javascript - ion-toggle ng-change 无法通过 Controller + 服务结构正确触发

Question

我创建了一个切换列表来选择蓝牙设备并连接它，并为它们创建了一个controller.js 和service.js。但是，ng-change 仅在 ion-toggles 首次加载到 View 中时触发，之后不会触发更改。

这是我的setting.html片段:

<ion-toggle ng-repeat="item in devicesList"
            ng-model="item.checked"
            ng-change="connectDevice(devicesList)">
     {{ item.address }}
</ion-toggle>

这是我的settingController.js:

(function () {
    'use strict';

    angular.module('i18n.setting').controller('SettingController', SettingController);
    SettingController.$inject = ['$scope','SettingService'];

    function SettingController($scope, SettingService) {
        $scope.devicesList = [];
        $scope.scanDevices = SettingService.scanDevices($scope.devicesList);
        $scope.connectDevice = SettingService.connectDevice($scope.devicesList);
    };

})();

这是我的settingService.js:

(function(){
    'use strict';

    angular.module('i18n.setting').service('SettingService', SettingService);

    SettingService.$inject = [];
    function SettingService(){
        var self = this;

        this.scanDevices = function(devicesCollection) {
            window.bluetoothSerial.discoverUnpaired(function(devices) {
                console.log("in discoverUnpaired callback, setting page");
                devices.forEach(function(device) {
                    console.log(device.name);
                    device.checked = false;
                    devicesCollection.push(device);
                });

            }, function(error) {
                console.log("in discoverUnpaired error function");
                console.log(error);
            });
        };

        this.connectDevice = function(devicesCollection) {
            console.log(devicesCollection);
            console.log("In connectDevice");
            for (var i =0; i<devicesCollection.length; i++)
            {
                console.log(devicesCollection[i].id + " " + devicesCollection[i].checked);
                if (devicesCollection[i].checked == true)
                {
                    console.log(devicesCollection[i].name);
                    window.bluetoothSerial.connect(devicesCollection[i].address,
                        function(data) {console.log("This device is"+macaddress); console.log(data);},
                        function(error) {console.log(error);});
                }
            }
        };
    }
})();

如果我直接在 settingController.js 中定义此函数，它就会正常工作并且可以检测到切换的每个更改。另外，我注意到即使我不单击按钮，我的 scanDevices 函数也会被触发。我不知道这是为什么。有没有人告诉我这是什么原因？任何帮助，谢谢

Answer 1

Controller 应该将服务功能放在作用域上；不是服务功能的调用。

(function () {
    'use strict';

    angular.module('i18n.setting').controller('SettingController', SettingController);
    SettingController.$inject = ['$scope','SettingService'];

    function SettingController($scope, SettingService) {
        $scope.devicesList = [];
        //$scope.scanDevices = SettingService.scanDevices($scope.devicesList);
        $scope.scanDevices = SettingService.scanDevices;
        //$scope.connectDevice = SettingService.connectDevice($scope.devicesList);
        $scope.connectDevice = SettingService.connectDevice;
    };

})();

由于 scanDevices 函数没有 return 语句，因此 scanDevices($scope.deviceList) 返回 undefined。因此，$scope.scanDevices 被设置为 undefined。

<小时/>

更新

Can you also explain why scanDevices get invoked before I press the Scan button?

Which was bind to:

<button class="button button-stable"
        ng-click="scanDevices(devicesList)">Scan Devices
</button>

通过将函数的调用绑定(bind)到范围变量而不是函数本身:

//ERRONEOUS
$scope.scanDevices = SettingService.scanDevices($scope.devicesList);

//CORRECT
$scope.scanDevices = SettingService.scanDevices;

表达式SettingService.scanDevices($scope.devicesList)在单击按钮之前调用函数。并将 undefined 分配给 $scope.scanDevices 变量。