为什么我可以通过mainActivity连接到我的服务器，但不能通过片段连接到我的服务器？
现在，我有两个节目。 第一个名为 mqtt_test ，其中包括MainActivity，Button和连接类Mqtt。所以有没有片段。
通过该程序，我可以连接到我的服务器，订阅和接收消息。
public class mqtt {
private Context context;
private String broker = "tcp://10.34.5.134:1883";
private String clientId= "DefaultName";
private MqttAndroidClient client;
private ConnectionListener connectionListener;
private static final String TAG_MQTT= "MQTT";
public mqtt(Context context)
{
this.context = context;
}
public void connect()
{
final String clientId = MqttClient.generateClientId();
//set options
MqttConnectOptions options = new MqttConnectOptions();
options.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1);
client =
new MqttAndroidClient(context, broker,
clientId);
try {
IMqttToken token = client.connect(options);
token.setActionCallback(new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
// We are connected
Log.d(TAG_MQTT, "onSuccess");
connectionListener.connected(true);
client.setCallback(new MqttCallback() {
@Override
public void connectionLost(Throwable cause) {
Log.d(TAG_MQTT, "connectionLost: ");
}
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
Log.d(TAG_MQTT, "messageArrived: Message: " + message.toString() + " with topic: " + topic);
}
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
Log.d(TAG_MQTT, "deliveryComplete: ");
}
});
}
@Override
public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
// Something went wrong e.g. connection timeout or firewall problems
Log.d(TAG_MQTT, "onFailure");
connectionListener.connected(false);
}
});
} catch (MqttException e) {
e.printStackTrace();
}
}
public void subscribe(final String topic, int qos)
{
if(client.isConnected())
{
try {
IMqttToken subToken = client.subscribe(topic, qos);
subToken.setActionCallback(new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
// The message was published
Log.d(TAG_MQTT, "onSuccess: Subscripted with topic: " + topic);
}
@Override
public void onFailure(IMqttToken asyncActionToken,
Throwable exception) {
// The subscription could not be performed, maybe the user was not
// authorized to subscribe on the specified topic e.g. using wildcards
Log.d(TAG_MQTT, "onFailure: The subscription failed");
}
});
} catch (MqttException e) {
e.printStackTrace();
}
}
}
public void publish(String topic, String payload, int qos)
{
byte[] encodedPayload = new byte[0];
try {
encodedPayload = payload.getBytes("UTF-8");
MqttMessage message = new MqttMessage(encodedPayload);
client.publish(topic, message);
Log.d(TAG_MQTT, "publish: Published message:" + payload + " to topic: " + topic);
} catch (UnsupportedEncodingException | MqttException e) {
e.printStackTrace();
Log.d(TAG_MQTT, "publish: Error");
}
}
public void setConnectionListener(ConnectionListener connectionListener) {
this.connectionListener = connectionListener;
}
}
在我的第二个程序中，我使用的代码几乎相同。但是，我正在使用片段进行未来业务。在一些片段中是按钮，它们正在调用正确的方法。 如果按下按钮，则会调用正确的方法，就像在第一个程序中一样。 但程序会跳过异步任务。 OnSucces或onFailure永远不会被调用。
IMqttToken token = client.connect(null, new IMqttActionListener() {
@Override
public void onSuccess(IMqttToken asyncActionToken) {
// connected
Log.d(TAG_CONNECTION, "onSuccess");
connectionListener.connected(true);
client.setCallback(new MqttCallback() {
@Override
public void connectionLost(Throwable cause) {
Log.d(TAG_CONNECTION, "connectionLost: ");
}
@Override
public void messageArrived(String topic, MqttMessage message) throws Exception {
Log.d(TAG_CONNECTION, "messageArrived: Message: " + message.toString() + " with topic: " + topic);
}
@Override
public void deliveryComplete(IMqttDeliveryToken token) {
Log.d(TAG_CONNECTION, "deliveryComplete: ");
}
});
}
@Override
public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
Log.d(TAG_CONNECTION, "onFailure");
connectionListener.connected(false);
Log.d(TAG_CONNECTION, exception.getMessage());
}
});
然后我通过一个新线程调用了connect-method：
@Override
public void doSmth() {
new Thread(new Runnable() {
public void run() {
// a potentially time consuming task
mqttConnection.connect();
}
}).start();
}
最后我得到了一个答案：
D/CONNECTION: cannot start service org.eclipse.paho.android.service.MqttService
我不明白为什么这不起作用。也许你有一些意见。
要明确：两个程序都具有相同的权限：
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />
我想，我必须使用更多的asycTasks来解决这个问题。
如果您可以分享一些链接，那将是非常棒的。在最好的情况下举一些例子。我只找到了在单个MainActivity中运行的示例。
答案 0 :(得分：0)
错误
D/CONNECTION: cannot start service org.eclipse.paho.android.service.MqttService
可能表示条目
<service android:name="org.eclipse.paho.android.service.MqttService">
</service>