTextView = [[[UITextView alloc] initWithFrame: self.textView.frame] autorelease]; 

dummyTextView.attributedText = [[NSAttributedString alloc] initWithString:plainText]; 
[dummyTextView.attributedText setFont:[UIFont fontWithName:@"HelveticaNeue" size:FONT_SIZE]]; 
[dummyTextView.attributedText setTextAlignment:NSTextAlignmentCenter]; 
[dummyTextView sizeToFit]; 
CGFloat expectedHeight = dummyTextView.bound.size.height; 

Answer 3

原谅我如果我回答我的问题，但我找到了解决方案，我认为它可以用于解决像我这样的问题。

我用这个函数在这个岗位评估正确的字体大小：

Resize font size to fill UITextView?

- (void)updateTextFont:(UITextView *)textView 
{ 
    // Only run if has text, otherwise it will make infinity loop 
    if (textView.text.length == 0 || CGSizeEqualToSize(textView.bounds.size, CGSizeZero)) return; 

    /* 
    - Update textView font size 
    If expectHeight > textViewHeight => descrease font size n point until it reach textViewHeight 
    If expectHeight < textViewHeight => inscrease font size n point until it reach textViewHeight 
    */ 
    CGSize textViewSize = textView.frame.size; 
    CGFloat fixedWidth = textViewSize.width; 
    CGSize expectSize = [textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)]; 

    UIFont *expectFont = textView.font; 
    if (expectSize.height > textViewSize.height) { 
     while ([textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)].height > textViewSize.height) { 
      expectFont = [textView.font fontWithSize:(textView.font.pointSize - 0.5)]; 
      textView.font = expectFont; 
     } 
    } else { 
     while ([textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)].height < textViewSize.height) { 
      expectFont = textView.font; 
      textView.font = [textView.font fontWithSize:(textView.font.pointSize + 0.5)]; 
     } 
     textView.font = expectFont; 
    } 
} 

和这个代码两行，我已applyText功能：

self.textview.frame = CGRectMake(0,0,self.view.frame.size.width,self.view.frame.size.height-47); 
    self.textview.contentSize = self.textview.frame.size; 

因为第一次UITextView的框架不正确。

感谢对您的支持