CTFrameGetVisibleStringRange（）返回0

Question

我有這樣的代碼，在讀取NSAttributedString的同時生成viewController數組。第一個循環後，即使有更多文本顯示，函數CTFrameGetVisibleStringRange（）也會返回0。

- (void)buildFrames 
{ 
/*here we do some setup - define the x & y offsets and create an empty frames array */ 
    float frameXOffset = 20; 
    float frameYOffset = 20; 

    self.frames = [NSMutableArray array]; 

    //buildFrames continues by creating a path and a frame for the view's bounds (offset slightly so we have a margin). 
    CGMutablePathRef path = CGPathCreateMutable(); 
    // create an insect rect for drawing 
    CGRect textFrame = CGRectInset(self.bounds, frameXOffset, frameYOffset); 
    CGPathAddRect(path, NULL, textFrame);// add it to the path 

    // Create a frame setter with my attributed String 
    CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributedString); 

    //This section declares textPos, which will hold the current position in the text. 
    //It also declares columnIndex, which will count how many columns are already created. 
    int textPos = 0; 
    int columnIndex = 0; 

    while (textPos < [attributedString length]) { 
     //The while loop here runs until we've reached the end of the text. Inside the loop we create a column bounds: colRect is a CGRect which depending on columnIndex holds the origin and size of the current column. Note that we are building columns continuously to the right (not across and then down). 

     CGPoint colOffset = CGPointMake(frameXOffset , frameYOffset); 
     CGRect columnRect = CGRectMake(0, 0 , textFrame.size.width, textFrame.size.height); 

     CGMutablePathRef path = CGPathCreateMutable(); 
     CGPathAddRect(path, NULL, colRect); 

     CTFrameRef frame = CTFramesetterCreateFrame(framesetter, CFRangeMake(textPos, 0), path, NULL); 
     CFRange frameRange = CTFrameGetVisibleStringRange(frame); 

     // MY CUSTOM UIVIEW 
     LSCTView* content = [[[LSCTView alloc] initWithFrame: CGRectMake(0, 0, self.bounds.size.width, self.bounds.size.height)] autorelease]; 
     content.backgroundColor = [UIColor clearColor]; 
     content.frame = CGRectMake(colOffset.x, colOffset.y, columnRect.size.width, columnRect.size.height) ; 

    /************* CREATE A NEW VIEW CONTROLLER WITH view=content *********************/ 

     textPos += frameRange.length; 

     CFRelease(path); 

     columnIndex++; 
    } 
} 

Answer 1

您是否更改了對齊字符串的對齊方式？我有這個samme問題，發現它發生在某些情況下，當文本對齊設置爲kCTJustifiedTextAlignment時，它應該適用於休息類型。