Android:从 URL 获取一个值作为静态字符串

Question

网址 = http://troyka.esy.es/numberofrows.php

如果你把它放在你的浏览器中，你会得到一个数字(目前是 9)

我正在尝试将该号码拉到我的 android 应用程序并将其显示在 TextView 上

我已经尝试过这种方法，但它在模拟器上没有显示任何内容 互联网和网络权限在 list 上设置

textview id = "textView"

我做错了什么？

import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;

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


public class MainActivity extends Activity {
    public static String ans;
    private TextView T1;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        T1 = new TextView(this);

        T1 = (TextView) findViewById(R.id.textView);
        T1.setText(ans);

    }
    public String getDATA() throws IOException {
        String fullString = "";
        URL url = new URL("http://troyka.esy.es/numberofrows.php");
        BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
        String line;
        while ((line = reader.readLine()) != null) {
            fullString += line;
        }
        reader.close();
        return fullString;
    }
    public void setAns() throws IOException {
        ans = getDATA();
    }
}

Answer 1

请试试这个答案:

首先，像这样创建一个 AsyncTask 类来在 android 主线程之外为您执行实际的 HTTP 请求:

public class FetchColumnAsync extends AsyncTask<String, Void, String> 
{
    private Context mContext;

    public FetchColumnAsync( Context ctx){
       this.mContext = ctx; 
    }

    protected String doInBackground(String... urls)
    {
       String fullString = "";
       try{

          URL url = new URL(urls[0]);
          BufferedReader reader = new BufferedReader(new InputStreamReader(url.openStream()));
          String line;
          while ((line = reader.readLine()) != null) {
             fullString += line;
          }
          reader.close();
        }catch(Exception e ){
           e.getMessage();
        }

        return fullString;
    }

    @Override
    protected void onPostExecute(String value){
       try{
          ((OnValueFetchedListener) mContext).onValueFetched(value);
       }catch(ClassCastException e){}
    }

    public interface OnValueFetchedListener{
        void onValueFetched(String columns);
    }

}

然后在你的 Activity 类中，像这样实现上面的接口(interface)；

public class MainActivity extends Activity implements FetchColumnAsync.OnValueFetchedListener{
   public static String ans;
   private TextView T1;

   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.activity_main);


       T1 = (TextView) findViewById(R.id.textView);

       //missing piece of code here
       new FetchColumnAsync(this).execute("http://troyka.esy.es/numberofrows.php");

   }

   @Override
   public void onValueFetched(String value){
      T1.setText(value);
   }

}