1.在viewdidload中添加一个默认字体的lable
placeHoderLable = [[UILabel alloc]initWithFrame:CGRectMake(3, 3, DeviceWidth-6, 40)];//根据情况调节位置
placeHoderLable.enabled = NO;
placeHoderLable.text = @"请在这里输入您要预测的内容，您的预言需要经过其他用户的审核才能发布。";
placeHoderLable.numberOfLines=0;
placeHoderLable.font = [UIFont systemFontOfSize:12];
placeHoderLable.textColor = [UIColor lightGrayColor];
[_myTextView addSubview:placeHoderLable];
_myTextView.delegate=self;//记得设置textview的代理
_myTextView.returnKeyType=UIReturnKeyDone;
2.在textview的代理方法中实现以下代码
-(void)textViewDidChange:(UITextView *)textView
{
if ([_myTextView.text length] == 0) {
[placeHoderLable setHidden:NO];
}else{
[placeHoderLable setHidden:YES];
}
}
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText: (NSString *)text
{
if([text isEqualToString:@"\n"]){
[textView resignFirstResponder];
return NO;
}
if (range.location>=100)
{
_yuNumLable.text=@"还能输入0字";
return NO;
}
else
{
_yuNumLable.text=[NSString stringWithFormat:@"还能输入%lu字",100-range.location];
return YES;
}
}
