Question

我必须使用java类，一个是活动，另一个是我想从中运行void的类。 Web.java看起来像：

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

public class Web {
    public Document requestPage(String urll) throws Exception {
        StringBuilder result = new StringBuilder();
        URL url = new URL(urll);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }
        rd.close();
        Document doc = Jsoup.parse(result.toString());
        return doc;
    }
}

我的MainActivity.java看起来像这样：

import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.EditText;
import android.view.View;
import android.widget.Toast;

import org.jsoup.Jsoup;
import org.jsoup.nodes.Document;


public class MainActivity extends AppCompatActivity {

    Button Visit;
    EditText Urlbox;
    Web web = new Web();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Visit = (Button)findViewById(R.id.Button);
        Urlbox = (EditText)findViewById(R.id.EditText);
        Visit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Document lol = web.requestPage(Urlbox.getText().toString());
                if(lol.text().toString() != null){
                    Toast.makeText(MainActivity.this, "Visit success!",Toast.LENGTH_SHORT).show();
                }
            }
        });
    }
}

这对主线程最好，但我想让它通过一个不同的线程，所以如果连接不好，我的UI不会卡住我如何在异步中完成这项工作？这是我第一次使用异步，但我只是不明白我应该如何使用它，我花了几天试图找出它绝对没有成功所以，如果我能得到一些做得很好的例子，那么我可以将它与我当前的代码进行比较并了解我做错了什么

Answer 1

我使用callback格式处理情境是Asynchronous networking的最佳选择，或者你可以使用AsyncTask但我解释cllback模式让我们让它成为现实

首先创建callback界面

public interface Request {

    void onSuccess(Document doc);

}

2 - 实现Runnable以在另一个线程上运行Asynchronous请求

public class Web implements Runnable {

   public final Request request;
   private final String urll;       

    Web(String urll,  Request request){
       this.urll = urll;
       this.request = request;
    }


    @Override public void run() {
       try{
        StringBuilder result = new StringBuilder();
        URL url = new URL(urll);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        conn.setRequestMethod("GET");
        BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = rd.readLine()) != null) {
            result.append(line);
        }
        rd.close();
        Document doc = Jsoup.parse(result.toString());
        // fill the cllback with result
        this.request.onSuccess(doc);
         }
       } catch (InterruptedException e) {
          Thread.currentThread().interrupt();
      }

//            return doc;
  }
}

3 - 现在我们使用ExecutorService（ThreadPools因为理由而创建了它的主题），简单的事情就在这里我们使用new Thread(Runnable)之前允许implement calback

public class MainActivity extends AppCompatActivity implement Request{

    Button Visit;
    EditText Urlbox;
    private Document lol;
  //Web web = new Web();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Visit = (Button)findViewById(R.id.Button);
        Urlbox = (EditText)findViewById(R.id.EditText);
        Visit.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                //Document lol = web.requestPage(Urlbox.getText().toString());
                String url = Urlbox.getText().toString();
                Thread thread = new Thread(new Web(url, this));
                 thread.start();
                if(lol.text().toString() != null){
                    Toast.makeText(MainActivity.this, "Visit success!",Toast.LENGTH_SHORT).show();
                }
                 thread.interrupt();
            }
        });
    }


    @Override
    public void onSuccess(Document doc) {
       lol = doc;
    }
}

并且您需要的每个地方new都会产生或请求您必须创建线程，如果您想分享结果，请在类或线程中分享这是另一回事

这种模式非常适合我。

什么是使这个运行Async的最佳方法

1 个答案: