ExtJS 4 - 检测用户是否按下了“打印"；在以编程方式调用的打印对话框上 [英] ExtJS 4 - detecting if the user pressed "Print" on the print dialog that was called programatically
问题描述
您好，我正在构建一个 Web 应用程序，用户可以在其中打印面板及其内容.我找到了一个代码 如此处所示 并对其进行了如下调整:
Good day, I am building a web application wherein the user can print a panel and its contents. I found a code as seen here and tweaked it as such:
Ext.define('My_app_name.override.form.Panel', {
override: 'Ext.form.Panel',
print: function(pnl) {
if (!pnl) {
pnl = this;
}
// instantiate hidden iframe
var iFrameId = "printerFrame";
var printFrame = Ext.get(iFrameId);
if (printFrame === null) {
printFrame = Ext.getBody().appendChild({
id: iFrameId,
tag: 'iframe',
cls: 'x-hidden',
style: {
display: "none"
}
});
}
var cw = printFrame.dom.contentWindow;
var stylesheets = "";
var markup;
// instantiate application stylesheets in the hidden iframe
var printTask = new Ext.util.DelayedTask(function(){
// print the iframe
cw.print();
// destroy the iframe
Ext.fly(iFrameId).destroy();
});
var strTask = new Ext.util.DelayedTask(function(){
var str = Ext.String.format('<html><head>{0}</head><body>{1}</body></html>',stylesheets,markup);
// output to the iframe
cw.document.open();
cw.document.write(str);
cw.document.close();
// remove style attrib that has hardcoded height property
// cw.document.getElementsByTagName('DIV')[0].removeAttribute('style');
printTask.delay(500);
});
var markUpTask = new Ext.util.DelayedTask(function(){
// get the contents of the panel and remove hardcoded overflow properties
markup = pnl.getEl().dom.innerHTML;
while (markup.indexOf('overflow: auto;') >= 0) {
markup = markup.replace('overflow: auto;', '');
}
while (markup.indexOf('background: rgb(255, 192, 203) !important;') >= 0) {
markup = markup.replace('background: rgb(255, 192, 203) !important;', 'background: pink !important;');
}
strTask.delay(500);
});
var styleSheetConcatTask = new Ext.util.DelayedTask(function(){
// various style overrides
stylesheets += ''.concat(
"<style>",
".x-panel-body {overflow: visible !important;}",
// experimental - page break after embedded panels
// .x-panel {page-break-after: always; margin-top: 10px}",
"</style>"
);
markUpTask.delay(500);
});
var styleSheetCreateTask = new Ext.util.DelayedTask(function(){
for (var i = 0; i < document.styleSheets.length; i++) {
stylesheets += Ext.String.format('<link rel="stylesheet" href="{0}" />', document.styleSheets[i].href);
}
styleSheetConcatTask.delay(500);
});
styleSheetCreateTask.delay(500);
}
});
我设置了延迟，让函数在打印网格和照片时更加一致，因为从样式中组装"需要时间.
I placed the delays to let the function be more consistent in printing out grids and photos as it takes time to "assemble" from the styles.
在函数组装"要打印的数据后，它调用浏览器的本地打印方法.我现在的问题是我不知道用户是否在他们的网络浏览器打印对话框中按下了打印"或取消".
After the function "assembles" the data to be printed, it calls the browsers native printing methods. My issue right now is that I don't know if I the user presses "Print" or "Cancel" in their web browsers Print Dialog.
有没有办法为这个覆盖函数创建一个回调，这样我就可以知道用户是否真的完成了打印或取消了打印作业?
Is there a way to create a callback for this override function so I can know if the user really did push through with printing or cancelled the printing job?
非常感谢任何帮助.
更新
我检查了以下 Mindparses 评论中的链接 导致我到这个页面.我尝试通过执行以下操作来实现代码:
I checked the link in mindparses' comment below which led me to this page. I tried to implement the code by doing such below:
var beforePrint = function() {
console.log('before print');
form.print();
};
var afterPrint = function() {
console.log('after print');
};
if (window.matchMedia) {
var mediaQueryList = window.matchMedia('print');
mediaQueryList.addListener(function(mql) {
if (mql.matches) {
console.log('mql matches');
beforePrint();
} else {
console.log('mql did NOT match');
afterPrint();
}
});
}
其中 form 是我的表单，print 是上面的打印覆盖功能.
Where form is my form and print is the print override function above.
所有这些代码都在一个按钮监听器中.
All of these codes are in a button listener.
但是，我对这个解决方案的问题是，它似乎只有在用户按下 Ctrl/Command + P 时才有效.如果像上面的覆盖函数那样以编程方式调用打印对话框，它就不起作用.我的第二个担忧是该函数在用户发出 Ctrl/Command + P 命令时触发.我想知道用户何时真正单击对话框中的打印"命令，而不是何时出现打印对话框.
However, the issue I have with this solution is that it only seems to work if the user presses Ctrl/Command + P. It does not work if the print dialog is programatically called like in my override function above. A second concern I have is that the function triggers when the user issues the Ctrl/Command + P command. What I want is to know when the user really clicks on the "Print" command in the dialog and not when a Print Dialog box appears.
推荐答案
虽然控制打印对话框很容易，但无法检测文档是否真的以跨浏览器方式打印.打印对话框中发生的事情由操作系统控制，JavaScript 不容易访问.
While it is easy to control the print dialog, it is not possible to detect if the document was really printed in a cross browser fashion. What is happening in the print dialog is controlled by the operating system and is not readily accessible by JavaScript.
我找到了两个关于这个问题的资源:
I found two resources about this issue :
第二个链接可能很有趣，因为它可以让您显示您可以完全控制的自己的打印对话框.
The second link might be interesting because it could allow you to show your own print dialog that you can fully control.
我意识到这只是部分答案，我不知道这个问题是否确实有答案.
I'm conscious that this is only a partial answer, and I don't know if this problem does have an answer.
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