評估NSString大小來填充UITextView

Question

我有一個不可滾動的UITextView，我想用動態文本填充這個框架。

這是我的類代碼：

#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功能評估的文字高度小於框的高度，它運作良好，否則測量的高度是錯誤的。

TextView的尺寸是300x620

什麼想法？謝謝在提前

Answer 1

sizeThatFits:從未增加了在傳入的大小要精確測量將被所需的最小尺寸，改變高度一些大的號碼之前，它被稱爲：

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

原諒我如果我回答我的問題，但我找到了解決方案，我認爲它可以用於解決像我這樣的問題。

我用這個函數在這個崗位評估正確的字體大小：

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; 
    } 
} 

和這個代碼兩行，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; 

因爲第一次UITextView的框架不正確。

感謝對您的支持