OkHttp，Android - 下載一個html頁面並在視圖中顯示此內容

Question

我想要下載一個html頁面以便在TextView中顯示一些信息。每次，我的程序都會在TextView中顯示「錯誤」。爲什麼我的程序不工作？

我在AndroidManifest.xml文件中添加這一行：

<uses-permission android:name="android.permission.INTERNET" /> 

這裏我activity_main.xml中的文件：

 <?xml version="1.0" encoding="utf-8"?> 
     <relativelayout xmlns:android="http://schemas.android.com/apk/res/android" 
      xmlns:tools="http://schemas.android.com/tools" 
      android:layout_width="match_parent" 
      android:layout_height="match_parent" 
      android:paddingbottom="@dimen/activity_vertical_margin" 
      android:paddingleft="@dimen/activity_horizontal_margin" 
      android:paddingright="@dimen/activity_horizontal_margin" 
      android:paddingtop="@dimen/activity_vertical_margin" 
      tools:context="blabla.test.mainactivity"> 

      <textview 
       android:id="@+id/aff" 
       android:layout_width="100dp" 
       android:layout_height="100dp" 
       android:text="error" /> 
     </relativelayout> 

在這裏，我MainActivity.java：

package blabla.test; 

    import android.support.v7.app.AppCompatActivity; 
    import android.os.Bundle; 
    import android.util.Log; 
    import android.widget.TextView; 

    import java.io.IOException; 

    import okhttp3.Call; 
    import okhttp3.Callback; 
    import okhttp3.OkHttpClient; 
    import okhttp3.Request; 
    import okhttp3.Response; 


    public class MainActivity extends AppCompatActivity { 

     public static String test = "error"; 

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

      String url = "http://square.github.io/okhttp/"; 
      OkHttpClient client = new OkHttpClient(); 
      Request request = new Request.Builder() 
        .url(url) 
        .build(); 

      client.newCall(request).enqueue(new Callback() { 
       @Override 
       public void onFailure(Call call, IOException e) { 
        Log.e("APp", e.toString()); 
       } 
       @Override 
       public void onResponse(Call call, Response response) throws IOException { 
        if (response.isSuccessful()) { 

         MainActivity.test = response.body().string(); 
         }else{ 
          Log.e("APp", "Error"); 
         } 
        } 
       }); 

      TextView aff = (TextView) findViewById(R.id.aff); 
      aff.setText(MainActivity.test); 
      } 
     } 

我提前感謝您的幫助:)

Answer 1

問題很簡單。當您查詢完成後，您不會更新TextView以顯示所需的信息。因此它會保留其在activity_main.xml佈局文件中定義的「錯誤」的原始消息。

Answer 2

我明白我的錯誤，我必須將我的代碼放入runOnUThread（）。 謝謝你的快速反應;）

這裏我糾正：

  package blabla.test; 

      import android.support.v7.app.AppCompatActivity; 
      import android.os.Bundle; 
      import android.util.Log; 
      import android.widget.TextView; 

      import java.io.IOException; 

      import okhttp3.Call; 
      import okhttp3.Callback; 
      import okhttp3.OkHttpClient; 
      import okhttp3.Request; 
      import okhttp3.Response; 


      public class MainActivity extends AppCompatActivity { 

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

        String url = "http://square.github.io/okhttp/"; 
        OkHttpClient client = new OkHttpClient(); 
        Request request = new Request.Builder() 
          .url(url) 
          .build(); 

        client.newCall(request).enqueue(new Callback() { 

         @Override 
         public void onFailure(Call call, IOException e) { 
          Log.e("APp", e.toString()); 
         } 

         @Override 
         public void onResponse(Call call, Response response) throws IOException { 
          if (response.isSuccessful()) { 

           final String aFinalString = response.body().string(); 

           runOnUiThread(new Runnable() { 
            @Override 
            public void run() { 
             TextView aff = (TextView) findViewById(R.id.aff); 
             aff.setText(aFinalString); 
            } 
           }); 

          } else { 
           Log.e("APp", "Error"); 
          } 
         } 
        }); 
       } 
      }