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运行时活动完全空白 - 可能是因为Internet权限？

2016-08-21 39 views
-2

我对java/android开发相当陌生，所以请耐心等待。运行时活动完全空白 - 可能是因为Internet权限？

我已经创建了一个应用程序，作为一个应该运行“猜名人游戏”的在线课程的一部分。

问题是当我运行我的代码的主要活动是完全空白的。

奇怪的是，在课程中呈现的应用程序运行没有问题，我已经遵循了代码字。我设法找到了另外一个具有相同问题并且无法解决的候选人。

在日志中没有错误（我可以找到），我似乎无法找到任何类似问题的帖子。

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

截图仿真器（也测试在真实设备）的：

https://s9.postimg.org/su0gc58gf/Capture.png/

从MainActivity代码时，我加在清单XML以下权限

这种怪异的行为只occours ：

public class MainActivity extends Activity { 

ArrayList<String> celebURLs = new ArrayList<String>(); 
ArrayList<String> celebNames = new ArrayList<String>(); 
int chosenCeleb = 0; 
int locationOfCorrectAnswer = 0; 
String[] answers = new String[4]; 

ImageView imageView; 
Button button0; 
Button button1; 
Button button2; 
Button button3; 

public void celebChosen(View view) { 

    if (view.getTag().toString().equals(Integer.toString(locationOfCorrectAnswer))) { 

     Toast.makeText(getApplicationContext(), "Correct!", Toast.LENGTH_LONG).show(); 

    } else { 

     Toast.makeText(getApplicationContext(), "Wrong! It was " + celebNames.get(chosenCeleb), Toast.LENGTH_LONG).show(); 

    } 

    createNewQuestion(); 

} 

public class ImageDownloader extends AsyncTask<String, Void, Bitmap> { 


    @Override 
    protected Bitmap doInBackground(String... urls) { 

     try { 

      URL url = new URL(urls[0]); 

      HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 

      connection.connect(); 

      InputStream inputStream = connection.getInputStream(); 

      Bitmap myBitmap = BitmapFactory.decodeStream(inputStream); 

      return myBitmap; 


     } catch (MalformedURLException e) { 

      e.printStackTrace(); 

     } catch (IOException e) { 

      e.printStackTrace(); 

     } 

     return null; 
    } 
} 


public class DownloadTask extends AsyncTask<String, Void, String> { 


    @Override 
    protected String doInBackground(String... urls) { 

     String result = ""; 
     URL url; 
     HttpURLConnection urlConnection = null; 

     try { 

      url = new URL(urls[0]); 

      urlConnection = (HttpURLConnection) url.openConnection(); 

      InputStream in = urlConnection.getInputStream(); 

      InputStreamReader reader = new InputStreamReader(in); 

      int data = reader.read(); 

      while (data != -1) { 

       char current = (char) data; 

       result += current; 

       data = reader.read(); 
      } 

      return result; 

     } catch (Exception e) { 

      e.printStackTrace(); 

     } 

     return null; 
    } 
} 

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

    imageView = (ImageView) findViewById(R.id.imageView); 
    button0 = (Button) findViewById(R.id.button1); 
    button1 = (Button) findViewById(R.id.button2); 
    button2 = (Button) findViewById(R.id.button3); 
    button3 = (Button) findViewById(R.id.button4); 

    DownloadTask task = new DownloadTask(); 
    String result = null; 

    try { 

     result = task.execute("http://www.posh24.com/celebrities").get(); 

     String[] splitResult = result.split("<div class=\"sidebarContainer\">"); 

     Pattern p = Pattern.compile("<img src=\"(.*?)\""); 
     Matcher m = p.matcher(splitResult[0]); 

     while (m.find()) { 

      celebURLs.add(m.group(1)); 

     } 

     p = Pattern.compile("alt=\"(.*?)\""); 
     m = p.matcher(splitResult[0]); 

     while (m.find()) { 

      celebNames.add(m.group(1)); 

     } 


    } catch (InterruptedException e) { 

     e.printStackTrace(); 

    } catch (ExecutionException e) { 

     e.printStackTrace(); 

    } 

    createNewQuestion(); 

} 

public void createNewQuestion() { 

    Random random = new Random(); 
    chosenCeleb = random.nextInt(celebURLs.size()); 

    ImageDownloader imageTask = new ImageDownloader(); 

    Bitmap celebImage; 

    try { 

     celebImage = imageTask.execute(celebURLs.get(chosenCeleb)).get(); 

     imageView.setImageBitmap(celebImage); 

     locationOfCorrectAnswer = random.nextInt(4); 

     int incorrectAnswerLocation; 

     for (int i = 0; i < 4; i++) { 

      if (i == locationOfCorrectAnswer) { 

       answers[i] = celebNames.get(chosenCeleb); 

      } else { 

       incorrectAnswerLocation = random.nextInt(celebURLs.size()); 

       while (incorrectAnswerLocation == chosenCeleb) { 

        incorrectAnswerLocation = random.nextInt(celebURLs.size()); 

       } 

       answers[i] = celebNames.get(incorrectAnswerLocation); 


      } 


     } 

     button0.setText(answers[0]); 
     button1.setText(answers[1]); 
     button2.setText(answers[2]); 
     button3.setText(answers[3]); 


    } catch (Exception e) { 
     e.printStackTrace(); 
    } 


} 

}

日志：

08-21 20:47:46.778 835-835/? I/Choreographer: Skipped 37 frames! The application may be doing too much work on its main thread. 
08-21 20:47:49.283 421-519/? W/AudioTrack: AUDIO_OUTPUT_FLAG_FAST denied by client 

              --------- beginning of system 
08-21 20:47:49.335 421-434/? I/ActivityManager: START u0 {act=android.intent.action.MAIN cat=[android.intent.category.LAUNCHER] flg=0x10000000 cmp=com.example.shenstone.guessthecelebrity2/.MainActivity (has extras)} from uid 10007 on display 0 
08-21 20:47:49.614 421-433/? I/art: Background sticky concurrent mark sweep GC freed 10530(678KB) AllocSpace objects, 3(608KB) LOS objects, 12% free, 9MB/10MB, paused 4.358ms total 263.235ms 
08-21 20:47:49.854 69-69/? I/art: Background concurrent mark sweep GC freed 794(33KB) AllocSpace objects, 0(0B) LOS objects, 90% free, 111KB/1135KB, paused 12.562ms total 112.418ms 
08-21 20:47:49.945 421-1030/? I/ActivityManager: Start proc com.example.shenstone.guessthecelebrity2 for activity com.example.shenstone.guessthecelebrity2/.MainActivity: pid=3562 uid=10055 gids={50055, 9997, 3003} abi=armeabi-v7a 
08-21 20:47:49.982 3562-3562/? I/art: Not late-enabling -Xcheck:jni (already on) 
08-21 20:47:52.244 3562-3574/? W/art: Suspending all threads took: 12.799ms 
08-21 20:47:52.262 3562-3574/? I/art: Background partial concurrent mark sweep GC freed 322(512KB) AllocSpace objects, 0(0B) LOS objects, 64% free, 555KB/1579KB, paused 14.923ms total 43.870ms 
08-21 20:47:52.395 3562-3574/? I/art: Background sticky concurrent mark sweep GC freed 219(436KB) AllocSpace objects, 0(0B) LOS objects, 28% free, 1129KB/1579KB, paused 9.677ms total 22.436ms 
08-21 20:47:52.534 3562-3574/? I/art: WaitForGcToComplete blocked for 10.763ms for cause Background 
08-21 20:47:53.258 3562-3574/? I/art: Background sticky concurrent mark sweep GC freed 469(1634KB) AllocSpace objects, 0(0B) LOS objects, 58% free, 660KB/1599KB, paused 6.830ms total 31.639ms 
08-21 20:47:56.495 3562-3573/? I/art: WaitForGcToComplete blocked for 21.032ms for cause HeapTrim 
08-21 20:47:59.381 421-443/? W/ActivityManager: Launch timeout has expired, giving up wake lock! 
08-21 20:48:00.154 3562-3574/? W/art: Suspending all threads took: 39.137ms 
08-21 20:48:00.183 3562-3574/? I/art: Background partial concurrent mark sweep GC freed 108(3KB) AllocSpace objects, 57(862KB) LOS objects, 60% free, 663KB/1687KB, paused 41.100ms total 174.221ms 
08-21 20:48:00.244 3562-3574/? W/art: Suspending all threads took: 10.311ms 
08-21 20:48:00.255 3562-3574/? I/art: Background sticky concurrent mark sweep GC freed 53(1872B) AllocSpace objects, 30(451KB) LOS objects, 56% free, 728KB/1687KB, paused 12.216ms total 26.132ms 
08-21 20:48:00.354 3562-3574/? W/art: Suspending all threads took: 9.038ms 
08-21 20:48:00.415 3562-3574/? I/art: Background partial concurrent mark sweep GC freed 135(4KB) AllocSpace objects, 81(1221KB) LOS objects, 48% free, 1094KB/2MB, paused 12.238ms total 111.401ms

任何帮助将不胜感激，谢谢！

来源

2016-08-21 AngryMan Studios

+1

'.get（）'不这样做 – codeMagic

+0

这是问题的原因还是只是建议？ –

+0

最有可能的是，两者。该方法在处理任何内容之前等待任务返回，以冻结UI。你几乎从不（如果有的话）想要使用它。 – codeMagic

回答

0

您正在使用AsyncTask，但没有启动它。使用execute（）方法启动异步任务。

来源

2016-08-21 21:06:07 rahul

+0

它在这里执行：'result = task.execute（“http://www.posh24.com/celebrities”）.get（）; “ –

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