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，最典型的就是導航欄顯示的標題文字，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 復制代碼#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); //設置一個行高上限
// 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 //動畫重復的主開關
// |UIViewAnimationOptionAutoreverse //動畫重復自動反向，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) {
}
];
}
}
注：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 復制代碼- (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)];
//設置顯示文字
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";
//設置字體:粗體，正常的是 SystemFontOfSize
label1.font = [UIFont boldSystemFontOfSize:20];
//設置文字顏色
label1.textColor = [UIColor orangeColor];
label2.textColor = [UIColor purpleColor];
//設置文字位置
label1.textAlignment = UITextAlignmentRight;
label2.textAlignment = UITextAlignmentCenter;
//設置字體大小適應label寬度
label4.adjustsFontSizeToFitWidth = YES;
//設置label的行數
label5.numberOfLines = 2;
UIlabel.backgroudColor=[UIColor clearColor]; //可以去掉背景色
//設置高亮
label6.highlighted = YES;
label6.highlightedTextColor = [UIColor orangeColor];
//設置陰影
label7.shadowColor = [UIColor redColor];
label7.shadowOffset = CGSizeMake(1.0,1.0);
//設置是否能與用戶進行交互
label7.userInteractionEnabled = YES;
//設置label中的文字是否可變，默認值是YES
label3.enabled = NO;
//設置文字過長時的顯示格式
label3.lineBreakMode = UILineBreakModeMiddleTruncation;//截去中間
// typedef enum {
// UILineBreakModeWordWrap = 0,
// UILineBreakModeCharacterWrap,
// UILineBreakModeClip,//截去多余部分
// UILineBreakModeHeadTruncation,//截去頭部
// UILineBreakModeTailTruncation,//截去尾部
// UILineBreakModeMiddleTruncation,//截去中間
// } UILineBreakMode;
//如果adjustsFontSizeToFitWidth屬性設置為YES，這個屬性就來控制文本基線的行為
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
