我的Android应用程序在运行特定类时保持关闭状态

每次尝试运行此类时，应用程序都会关闭强制关闭。当我在Android设备或模拟器上运行此类时，它会告诉我应用程序已停止。在这个课程运行之前，它工作得很好。 Android Studio向我展示了没有错误。我的Android应用程序在运行特定类时保持关闭状态

import android.os.Handler; 
import android.view.animation.Animation; 
import android.view.animation.AnimationUtils; 
import android.widget.ImageView; 
import android.widget.TextView; 

public class Predictions { 

    private static Predictions predictions; 
    private String[] answers; 
    public ImageView ball; 
    public TextView answerText; 
    public Animation animationslideintop; 

    private Predictions() { 
     int randomNumber = (int) ((Math.random() * 4) + 1); 
     if (randomNumber == 1) { 
     answerText.setText(""); 
     Handler handler = new Handler(); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball02); 
      } 
     }, 100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball03); 
      } 
     }, 200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball04); 
      } 
     }, 300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball05); 
      } 
     }, 400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball06); 
      } 
     }, 500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball07); 
      } 
     }, 600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball08); 
      } 
     }, 700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball09); 
      } 
     }, 800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball10); 
      } 
     }, 900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball11); 
      } 
     }, 1000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball12); 
      } 
     }, 1100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball13); 
      } 
     }, 1200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball14); 
      } 
     }, 1300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball15); 
      } 
     }, 1400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball16); 
      } 
     }, 1500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball17); 
      } 
     }, 1600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball18); 
      } 
     }, 1700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball19); 
      } 
     }, 1800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball20); 
      } 
     }, 1900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball21); 
      } 
     }, 2000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball22); 
      } 
     }, 2100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball23); 
      } 
     }, 2200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball24); 
      } 
     }, 2300); 
     answers = new String[] { 
       "Your dreams will come true." 
     }; 
     answerText.startAnimation(animationslideintop); 
     } 
     else if (randomNumber == 2) { 
     answerText.setText(""); 
     Handler handler = new Handler(); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball02); 
      } 
     }, 100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball03); 
      } 
     }, 200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball04); 
      } 
     }, 300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball05); 
      } 
     }, 400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball06); 
      } 
     }, 500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball07); 
      } 
     }, 600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball08); 
      } 
     }, 700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball09); 
      } 
     }, 800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball10); 
      } 
     }, 900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball11); 
      } 
     }, 1000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball12); 
      } 
     }, 1100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball13); 
      } 
     }, 1200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball14); 
      } 
     }, 1300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball15); 
      } 
     }, 1400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball16); 
      } 
     }, 1500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball17); 
      } 
     }, 1600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball18); 
      } 
     }, 1700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball19); 
      } 
     }, 1800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball20); 
      } 
     }, 1900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball21); 
      } 
     }, 2000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball22); 
      } 
     }, 2100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball23); 
      } 
     }, 2200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball24); 
      } 
     }, 2300); 
     answers = new String[] { 
      "Your dreams will NEVER come true." 
     }; 
     answerText.startAnimation(animationslideintop); 
     } 
     else if(randomNumber == 3) { 
     answerText.setText(""); 
     Handler handler = new Handler(); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball02); 
      } 
     }, 100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball03); 
      } 
     }, 200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball04); 
      } 
     }, 300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball05); 
      } 
     }, 400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball06); 
      } 
     }, 500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball07); 
      } 
     }, 600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball08); 
      } 
     }, 700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball09); 
      } 
     }, 800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball10); 
      } 
     }, 900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball11); 
      } 
     }, 1000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball12); 
      } 
     }, 1100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball13); 
      } 
     }, 1200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball14); 
      } 
     }, 1300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball15); 
      } 
     }, 1400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball16); 
      } 
     }, 1500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball17); 
      } 
     }, 1600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball18); 
      } 
     }, 1700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball19); 
      } 
     }, 1800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball20); 
      } 
     }, 1900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball21); 
      } 
     }, 2000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball22); 
      } 
     }, 2100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball23); 
      } 
     }, 2200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball24); 
      } 
     }, 2300); 
     answers = new String[] { 
      "Your future does not exist." 
     }; 
     answerText.startAnimation(animationslideintop); 
     } 
    else if(randomNumber == 4) { 
     answerText.setText(""); 
     Handler handler = new Handler(); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball02); 
      } 
     }, 100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball03); 
      } 
     }, 200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball04); 
      } 
     }, 300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball05); 
      } 
     }, 400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball06); 
      } 
     }, 500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball07); 
      } 
     }, 600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball08); 
      } 
     }, 700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball09); 
      } 
     }, 800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball10); 
      } 
     }, 900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball11); 
      } 
     }, 1000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball12); 
      } 
     }, 1100); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball13); 
      } 
     }, 1200); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball14); 
      } 
     }, 1300); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball15); 
      } 
     }, 1400); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball16); 
      } 
     }, 1500); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball17); 
      } 
     }, 1600); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball18); 
      } 
     }, 1700); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball19); 
      } 
     }, 1800); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball20); 
      } 
     }, 1900); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball21); 
      } 
     }, 2000); 
     handler.postDelayed(new Runnable() { 
      public void run() { 
       ball.setImageResource(R.drawable.ball22); 
      } 
     }, 2100); 
      handler.postDelayed(new Runnable() { 
       public void run() { 
        ball.setImageResource(R.drawable.ball23); 
       } 
      }, 2200); 
       handler.postDelayed(new Runnable() { 
       public void run() { 
        ball.setImageResource(R.drawable.ball24); 
       } 
      }, 2300); 
      answers = new String[] { 
       "You will be slaughtered. Brutally." 
      }; 
      answerText.startAnimation(animationslideintop); 
     } 
    } 


    public static Predictions get() 

    { 
     if (predictions == null) { 
      predictions = new Predictions(); 
     } 
     return predictions; 
    } 

    public String getPrediction() { 
    return answers[0]; 
} 

}

以下是错误日志：

Logcat: 09-05 00:04:28.173 24524-24524/<MyPackage> I/art﹕ Late-enabling 
-Xcheck:jni 09-05 00:04:28.543 24524-24544/<MyPackage> D/OpenGLRenderer﹕ Use EGL_SWAP_BEHAVIOR_PRESERVED: true 09-05 00:04:28.572 24524-24524/<MyPackage> D/﹕ HostConnection::get() New Host Connection established 0xb3ecc750, tid 24524 09-05 00:04:28.596 24524-24524/<MyPackage> D/Atlas﹕ Validating map... 09-05 00:04:28.611 24524-24524/<MyPackage> E/SensorManager﹕ Exception dispatching input event. 09-05 00:04:28.611 24524-24524/<MyPackage> D/AndroidRuntime﹕ Shutting down VM 09-05 00:04:28.613 24524-24524/<MyPackage> E/AndroidRuntime﹕ FATAL EXCEPTION: main 
    Process: <MyPackage>, PID: 24524 
    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference 
      at <MyPackage>.Predictions.<init>(Predictions.java:20) 
      at <MyPackage>.Predictions.get(Predictions.java:518) 
      at <MyPackage>.CrystalBall$1.onSensorChanged(CrystalBall.java:56) 
      at android.hardware.SystemSensorManager$SensorEventQueue.dispatchSensorEvent(SystemSensorManager.java:405) 
      at android.os.MessageQueue.nativePollOnce(Native Method) 
      at android.os.MessageQueue.next(MessageQueue.java:143) 
      at android.os.Looper.loop(Looper.java:122) 
      at android.app.ActivityThread.main(ActivityThread.java:5254) 
      at java.lang.reflect.Method.invoke(Native Method) 
      at java.lang.reflect.Method.invoke(Method.java:372) 
      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)

来源

2015-09-05 user3697974

请创建一个最小的可核查的例子 –

请发表您的崩溃logcat的！ – iagreen

你似乎没有初始化你的'ball'或'answerText'成员变量。 – iagreen

首先，你应该把你的活动context，然后试图找出布局的XML ID你指的是使用findViewById方法。

因此，举例来说，你可以修改你的代码转换成类似

private Predictions(Context context) { 
    ball = (ImageView) ((Activity) context).findViewById(R.id.ball_image_view); 
    answerText = (TextView) ((Activity) context).findViewById(R.id.answer_text_view); 

    // The rest of the code here ... 
} 

public static Predictions get(Context context) { 
    if (predictions == null) { 
     predictions = new Predictions(context); 
    } 
    return predictions; 
}

但性能明智的，这仍然是不够好。一般来说，你只能拨打findViewById一次。因此，一个更好的方法是试图在你的主要活动中找到这些元素，然后将它传递给类。

来源

2015-09-05 04:49:02

我认为ball =（ImageView）（（Activity）context）.findViewById（R.id.ball_image_view） – arun

是的，你是对的。让我更新答案 – 2015-09-05 04:56:06

检查您的Android清单文件，根据你的问题可能是您的Android清单文件的问题

来源

2015-09-07 05:58:51 Mauran

我的Android应用程序在运行特定类时保持关闭状态

回答

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