如何将事件处理程序附加到 extJS 中的面板? [英] How do I attach an event handler to a panel in extJS?

问题描述

我想要做的就是处理 extJS 面板上的点击.

我已经尝试了关于.]

您遗漏了几个关键概念:

click 是不是有效的面板事件，因此在面板上添加点击处理程序将无济于事(这是您上面发布的大多数代码中的问题).

在这段代码中:

var menuItem1 = new Ext.Panel({...});内容体

您从另一个答案复制粘贴，但不正确.其他代码中的 content 引用了创建的面板——它是一个变量.在此代码中，您将面板创建为 menuItem1，但随后尝试将其引用为 content?

请重新阅读我之前关于渲染如何在我给您的另一个答案中的解释.您必须向渲染它的容器添加一个面板，或直接渲染它(通过renderTo配置).如果两者都不做，面板将不会显示.

使用 jQuery 的委托函数不是处理 Ext JS 组件的正确方法.

All I want to do is handle a click on an extJS panel.

I've tried all the of suggestions on this question plus all I could find elsewhere but each of them fail in the ways described below.

What is the correct syntax to add a click event handler to a extJS panel?

[Edit: For the sake of others who may find this question later, I'll add some comments inline to make this easier to decipher --@bmoeskau]

doesn't execute handler:

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem',
    listeners: {
        click: function() {
            alert('ok');
        }
    }
}); 

[Ed: click is not a Panel event]

doesn't execute handler:

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem',
    listeners: {
        render: function(c) {
            c.body.on('click', function() {
                alert('ok');
            });
        }
    }
}); 

[Ed: The Panel is never being rendered -- add renderTo config. Next, you'll hit a null error telling you that c is not a valid variable. Do you mean menuItem1 instead?]

doesn't execute handler:

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem'
}); 
Ext.getCmp('panelStart').on('click', function() {
    alert('ok');
});

[Ed: click is not a Panel event. Also, the Panel is not yet rendered, so if you switched the callback to be on the element rather than the Component you'd get a null error.]

gets error: Ext.get('panelStart') is null:

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem'
}); 
Ext.get('panelStart').on('click', function() {
    alert('ok');
});

[Ed: It's not rendered, see above. Switching from getCmp to get means you are switching from referencing the Component (which does exist, but does not have a click event) to referencing the Element (which does have a click event, but is not yet rendered/valid).]

makes the panel disappear:

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem',
    listeners: {
        'render': {
            fn: function() {
                this.body.on('click', this.handleClick, this);
            },
            scope: content,
            single: true
        }
    },
    handleClick: function(e, t){
        alert('ok');
    }        
}); 

[Ed: The scope being passed into the callback (content) is not a valid ref in this code (this was copy-pasted incorrectly from another sample). Since the Panel var is created as menuItem1 and the callback is intended to run in the panel's scope, scope var should be menuItem1. Also, this Panel is never rendered, see prev comments.]

gives the error "Ext.fly(menuItem1.id) is null":

var menuItem1 = new Ext.Panel({
    id: 'panelStart',
    title: 'Start',
    html: 'This is the start page.',
    cls:'menuItem'
}); 
Ext.fly(menuItem1.id).addListener('click', Ext.getCmp(menuItem1.id) , this);

[Ed: Panel is not rendered, see above]

...put outside Ext.onReady()... gets error: Ext.getCmp('panelStart') is null

Ext.getCmp('panelStart').on('click', function() {
    alert('okoutside');
});

[Ed: Panel is likely not rendered at the time this code is run. Also, click is not a Panel event.]

...put outside Ext.onReady()... gets error: Ext.get('panelStart') is null

Ext.get('panelStart').on('click', function() {
    alert('okoutside');
});

[Ed: See above]

...put outside Ext.onReady()... gets error: Ext.fly('panelStart') is null

Ext.fly('panelStart').on('click', function() {
    alert('okoutside');
});

[Ed: See above]

For the last three, I checked in Firebug and <div id="startPanel"> exists:

It works with JQuery:

So with JQuery I simply have to do this and it works:

$('body').delegate(('#panelStart'), 'click', function(){
    alert('ok with jquery');
});

[Ed: This is not a good approach. It's simply delaying attaching of the handler until later, when the element actually shows up in the DOM (which could also be done via Ext btw, but would still not be the proper approach). I spelled out the correct approach, as linked in my answer below. The OP's attempts are all very close, but each is missing one or two key pieces.]

How can I attach a click handler like this with extJS?

解决方案

[For anyone else reading this, I went through a fairly thorough explanation of this already here.]

You are missing a few key concepts:

click is not a valid Panel event, so adding a click handler on a Panel will do nothing (this is the issue in most of the code you posted above).

In this code:

var menuItem1 = new Ext.Panel({
   ...
}); 
content.body

You copy-pasted from another answer, but incorrectly. content in the other code referenced the Panel that was created -- it is a variable. In this code you created the Panel as menuItem1 but then are trying to reference it as content?

Please re-read my previous explanation about how rendering works in the other answer I gave you. You must either add a Panel to a container that renders it, or render it directly (via the renderTo config). If you do neither, the Panel will not show up.

Using jQuery's delegate function is not the proper approach with Ext JS components.

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