仿Angular Bootstrap TimePicker创建分钟数-秒数的输入控件

在一个项目中需要一个用来输入分钟数和秒数的控件，然而调查了一些开源项目后并未发现合适的控件。在Angular Bootstrap UI中有一个类似的控件TimePicker，但是它并没有深入到分钟和秒的精度。
因此，决定参考它的源码然后自己进行实现。 
最终的效果如下：

首先是该directive的定义：

 app.directive('minuteSecondPicker', function() {
 return {
 restrict: 'EA',
 require: ['minuteSecondPicker', '?^ngModel'],
 controller: 'minuteSecondPickerController',
 replace: true,
 scope: {
  validity: '='
 },
 templateUrl: 'partials/directives/minuteSecondPicker.html',
 link: function(scope, element, attrs, ctrls) {
  var minuteSecondPickerCtrl = ctrls[0],
  ngModelCtrl = ctrls[1];

  if(ngModelCtrl) {
  minuteSecondPickerCtrl.init(ngModelCtrl, element.find('input'));
  }
 }
 };
});

在以上的link函数中，ctrls是一个数组： ctrls[0]是定义在本directive上的controller实例，ctrls[1]是ngModelCtrl，即ng-model对应的controller实例。这个顺序实际上是通过require: ['minuteSecondPicker', '?^ngModel']定义的。
注意到第一个依赖就是directive本身的名字，此时会将该directive中controller声明的对应实例传入。第二个依赖的写法有些奇怪："?^ngModel"，?的含义是即使没有找到该依赖，也不要抛出异常，即该依赖是一个可选项。^的含义是查找父元素的controller。
然后，定义该directive中用到的一些默认设置，通过constant directive实现：

app.constant('minuteSecondPickerConfig', {
 minuteStep: 1,
 secondStep: 1,
 readonlyInput: false,
 mousewheel: true
});

紧接着是directive对应的controller，它的声明如下：

 app.controller('minuteSecondPickerController', ['$scope', '$attrs', '$parse', 'minuteSecondPickerConfig',
 function($scope, $attrs, $parse, minuteSecondPickerConfig) {
 ...
}]); 

在directive的link函数中，调用了此controller的init方法：

 this.init = function(ngModelCtrl_, inputs) {
 ngModelCtrl = ngModelCtrl_;
 ngModelCtrl.$render = this.render;

 var minutesInputEl = inputs.eq(0),
  secondsInputEl = inputs.eq(1);

 var mousewheel = angular.isDefined($attrs.mousewheel) ?
  $scope.$parent.$eval($attrs.mousewheel) : minuteSecondPickerConfig.mousewheel;
 if(mousewheel) {
  this.setupMousewheelEvents(minutesInputEl, secondsInputEl);
 }

 $scope.readonlyInput = angular.isDefined($attrs.readonlyInput) ?
  $scope.$parent.$eval($attrs.readonlyInput) : minuteSecondPickerConfig.readonlyInput;
 this.setupInputEvents(minutesInputEl, secondsInputEl);
 };

init方法接受的第二个参数是inputs，在link函数中传入的是：element.find('input')。 所以第一个输入框用来输入分钟，第二个输入框用来输入秒。
然后，检查是否覆盖了mousewheel属性，如果没有覆盖则使用在constant中设置的默认mousewheel，并进行相关设置如下：

// respond on mousewheel spin
 this.setupMousewheelEvents = function(minutesInputEl, secondsInputEl) {
 var isScrollingUp = function(e) {
  if(e.originalEvent) {
  e = e.originalEvent;
  }

  // pick correct delta variable depending on event
  var delta = (e.wheelData) ? e.wheelData : -e.deltaY;
  return (e.detail || delta > 0);
 };

 minutesInputEl.bind('mousewheel wheel', function(e) {
  $scope.$apply((isScrollingUp(e)) ? $scope.incrementMinutes() : $scope.decrementMinutes());
  e.preventDefault();
 });

 secondsInputEl.bind('mousewheel wheel', function(e) {
  $scope.$apply((isScrollingUp(e)) ? $scope.incrementSeconds() : $scope.decrementSeconds());
  e.preventDefault();
 });
 };

init方法最后会对inputs本身进行一些设置：

// respond on direct input
 this.setupInputEvents = function(minutesInputEl, secondsInputEl) {
 if($scope.readonlyInput) {
  $scope.updateMinutes = angular.noop;
  $scope.updateSeconds = angular.noop;
  return;
 }

 var invalidate = function(invalidMinutes, invalidSeconds) {
  ngModelCtrl.$setViewValue(null);
  ngModelCtrl.$setValidity('time', false);
  $scope.validity = false;
  if(angular.isDefined(invalidMinutes)) {
  $scope.invalidMinutes = invalidMinutes;
  }
  if(angular.isDefined(invalidSeconds)) {
  $scope.invalidSeconds = invalidSeconds;
  }
 };

 $scope.updateMinutes = function() {
  var minutes = getMinutesFromTemplate();

  if(angular.isDefined(minutes)) {
  selected.minutes = minutes;
  refresh('m');
  } else {
  invalidate(true);
  }
 };

 minutesInputEl.bind('blur', function(e) {
  if(!$scope.invalidMinutes && $scope.minutes < 10) {
  $scope.$apply(function() {
   $scope.minutes = pad($scope.minutes);
  });
  }
 });

 $scope.updateSeconds = function() {
  var seconds = getSecondsFromTemplate();

  if(angular.isDefined(seconds)) {
  selected.seconds = seconds;
  refresh('s');
  } else {
  invalidate(undefined, true);
  }
 };

 secondsInputEl.bind('blur', function(e) {
  if(!$scope.invalidSeconds && $scope.seconds < 10) {
  $scope.$apply(function() {
   $scope.seconds = pad($scope.seconds);
  });
  }
 });
 };

此方法中，声明了用于设置输入非法的invalidate函数，它会在scope中暴露一个validity = false属性让页面有机会做出合适的反应。
 如果用户使用了一个变量来表示minuteStep或者secondStep，那么还需要设置相应的watchers：

var minuteStep = minuteSecondPickerConfig.minuteStep;
 if($attrs.minuteStep) {
 $scope.parent.$watch($parse($attrs.minuteStep), function(value) {
  minuteStep = parseInt(value, 10);
 });
 }

 var secondStep = minuteSecondPickerConfig.secondStep;
 if($attrs.secondStep) {
 $scope.parent.$watch($parse($attrs.secondStep), function(value) {
  secondStep = parseInt(value, 10);
 });
 }

完整的directive实现代码如下：

var app = angular.module("minuteSecondPickerDemo");

app.directive('minuteSecondPicker', function() {
 return {
 restrict: 'EA',
 require: ['minuteSecondPicker', '?^ngModel'],
 controller: 'minuteSecondPickerController',
 replace: true,
 scope: {
  validity: '='
 },
 templateUrl: 'partials/directives/minuteSecondPicker.html',
 link: function(scope, element, attrs, ctrls) {
  var minuteSecondPickerCtrl = ctrls[0],
  ngModelCtrl = ctrls[1];

  if(ngModelCtrl) {
  minuteSecondPickerCtrl.init(ngModelCtrl, element.find('input'));
  }
 }
 };
});

app.constant('minuteSecondPickerConfig', {
 minuteStep: 1,
 secondStep: 1,
 readonlyInput: false,
 mousewheel: true
});

app.controller('minuteSecondPickerController', ['$scope', '$attrs', '$parse', 'minuteSecondPickerConfig',
 function($scope, $attrs, $parse, minuteSecondPickerConfig) {

 var selected = {
  minutes: 0,
  seconds: 0
 },
 ngModelCtrl = {
  $setViewValue: angular.noop
 };

 this.init = function(ngModelCtrl_, inputs) {
 ngModelCtrl = ngModelCtrl_;
 ngModelCtrl.$render = this.render;

 var minutesInputEl = inputs.eq(0),
  secondsInputEl = inputs.eq(1);

 var mousewheel = angular.isDefined($attrs.mousewheel) ?
  $scope.$parent.$eval($attrs.mousewheel) : minuteSecondPickerConfig.mousewheel;
 if(mousewheel) {
  this.setupMousewheelEvents(minutesInputEl, secondsInputEl);
 }

 $scope.readonlyInput = angular.isDefined($attrs.readonlyInput) ?
  $scope.$parent.$eval($attrs.readonlyInput) : minuteSecondPickerConfig.readonlyInput;
 this.setupInputEvents(minutesInputEl, secondsInputEl);
 };

 var minuteStep = minuteSecondPickerConfig.minuteStep;
 if($attrs.minuteStep) {
 $scope.parent.$watch($parse($attrs.minuteStep), function(value) {
  minuteStep = parseInt(value, 10);
 });
 }

 var secondStep = minuteSecondPickerConfig.secondStep;
 if($attrs.secondStep) {
 $scope.parent.$watch($parse($attrs.secondStep), function(value) {
  secondStep = parseInt(value, 10);
 });
 }

 // respond on mousewheel spin
 this.setupMousewheelEvents = function(minutesInputEl, secondsInputEl) {
 var isScrollingUp = function(e) {
  if(e.originalEvent) {
  e = e.originalEvent;
  }

  // pick correct delta variable depending on event
  var delta = (e.wheelData) ? e.wheelData : -e.deltaY;
  return (e.detail || delta > 0);
 };

 minutesInputEl.bind('mousewheel wheel', function(e) {
  $scope.$apply((isScrollingUp(e)) ? $scope.incrementMinutes() : $scope.decrementMinutes());
  e.preventDefault();
 });

 secondsInputEl.bind('mousewheel wheel', function(e) {
  $scope.$apply((isScrollingUp(e)) ? $scope.incrementSeconds() : $scope.decrementSeconds());
  e.preventDefault();
 });
 };

 // respond on direct input
 this.setupInputEvents = function(minutesInputEl, secondsInputEl) {
 if($scope.readonlyInput) {
  $scope.updateMinutes = angular.noop;
  $scope.updateSeconds = angular.noop;
  return;
 }

 var invalidate = function(invalidMinutes, invalidSeconds) {
  ngModelCtrl.$setViewValue(null);
  ngModelCtrl.$setValidity('time', false);
  $scope.validity = false;
  if(angular.isDefined(invalidMinutes)) {
  $scope.invalidMinutes = invalidMinutes;
  }
  if(angular.isDefined(invalidSeconds)) {
  $scope.invalidSeconds = invalidSeconds;
  }
 };

 $scope.updateMinutes = function() {
  var minutes = getMinutesFromTemplate();

  if(angular.isDefined(minutes)) {
  selected.minutes = minutes;
  refresh('m');
  } else {
  invalidate(true);
  }
 };

 minutesInputEl.bind('blur', function(e) {
  if(!$scope.invalidMinutes && $scope.minutes < 10) {
  $scope.$apply(function() {
   $scope.minutes = pad($scope.minutes);
  });
  }
 });

 $scope.updateSeconds = function() {
  var seconds = getSecondsFromTemplate();

  if(angular.isDefined(seconds)) {
  selected.seconds = seconds;
  refresh('s');
  } else {
  invalidate(undefined, true);
  }
 };

 secondsInputEl.bind('blur', function(e) {
  if(!$scope.invalidSeconds && $scope.seconds < 10) {
  $scope.$apply(function() {
   $scope.seconds = pad($scope.seconds);
  });
  }
 });
 };

 this.render = function() {
 var time = ngModelCtrl.$modelValue ? {
  minutes: ngModelCtrl.$modelValue.minutes,
  seconds: ngModelCtrl.$modelValue.seconds
 } : null;

 // adjust the time for invalid value at first time
 if(time.minutes < 0) {
  time.minutes = 0;
 }
 if(time.seconds < 0) {
  time.seconds = 0;
 }

 var totalSeconds = time.minutes * 60 + time.seconds;
 time = {
  minutes: Math.floor(totalSeconds / 60),
  seconds: totalSeconds % 60
 };

 if(time) {
  selected = time;
  makeValid();
  updateTemplate();
 }
 };

 // call internally when the model is valid
 function refresh(keyboardChange) {
 makeValid();
 ngModelCtrl.$setViewValue({
  minutes: selected.minutes,
  seconds: selected.seconds
 });
 updateTemplate(keyboardChange);
 }

 function makeValid() {
 ngModelCtrl.$setValidity('time', true);
 $scope.validity = true;
 $scope.invalidMinutes = false;
 $scope.invalidSeconds = false;
 }

 function updateTemplate(keyboardChange) {
 var minutes = selected.minutes,
  seconds = selected.seconds;

 $scope.minutes = keyboardChange === 'm' ? minutes : pad(minutes);
 $scope.seconds = keyboardChange === 's' ? seconds : pad(seconds);
 }

 function pad(value) {
 return ( angular.isDefined(value) && value.toString().length < 2 ) ? '0' + value : value;
 }

 function getMinutesFromTemplate() {
 var minutes = parseInt($scope.minutes, 10);
 return (minutes >= 0) ? minutes : undefined;
 }

 function getSecondsFromTemplate() {
 var seconds = parseInt($scope.seconds, 10);
 if(seconds >= 60) {
  seconds = 59;
 }

 return (seconds >= 0) ? seconds : undefined;
 }

 $scope.incrementMinutes = function() {
 addSeconds(minuteStep * 60);
 };

 $scope.decrementMinutes = function() {
 addSeconds(-minuteStep * 60);
 };

 $scope.incrementSeconds = function() {
 addSeconds(secondStep);
 };

 $scope.decrementSeconds = function() {
 addSeconds(-secondStep);
 };

 function addSeconds(seconds) {
 var newSeconds = selected.minutes * 60 + selected.seconds + seconds;
 if(newSeconds < 0) {
  newSeconds = 0;
 }

 selected = {
  minutes: Math.floor(newSeconds / 60),
  seconds: newSeconds % 60
 };

 refresh();
 }

 $scope.previewTime = function(minutes, seconds) {
 var totalSeconds = parseInt(minutes, 10) * 60 + parseInt(seconds, 10),
  hh = pad(Math.floor(totalSeconds / 3600)),
  mm = pad(minutes % 60),
  ss = pad(seconds);

 return hh + ':' + mm + ':' + ss;
 };
}]);

对应的Template实现：

<table>
 <tbody>
 <tr class="text-center">
  <td>
  <a ng-click="incrementMinutes()" class="btn btn-link">
   <span class="glyphicon glyphicon-chevron-up"></span>
  </a>
  </td>
  <td> </td>
  <td>
  <a ng-click="incrementSeconds()" class="btn btn-link">
   <span class="glyphicon glyphicon-chevron-up"></span>
  </a>
  </td>
  <td> </td>
 </tr>
 <tr>
  <td style="width:50px;" class="form-group" ng-class="{'has-error': invalidMinutes}">
  <input type="text" ng-model="minutes" ng-change="updateMinutes()" class="form-control text-center" ng-mousewheel="incrementMinutes()" ng-readonly="readonlyInput" maxlength="3">
  </td>
  <td>:</td>
  <td style="width:50px;" class="form-group" ng-class="{'has-error': invalidSeconds}">
  <input type="text" ng-model="seconds" ng-change="updateSeconds()" class="form-control text-center" ng-mousewheel="incrementSeconds()" ng-readonly="readonlyInput" maxlength="2">
  <td>
  <!-- preview column -->
  <td>
  <span class="label label-primary" ng-show="validity">
   {{ previewTime(minutes, seconds) }}
  </span>
  </td>
 </tr>
 <tr class="text-center">
  <td>
  <a ng-click="decrementMinutes()" class="btn btn-link">
   <span class="glyphicon glyphicon-chevron-down"></span>
  </a>
  </td>
  <td> </td>
  <td>
  <a ng-click="decrementSeconds()" class="btn btn-link">
   <span class="glyphicon glyphicon-chevron-down"></span>
  </a>
  </td>
  <td> </td>
 </tr>
 </tbody>
</table>

测试代码(即前面截图dialog的源代码)：

 <div class="modal-header">
 <h3 class="modal-title">Highlight on <span class="label label-primary">{{ movieName }}</span></h3>
</div>
<div class="modal-body">

 <div class="row">
 <div id="highlight-start" class="col-xs-6">
  <h4>Start Time:</h4>
  <minute-second-picker ng-model="startTime" validity="startTimeValidity"></minute-second-picker>
 </div>

 <div id="highlight-end" class="col-xs-6">
  <h4>End Time:</h4>
  <minute-second-picker ng-model="endTime" validity="endTimeValidity"></minute-second-picker>
 </div>
 </div>
 <div class="row">
 <div class="col-xs-2">
  Tags:
 </div>
 <div class="col-xs-10">
  <tags model="tags" src="s as s.name for s in sourceTags" options="{ addable: 'true' }"></tags>
 </div>
 </div>
</div>
<div class="modal-footer">
 <button class="btn btn-primary" ng-click="ok()" ng-disabled="!startTimeValidity || !endTimeValidity || durationIncorrect(endTime, startTime)">OK</button>
 <button class="btn btn-warning" ng-click="cancel()">Cancel</button>
</div>

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