java - 如何在Android Studio中从java中的另一个文件导入类？

Question

我正在尝试将 seismic_text.java 文件内的函数 getUrlContents(string) 调用到我的 MainActivity.java 文件。如何从文件中的任何位置调用该函数？任何信息或提示表示赞赏。我将我的文件放在下面。

这是我的MainActivity.java:

package bt.alfaquake;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.app.NotificationManager;
import android.content.Intent;
import android.view.View;
import android.app.PendingIntent;
import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.NotificationCompat;
import bt.alfaquake.seismic_text;

public class MainActivity extends AppCompatActivity {   

    NotificationCompat.Builder notification;
    private static final int uniqueID = 123;

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

        notification = new NotificationCompat.Builder(this);
    }    
}

这是我的seismic_text.java: 包 bt.alfaquake;

import java.net.*;
import java.io.*;

public class seismic_text {

        public static String getUrlContents(String theUrl) {
            StringBuilder content = new StringBuilder();
            try
            {
                URL url = new URL(theUrl);
                URLConnection urlConnection = url.openConnection();

                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
                String line;

                while ((line = bufferedReader.readLine()) != null)
                {
                    content.append(line + "\n");
                }
                bufferedReader.close();
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }
            return content.toString();
        }
    }
}

Answer 1

可以调用地震_text.getUrlContents(url);但这会导致NetworkOnMainThreadException

只需将此调用包装到 Simple AsynkTask 即可。

class MyTask extends AsyncTask<Void, Void, String> {

    @Override
    protected String doInBackground(Void... params) {
      try {
        return seismic_text.getUrlContents(url);
      } catch (InterruptedException e) {
        e.printStackTrace();
      }
      return null;
    }

    @Override
    protected void onPostExecute(String result) {
      super.onPostExecute(result);
      // TODO handle result here
    }
  }

并从您的代码中调用它:

new MyTask().execute();