我觉得最简单，最快，最正确的解决办法是有一个标志来跟踪哪些领域正在被编辑，只允许从该领域的更新。

I think the simplest, fastest, and most correct solution is to have a flag to track which field is being edited, and only allow updates from that field.

您只需要使用 NG-变化指令设置标志场上正在编辑中。

All you need is to use the ng-change directive to set the flag on the field being edited.

工作普拉克

code必要的修改：

Code changes necessary:

修改控制器看起来是这样的：

Modify the controller to look like this:

function TemperatureConverterCtrl($scope) {
  // Keep track of who was last edited
  $scope.edited = null;
  $scope.markEdited = function(which) {
    $scope.edited = which;
  };

  // Only edit if the correct field is being modified
  $scope.$watch('fahrenheit', function(value) {
    if($scope.edited == 'F') {
      $scope.celsius = (value - 32) * 5.0/9.0;
    }
  });
  $scope.$watch('celsius', function(value) {
    if($scope.edited == 'C') {
      $scope.fahrenheit = value * 9.0 / 5.0 + 32;
    }
  });
}

然后这个简单的指令添加到输入字段（使用˚F或 C 如适用）：

<input ... ng-change="markEdited('F')/>

现在仅领域正在键入在可改变的另一个。

Now only the field being typed in can change the other one.

如果您需要修改的能力，这些领域的之外的输入，你可以添加，看起来像这样的范围或控制器功能：

If you need the ability to modify these fields outside an input, you could add a scope or controller function that looks something like this:

$scope.setFahrenheit = function(val) {
  $scope.edited = 'F';
  $scope.fahrenheit = val;
}

然后摄氏度场将在接下来的$更新周期消化

Then the Celsius field will be updated on the next $digest cycle.

此溶液具有的额外code进行最低限度，消除了每个周期的多个更新的任何机会，并不会导致任何性能问题。

This solution has a bare minimum of extra code, eliminates any chance of multiple updates per cycle, and doesn't cause any performance issues.