All of the solutions offered up so far have a single common problem. The directives are not reusable, they require knowledge of variables created in the parent $scope provided by the controller. That means if you wanted to use the same directive in a different view you would need to re-implement everything you did the previous controller and ensure you are using the same variable names for things, since the directives basically have hard coded $scope variable names in them. You definitely wouldn’t be able to use the same directive twice within the same parent scope.
The way around this is to use isolated scope in the directive. By doing this you can make the directive reusable regardless of the parent $scope by generically parameterizing items required from the parent scope.
In my solution the only thing that the controller needs to do is provide a selectedIndex variable that the directive uses to track which row in the table is currently selected. I could have isolated the responsibility of this variable to the directive but by making the controller provide the variable it allows you to manipulate the currently selected row in the table outside of the directive. For example you could implement “on click select row” in your controller while still using the arrow keys for navigation in the directive.
The Directive:
angular
.module('myApp')
.directive('cdArrowTable', cdArrowTable);
.directive('cdArrowRow', cdArrowRow);
function cdArrowTable() {
return {
restrict:'A',
scope: {
collection: '=cdArrowTable',
selectedIndex: '=selectedIndex',
onEnter: '&onEnter'
},
link: function(scope, element, attrs, ctrl) {
// Ensure the selectedIndex doesn't fall outside the collection
scope.$watch('collection.length', function(newValue, oldValue) {
if (scope.selectedIndex > newValue - 1) {
scope.selectedIndex = newValue - 1;
} else if (oldValue <= 0) {
scope.selectedIndex = 0;
}
});
element.bind('keydown', function(e) {
if (e.keyCode == 38) { // Up Arrow
if (scope.selectedIndex == 0) {
return;
}
scope.selectedIndex--;
e.preventDefault();
} else if (e.keyCode == 40) { // Down Arrow
if (scope.selectedIndex == scope.collection.length - 1) {
return;
}
scope.selectedIndex++;
e.preventDefault();
} else if (e.keyCode == 13) { // Enter
if (scope.selectedIndex >= 0) {
scope.collection[scope.selectedIndex].wasHit = true;
scope.onEnter({row: scope.collection[scope.selectedIndex]});
}
e.preventDefault();
}
scope.$apply();
});
}
};
}
function cdArrowRow($timeout) {
return {
restrict: 'A',
scope: {
row: '=cdArrowRow',
selectedIndex: '=selectedIndex',
rowIndex: '=rowIndex',
selectedClass: '=selectedClass',
enterClass: '=enterClass',
enterDuration: '=enterDuration' // milliseconds
},
link: function(scope, element, attrs, ctr) {
// Apply provided CSS class to row for provided duration
scope.$watch('row.wasHit', function(newValue) {
if (newValue === true) {
element.addClass(scope.enterClass);
$timeout(function() { scope.row.wasHit = false;}, scope.enterDuration);
} else {
element.removeClass(scope.enterClass);
}
});
// Apply/remove provided CSS class to the row if it is the selected row.
scope.$watch('selectedIndex', function(newValue, oldValue) {
if (newValue === scope.rowIndex) {
element.addClass(scope.selectedClass);
} else if (oldValue === scope.rowIndex) {
element.removeClass(scope.selectedClass);
}
});
// Handles applying/removing selected CSS class when the collection data is filtered.
scope.$watch('rowIndex', function(newValue, oldValue) {
if (newValue === scope.selectedIndex) {
element.addClass(scope.selectedClass);
} else if (oldValue === scope.selectedIndex) {
element.removeClass(scope.selectedClass);
}
});
}
}
}
This directive not only allows you to navigate a table using the arrow keys but it allows you to bind a callback method to the Enter key. So that when the enter key is pressed the row that is currently selected will be included as an argument to the callback method registered with the directive (onEnter).
As a little bit of an added bonus you can also pass a CSS class and duration to the cdArrowRow directive so that when the enter key is hit on a selected row the CSS class passed in will be applied to the row element then removed after the passed in duration (in milliseconds). This basically allows you to do something like making the row flash a different color when the enter key is hit.
View Usage:
<table cd-arrow-table="displayedCollection"
selected-index="selectedIndex"
on-enter="addToDB(row)">
<thead>
<tr>
<th>First Name</th>
<th>Last Name</th>
</tr>
</thead>
<tbody>
<tr ng-repeat="row in displayedCollection"
cd-arrow-row="row"
selected-index="selectedIndex"
row-index="$index"
selected-class="'mySelcetedClass'"
enter-class="'myEnterClass'"
enter-duration="150"
>
<td>{{row.firstName}}</td>
<td>{{row.lastName}}</td>
</tr>
</tbody>
</table>
Controller:
angular
.module('myApp')
.controller('MyController', myController);
function myController($scope) {
$scope.selectedIndex = 0;
$scope.displayedCollection = [
{firstName:"John", lastName: "Smith"},
{firstName:"Jane", lastName: "Doe"}
];
$scope.addToDB;
function addToDB(item) {
// Do stuff with the row data
}
}
