您可以使用UITextView
其子类为NSLayoutManager
,覆盖-fillBackgroundRectArray:count:forCharacterRange:color:
。
只是一个小示例如何做到这一点:
@implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// setup text handling
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithString:@"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."];
// use our subclass of NSLayoutManager
MyLayoutManager *textLayout = [[MyLayoutManager alloc] init];
[textStorage addLayoutManager:textLayout];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:self.view.bounds.size];
[textLayout addTextContainer:textContainer];
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(0,20,self.view.bounds.size.width,self.view.bounds.size.height-20)
textContainer:textContainer];
[self.view addSubview:textView];
// set some background color to our text
[textView.textStorage setAttributes:[NSDictionary dictionaryWithObject:[UIColor blueColor] forKey:NSBackgroundColorAttributeName] range:NSMakeRange(22, textView.text.length - 61)];
}
@end
@interface MyLayoutManager : NSLayoutManager
@end
- (void)fillBackgroundRectArray:(const CGRect *)rectArray count:(NSUInteger)rectCount forCharacterRange:(NSRange)charRange color:(UIColor *)color
{
CGFloat halfLineWidth = 4.; // change this to change corners radius
CGMutablePathRef path = CGPathCreateMutable();
if (rectCount == 1
|| (rectCount == 2 && (CGRectGetMaxX(rectArray[1]) < CGRectGetMinX(rectArray[0])))
)
{
// 1 rect or 2 rects without edges in contact
CGPathAddRect(path, NULL, CGRectInset(rectArray[0], halfLineWidth, halfLineWidth));
if (rectCount == 2)
CGPathAddRect(path, NULL, CGRectInset(rectArray[1], halfLineWidth, halfLineWidth));
}
else
{
// 2 or 3 rects
NSUInteger lastRect = rectCount - 1;
CGPathMoveToPoint(path, NULL, CGRectGetMinX(rectArray[0]) + halfLineWidth, CGRectGetMaxY(rectArray[0]) + halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMinX(rectArray[0]) + halfLineWidth, CGRectGetMinY(rectArray[0]) + halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMaxX(rectArray[0]) - halfLineWidth, CGRectGetMinY(rectArray[0]) + halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMaxX(rectArray[0]) - halfLineWidth, CGRectGetMinY(rectArray[lastRect]) - halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMaxX(rectArray[lastRect]) - halfLineWidth, CGRectGetMinY(rectArray[lastRect]) - halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMaxX(rectArray[lastRect]) - halfLineWidth, CGRectGetMaxY(rectArray[lastRect]) - halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMinX(rectArray[lastRect]) + halfLineWidth, CGRectGetMaxY(rectArray[lastRect]) - halfLineWidth);
CGPathAddLineToPoint(path, NULL, CGRectGetMinX(rectArray[lastRect]) + halfLineWidth, CGRectGetMaxY(rectArray[0]) + halfLineWidth);
CGPathCloseSubpath(path);
}
[color set]; // set fill and stroke color
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextSetLineWidth(ctx, halfLineWidth * 2.);
CGContextSetLineJoin(ctx, kCGLineJoinRound);
CGContextAddPath(ctx, path);
CGPathRelease(path);
CGContextDrawPath(ctx, kCGPathFillStroke);
}
@end