UITextField 座位用户交互的一个必备使用的控件，其使用频率较高。
定义一个UITextField 及其基本的属性：
UITextField _telNum = [[UITextField alloc] init];
_telNum.clearsOnBeginEditing = NO;//在输入时不清除原来输入的文字
_telNum.delegate = self;//
[_telNum addTarget:self action:@selector(textFieldDoneEditing:) forControlEvents:UIControlEventEditingDidEndOnExit];//
_telNum.font = [UIFont boldSystemFontOfSize:14];//
_telNum.textColor = [UIColor blackColor];//
_telNum.backgroundColor = [UIColor clearColor];//
_telNum.borderStyle = UITextBorderStyleNone;
_telNum.clearButtonMode = UITextFieldViewModeWhileEditing;
_telNum.autocorrectionType = UITextAutocorrectionTypeNo;
_telNum.autocapitalizationType = UITextAutocapitalizationTypeNone;
_telNum.returnKeyType = UIReturnKeyDefault;
_telNum.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
_telNum.placeholder = @"默认的文本";
_telNum.keyboardType = UIKeyboardTypeNumberPad;//文本输入时，按键弹出的按键为数字
下面为UITextField 的一些代理方法：
1.开始输入文本时，一般需要判断键盘是否遮挡住了UITextField 视图，是的话需要调整整个视图的位置。
-(BOOL)textFieldShouldBeginEditing:(UITextField *)textField {
CGRect textFrame = textField.frame;
float textY = textFrame.origin.y+textFrame.size.height;
float bottomY = self.view.frame.size.height-textY;
if(bottomY<216) //判断当前的高度是否已经有216，如果超过了就不需要再移动主界面的View高度
{
float moveY = 216-bottomY;
prewMoveY = moveY;
NSTimeInterval animationDuration = 0.30f;
CGRect frame = self.view.frame;
frame.origin.y -=moveY;//view的Y轴上移
frame.size.height +=moveY; //View的高度增加
self.view.frame = frame;
[UIView beginAnimations:@"ResizeView" context:nil];
[UIView setAnimationDuration:animationDuration];
self.view.frame = frame;
[UIView commitAnimations];//设置调整界面的动画效果
}
return YES;
}
2. 输入文本结束时，调回输入前的视图布局
-(void ) textFieldDoneEditing:(id) sender{
if (sender == _telNum) {
_payButton.enabled = YES;
NSTimeInterval animationDuration = 0.30f;
CGRect frame = self.view.frame;
//还原界面
frame.origin.y +=prewMoveY;
frame.size. height -=prewMoveY;
self.view.frame = frame;
//self.view移回原位置
[UIView beginAnimations:@"ResizeView" context:nil];
[UIView setAnimationDuration:animationDuration];
self.view.frame = frame;
[UIView commitAnimations];
[sender resignFirstResponder];
}
}
3.决定文本输入的字数，超过一定的范围则弹出提示框：
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (range.location>=11)
{
alertMessage(nil, @"超过了电话号码的长度！");
return NO;
}
else
{
return YES;
}
}