WinJs中的视图状态更改事件在哪里？

Question

在Windows 8中，当视图状态从快照变为填充到全屏时;

如何捕获这些事件并用WinJs对它们做出响应？

Answer 1

请参阅this关于如何捕捉视图状态更改的博文。基本上，建议归结为抓住调整大小事件，然后检查视图状态是这样的：

window.addEventListener("resize", onResize); 


function onResize() { 
    // Update view for the new window size 
    updateView(); 
} 

function updateView() { 
    // Query for the current view state 
    var myViewState = Windows.UI.ViewManagement.ApplicationView.value; 

    var viewStates = Windows.UI.ViewManagement.ApplicationViewState; 
    var statusText; 

    // Assign text according to view state 
    switch (myViewState) { 
     case viewStates.snapped: 
      statusText = "This app is snapped!"; 
      break; 
     case viewStates.filled: 
      statusText = "This app is in filled state!"; 
      break; 
     case viewStates.fullScreenLandscape: 
      statusText = "This app is full screen landscape!"; 
      break; 
     case viewStates.fullScreenPortrait: 
      statusText = "This app is full screen portrait!"; 
      break; 
     default: 
      statusText = "Error: Invalid view state returned."; 
      break; 
    } 

如果您在Microsoft Visual Studio Express的2012 RC期待的Windows 8 template for Javascript你会看到导航这样的事情。 JS：

window.onresize = this._resized.bind(this); 

_resized: function(args) { 
    if (this.pageControl && this.pageControl.updateLayout) { 
     this.pageControl.updateLayout.call(this.pageControl, this.pageElement, appView.value, this.lastViewstate); 
    } 
    this.lastViewstate = appView.value; 
}, 

//*page*.js 

updateLayout: function (element, viewState, lastViewState) { 
    /// <param name="element" domElement="true" /> 
    var listView = element.querySelector(".itemslist").winControl; 
    if (lastViewState !== viewState) { 
      if (lastViewState === appViewState.snapped || viewState === appViewState.snapped) { 
       var handler = function (e) { 
       listView.removeEventListener("contentanimating", handler, false); 
       e.preventDefault(); 
      } 
      listView.addEventListener("contentanimating", handler, false); 
      var firstVisible = listView.indexOfFirstVisible; 
      this._initializeLayout(listView, viewState); 
      if (firstVisible >= 0 && listView.itemDataSource.list.length > 0) { 
       listView.indexOfFirstVisible = firstVisible; 
      } 
     } 
    } 
}, 

_initializeLayout: function (listView, viewState) { 

    if (viewState === appViewState.snapped) { 
     listView.layout = new ui.ListLayout(); 
    } else { 
     listView.layout = new ui.GridLayout(); 
    } 
}, 

根据this MSDN页面，您还可以使用媒体查询时，视图状态的变化会影响在CSS中指定的CSS属性或布局。对于所有其他更改，应使用onResize。