解决NSTextContainer分页时文本截断问题

NSTextContainer与NSLayoutManager配合使用可以将大文本文件分页,但是,分页过程中会遇到问题,显示字符被截断的问题:)

- (void)viewDidLoad
{[super viewDidLoad];// 数据源NSString *string = [NSString stringWithContentsOfURL:[NSBundle.mainBundle URLForResource:@"bubizhidaowoshishui" withExtension:@"txt"] usedEncoding:nilerror:nil];// 文本容器NSTextStorage *storage = [[NSTextStorage alloc] initWithString:string];// 文本容器的布局管理器NSLayoutManager *layoutManager = [NSLayoutManager new];[storage addLayoutManager:layoutManager];// 分段显示文本容器中的内容CGSize size = CGSizeMake(300, 540);NSTextContainer *textContainer1 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer1];NSTextContainer *textContainer2 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer2];NSTextContainer *textContainer3 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer3];UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(10, 20,size.width,size.height)textContainer:textContainer3];textView.layer.borderWidth = 1;textView.scrollEnabled     = NO;textView.editable          = NO;[self.view addSubview:textView];
}

以下是我的运行结果(注意看底下红色的部分,文本被截断了哦):

为什么会被截断呢,按理说,NSLayoutManager会计算好一个size值然后给NSTextContainer让这个NSTextContainer自己适应的.

苹果官方文档里面有描述:

这个问题有这么棘手么?其实,我是在黔驴技穷的情况下(github上下载了7-8个相关demo,stackoverflow上搜寻等等途径都无效的情况下)细致研究官方提供的pdf文档才明白过来的:),你懂的.

附录:

使用自定义字体不是梦:)

- (void)viewDidLoad
{[super viewDidLoad];// 数据源NSString *string = [NSString stringWithContentsOfURL:[NSBundle.mainBundle URLForResource:@"bubizhidaowoshishui" withExtension:@"txt"] usedEncoding:nilerror:nil];// 文本容器NSTextStorage *storage = [[NSTextStorage alloc] initWithString:string];// 文本容器的布局管理器NSLayoutManager *layoutManager = [NSLayoutManager new];[storage addLayoutManager:layoutManager];// 段落属性NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];paragraphStyle.lineHeightMultiple  = 1.f;                    // 可变行高,乘因数paragraphStyle.lineSpacing         = 5.f;                    // 行间距paragraphStyle.minimumLineHeight   = 10.f;                   // 最小行高paragraphStyle.maximumLineHeight   = 20.f;                   // 最大行高paragraphStyle.paragraphSpacing    = 10.f;                   // 段间距paragraphStyle.alignment           = NSTextAlignmentLeft;    // 对齐方式paragraphStyle.firstLineHeadIndent = 30.f;                   // 段落首文字离边缘间距paragraphStyle.headIndent          = 0.f;                    // 段落除了第一行的其他文字离边缘间距paragraphStyle.tailIndent          = 0.f;                    // ???????[storage addAttribute:NSParagraphStyleAttributeNamevalue:paragraphStylerange:NSMakeRange(0, storage.string.length)];// 字体属性[storage addAttribute:NSFontAttributeNamevalue:[UIFont fontWithName:CUSTOM_FONT(@"新蒂小丸子体", 0) size:15.f]range:NSMakeRange(0, storage.string.length)];[storage addAttribute:NSForegroundColorAttributeNamevalue:[UIColor redColor]range:NSMakeRange(0, storage.string.length)];// 分段显示文本容器中的内容CGSize size = CGSizeMake(300, 520);NSTextContainer *textContainer1 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer1];NSTextContainer *textContainer2 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer2];NSTextContainer *textContainer3 = [[NSTextContainer alloc] initWithSize:size];[layoutManager addTextContainer:textContainer3];UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(10, 20,size.width,size.height + 20)textContainer:textContainer3];textView.layer.borderWidth = 1;textView.scrollEnabled     = NO;textView.editable          = NO;[self.view addSubview:textView];
}