cordova - 如何使用 cordova/phonegap 将数据或消息从 java 应用程序/插件发送到 javascript

Question

我想我在这里遗漏了一些东西。我习惯于通过调用execute 和callbackContext 方法将数据从javascript 发送到java 并返回。

但如果在某些时候，假设我有一个正在运行的线程需要定期向 JavaScript 发送数据，那么我应该怎么做呢？ (这假设该任务正在运行并且尚未由 javascript 操作触发，因此没有可用的callbackContext)

Answer 1

您始终可以通过 java 执行 javascript:

String js = "alert('test')";
webView.loadUrlNow("javascript:" + js);

或者您可以初始化插件并保持回调执行此操作

PluginResult pgRes = new PluginResult(PluginResult.Status.OK, "message");
pgRes.setKeepCallback(true);
callbackContext.sendPluginResult(pgRes);

添加了Sephy提供的示例

private String myCbkId;
// Store callbackId from a call to execute 
@Override public boolean execute(String action, JSONArray arr, CallbackContext cbkCtx) throws JSONException { 

    myCbkId = cbkCtx.getCallbackId(); 
    JSONObject data = arr.getJSONObject(0); 
    String ack = data.getString("data"); // You can acknowledge to the callback for instance and keep it alive 
    Log.d(TAG, "ack".equals(ack) ? "ack !" : "not ack !");

    // These lines can be reused anywhere in your app to send data to the javascript
    PluginResult result = new PluginResult(PluginResult.Status.OK, ack);
    result.setKeepCallback(true);//This is the important part that allows executing the callback more than once, change to false if you want the callbacks to stop firing  
    this.webView.sendPluginResult(result, this.myCbkId); 

    return true; 
}