蘋果iOS UILabel文字跑馬燈效果

在實際開發過程中，我們會遇到這樣的情況，一句話太長，顯示不完全，最典型的就是導覽列顯示的標題文字，如果過長的文字就會出現顯示不完全的情況，用UILabel可以實現跑馬燈的效果，將文字展示完整。具體代碼如下：

代碼如下

複製代碼

#pragma mark - 動畫 -(void)startAnimationIfNeeded{     //取消、停止所有的動畫     [titleLabel.layer removeAllAnimations]; //這裡的titleLabel就是要實現跑馬燈文字的label          CGSize size = CGSizeMake(320,2000); //設定一個行高上限      //    CGSize textSize = [titleLabel.text sizeWithFont:titleLabel.font];     NSDictionary *attribute = @{NSFontAttributeName: titleLabel.font};     CGSize textSize = [titleLabel.text boundingRectWithSize:size options: NSStringDrawingTruncatesLastVisibleLine attributes:attribute context:nil].size;       CGRect lframe = titleLabel.frame;     lframe.size.width = textSize.width;     titleLabel.frame = lframe;     const float oriWidth = 10;     if (textSize.width > oriWidth) {         float offset = textSize.width - oriWidth;         [UIView animateWithDuration:18.0                               delay:0                             options:          UIViewAnimationOptionRepeat //動畫重複的主開關 //         |UIViewAnimationOptionAutoreverse //動畫重複自動反向，需要和上面這個一起用          | UIViewAnimationOptionCurveLinear //動畫的時間曲線，滾動字幕線性比較合理                          animations:^{                              titleLabel.transform = CGAffineTransformMakeTranslation(- offset - 400, 0);                          }                          completion:^(BOOL finished) {                                                        }          ];     } }

註：跑動的距離寬度可根據自己的需要對方法進行修改，動畫跑動的速度也可以修改的，效果看起來還不錯。

再補充一篇

代碼如下

複製代碼

- (void)viewDidLoad {         UILabel *label1 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 20.0, 200.0, 50.0)];         UILabel *label2 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 80.0, 200.0, 50.0)];         UILabel *label3 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 140.0, 200.0, 50.0)];         UILabel *label4 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 200.0, 200.0, 50.0)];         UILabel *label5 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 260.0, 200.0, 50.0)];         UILabel *label6 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 320.0, 200.0, 50.0)];         UILabel *label7 = [[UILabel alloc]initWithFrame:CGRectMake(50.0, 380.0, 200.0, 50.0)];         //設定顯示文字         label1.text = @"label1";         label2.text = @"label2";         label3.text = @"label3--label3--label3--label3--label3--label3--label3--label3--label3--label3--label3--";         label4.text = @"label4--label4--label4--label4--";         label5.text = @"label5--label5--label5--label5--label5--label5--";         label6.text = @"label6";         label7.text = @"label7";         //設定字型:粗體，正常的是 SystemFontOfSize         label1.font = [UIFont boldSystemFontOfSize:20];         //設定文字顏色      label1.textColor = [UIColor orangeColor];         label2.textColor = [UIColor purpleColor];         //設定文字位置         label1.textAlignment = UITextAlignmentRight;         label2.textAlignment = UITextAlignmentCenter;         //設定字型大小適應label寬度         label4.adjustsFontSizeToFitWidth = YES;           //設定label的行數         label5.numberOfLines = 2;        UIlabel.backgroudColor=[UIColor clearColor]; //可以去掉背景色         //設定高亮         label6.highlighted = YES;         label6.highlightedTextColor = [UIColor orangeColor];         //設定陰影         label7.shadowColor = [UIColor redColor];         label7.shadowOffset = CGSizeMake(1.0,1.0);         //設定是否能與使用者進行互動         label7.userInteractionEnabled = YES;         //設定label中的文字是否可變，預設值是YES         label3.enabled = NO;         //設定文字過長時的顯示格式         label3.lineBreakMode = UILineBreakModeMiddleTruncation;//截去中間     //  typedef enum {     //      UILineBreakModeWordWrap = 0,     //      UILineBreakModeCharacterWrap,     //      UILineBreakModeClip,//截去多餘部分     //      UILineBreakModeHeadTruncation,//截去頭部     //      UILineBreakModeTailTruncation,//截去尾部     //      UILineBreakModeMiddleTruncation,//截去中間     //  } UILineBreakMode;         //如果adjustsFontSizeToFitWidth屬性設定為YES，這個屬性就來控制文本基準的行為         label4.baselineAdjustment = UIBaselineAdjustmentNone;     //  typedef enum {     //      UIBaselineAdjustmentAlignBaselines,     //      UIBaselineAdjustmentAlignCenters,     //      UIBaselineAdjustmentNone,     //  } UIBaselineAdjustment;         [self.view addSubview:label1];         [self.view addSubview:label2];         [self.view addSubview:label3];         [self.view addSubview:label4];         [self.view addSubview:label5];         [self.view addSubview:label6];         [self.view addSubview:label7];         [label1 release];         [label2 release];         [label3 release];         [label4 release];         [label5 release];         [label6 release];         [label7 release];         [super viewDidLoad];     }     /*    // Override to allow orientations other than the default portrait orientation.    - (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {    // Return YES for supported orientations    return (interfaceOrientation == UIInterfaceOrientationPortrait);    }    */    - (void)didReceiveMemoryWarning {         // Releases the view if it doesn't have a superview.         [super didReceiveMemoryWarning];         // Release any cached data, images, etc that aren't in use.     }     - (void)viewDidUnload {         // Release any retained subviews of the main view.         // e.g. self.myOutlet = nil;     }     - (void)dealloc {         [super dealloc];     }     @end