ios开发之--textview意见反馈页面（占位label，字数统计，提交按钮的交互设置）

@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;

self.FKTextView.delegate = self;
    self.descLab.userInteractionEnabled = NO;
    self.sendBtn.userInteractionEnabled = NO;
    self.sendBtn.backgroundColor = [UIColor lightGrayColor];

-(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];
    }
    
    //取消按钮点击权限，并显示文字
    if (textView.text.length == 0) {
        self.descLab.hidden = NO;
        self.sendBtn.userInteractionEnabled = NO;
        self.sendBtn.backgroundColor = [UIColor lightGrayColor];
    }
}

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