无法解析符号“ GoogleCloudMessaging” GCM

Question

我正在尝试GCM在我的应用程序中工作（在工作时间变更或正在进行任何促销时通知用户），但是Cannot resolve symbol 'GoogleCloudMessaging'在尝试使用Google Cloud Messaging API时，我一直收到错误消息。

我正在使用新发布的Android Studio IDE对此进行编码。

这是我的GcmBroadcastReciever.java代码：

import android.R;
import android.app.Activity;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class GcmBroadcastReceiver extends BroadcastReceiver 
{
    static final String TAG = "GCMDemo";
    public static final int NOTIFICATION_ID = 1;
    private NotificationManager mNotificationManager;
    Context ctx;
    GoogleCloudMessaging gcm; // I get the error here

    @Override
    public void onReceive(Context context, Intent intent) {
        GoogleCloudMessaging gcm = GoogleCloudMessaging.getInstance(context); //error
        ctx = context;
        String messageType = gcm.getMessageType(intent); //cannot resolve method here
        if (GoogleCloudMessaging.MESSAGE_TYPE_SEND_ERROR.equals(messageType)) { //error
            sendNotification("Send error: " + intent.getExtras().toString());
        } else if (GoogleCloudMessaging.MESSAGE_TYPE_DELETED.equals(messageType)) { //error
            sendNotification("Deleted messages on server: " +
                    intent.getExtras().toString());
        } else {
            sendNotification("Received: " + intent.getExtras().toString());
        }
        setResultCode(Activity.RESULT_OK);
    }

    // Put the GCM message into a notification and post it.
    private void sendNotification(String msg) {
        mNotificationManager = (NotificationManager)
                ctx.getSystemService(Context.NOTIFICATION_SERVICE);

        PendingIntent contentIntent = PendingIntent.getActivity(ctx, 0,
                new Intent(ctx, Activity.class), 0);

        Toast.makeText(ctx, msg, Toast.LENGTH_SHORT).show();
    }
}

Answer 1

以下各节将指导您完成设置GCM实施的过程。开始之前，请确保设置Google Play服务SDK。
您需要此SDK才能使用GoogleCloudMessaging方法
。严格来说，您唯一需要此API的唯一东西是上游（设备到云）消息传递，但它还提供了推荐的简化注册API。

您是否设置了Google Play服务SDK？

你必须 ：

1. 安装Google Play服务SDK
2. <android-sdk>/extras/google/google_play_services/libproject/google-play-services_lib/在您的Android项目中引用库项目。

要安装Google Play服务SDK进行开发，请执行以下操作：

 1. Launch the SDK Manager.
     - From Eclipse (with ADT), select Window > Android SDK Manager.
     - On Windows, double-click the SDK Manager.exe file at the root of

the Android
SDK directory.
- On Mac or Linux, open a terminal and navigate to the tools/
directory in
the Android SDK, then execute android sdk.
2. Install the Google Play services SDK.
Scroll to the bottom of the package list, expand Extras, select
Google Play
services, and install it.
The Google Play services SDK is saved in your Android SDK
environment at
/extras/google/google_play_services/.
3. Install a compatible version of the Google APIs platform.
If you want to test your app on the emulator, expand the directory
for
Android 4.2.2 (API 17) or a higher version, select Google APIs, and
install it. Then create a new AVD with Google APIs as the platform
target.
Note: Only Android 4.2.2 and higher versions of the Google APIs
platform
include Google Play services.