从顶部删除项目时,如何在AngularJS中保留ng-repeat的滚动位置

我尝试从解决方案到这个工作

How to retain scroll position of ng-repeat in AngularJS?

在删除ng-repeat中的顶部项目时保持滚动位置,但无法找出执行此操作的代码.

另外,请注意,列表应按照与项目数组相同的顺序打印,而不是像示例那样反向打印.

angular.module("Demo",[])

.controller("DemoCtrl",function($scope) {
  $scope.items = [];

  for (var i = 0; i < 10; i++) {
    $scope.items[i] = {
      id: i,name: 'item ' + i
    };
  }

  $scope.addNewItem = function() {
    $scope.items = $scope.items.concat({
      id: $scope.items.length,name: "item " + $scope.items.length
    });
  };
})

.directive("keepScroll",function(){

  return {

    controller : function($scope){
      var element = 0;

      this.setElement = function(el){
        element = el;
      }

      this.addItem = function(item){
        console.log("Adding item",item,item.clientHeight);
        element.scrollTop = (element.scrollTop+item.clientHeight+1); //1px for margin
      };

    },link : function(scope,el,attr,ctrl) {

     ctrl.setElement(el[0]);

    }

  };

})

.directive("scrollItem",function(){


  return{
    require : "^keepScroll",att,scrCtrl){
      scrCtrl.addItem(el[0]);
    }
  }
})

我尝试做的是改变

element.scrollTop = (element.scrollTop + item.clientHeight+1)

至

element.scrollTop = (element.scrollTop - item.clientHeight+1)

并按’id’而不是’-id’按顺序打印

我认为最初的解决方案有点像hacky ……但这是一个以它为基础的工作编辑.

问题是解决方案取决于添加到ng-repeat的项目.如果查看scrollItem指令,它只会导致keepScroll指令在链接器执行时重新调整scrollTop.这仅在项目添加而不是删除时发生.

而编辑则侦听范围.$on(‘$destroy’)事件.但是,此时的问题是该元素不再具有clientHeight,因为它已从DOM中删除.因此解决方案是在创建时保存其高度,然后告诉keepScroll删除元素的高度是多少.

注意：如果滚动条一直到底部,这似乎会导致滚动跳转,因此您需要将该情况视为异常.

工作JSBin：http://jsbin.com/geyapugezu/1/edit?html,output

以供参考：

HTML

<!DOCTYPE html>
<html>
<head>
<script src="//code.angularjs.org/1.3.0-beta.7/angular.js"></script>
  <Meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body ng-app="Demo" ng-controller="DemoCtrl">
  <div class="wrapper" keep-scroll>
    <div class="item" scroll-item ng-repeat="item in items | orderBy: 'id'">
      {{ item.name }}
    </div>
  </div>
  <button ng-click="removeItem()">
    Remove item
  </button>
</body>
</html>

CSS

.wrapper {
  width: 200px;
  height: 300px;
  border: 1px solid black;
  overflow: auto;
}
.item {
  background-color: #ccc;
  height: 100px;
  margin-bottom: 1px;
}

angular.module("Demo",[])
  .controller("DemoCtrl",function($scope) {
    $scope.items = [];

    for (var i = 0; i < 10; i++) {
      $scope.items[i] = {
        id: i,name: 'item ' + i
      };
    }

    $scope.removeItem = function() {
      $scope.items = $scope.items.slice(1);
    };
})
.directive("keepScroll",function(){

  return {
    controller : function($scope){
      var element = 0;

      this.setElement = function(el){
        element = el;
      };

      this.itemRemoved = function(height){
        element.scrollTop = (element.scrollTop - height - 1); //1px for margin
        console.log("Item removed",element.scrollTop);
      };

    },ctrl) {
     ctrl.setElement(el[0]);

    }

  };

})
.directive("scrollItem",function(){


  return {
    require : "^keepScroll",scrCtrl){
      var height = el[0].clientHeight;

      scope.$on('$destroy',function() {
        scrCtrl.itemRemoved(height);
      });
    }
  };
});

编辑

或者,这样做.不需要scrollItem,而是我们观察ng-repeat项目的更改并相应地重新调整scrollTop.

JSBin：http://jsbin.com/dibeqivubi/edit?html,output

angular.module("Demo",['$scope',name: 'item ' + i
      };
    }

    $scope.removeItem = function() {
      $scope.items = $scope.items.slice(1);
    };
}])
.directive("keepScroll",function() {
  return {
    link : function(scope,ctrl) {
      var scrollHeight;

      scope.$watchCollection('items',function(n,o) {
        // Instantiate scrollHeight when the list is
        // done loading.
        scrollHeight = scrollHeight || el[0].scrollHeight;
        // Adjust scrollTop if scrollHeight has changed (items
        // have been removed)
        el[0].scrollTop = el[0].scrollTop - (scrollHeight - el[0].scrollHeight);
        // Remember current scrollHeight for next change.
        scrollHeight = el[0].scrollHeight;
      });
    }

  };
});

HTML

<!DOCTYPE html>
<html>
<head>
<script src="//code.angularjs.org/1.3.0-beta.7/angular.js"></script>
  <Meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body ng-app="Demo" ng-controller="DemoCtrl">
  <div class="wrapper" keep-scroll>
    <div class="item" ng-repeat="item in items | orderBy: 'id'">
      {{ item.name }}
    </div>
  </div>
  <button ng-click="removeItem()">
    Remove item
  </button>
</body>
</html>

原文地址：https://www.jb51.cc/angularjs/141106.html

从顶部删除项目时,如何在AngularJS中保留ng-repeat的滚动位置

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