很多學習iOS6編程都是從storyboard開始，用到UILabel時是將控件拖到storyboard中生成實現，如果想要在-(void)viewDidLoad中用代碼如[_label initWithFrame:CGRectMake(X,Y,WIDTH,HEIGHT)]方法改變拖拽到storyboard的label的大小是行不通的，因為程序加載時先執行了-(void)viewDidLoad的代碼，然后再加載storyboard，而storyboard會按照拖拽控件時設置的大小來生成label，即覆蓋了在-(void)viewDidLoad中設置的大小，所以要動態設置label的大小應該用代碼實現UILabel的創建。
- 11UILabel * label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 400)];
- [self.view addSubview:label];
或者用下面的代碼來改變label的大小
- label.frame = CGRectMake(97, 47, 223, 19);
設置label的文本內容
- label.text =@"abcd" 或者
- NSString *labelText = @"abcd";
- label.text = labelText;
- label.font = [UIFont systemFontOfSize:12];
- label.font = [UIFont fontWithName:@"Arial" size:30];
設置label的文字顏色
- label.textColor = [UIColor lightGrayColor];
設置文本的對齊方式
- label.textAlignment = NSTextAlignmentLeft;
其中textAlignment有三種設置方式：NSTextAlignmentLeft為向左對齊，NSTextAlignmentCenter為居中對齊，NSTextAlignmentRight為向右對齊
如果有一些文章介紹時用的是UITextAlignmentCenter/UITextAlignmentLeft/UITextAlignmentRight,那是iOS6以前的用法，iOS6的最新用法已改 當文本內容很多，label無法全部顯示時label會將文本內容以省略號的方式代替，下面說一下label文本省略方式的設置
- label.lineBreakMode =NSLineBreakByCharWrapping;
- linBreakMode enum{
- NSLineBreakByWordWrapping = 0,
- NSLineBreakByCharWrapping,
- NSLineBreakByClipping,
- NSLineBreakByTruncatingHead,
- NSLineBreakByTruncatingTail,
- NSLineBreakByTruncatingMiddle
- }
- commentTextLabel.lineBreakMode = NSLineBreakByCharWrapping;
- commentTextLabel.numberOfLines = 0;
- label.numberOfLines =1;
- label.adjustsFontSizeToFitWidth =YES;
- CGSize size = [text sizeWithFont:font constrainedToSize:CGSizeMake(100, 180) lineBreakMode:NSLineBreakByCharWrapping];
來得到字體在某一字號下的高度，判斷與label高度是否一致，其中text是輸入label的文本內容，sizWithFont設置字體，constrainedToSize設置約束文本的矩形大小參數，其中寬度要和label一致，高度設置要足夠高，要比label高很多，否則會出現文本顯示不全的問題，lineBreakMode的作用上文有講過。如果算出的高度超出了label高度，就把字號以循環的方式減小直到高度符合就跳出循環。
- float maxHeight =50;
- float minFontSize =9;
- float height;
- int fontSize = 31;
- NSString *text = @"輸入文本內容";
- do {
- fontSize = fontSize - 1;
- UIFont *font =[UIFont fontWithName:@"Arial" size:fontSize];
- CGSize size = [text sizeWithFont:font constrainedToSize:CGSizeMake(100, 180)
- height = size.height;
- NSLog(@"height=%f,fontSize=%d,text=%@",height,fontSize,text);
- } while (height > maxHeight&&fontSize>minFontSize);
-
- UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 50)];
- label.text =text;
- if (fontSize ==9) {
- label.font = [UIFont fontWithName:@"Arial" size:15];
- }
- else{
- label.font = [UIFont fontWithName:@"Arial" size:fontSize];
- label.lineBreakMode = NSLineBreakByCharWrapping;
- label.numberOfLines = 0;
- }
- [self.view addSubview:label];
- NSString *text =[[NSString alloc]init];
- text = @"輸入文本內容";
- CGSize size = CGSizeMake(280, 180);
- UIFont *fonts = [UIFont systemFontOfSize:14.0];
- CGSize msgSie = [text sizeWithFont:fonts constrainedToSize:size lineBreakMode: NSLineBreakByCharWrapping];
- UILabel *textLabel = [[UILabel alloc] init];
- [textLabel setFont:[UIFont boldSystemFontOfSize:14]];
- textLabel.frame = CGRectMake(20,70, 280,msgSie.height);
- textLabel.text = text;
- textLabel.lineBreakMode = NSLineBreakByCharWrapping;
- textLabel.numberOfLines = 0;
- [self.view addSubview:textLabel];
- label.layer.borderColor = [UIColor lightGrayColor].CGColor;
- label.layer.borderWidth = 1;
- label.backgroundColor =[UIColor yellowColor];
- UILabel * label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 200, 400)];
- UIImageView *imageView =[[UIImageView alloc]init];
- imageView.frame =CGRectMake(50, 50, 200, 400);
- UIImage *image=[UIImage imageNamed:@"1.jpg"];
- imageView.image =image;
- label.backgroundColor = [UIColor clearColor];
- label.text =@"hello world";
- label.font = [UIFont systemFontOfSize:30];
- label.textColor = [UIColor yellowColor];
- [self.view addSubview:imageView];
- [self.view addSubview:label];
UIColor * color = [UIColor colorWithPatternImage:image];
- UILabel * label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 200)];
- [label setBackgroundColor:color];
- [self.view addSubview:label];
- -(UIImage *)scaleImage:(UIImage *)img ToSize:(CGSize)itemSize{
- UIImage *i;
-
- UIGraphicsBeginImageContext(itemSize);
- CGRect imageRect=CGRectMake(0, 0, itemSize.width, itemSize.height);
-
- [img drawInRect:imageRect];
-
- i=UIGraphicsGetImageFromCurrentImageContext();
-
- UIGraphicsEndImageContext();
-
- return i;
- }
- CGSize size= CGSizeMake(100, 200);
- UIImage *image =[UIImage imageNamed:@"1.jpg"];
- UIImage *laterImage =[self scaleImage:image ToSize:size];
- UIColor * color = [UIColor colorWithPatternImage:laterImage];
- UILabel * label = [[UILabel alloc] initWithFrame:CGRectMake(50, 50, 100, 200)];
- [label setBackgroundColor:color];
- [self.view addSubview:label];
- label.shadowColor =[UIColor grayColor];
- label.shadowOffset = CGSizeMake(2.0, 2.0);
- label.layer.cornerRadius = 10;
