BroadcastReceiver onReceive 方法中的异步任务不是运行？

Question

我有一个工作应用程序，它可以将字符串数据从应用程序的输入文本字段发送到我电脑上的 TCP 服务器。我添加了 BroadcastReceiver class 以在收到消息时将消息发送到计算机。应用程序接收消息（Toast 正在运行），但我无法将接收到的消息发送到 PC。

没有错误。应用程序只是跳过调用的方法。

如何在 onReceive 中调用方法？

感谢您的帮助！

public class SmsReceiver extends BroadcastReceiver {
String phone;
String message;

@Override
public void onReceive(Context context, Intent intent) {
    Bundle intentExtras = intent.getExtras();

    if (intentExtras != null) {
        // Get Messages
        Object[] sms = (Object[]) intentExtras.get("pdus");

        for (int i = 0; i < sms.length; ++i) {
            // Parse Each Message
            SmsMessage smsMessage = SmsMessage.createFromPdu((byte[]) sms[i]);

            phone = smsMessage.getOriginatingAddress();
            message = smsMessage.getMessageBody().toString();
            System.out.println("Message is: "+message);
            Log.i("sth","message "+message);

            //What i have tried
            sendMessage(message);

            //creating instance
            MessageSender messageSender = new MessageSender();
            messageSender.execute(message);

            //calling metod from MainActivity
            ((MainActivity)context.getApplicationContext()).send2(message);

            MainActivity.send2(message);

            //toast is working fine
            Toast.makeText(context,"Alert:"+ phone + ": " + message, Toast.LENGTH_SHORT).show();
        }
    }
}
public void sendMessage(String s)
{
    MessageSender messageSender = new MessageSender();
    messageSender.execute(s);
}

主要活动

public class MainActivity extends AppCompatActivity {

EditText e1;

@Override
protected void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    e1 = (EditText)findViewById(R.id.editText);
    //This works
    MessageSender messageSender = new MessageSender();
    messageSender.execute("App launched!");
}

//On Button click. Working good.
public void send(View v)
{
    MessageSender messageSender = new MessageSender();
    messageSender.execute(e1.getText().toString());
}
//For test purposes
public static void send2(String s)
{
    MessageSender messageSender = new MessageSender();
    messageSender.execute(s);
}

消息发送者

public class MessageSender extends AsyncTask<String,Void,Void>
{
Socket s;
DataOutputStream dos;
PrintWriter pw;

@Override
public Void doInBackground(String... voids) {

    String message = voids[0];
try {
    s = new Socket("192.168.1.69", 7800);
    pw = new PrintWriter(s.getOutputStream());
    pw.write(message);
    pw.flush();
    pw.close();
    s.close();

}catch(IOException e)
{
    e.printStackTrace();
}
    return null;
}

}

添加的服务器代码：

  public class MyServerFrame extends javax.swing.JFrame 
  {
  static Socket s;
   static ServerSocket ss;
  static InputStreamReader isr;
  static BufferedReader br;
  static String message;public MyServerFrame() 
 {

}

public static void main(String args[]) 
{   
    try 
    {
        ss = new ServerSocket(7800);
        while(true)
        {
            s=ss.accept();
            isr = new InputStreamReader(s.getInputStream());
            br = new BufferedReader(isr);
            StringBuilder everything = new StringBuilder();
            String line;
            while( (line = reader.readLine()) != null) 
            {
               everything.append(line);
            }
            message = everything.toString();//multiple to onelinestring 
            System.out.println(message);
        }   
    }catch (IOException e) 
    {
        e.printStackTrace();
    }
}

}

Answer 1

问题在于，由于您在 onReceive 方法中使用异步任务执行网络请求，onReceive 方法 returns 在 AsyncTask 执行之前执行，因为异步任务是异步的。因此，运行onRequest 方法的进程变为低优先级，因为 onReceive 方法已返回并且操作系统将在异步任务实际执行之前将其终止。

这里有两种解决方法：

首先确保接收方已在您的 Android 清单中声明，然后执行以下操作之一。

与其调用异步任务来执行您的网络请求，不如创建一个服务并将该服务用于运行网络代码。

可以在onReceive方法中调用goAsync()方法，告诉系统给接收者更多的时间去执行它的Async Task。代码如下：

@Override
public void onReceive(final Context context, final Intent intent) {
//create a pending intend that you will pass to the Async task so you can tell the system when the Async Task finished so that it can recycle.
final PendingResult pendingResult = goAsync();
 AsyncTask<String, Integer, String> asyncTask = new AsyncTask<String,  Integer, String>() {
    @Override
    protected String doInBackground(String... params) {
        //put the network calling code in here

        // Must call finish() so the BroadcastReceiver can be recycled.
        pendingResult.finish();
        return data;
    }
};
asyncTask.execute();
 }

我认为第二种方式会更简单，所以我建议使用它，因为它不需要您创建全新的服务。

Answer 2

感谢 SteelToe 引导我找到这个简单的解决方案：

Receiver was not declared in manifest file.

BroadcastReceiver onReceive 方法中的异步任务不是运行？

Async Task inside BroadcastReceiver onReceive method not running?

java

android