iOS 开发之TextView的属性使用和代理方法使用
iOS开发中遇到要写textview的提示文字 写这些东西要用到textview的代理方法
下面有我和大家分享一下是如何实现的吧
1. 要创建一个UITextView 对象和一个Label对象
import "TextViewController.h"
@interface TextViewController ()<UITextViewDelegate>//添加textview的代理
@property(nonatomic,strong) UITextView *textView;
@property(nonatomic,strong) UILabel *promptTitle;
@end
//后面代理方法会用到创建的对象 所以尽量创建一个全局的
self.textView = [[UITextView alloc]initWithFrame:CGRectMake(20, label.frame.size.height +10, 260, 110)];
self.textView.pagingEnabled = YES;
self.textView.clipsToBounds = YES;
self.textView.layer.borderWidth = 1;
self.textView.tag = 100;
self.textView.delegate = self;//将代理设置给本类
[self.view addSubview:self.textView];
//创建Label 加提示语
self.promptTitle = [[UILabel alloc]initWithFrame:CGRectMake(5,5,100,20)];
self.promptTitle.text = @"最多可输入140字";
self.promptTitle.font = [UIFont systemFontOfSize:12.0];
[self.promptTitle setTextColor:[UIColor colorWithRed:190/255.0 green:190/255.0 blue:190/255.0 alpha:0.8]]; //
[self.textView addSubview:self.promptTitle];
2.textView的代理方法
//判断是否超出最大限额 140
- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text{
if ([text isEqualToString:@""] && range.length > 0) {
//删除字符肯定是安全的
return YES;
}
else {
if (textView.text.length - range.length + text.length > 140) {
UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"超出最大可输入长度" message:nil delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];//如果输入的文字大于140 则提示 <span style="font-family: Arial, Helvetica, sans-serif;">"超出最大可输入长度" 并不能继续输入文字</span>
[alert show];
return NO;
}
else {
return YES;
}
}
}
3.点击textview的输入框使其文字隐藏
-(void)textViewDidChange:(UITextView *)textView
{
if(textview.length>0)
{
promptTitle.hidden = yes;
}
else
{
promptTitle.hidden =NO;
}
}
//点击屏幕任意一处取消键盘的第一响应项
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
[self.view endEditing:YES];
}