从Electron简单起步之后,接下来应该就是写Hello World了。但是Hello World已经包含在Quick Start程序里了,怎么办呢?

所以接下来先来看一看Quick Start中的Hello World是怎么写的吧。

electron-quick-start

首先进入Quick Start的文件夹,可以发现其中包含了以下文件:

1
2
3
4
5
6
index.html
LICENSE.md
main.js
node_modules/
package.json
README.md

其中有三类文件:程序资源文件(index.html,main.js),说明文件(LICENSE.mdREADME.md),Node文件(node_modules/,package.json)。在这里我们只关心程序资源文件。

index.html文件中包含程序的主体架构

1
2
3
4
5
6
7
8
9
10
11
12
13
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Hello World!</title>
</head>
<body>
<h1>Hello World!</h1>
We are using node <script>document.write(process.versions.node)</script>,
Chrome <script>document.write(process.versions.chrome)</script>,
and Electron <script>document.write(process.versions.electron)</script>.
</body>
</html>

通过源代码可以看出index.html就是一个平常的HTML文件。需要关注的是<script>标签里的脚本,通过这些脚本输出了一些常量。

如果把index.html比作视图框架,那么main.js中的就是程序逻辑了

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
'use strict';
const electron = require('electron');
// Module to control application life.
const app = electron.app;
// Module to create native browser window.
const BrowserWindow = electron.BrowserWindow;
// Keep a global reference of the window object, if you don't, the window will
// be closed automatically when the JavaScript object is garbage collected.
let mainWindow;
function createWindow () {
// Create the browser window.
mainWindow = new BrowserWindow({width: 800, height: 600});
// and load the index.html of the app.
mainWindow.loadURL('file://' + __dirname + '/index.html');
// Open the DevTools.
mainWindow.webContents.openDevTools();
// Emitted when the window is closed.
mainWindow.on('closed', function() {
// Dereference the window object, usually you would store windows
// in an array if your app supports multi windows, this is the time
// when you should delete the corresponding element.
mainWindow = null;
});
}
// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
app.on('ready', createWindow);
// Quit when all windows are closed.
app.on('window-all-closed', function () {
// On OS X it is common for applications and their menu bar
// to stay active until the user quits explicitly with Cmd + Q
if (process.platform !== 'darwin') {
app.quit();
}
});
app.on('activate', function () {
// On OS X it's common to re-create a window in the app when the
// dock icon is clicked and there are no other windows open.
if (mainWindow === null) {
createWindow();
}
});

程序的逻辑体现在createWindow函数中,首先创建了一个800*600的窗体,然后加载资源文件index.html,打开控制台工具,注册closed事件。虽然代码使用了Node的形式编写,但是比对注释大体还是能明白个所以然。

通过官方的Quick Start程序,可以大致了解Electron程序的流程形式。但要想编写复杂Electron程序,这些还远远不够。