Keep keyboard open issue

I’m looking for a way to keep the keyboard open when the user presses the button “send”.
Searching on the forum, the solution is to reset the focus on the input field.
But I have a really strange behavior … when I set the variable “IsFocused” to false is always called the blur event!
I started from the repo ionic-chat and I included this directive:

.directive('isFocused', function($timeout) {
    return {
        scope : {trigger : '@isFocused'},
        link : function(scope, element) {
            console.log('start directive');
            scope.$watch('trigger', function(value) {
                console.log('TRIGGER');
                console.log(value);
                if(value === "true") {
                    console.log("TRUE");
                    $timeout(function() {
                        console.log("FOCUS");
                        element[0].focus();

                        element.on('blur', function() {
                            console.log("BLUR");
                            if(value === "true") {
                                console.log("BLUR TRUE");
                                element[0].focus();
                            }
                        });
                    });
                }

            });
        }
    };
})

the controller is:

.controller('Messages', function($scope, $timeout, $ionicScrollDelegate, $window) {

    var alternate;
    $scope.isFocused = "false";

    $scope.noFocus = function() {
        console.log("NO FOCUS");
        $scope.isFocused = "false";
    };

    $scope.onFocus = function() {
        console.log('ON FOCUS');
        $scope.isFocused = "true";
    };

    $window.addEventListener('native.keyboardshow', function (event) {
        console.log('native.keyboardshow');
    });

    $scope.sendMessage = function() {
        alternate = !alternate;
        $scope.messages.push({
            userId : alternate ? '12345' : '54321',
            text : $scope.data.message
        });
        delete $scope.data.message;
        $ionicScrollDelegate.scrollBottom(true);
    }

    $scope.data = {};
    $scope.myId = '12345';
    $scope.messages = [];

});

the template:

 <ion-content class="content-stable" ng-style="{ bottom: data.keyboardHeight + 'px' }" ng-click="noFocus()">
  <div ng-repeat="message in messages" ng-class="{ other: message.userId != myId }" class="message">
    <div class="photo icon ion-person"></div>
    <div class="message"><span>{{ message.text }}</span>
    </div>
  </div>
</ion-content>
<ion-footer-bar keyboard-attach class="bar-stable item-input-inset">
  <label class="item-input-wrapper">
    <input type="text" placeholder="Type your message" ng-model="data.message" is-focused="{{ isFocused }}" ng-click="onFocus()" />
  </label>
  <button class="button button-clear" ng-click="sendMessage()">
    Send
  </button>
</ion-footer-bar>

when I hit the send button everything is ok, when in fact I press anywhere in the ion-content variable is set to false but the keyboard is open!
Here the logs when I open the keyboard the first time:

2014-11-01 12:40:48.964 HelloCordova[1110:309898] ON FOCUS
2014-11-01 12:40:48.965 HelloCordova[1110:309898] TRIGGER
2014-11-01 12:40:48.965 HelloCordova[1110:309898] true
2014-11-01 12:40:48.965 HelloCordova[1110:309898] TRUE
2014-11-01 12:40:48.965 HelloCordova[1110:309898] native.keyboardshow
2014-11-01 12:40:49.212 HelloCordova[1110:309898] FOCUS

here the log when I press the button “send”:

2014-11-01 12:41:29.418 HelloCordova[1110:309898] BLUR
2014-11-01 12:41:29.419 HelloCordova[1110:309898] BLUR TRUE
2014-11-01 12:41:29.422 HelloCordova[1110:309898] native.keyboardshow

here the log when I press anywhere in the ion-content:

2014-11-01 12:42:13.518 HelloCordova[1110:309898] NO FOCUS
2014-11-01 12:42:13.519 HelloCordova[1110:309898] TRIGGER
2014-11-01 12:42:13.519 HelloCordova[1110:309898] false
2014-11-01 12:42:13.520 HelloCordova[1110:309898] BLUR
2014-11-01 12:42:13.521 HelloCordova[1110:309898] BLUR TRUE
2014-11-01 12:42:13.530 HelloCordova[1110:309898] native.keyboardshow

How can I fix this?
Thanks to all

EDIT: I’m trying to ios directly on the device