Chrome API: sendMessage 没有从内容脚本正确接收到 background.js

Question

我正在尝试设置我的 content_script.js 以将消息发送到 background.js。 Background.js 能够接收消息并对其进行处理，但是 content_script.js 遇到了问题 receiving/printing。

content_script.js

chrome.runtime.sendMessage({method: "getSettings"}, function(response) {
    console.log(response.data);
    console.log("This is not printing either");
});

background.js

chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if (request.method == "getSettings") {
        chrome.storage.sync.get(null, function (val) {
            sendResponse({data: "test"});
            console.log("Responding: " + val.radioSettings);
        });
    }
});

background.js 中的

Console.log 打印来自 chrome.storage 的正确消息，但我的 content_script.js 中的 console.log 永远不会打印。

我觉得这很接近，但只是缺少一些小东西。这是我的清单的一部分：

manifest.json

{
  "version": "0.0.1",
  "manifest_version": 2,
  "browser_action": {
    "default_icon": "icons/icon19.png",
    "default_popup": "popup.html"
  },
  "background": {
    "scripts": ["js/background.js"]
  },
  "permissions": [
    "storage",
    "tabs"
  ],
  "content_scripts": [
    {
      "matches": ["<all_urls>"],
      "js": ["js/jquery-1.11.3.min.js", "js/content_script.js"]
    }
  ]
}

Answer 1

那就解决了 -- 感谢重复问题 link。

为了让其他人更容易，这是其他答案所说的：

From the documentation for chrome.runtime.onMessage.addListener:

This function becomes invalid when the event listener returns, unless you return true from the event listener to indicate you wish to send a response asynchronously (this will keep the message channel open to the other end until sendResponse is called).

So you just need to add return true; after the [end of addListener] to indicate that you'll call the response function asynchronously.

这是代码的正确版本：

background.js

chrome.runtime.onMessage.addListener(function(request, sender, sendResponse) {
    if (request.method == "getSettings") {
        chrome.storage.sync.get(null, function (val) {
            sendResponse({data: "test"});
            console.log("Responding: " + val.radioSettings);
        });
    }
    return true;
});