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[英]How to fetch string from AsyncTask class method to MainActivity?
[英]How to get string from a server in AsyncTask to a MainActivity?
我想顯示一個從服務器獲取的字符串,該字符串位於MainActivity
textView 上的AsyncTask
(或者我稱之為MessageSender
類)中。 我知道我需要使用setText()
方法。 我從服務器獲取字符串,它顯示在控制台中。
這是我的MessageSender
類:
public class MessageSender extends AsyncTask<String, Object, String> {
Socket socket;
ObjectInputStream ois;
ObjectOutputStream oos;
BufferedInputStream bis;
Object player;
String userName;
String level;
String input = null;
@Override
protected String doInBackground(String... strings) {
userName = strings [0];
level = strings [1];
player = userName +"\n" + level ;
try {
socket= new Socket("192.168.1.179", 8884);
System.out.println("********************");
System.out.println("Connected to server");
System.out.println("********************");
oos = new ObjectOutputStream(socket.getOutputStream());
oos.writeObject(player);
oos.flush();
ois = new ObjectInputStream(socket.getInputStream());
input = ois.readUTF();
System.out.println(input);
} catch (IOException e) {
e.printStackTrace();
// socket.close();
}
return input;
}
}
這是我的MainActivity
類:
package com.example.whack_a_mole;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import com.google.android.material.button.MaterialButton;
public class MainActivity4 extends AppCompatActivity {
private TextView textView;
private MaterialButton newGameBtn;
MessageSender ms=new MessageSender();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main4);
textView=findViewById(R.id.first_place);
textView.setText(ms.input);
newGameBtn= findViewById(R.id.newGameBtn);
newGameBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent= new Intent(MainActivity4.this, MainActivity.class);
startActivity(intent);
//uppdatera listan
}
});
}
}
AsyncTask
已棄用,請考慮使用其他東西。
您可以創建一個接口,例如使用一種方法onInputReceived
將其稱為MessageInputListener
:
public interface MessageInputListener {
public void onInputReceived(String input);
}
通過MainActivity4
實現該接口,將MessageInputListener
作為參數添加到MessageSender
構造函數,在創建MessageSender
this
MainActivity4
MessageSender
onPostExecute
:
public class MainActivity4 extends AppCompatActivity implements MessageInputListener {
// ...
MessageSender ms = new MessageSender(this);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// ...
ms.execute(...);
}
@Override
public void onInputReceived(String input) {
textView.setText(input);
}
}
public class MessageSender extends AsyncTask<String, Object, String> {
//...
private MessageInputListener mListener;
public MessageSender(MessageInputListener listener) {
mListener = listener;
}
@Override
protected void onPostExecute(String message) {
if (mListener != null) {
mListener.onInputReceived(message)
}
}
}
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