您不能强迫 $ http.get（）进入同步。由于 $ http.get（）不可避免地异步的，你只能返回一个值，而不是值本身的承诺。

You can't force $http.get() into synchronism. Since $http.get() is unavoidably asynchronous, you can only return a promise of a value not the value itself.

因为你需要做到这一点时， $ http.get（）被调用时，还必须其他情况下返回一个承诺 - 当 vCardFromLS 成功从localStorage的retreived。这确保了对象返回到 $ scope.getVCard的任何呼叫（）有一个。然后（）方法，也就是说，它是一个承诺，无论 $ http.get（）被称为与否。

And because you need to do this when $http.get() is called, you must also return a promise under the other condition - when vCardFromLS is successfully retreived from localstorage. This ensures that the object returned to any call of $scope.getVCard() has a .then() method, ie it is a promise, regardless of whether $http.get() was called or not.

所以，code应该是这样的：

So the code should be something like this :

$scope.getVCard = function(id) {
    var vcardKey = vcardKeyPrefix + id;
    var vCardFromLS = localStorageService.get(vCardKey);
    var dfrd = $q.defer();
    if(vCardFromLS) {
        dfrd.resolve(localStorageService.get(vCardKey));
    }
    else {
        $http.get(app.common.vcardUrl(id)).success(function(data) {
            localStorageService.add(vCardKey, data);//.add() rather than .set() ?
            dfrd.resolve(data);
        }).error(function(error) {
            F1.common.error(data, function() {
                dfrd.reject('$http.get(app.common.vcardUrl(id)) failed');
            });
        });
    }
    return dfrd.promise;
};

现在，你需要确保对 $ scope.getVCard响应（）是适当的处理，例如：

Now you need to ensure that the response to $scope.getVCard() is handled appropriately, eg :

$scope.getVCard(id).then(function(data) {
    //success - do whatever is required with data
}, function(reason) {
    //failure - log and/or display `reason` as an error message
})

编辑：

我的......您必须同时返回其他条件下的诺言......是言过其实。

My "... you must also return a promise under the other condition ..." is an overstatement.

我应该说，......你的可以，使事情变得简单，其他情况下返回一个承诺......

I should have said, "... you can, to make things simple, return a promise under the other condition ...".

另一种可能性是，这取决于是否返回一个承诺或其他类型的对象/值的分支。然而，这是混乱的，通常会导致code一些重复。

Another possibility is to branch depending on whether a Promise or another type of object/value was returned. However, this is messy and will typically lead to some duplication of code.