titanium 插件：validate ( titanium validate module)

refer to:   https://github.com/haberdasheryjs/hdjs.validate.js ，它基于 validate.js 

另外还有个插件：https://github.com/mwfire/titanium-module-validation，但是由于它大量的使用了 createXXField方法，属于view 与controller耦合的相当严重，所以不考虑。 （但是作者还是很有才的）

表单验证是永远需要的插件。这个的用法：

in your app/lib:  hdjs.validate.js 

in your view:

<Alloy>
  <Window id="win">
    <ScrollView>
      <View id="container">
        <TextField id="nameField" hintText='Enter name' />
        <TextField id="emailField" hintText='Enter email address' />
        <TextField id="passwordField" passwordMask="true" hintText='Enter password' />
        <View id="privacyContainer">
          <Label id="privacyLabel" text="Posts are private" />
          <Switch id="privacySwitch" value="false" />
        </View>
        <Button id="submitButton" class="button" title="Submit" />
      </View>
    </ScrollView>
  </Window>
</Alloy>

in your controller:

var validate = require('hdjs.validate');
var validator = new validate.FormValidator();

var validationCallback = function(errors) {
	if(errors.length > 0) {
		for (var i = 0; i < errors.length; i++) {
			Ti.API.debug(errors[i].message);
		}
		alert(errors[0].message);
	} else {
		alert('Hooray! Your form is valid!');
	}
};


var returnCallback = function() {
	validator.run([
				{
					id: 'nameField',
				    value: $.nameField.value,
				    display: 'Name',    
				    rules: 'required|min_length[6]|max_length[12]'
				},
				{
					id: 'emailField',
				    value: $.emailField.value,
				    display: 'Email',    
				    rules: 'required|valid_email'
				},
				{
					id: 'passwordField',
				    value: $.passwordField.value,
				    display: 'Password',    
				    rules: 'required|alpha_numeric|exact_length[10]'
				},
				{
					id: 'privacyField',
				    value: $.privacySwitch.value,
				    display: 'Privacy',    
				    rules: 'matches[true]'
				}
			], validationCallback);	
};

$.submitButton.addEventListener('click', returnCallback);

$.win.open();

补充： 如果不使用插件的话，你的代码看起来就是这样的： （感谢：https://gist.github.com/dawsontoth/812022 )

function validateForm() {
    var formIsValid = true;
    function enforceTextFieldMinLength(field, minLength) {
        if (!field.value || field.value.length < minLength) {
            formIsValid = false;
        }
    }
    function enforceLabelHasText(label) {
        if (!label.text) {
            formIsValid = false;
        }
    }
    // check first name
    enforceTextFieldMinLength(tfFirstName, 5);
    // check last name
    enforceTextFieldMinLength(tfLastName, 5);
    // check label connected to gender drop down
    enforceLabelHasText(lGender);
    if (formIsValid) {
        alert('Form is valid!');
    }
    else {
        alert('Form is invalid...');
    }
}