javascript - 无法使用 AngularJS 移动元素

Question

这是我的标记:

<button class="left" ng-mousedown="moveLeft()">Left</button>

这是我的代码:

angular.module('ionicApp', ['ionic'])

.controller("wallControl", function($scope) {

    var leftTimer;

    $scope.mousePress = function() {
        moveLeft();
    };

    var moveLeft = function() {
        if (circleX > 0) {
            circleX -= 4;
        }
        leftInterval = $timeout(moveLeft, 1000);
    };

    $scope.mouseRelease = function() {
        $timeout.cancel(leftTimer);
    };
});

控制台中没有错误。为什么变量circleX没有改变？我以前从未使用过 Angular，所以我可能犯了一个愚蠢的错误。

Answer 1

一个问题是您正在调用 mouseLeft()，但该函数未在 $scope 上公开。

另一个问题是您从未向 leftTimer 分配任何内容。

另一个问题是您没有注入(inject)$timeout。

我会尝试这样的事情:

<button class="left" ng-mousedown="mousePress()" ng-mouseup="mouseRelease()">Left</button>

和

angular.module('ionicApp', ['ionic'])

// notice the DI syntax (which is not only a best practice, but is necessary if you minify your code)
// notice $interval service is injected
.controller("wallControl", ['$scope', '$interval', function($scope, $interval) {

    // used to store the $interval handle so it can be cancelled
    var leftTimer;

    $scope.mousePress = function() {
        // start running moveLeft every 1000ms
        leftTimer = $interval(moveLeft, 1000);
    };

    var moveLeft = function() {
        if (circleX > 0) {
            circleX -= 4;
        }
        // no need to call itself on $timeout - $interval doing that
    };

    $scope.mouseRelease = function() {
        // stop the moveLeft interval
        $interval.cancel(leftTimer);
    };
}]);

更新:多方向

非常简单，只需对代码进行一些小更改即可。我更进一步详细阐述了几个其他概念，以使代码稍微更加实际。

<button class="left" ng-mousedown="startMoveX(-1)" ng-mouseup="stopMoveX()">Left</button>
<button class="right" ng-mousedown="startMoveX(1)" ng-mouseup="stopMoveX()">Right</button>

和

angular.module('ionicApp', ['ionic'])

.controller("wallControl", ['$scope', '$interval', function($scope, $interval) {
    // some settings (magic numbers are bad m'kay)
    var xSpeed = 4;
    var xBounds = { min: 0, max: 1000 };

    // circleX need to be defined somewhere
    // how you will use it for drawing is another story
    var circleX = (xBounds.min + xBounds.max) / 2.0;

    // x-motion variables
    var xMoveTimer;
    var xDirection;

    // starts the x-motion
    $scope.startMoveX = function(direction) {
        // track which direction to move (used as multiplier on speed)
        xDirection = direction;

        // make sure the xMoveTimer is not already running
        if(!xMoveTimer){
            // start running moveX every 1000ms
            xMoveTimer = $interval(moveX, 1000);
        }
    };

    // stops the x-motion
    $scope.stopMoveX = function() {
        if(xMoveTimer){
            // stop it
            $interval.cancel(xMoveTimer);

            // release it
            xMoveTimer = undefined;
        }
    };

    // performs the x-motion
    var moveX = function() {
        // move it move it
        circleX += xSpeed * xDirection;

        // lock it to bounds
        if(circleX < xBounds.min){
            circleX = xBounds.min;
        }
        else if(circleX > xBounds.max){
            circleX = xBounds.max;
        }
    };
}]);