ios开发之--实现TextView提示文字并且输入字数限制

实现字数控制和限制，并展示当前输入的字符串长度，以及按钮的点击状态，代码如下：

1，设置代理

@interface FKViewController ()<UITextViewDelegate>
@property (weak, nonatomic) IBOutlet UITextView *FKTextView;
@property (weak, nonatomic) IBOutlet UILabel *descLab;
@property (weak, nonatomic) IBOutlet UIButton *sendBtn;
@property (weak, nonatomic) IBOutlet UILabel *stringlenghtLab;

2，设置初始状态

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    
    self.view.backgroundColor = BackgroundColor;
    self.navigationController.navigationBarHidden = YES;
    CustomNavigationBar *nav = [[CustomNavigationBar alloc]initWithFrame:CGRectMake(0, 0, KscreenW, NavHeight) withTitle:@"意见反馈" withLeftBtnHidden:NO withRightBtn:YES];
    nav.delegate = self;
    [self.view addSubview:nav];
    
    self.FKTextView.delegate = self;
    self.descLab.userInteractionEnabled = NO;
    self.sendBtn.userInteractionEnabled = NO;
    self.sendBtn.backgroundColor = [UIColor lightGrayColor];
}

3，代理方法的实现

-(void)textViewDidChange:(UITextView *)textView
{
    self.descLab.hidden = YES;
    self.sendBtn.userInteractionEnabled = YES;
    self.sendBtn.backgroundColor = MainColor;
    //实时显示字数
    self.stringlenghtLab.text = [NSString stringWithFormat:@"%ld/100",(long)textView.text.length];
    
    //字数限制
    if (textView.text.length >= 100) {
        textView.text = [textView.text substringToIndex:100];
    }
    
    //取消安润点击权限，并显示文字
    if (textView.text.length == 0) {
        self.descLab.hidden = NO;
        self.sendBtn.userInteractionEnabled = NO;
        self.sendBtn.backgroundColor = [UIColor lightGrayColor];
    }
}

字符串长度为0时，按钮返回初始状态，有输入字符时，显示为可点击状态，很简单，仅做记录用！