GCM sendRegistrationIdToBackend未定义

Question

我正在尝试设置GCM但我的项目并不能识别某些方法。我遵循许多其他链接的建议，即导入GCM和谷歌播放服务，但我仍然没有运气。谢谢你的期待。

编辑：我已经清理了一百万次并重建了。

Answer 1

我不确定你从哪里获得了演示应用的代码，但是它有几个问题。

首先，您所缺少的方法未在演示中实现。它有一个空体：

/**
 * Sends the registration ID to your server over HTTP, so it can use GCM/HTTP or CCS to send
 * messages to your app. Not needed for this demo since the device sends upstream messages
 * to a server that echoes back the message using the 'from' address in the message.
 */
private void sendRegistrationIdToBackend() {
  // Your implementation here.
}

您有责任实施它，因为它的实施取决于您的服务器实施。

另一个错误（修复编译错误后出现异常）是从主线程调用gcm.register()。你必须在后台调用它：

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);
    mDisplay = (TextView) findViewById(R.id.display);

    context = getApplicationContext();

    // Check device for Play Services APK. If check succeeds, proceed with GCM registration.
    if (checkPlayServices()) {
        gcm = GoogleCloudMessaging.getInstance(this);
        regid = getRegistrationId(context);

        if (regid.isEmpty()) {
            registerInBackground();
        }
    } else {
        Log.i(TAG, "No valid Google Play Services APK found.");
    }
}

/**
 * Registers the application with GCM servers asynchronously.
 * <p>
 * Stores the registration ID and the app versionCode in the application's
 * shared preferences.
 */
private void registerInBackground() {
    new AsyncTask<Void, Void, String>() {
        @Override
        protected String doInBackground(Void... params) {
            String msg = "";
            try {
                if (gcm == null) {
                    gcm = GoogleCloudMessaging.getInstance(context);
                }
                regid = gcm.register(SENDER_ID);
                msg = "Device registered, registration ID=" + regid;

                // You should send the registration ID to your server over HTTP, so it
                // can use GCM/HTTP or CCS to send messages to your app.
                sendRegistrationIdToBackend();

                // For this demo: we don't need to send it because the device will send
                // upstream messages to a server that echo back the message using the
                // 'from' address in the message.

                // Persist the regID - no need to register again.
                storeRegistrationId(context, regid);
            } catch (IOException ex) {
                msg = "Error :" + ex.getMessage();
                // If there is an error, don't just keep trying to register.
                // Require the user to click a button again, or perform
                // exponential back-off.
            }
            return msg;
        }

        @Override
        protected void onPostExecute(String msg) {
            mDisplay.append(msg + "\n");
        }
    }.execute(null, null, null);
}

所有代码示例均来自official GCM Demo app。