UITextField

#pragma mark - 加载视图
- (void)viewDidLoad {
    [super viewDidLoad];
    
    //   @interface ViewController : UIViewController<UITextFieldDelegate>
    //UITextField常用的输入控件，输用户名或者密码
    //是否显示密码，是否显示提示信息，是否显示清除按钮
    CGRect frame = CGRectMake(20, 20, 150, 40);
    self.textFiel = [[UITextField alloc] initWithFrame:frame];
    self.textFiel.delegate = self;
    //提示信息
    self.textFiel.placeholder = @"这是一个提示信息";
    //边框样式
    self.textFiel.borderStyle = UITextBorderStyleRoundedRect;
    //内容垂直方向对齐
    self.textFiel.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
    //内容水平方向对齐
    self.textFiel.textAlignment = NSTextAlignmentLeft;
    //密码
    self.textFiel.secureTextEntry = YES;
    //是否自动验证输入内容
    self.textFiel.autocorrectionType = UITextAutocorrectionTypeNo;
    //单词首字母大小写
    self.textFiel.autocapitalizationType = UITextAutocapitalizationTypeNone;
    //键盘返回类型
    self.textFiel.returnKeyType = UIReturnKeyDone;
    //编辑时的清除按钮
    self.textFiel.clearButtonMode = UITextFieldViewModeWhileEditing;
    [self.view addSubview:self.textFiel];
    
}
#pragma mark - 做todo事件
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
#pragma mark -
- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField{
    NSLog(@"textFieldShouldBeginEditing");
    return YES;
}
- (void)textFieldDidBeginEditing:(UITextField *)textField{
    NSLog(@"textFieldDidBeginEditing");
}
- (BOOL)textFieldShouldEndEditing:(UITextField *)textField{
    NSLog(@"textFieldShouldEndEditing");
    return YES;
}
- (void)textFieldDidEndEditing:(UITextField *)textField{
    NSLog(@"textFieldDidEndEditing");
}

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    NSLog(@"shouldChangeCharactersInRange");
    return YES;
}

- (BOOL)textFieldShouldClear:(UITextField *)textField{
    NSLog(@"textFieldShouldClear");
    return YES;
}

- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    //隐藏键盘
    [self.textFiel resignFirstResponder];
    NSLog(@"textFieldShouldReturn");
    return YES;
}

点击next，下一个文本域聚焦（光标移到下一个文本域）和最后一个之后就关闭键盘

#pragma mark - 点击next或者done事件
- (BOOL)textFieldShouldReturn:(UITextField *)textField{
    if (textField == _inputCardNumber) {
        [_inputBirthDay becomeFirstResponder];
    }else if(textField == _inputBirthDay){
        [_inputIDNumber becomeFirstResponder];
    }else if(textField == _inputIDNumber){
        [_inputCardCheckNumber becomeFirstResponder];
    }else if(textField==_inputCardCheckNumber){
        [_inputPhoneNumber becomeFirstResponder];
    }else if(textField == _inputPhoneNumber){
        [_inputCardNumber resignFirstResponder];
        [_inputPhoneNumber resignFirstResponder];
        [_inputIDNumber resignFirstResponder];
        [_inputBirthDay resignFirstResponder];
        [_inputCardCheckNumber resignFirstResponder];
        return YES;
    }
    [self scrolleInputViewToFitKeyboard:kbHeight animationDuration:keyboardAnimationDuration];
    return  YES;
}

键盘弹出来的时候，整个view上移动

#pragma mark - keyboard events
- (void) keyboardWillShow:(NSNotification *)notification {
    //获取键盘高度，在不同设备上，以及中英文下是不同的
    kbHeight = [[notification.userInfo objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue].size.height;
    // 取得键盘的动画时间，这样可以在视图上移的时候更连贯
    keyboardAnimationDuration = [[notification.userInfo objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    [self scrolleInputViewToFitKeyboard:kbHeight animationDuration:keyboardAnimationDuration];
   
}
#pragma mark - 滚动屏幕
- (void) scrolleInputViewToFitKeyboard:(CGFloat)keyHeight animationDuration: (double) duration{
    //计算出键盘顶端到底端的距离
    CGFloat inputViewContainerPositionY = _inputViewContainer.frame.origin.y;
    CGFloat responsPositionY = responsView.frame.origin.y;
    CGFloat responsPositionHeight = responsView.frame.size.height;
    CGFloat viewHeight = self.view.frame.size.height;
    CGFloat offset = inputViewContainerPositionY + responsPositionY + responsPositionHeight/2 - (viewHeight - kbHeight);
    
    //将视图上移计算好的偏移
    if(offset > 0) {
        [UIView animateWithDuration:duration animations:^{
            self.view.frame = CGRectMake(0.0f, -offset, self.view.frame.size.width, self.view.frame.size.height);
        }];
    }

}

设置密码形式

1.通过XIB方式实现：

将UITextField中的secure选项勾中即可。 

storyboard 勾选 Secure Text Entry即可

2.通过代码实现：

UItextField * test = [ UItextField alloc] init ];
test.secureTextEntry = YES;

以上两种方式实现文本框的密码样式。

几个密码框组成密码控件，下一个聚焦和删除之后聚焦下一个

注意 返回 NO 此次编辑的文字不会写在第一响应的文本框里面，这里强调第一响应，如果设置为YES 那么就是会显示在下一个文本域里面了，这也是为什么 写了一个之后，就显示在下一个里面了。

#pragma mark - 文本框改变内容 -
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    NSLog(@"%d",range.location);//0代表有一位数 1是两位数,代表光标位置
    NSLog(@"%d",range.length);//长度  0 为增加一位数  1为删除一位数
    NSLog(@"%@",string);
    textField.text = string;//设置文字
    
    if (textField == _textfieldPWD0) {
        if(range.length == 0){//增加 移到下一位
            [_textfieldPWD1 becomeFirstResponder];//获得第一响应焦点
        }
        return NO;
    }else if(textField == _textfieldPWD5){
        if (range.length == 0) {
            [self resignPWDFirstResponder];
        }else{
            [_textfieldPWD4 becomeFirstResponder];
        }
        return NO;
    }
    
    int length = [textfiledPWDs count];
    for (int i = 1; i < length - 1; i++) {
        if (textField == [textfiledPWDs objectAtIndex:i]) {
            if (range.length == 0) {
                [[textfiledPWDs objectAtIndex:i+1] becomeFirstResponder];
            }else{
                [[textfiledPWDs objectAtIndex:i-1] becomeFirstResponder];
            }
            return NO;
        }
    }
    //返回 NO 此次编辑的文字不会被写到第一响应的文本域里面
    return NO;
}