UITextView的常用方法

1.創建並初始化

創建UITextView的文件，並在.h文件中寫入如下代碼：

<span style="font-family:Times New Roman;font-size:14px;"><strong>#import <UIKit/UIKit.h>

@interface TextViewController : UIViewController <UITextViewDelegate>{
      UITextView *textView;
}

@property (nonatomic, retain) UITextView *textView; 

@end</strong></span>

在.m文件中初始化這個textview，寫入代碼如下

<span style="font-family:Times New Roman;font-size:14px;"><strong>self.textView = [[[UITextView  alloc] initWithFrame:self.view.frame] autorelease]; //初始化大小並自動釋放

self.textView.textColor = [UIColor blackColor];//設置textview裏面的字體顏色  

self.textView.font = [UIFont fontWithName:@"Arial" size:18.0];//設置字體名字和字體大小  

self.textView.delegate = self;//設置它的委託方法  

self.textView.backgroundColor = [UIColor whiteColor];//設置它的背景顏色

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.";//設置它顯示的內容  

self.textView.returnKeyType = UIReturnKeyDefault;//返回鍵的類型  

self.textView.keyboardType = UIKeyboardTypeDefault;//鍵盤類型  

self.textView.scrollEnabled = YES;//是否可以拖動  

self.textView.autoresizingMask = UIViewAutoresizingFlexibleHeight;//自適應高度

[self.view addSubview: self.textView];//加入到整個頁面中</strong></span>

2. UITextView退出鍵盤的幾種方式
（1）如果你程序是有導航條的，可以在導航條上面加多一個Done的按鈕，用來退出鍵盤，當然要先實現UITextViewDelegate。

<span style="font-family:Times New Roman;font-size:14px;"><strong>- (void)textViewDidBeginEditing:(UITextView *)textView {    

   UIBarButtonItem *done =    [[[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDone target:self action:@selector(leaveEditMode)] autorelease];    

   self.navigationItem.rightBarButtonItem = done;        

}    

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

    self.navigationItem.rightBarButtonItem = nil;  

} 

- (void)leaveEditMode {

    [self.textView resignFirstResponder];   

}</strong></span>

（2）如果你的textview裏不用回車鍵，可以把回車鍵當做退出鍵盤的響應鍵。

<span style="font-family:Times New Roman;"><strong><span style="font-size:14px;">#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;    

}</span></strong></span>

（3）還有你也可以自定義其他視圖控件加載到鍵盤上用來退出，比如在彈出的鍵盤上面加一個view來放置退出鍵盤的Done按鈕。

<span style="font-family:Times New Roman;font-size:14px;"><strong>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];  

}</strong></span>

3. UITextView根據內容自動調試高度

（1）使用sizeWithFont在編輯過程中調節高度

<span style="font-family:Times New Roman;color:#000000;">- (void)textViewDidChange:(UITextView *)textView{

if(textView.text.length > 20)//一行最多多少字節

{

        //TextView底面背景圖片根據內容自動調整高度

UIImage *img = [UIImage imageWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@”inputbox”ofType:@”png”]];

[BgImage setImage:[img stretchableImageWithLeftCapWidth:21 topCapHeight:14]];


UIFont *font = [UIFont systemFontOfSize:12];

CGSize size = [textView.text sizeWithFont:font constrainedToSize:CGSizeMake(320, 140)lineBreakMode:UILineBreakModeWordWrap];

BgImage.frame = CGRectMake(0, 202-size.height+15, 320, size.height+28);

InputTextVeiw.contentInset = UIEdgeInsetsZero;//以換行爲基準

[textView setFrame:CGRectMake(51, 210-size.height+18, 200, size.height+5)];

}

}</span>

（2）使用boundingRectWithsizet在編輯過程中調節高度

-(void)textViewDidChange:(UITextView *)textView{
    
   CGFloat height = [textView.text boundingRectWithSize:CGSizeMake(textView.frame.size.width,
<span style="font-family:Times New Roman;">                                             </span> CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin|
<span style="font-family:Times New Roman;">                                              </span>NSStringDrawingUsesFontLeading attributes:[NSDictionary 
<span style="font-family:Times New Roman;">                                             </span>dictionaryWithObjectsAndKeys:[UIFont systemFontOfSize:[textView.font pointSize]],
<span style="font-family:Times New Roman;">                                              </span>NSFontAttributeName, nil] context:nil].size.height;
    
       textView.frame = CGRectMake(textView.frame.origin.x, textView.frame.origin.y, 
<span style="font-family:Times New Roman;">                                                         </span>textView.frame.size.width, height);
 
}

4. UITextView根據設置行距
（1）如果只是靜態顯示textView的內容爲設置的行間距，執行如下代碼

<span style="font-family:Times New Roman;color:#000000;">//    textview 改變字體的行間距 
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init]; 
    paragraphStyle.lineSpacing = 10;// 字體的行間距 
     
    NSDictionary *attributes = @{ 
                                 NSFontAttributeName:[UIFont systemFontOfSize:15], 
                                 NSParagraphStyleAttributeName:paragraphStyle 
                                 }; 
    textView.attributedText = [[NSAttributedString alloc] initWithString:@"輸入你的內容" attributes:attr</span><span style="color:#000000;">ibutes];</span>

（2）如果是想在輸入內容的時候就按照設置的行間距進行動態改變，那就需要將上面代碼放到textView的delegate方法裏

-(void)textViewDidChange:(UITextView *)textView

{

    //    textview 改變字體的行間距

    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

    paragraphStyle.lineSpacing = 20;// 字體的行間距

    NSDictionary *attributes = @{

                                 NSFontAttributeName:[UIFont systemFontOfSize:15],

                                 NSParagraphStyleAttributeName:paragraphStyle

                                 };

    textView.attributedText = [[NSAttributedString alloc] initWithString:textView.text attributes:attributes];

}

4. UITextView設置Placeholder
(1)UITextView上如何加上類似於UITextField的placeholder呢，我們可以在UITextView上加一個UILabel或者一個UITextView，在適當的適合出現或隱藏就好

<span style="font-family:Times New Roman;font-size:14px;"><strong>- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text

{    if (![text isEqualToString:@""])

        {

            _placeholderLabel.hidden = YES;

        }

     if ([text isEqualToString:@""] && range.location == 0 && range.length == 1)

        {

            _placeholderLabel.hidden = NO;

        }

    return YES;

}</strong></span>

注意點：

     (1) _placeholderLabel 是加在UITextView後面的UITextView，_placeholderLabel要保證和真正的輸入框的設置一樣，字體設置成淺灰色，然後[_placeholderLabel setEditable:NO];真正的輸入框要設置背景色透明，保證能看到底部的_placeholderLabel。

    (2) [text isEqualToString:@""] 表示輸入的是退格鍵

    (3) range.location == 0 && range.length == 1 表示輸入的是第一個字符

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