使用转换事件

UI-Router 公开转换事件，这些事件有助于处理转换错误，基于某些参数值处理/阻止转换，自定义身份验证等。

这些事件可以绑定到 $rootScope 以获得全局效果，或者绑定到 $scope 以获得每个控制器效果。

$stateChangeError - 当尝试更改状态失败并抛出错误时，此事件被广播，此事件使用以下签名触发回调函数：

callback(event，toState，toParams，fromState，fromParams，error)

event ：事件对象

toState ：目标状态

toParams ：传递给目标状态的参数

fromState ：当前状态

fromParams ：传递给当前状态的参数

错误 ：错误对象

$stateChangeStart - 当状态转换开始时广播此事件，此事件使用以下签名触发回调函数：

callback(event，toState，toParams，fromState，fromParams，options)

options ：状态选项对象

$stateChangeSuccess - 当状态转换完成时，广播此事件，此事件使用以下签名触发回调函数：

callback(event，toState，toParams，fromState，fromParams，options)

$stateNotFound - 当找不到你请求转换到的状态时，此事件将被广播，此事件将使用以下签名触发回调函数：

callback(event，unfoundState，fromParams，fromState)

unfoundState - 表示未找到状态的对象

例：

$rootScope.$on('$stateChangeSuccess', function (event, toState, toParams, fromState, fromParams, options) {
    $log.debug("$stateChangeSuccess: event: %o toState: %o, toParams: %o, fromState: %o, fromParams: %o, options: %o", event, toState, toParams, fromState, fromParams, options);
    // runs when the state has successfully changed
});

$rootScope.$on('$stateChangeStart', function (event, toState, toParams, fromState, fromParams, options) {
    $log.debug("$stateChangeStart: event: %o toState: %o, toParams: %o, fromState: %o, fromParams: %o, options: %o", event, toState, toParams, fromState, fromParams, options);
    // runs when the state has just started to transition
});

$rootScope.$on('$stateNotFound', function (event, unfoundState, fromParams, fromState) {
    $log.debug("$stateNotFound: event: %o unfoundState: %o, fromParams: %o, fromState: %o", event, unfoundState, fromParams, fromState);
    // runs when the state wsa not found
});

$rootScope.$on('$stateChangeError', function (event, toState, toParams, fromState, fromParams, error) {
    $log.debug("$stateChangeError: event: %o toState: %o, toParams: %o, fromState: %o, fromParams: %o, error: %o", event, toState, toParams, fromState, fromParams, error);
    // runs when there was an error while attempting to transition
});