Managing windows

To manipulate a window, you must first get the window instance. You can get a window instance from one of the following places:

• The native window constructor used to create the window:

  var nativeWin = new air.NativeWindow(initOptions);

• The stage property of a display object in the window:

  var nativeWin = window.htmlLoader.stage.nativeWindow;

• The target property of a native window event dispatched by the window:

  function onNativeWindowEvent(event) 
  { 
      var nativeWin = event.target; 
  }

• The nativeWindow property of an HTML page displayed in the window:

  var nativeWin = window.nativeWindow;

• The activeWindow and openedWindows properties of the NativeApplication object:

  var win = NativeApplication.nativeApplication.activeWindow; 
  var firstWindow = NativeApplication.nativeApplication.openedWindows[0];

  NativeApplication.nativeApplication.activeWindow references the active window of an application (but returns null if the active window is not a window of this AIR application). The NativeApplication.nativeApplication.openedWindows array contains all of the windows in an AIR application that have not been closed.

Because the Flex mx:WindowedApplication, and mx:Window objects are display objects, you can easily reference the application window in an MXML file using the stage property, as follows:

<?xml version="1.0" encoding="utf-8"?> 
<mx:WindowedApplication xmlns:mx="http://www.adobe.com/2006/mxml" applicationComplete="init();"> 
    <mx:Script> 
        <![CDATA[ 
            import flash.display.NativeWindow; 
 
            public function init():void{ 
                var appWindow:NativeWindow = this.stage.nativeWindow; 
                //set window properties 
                appWindow.visible = true; 
            } 
        ]]> 
    </mx:Script> 
</WindowedApplication

To activate a window, call the NativeWindow activate() method. Activating a window brings the window to the front, gives it keyboard and mouse focus, and, if necessary, makes it visible by restoring the window or setting the visible property to true . Activating a window does not change the ordering of other windows in the application. Calling the activate() method causes the window to dispatch an activate event.

To show a hidden window without activating it, set the visible property to true . This brings the window to the front, but will not assign the focus to the window.

To hide a window from view, set its visible property to false . Hiding a window suppresses the display of both the window, any related taskbar icons, and, on Mac OS X, the entry in the Windows menu.

When you change the visibility of a window, the visibility of any windows that window owns is also changed. For example, if you hide a window, all of its owned windows are also hidden.

AIR provides several methods for directly changing the display order of windows. You can move a window to the front of the display order or to the back; you can move a window above another window or behind it. At the same time, the user can reorder windows by activating them.

You can keep a window in front of other windows by setting its alwaysInFront property to true . If more than one window has this setting, then the display order of these windows is sorted among each other, but they are always sorted above windows which have alwaysInFront set to false.

Windows in the top-most group are also displayed above windows in other applications, even when the AIR application is not active. Because this behavior can be disruptive to a user, setting alwaysInFront to true should only be done when necessary and appropriate. Examples of justified uses include:

• Temporary pop-up windows for controls such as tool tips, pop-up lists, custom menus, or combo boxes. Because these windows should close when they lose focus, the annoyance of blocking a user from viewing another window can be avoided.

• Extremely urgent error messages and alerts. When an irrevocable change may occur if the user does not respond in a timely manner, it may be justified to push an alert window to the forefront. However, most errors and alerts can be handled in the normal window display order.

• Short-lived toast-style windows.

If a window owns other windows, those windows are always ordered in front of it. If you call orderToFront() or set alwaysInFront to true on a window that owns other windows, then the owned windows are re-ordered along with the owner window in front of other windows, but the owned windows still display in front of the owner.

Calling the window ordering methods on owned windows works normally among windows owned by the same window, but can also change the ordering of the entire group of owned windows compared to windows outside that group. For example, if you call orderToFront() on an owned window, then both that window, its owner, and any other windows owned by the same owner are moved to the front of the window display order.

The NativeWindow class provides the following properties and methods for setting the display order of a window relative to other windows:

On the Linux operating system, different window managers enforce different rules regarding the window display order:

• On some window managers, utility windows are always displayed in front of normal windows.

• On some window managers, a full screen window with alwaysInFront set to true is always displayed in front of other windows that also have alwaysInFront set to true .

To close a window, use the NativeWindow.close() method.

Closing a window unloads the contents of the window, but if other objects have references to this content, the content objects will not be destroyed. The NativeWindow.close() method executes asynchronously, the application that is contained in the window continues to run during the closing process. The close method dispatches a close event when the close operation is complete. The NativeWindow object is still technically valid, but accessing most properties and methods on a closed window generates an IllegalOperationError. You cannot reopen a closed window. Check the closed property of a window to test whether a window has been closed. To simply hide a window from view, set the NativeWindow.visible property to false .

If the Nativeapplication.autoExit property is true , which is the default, then the application exits when its last window closes.

Any windows that have an owner are closed when the owner is closed. The owned windows do not dispatch a closing event and hence cannot prevent closure. A close event is dispatched.

When a window uses system chrome, user interaction with the window can be canceled by listening for, and canceling the default behavior of the appropriate events. For example, when a user clicks the system chrome close button, the closing event is dispatched. If any registered listener calls the preventDefault() method of the event, then the window does not close.

When a window does not use system chrome, notification events for intended changes are not automatically dispatched before the change is made. Hence, if you call the methods for closing a window, changing the window state, or set any of the window bounds properties, the change cannot be canceled. To notify components in your application before a window change is made, your application logic can dispatch the relevant notification event using the dispatchEvent() method of the window.

For example, the following logic implements a cancelable event handler for a window close button:

function onCloseCommand(event){ 
    var closingEvent = new air.Event(air.Event.CLOSING,true,true); 
    dispatchEvent(closingEvent); 
    if(!closingEvent.isDefaultPrevented()){ 
        win.close(); 
    } 
}

The dispatchEvent() method returns false if the event preventDefault() method is called by a listener. However, it can also return false for other reasons, so it is better to explicitly use the isDefaultPrevented() method to test whether the change should be canceled.

To maximize the window, use the NativeWindow maximize() method.

window.nativeWindow.maximize();

To minimize the window, use the NativeWindow minimize() method.

 
window.nativeWindow.minimize();

To restore the window (that is, return it to the size that it was before it was either minimized or maximized), use the NativeWindow restore() method.

 
window.nativeWindow.restore();

A window that has an owner is minimized and restored when the owning window is minimized or restored. No events are dispatched by the owned window when it is minimized because its owner is minimized.

On the Linux operating system, different window managers enforce different rules regarding setting the window display state:

• On some window managers, utility windows cannot be maximized.

• If a maximum size is set for the window, then some windows do not allow a window to be maximized. Some other window managers set the display state to maximized, but do not resize the window. In either of these cases, no display state change event is dispatched.

• Some window managers do not honor the window maximizable or minimizable settings.

The following short HTML page demonstrates the NativeWindow maximize() , minimize() , restore() , and close() methods:

<html> 
<head> 
<title>Change Window Display State</title> 
<script src="AIRAliases.js"/> 
<script type="text/javascript"> 
     function onMaximize(){ 
         window.nativeWindow.maximize(); 
     } 
     
     function onMinimize(){ 
         window.nativeWindow.minimize(); 
     } 
     
     function onRestore(){ 
         window.nativeWindow.restore(); 
     } 
     
     function onClose(){ 
         window.nativeWindow.close(); 
     } 
</script> 
</head> 
 
<body> 
     <h1>AIR window display state commands</h1> 
         <button onClick="onMaximize()">Maximize</button> 
         <button onClick="onMinimize()">Minimize</button> 
         <button onClick="onRestore()">Restore</button> 
    <button onClick="onClose()">Close</button> 
</body> 
</html>

When a window uses system chrome, the chrome provides drag controls for resizing the window and moving around the desktop. If a window does not use system chrome you must add your own controls to allow the user to resize and move the window.

The following example shows how to initiate resizing and moving operations on a window:

<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<script src="AIRAliases.js"/> 
<script type="text/javascript"> 
     function onResize(type){ 
         nativeWindow.startResize(type); 
     } 
     
     function onNativeMove(){ 
         nativeWindow.startMove(); 
     } 
</script> 
<style type="text/css" media="screen"> 
 
.drag { 
    width:200px; 
    height:200px; 
    margin:0px auto; 
    padding:15px; 
    border:1px dashed #333; 
    background-color:#eee; 
    } 
 
.resize { 
    background-color:#FF0000; 
    padding:10px; 
    } 
.left { 
        float:left; 
        }     
.right { 
    float:right; 
}     
 
</style> 
<title>Move and Resize the Window</title> 
</head> 
 
<body> 
<div class="resize left" onmousedown="onResize(air.NativeWindowResize.TOP_LEFT)">Drag to resize</div> 
<div class="resize right" onmousedown="onResize(air.NativeWindowResize.TOP_RIGHT)">Drag to resize</div> 
<div class="drag" onmousedown="onNativeMove()">Drag to move</div> 
<div class="resize left" onmousedown="onResize(air.NativeWindowResize.BOTTOM_LEFT)">Drag to resize</div> 
<div class="resize right" onmousedown="onResize(air.NativeWindowResize.BOTTOM_RIGHT)">Drag to resize</div> 
</body> 
</html>