ios開發之UITextView實現首行文字縮排和預設文字例子

在使用UITextView時可能會遇到各種各樣的效果，例如在UITextView首行前面有提示文字，並且後面輸入的內容在提示的文字後面，在輸入之前有預設的文字，輸入過程中預設的文字會消失隱藏，具體實現代碼如下：

#import "UItextviewSuoJinViewController.h"
 
@interface UItextviewSuoJinViewController ()<UITextViewDelegate>{
    //意見內容
    UITextView *contentTextView;
    //在UITextView上面覆蓋個UILable
    UILabel *promptLabel;
}
 
@end
 
@implementation UItextviewSuoJinViewController
 
- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor grayColor];
    //意見內容
    contentTextView = [[UITextView alloc] initWithFrame:CGRectMake(0, kHeaderHeight, kScreenWidth, 86)];
    contentTextView.font = FONT(13);
    contentTextView.delegate = self;
    [self.view addSubview:contentTextView];
    
    UILabel *contentLabel = [[UILabel alloc] initWithFrame:CGRectMake(14, 0, 60, 35)];
    contentLabel.font = FONT(13);
    contentLabel.text = @"*您的意見";
    [contentTextView addSubview:contentLabel];
    
    //在UITextView上面覆蓋個UILable
    promptLabel = [[UILabel alloc] init];
    promptLabel.frame =CGRectMake(5,5,200,25);
    promptLabel.text = @"                         請輸入意見";
    promptLabel.enabled = NO;
    promptLabel.backgroundColor = [UIColor clearColor];
    promptLabel.font =  [UIFont systemFontOfSize:13];
    promptLabel.textColor = RGB(245, 245, 245);
    [contentTextView addSubview:promptLabel];
    
    //改變五角星的顏色
    NSMutableAttributedString *contentStr = [[NSMutableAttributedString alloc] initWithString:contentLabel.text];
    [contentStr addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0, 1)];
    contentLabel.attributedText = contentStr;
}
#pragma mark -UITextView的代理方法
-(void)textViewDidChange:(UITextView *)textView{
    if (textView.text.length == 0) {
        promptLabel.hidden = NO;
    }else{
        promptLabel.hidden = YES;
    }
    //首行縮排
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    paragraphStyle.lineSpacing = 3;    //行間距
    //    paragraphStyle.maximumLineHeight = 60;   /**最大行高*/
    paragraphStyle.firstLineHeadIndent = 93.f;    /**首行縮排寬度*/
    paragraphStyle.alignment = NSTextAlignmentJustified;
    NSDictionary *attributes = @{
                                 NSFontAttributeName:[UIFont systemFontOfSize:13],
                                 NSParagraphStyleAttributeName:paragraphStyle
                                 };
    textView.attributedText = [[NSAttributedString alloc] initWithString:textView.text attributes:attributes];
}

可以將代碼拷到自己的工程檔案中實現看看效果。