UITextView添加planceholder

mainTextView=[[UITextView
alloc]initWithFrame:CGRectMake(50,
100,
200, 80)];

mainTextView.layer.borderColor=[UIColor
grayColor].CGColor;

mainTextView.layer.borderWidth=1.0;

mainTextView.clipsToBounds=YES;

mainTextView.layer.cornerRadius=5.0;

mainTextView.delegate=self;

mainTextView.font=[UIFont
systemFontOfSize:15.0];

[self.view
addSubview:mainTextView];

NSString*str=@"长度在10-200个字之间\n写下购买体会或使用过程中带来的帮助等，\n可以为其他小伙伴提供参考～";

UILabel*planceholder =[[UILabel
alloc]initWithFrame:CGRectMake(0,
0, 80,
60)];

planceholder.text=str;

planceholder.tag=100;

planceholder.numberOfLines=0;

planceholder.font=[UIFont
systemFontOfSize:15.0];

[mainTextView
addSubview:planceholder];

///////////////////////////////////////////////////////////////////////

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

[mainTextView
resignFirstResponder];

}

#pragma mark UITextViewDelegate

-(BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString*)text

{

UILabel*plancehoder=(UILabel*)[mainTextView
viewWithTag:100];

if(![text
isEqualToString:@""]&&![text
isEqualToString:@"\n"])

{

[plancehoder setHidden:YES];

}

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

{

plancehoder.hidden =
NO;

}

if ([text isEqualToString:@"\n"]) {

[textView resignFirstResponder];

return NO;

}

return
YES;

}