通过离子触摸事件更新moment.js持续时间

Question

I am building an iOS application with Ionic. The application is a timer where the user will specify a time limit and then countdown that time for a certain activity. I am trying to achieve an interaction where the user will drag a handle around the outside of a circle and each clockwise rotation will increment the time limit by one minute, and going the opposite direction will decrement by one.

I have the circle working, where you can drag the handle and it will adhere to the bounds of the container. Now I am trying to use Moment.js to create the countdown, but am having a tough time getting the timer values to update inside of the touch event.

The $scope.duration variable is what I am using to track the timer value. I have tried using the moment().duration() method to specify a duration object and am initializing it to '00:00:00'. When I try to update that value in the touch gesture event, I am unable to update the timer value. I am assuming I either don't understand how to correctly apply updated scope values in Angular/Ionic, I don't know how to correctly use Moment.js, or quite possibly - both.

Here is my template code:

<ion-view hide-nav-bar="true" view-title="Dashboard">
  <ion-content>
    <div class="timer">
      <div class="timer-slider"></div>
      <span class="timer-countdown">
        {{duration}}
      </span>
    </div>
  </ion-content>
</ion-view>

And my large controller:

.controller('DashCtrl', function($scope, $ionicGesture) {

  var $timer = angular.element(document.getElementsByClassName('timer')[0]);
  var $timerSlider = angular.element(document.getElementsByClassName('timer-slider')[0]);
  var timerWidth = $timer[0].getBoundingClientRect().width;
  var sliderWidth = $timerSlider[0].getBoundingClientRect().width;
  var radius = timerWidth / 2;
  var deg = 0;
  var X = Math.round(radius * Math.sin(deg*Math.PI/180));
  var Y = Math.round(radius *  -Math.cos(deg*Math.PI/180));

  var counter = 0;
  $scope.duration = moment().hour(0).minute(0).second(0).format('HH : mm : ss');

  // Set timer circle aspect ratio
  $timer.css('height', timerWidth + 'px');
  $timerSlider.css({
    left: X + radius - sliderWidth / 2 + 'px',
    top: Y + radius - sliderWidth / 2 + 'px'
  });

  $ionicGesture.on('drag', function(e) {
    e.preventDefault();
    var pos = {
      x: e.gesture.touches[0].clientX,
      y: e.gesture.touches[0].clientY
    };
    var atan = Math.atan2(pos.x - radius, pos.y - radius);
    deg = -atan/(Math.PI/180) + 180; // final (0-360 positive) degrees from mouse position
    // for attraction to multiple of 90 degrees
    var distance = Math.abs( deg - ( Math.round(deg / 90) * 90 ) );
    if ( distance <= 5 || distance >= 355 )
      deg = Math.round(deg / 90) * 90;

    if(Math.floor(deg) % 6 === 0) {
      console.log(Math.floor(deg));
      $scope.duration = moment().hour(0).minute(0).second(counter++).format('HH : mm : ss');
    }

    if (deg === 360)
      deg = 0;

    X = Math.round(radius * Math.sin(deg * Math.PI / 180));
    Y = Math.round(radius *  -Math.cos(deg * Math.PI / 180));

    $timerSlider.css({
      left: X + radius - sliderWidth / 2 + 'px',
      top: Y + radius - sliderWidth / 2 + 'px'
    });
  }, $timerSlider);
})

I hacked up a CodePen demo. It doesn't track the drag event all that well without a mobile format, but you can get the idea of what I am going for.

http://codepen.io/stat30fbliss/pen/xZRrXY

Here's a screenshot of the app in-progress

Answer 1

更新$scope.duration ，运行$scope.$apply()它将开始工作:)