UITextView控件的用法详解

1.创建并初始化
创建UITextView的文件，并在.h文件中写入如下代码：

 #import <UIKit/UIKit.h>
 
 @interface TextViewController : UIViewController <UITextViewDelegate>{
       UITextView *textView;
 }
 
 @property (nonatomic, retain) UITextView *textView;  
@end

在.m文件中初始化这个textview，写入代码如下：

 

self.textView = [[[UITextView  alloc] initWithFrame:self.view.frame] autorelease]; //初始化大小并自动释放
 
 self.textView.textColor = [UIColor blackColor];//设置textview里面的字体颜色  
 
 self.textView.font = [UIFont fontWithName:@"Arial" size:18.0];//设置字体名字和字体大小  
 
 self.textView.delegate = self;//设置它的委托方法  
 
 self.textView.backgroundColor = [UIColor whiteColor];//设置它的背景颜色
 
 self.textView.text = @"Now is the time for all good developers to come to serve their country.\n\nNow is the time for all good developers to come to serve their country.";//设置它显示的内容  
 
 self.textView.returnKeyType = UIReturnKeyDefault;//返回键的类型  
 
 self.textView.keyboardType = UIKeyboardTypeDefault;//键盘类型  
 
 self.textView.scrollEnabled = YES;//是否可以拖动  
 
 self.textView.autoresizingMask = UIViewAutoresizingFlexibleHeight;//自适应高度
 
 [self.view addSubview: self.textView];//加入到整个页面中 

文本字段实现了UITextInputTrait协议，其提供了7个属性来定义字段处理文本输入的方式：autocapitalizationType、autocorrectionType、enablesReturnKeyAutomatically、keyboardAppearance、keyboardType、returnKeyType、secureTextEntry。

其它，当文本字段为空时，placeholder文本以浅灰色显示，提供一个用户提示。通过设置clearButtonMode可以指定是否以及何时显示清除按钮。
2. UITextView退出键盘的几种方式

（1）如果你程序是有导航条的，可以在导航条上面加多一个Done的按钮，用来退出键盘，当然要先实现UITextViewDelegate。

- (void)textViewDidBeginEditing:(UITextView *)textView {    

   UIBarButtonItem *done =    [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(leaveEditMode)] ;    
   self.navigationItem.rightBarButtonItem = done;        
}    

- (void)textViewDidEndEditing:(UITextView *)textView {    
    self.navigationItem.rightBarButtonItem = nil;  
}

- (void)leaveEditMode {
    [self.textView resignFirstResponder];   
}

（2）如果你的textview里不用回车键，可以把回车键当做退出键盘的响应键。

#pragma mark - UITextView Delegate Methods     

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text
{    
    if ([text isEqualToString:@"\n"]) {    
        [textView resignFirstResponder];    
        return NO;    
    }

    return YES;    
}

（3）还有你也可以自定义其他视图控件加载到键盘上用来退出，比如在弹出的键盘上面加一个view来放置退出键盘的Done按钮。

 UIToolbar * topView = [[UIToolbar alloc]initWithFrame:CGRectMake(0, 0, 320, 30)];  
 
     [topView setBarStyle:UIBarStyleBlack];  
 
     UIBarButtonItem * helloButton = [[UIBarButtonItem alloc]initWithTitle:@"Hello" style:UIBarButtonItemStyleBordered target:self action:nil];        
 
     UIBarButtonItem * btnSpace = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace target:self action:nil];  
 
       
 
     UIBarButtonItem * doneButton = [[UIBarButtonItem alloc]initWithTitle:@"Done" style:UIBarButtonItemStyleDone target:self action:@selector(dismissKeyBoard)];  
 
     NSArray * buttonsArray = [NSArray arrayWithObjects:helloButton,btnSpace,doneButton,nil];  
 
     [doneButton release];  
 
     [btnSpace release];  
 
     [helloButton release];  
 
     [topView setItems:buttonsArray];  
 
     [tvTextView setInputAccessoryView:topView];  
 
 -(IBAction)dismissKeyBoard  
 
 {  
 
     [tvTextView resignFirstResponder];  

}