스위치 케이스가 작동하지 않습니다

나는 그/그녀가 튀고 싶은 공 숫자 을 사용자로부터받습니다. 그런 다음 사용자가 입력 한 숫자에 따라 추가 코드를 작성하기 위해 스위치 케이스를 사용하고 있습니다. 프로젝트를 실행하면 activity_two로 이동하려고하면 "불행히도 응용 프로그램이 중지되었습니다"라는 오류가 표시됩니다. 스위치 또는 다른 문제를 호출하기 전에 변수 '값'이 초기화되지 않았습니까? .I은 그와 함께 많은 것을 시도 ..스위치 케이스가 작동하지 않습니다

SecondActivity.java

을

import android.app.Activity; 
import android.content.Context; 
import android.content.Intent; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.RectF; 
import android.os.Bundle; 
import android.view.Menu; 
import android.view.View; 

public class SecondActivity extends Activity { 
    AnimationView animationview; 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     Intent i = getIntent(); 
     int text = i.getIntExtra("TextBox",3); 
     System.out.println(text); 
     setContentView(R.layout.activity_two); 
      animationview=(AnimationView)findViewById(R.id.animationView); 
     animationview.setString(text); 


    } 

    @Override 
    public boolean onCreateOptionsMenu(Menu menu) { 
     // Inflate the menu; this adds items to the action bar if it is present. 
     getMenuInflater().inflate(R.menu.main, menu); 
     return true; 
    } 

}

AnimationView.java

import android.content.Context; 

import android.content.Intent; 
import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.os.Handler; 
import android.util.AttributeSet; 
import android.app.Activity; 
import android.view.View; 
import android.widget.Toast; 
public class AnimationView extends View{ 
    private final int FRAME_RATE=15; 
    private Paint paint; 
    private Handler h; 
    Ball myball; 
    Ball greenball; 
    Ball redball; 
    Ball cyanball; 
    Ball yellowball; 
    Ball greyball; 
    Ball magentaball; 
    Ball grey; 
    int value; 
    public void setString(int value) 
    { 
    this.value = value; 
    System.out.println("value="+value); 
    } 

    public AnimationView(Context context,AttributeSet attrs) { 
     super(context,attrs); 
     // TODO Auto-generated constructor stub 

     h=new Handler(); 
     paint=new Paint(); 
     paint.setColor(Color.BLUE); 
     switch(value) 
     { 
     case 1: 
      myball=new Ball(100,100,Color.BLUE,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      break; 
     case 2: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      break; 
     case 3: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      redball=new Ball(50,400,Color.RED,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      redball.setDX(10); 
      redball.setDY(10); 
      break; 
     case 4: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      redball=new Ball(50,400,Color.RED,50); 
      cyanball=new Ball(100,300,Color.CYAN,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      redball.setDX(10); 
      redball.setDY(10); 
      cyanball.setDX(10); 
      cyanball.setDY(10); 
      break; 
     case 5: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      redball=new Ball(50,400,Color.RED,50); 
      cyanball=new Ball(100,300,Color.CYAN,50); 
      yellowball=new Ball(10,300,Color.YELLOW,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      redball.setDX(10); 
      redball.setDY(10); 
      cyanball.setDX(10); 
      cyanball.setDY(10); 
      yellowball.setDX(10); 
      yellowball.setDY(10); 
      break; 
     case 6: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      redball=new Ball(50,400,Color.RED,50); 
      cyanball=new Ball(100,300,Color.CYAN,50); 
      yellowball=new Ball(10,300,Color.YELLOW,50); 
      magentaball=new Ball(150,300,Color.MAGENTA,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      redball.setDX(10); 
      redball.setDY(10); 
      cyanball.setDX(10); 
      cyanball.setDY(10); 
      yellowball.setDX(10); 
      yellowball.setDY(10); 
      magentaball.setDX(10); 
      magentaball.setDY(10); 
      break; 
     case 7: 
      myball=new Ball(100,100,Color.BLUE,50); 
      greenball=new Ball(200,200,Color.GREEN,50); 
      redball=new Ball(50,400,Color.RED,50); 
      cyanball=new Ball(100,300,Color.CYAN,50); 
      yellowball=new Ball(10,300,Color.YELLOW,50); 
      magentaball=new Ball(150,300,Color.MAGENTA,50); 
      grey=new Ball(100,150,Color.GRAY,50); 
      myball.setDX(10); 
      myball.setDY(10); 
      greenball.setDX(10); 
      greenball.setDY(10); 
      redball.setDX(10); 
      redball.setDY(10); 
      cyanball.setDX(10); 
      cyanball.setDY(10); 
      yellowball.setDX(10); 
      yellowball.setDY(10); 
      magentaball.setDX(10); 
      magentaball.setDY(10); 
      grey.setDX(10); 
      grey.setDY(10); 
      break; 
      default:System.out.println("invalid value"); 


     } 



    } 
    protected void onDraw(Canvas c) 
    { 
     switch(value) 
     { 
     case 1: 
      myball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      break; 
     case 2: 
      myball.bounce(c); 
      greenball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      break; 
     case 3: 
      myball.bounce(c); 
      greenball.bounce(c); 
      redball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      break; 
     case 4: 
      myball.bounce(c); 
      greenball.bounce(c); 
      redball.bounce(c); 
      cyanball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      break; 
     case 5: 
      myball.bounce(c); 
      greenball.bounce(c); 
      redball.bounce(c); 
      cyanball.bounce(c); 
      yellowball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      c.drawCircle(yellowball.getX(), yellowball.getY(),yellowball.getRadius(), yellowball.getPaint()); 
      break; 
     case 6: 

      myball.bounce(c); 
      greenball.bounce(c); 
      redball.bounce(c); 
      cyanball.bounce(c); 
      yellowball.bounce(c); 
      magentaball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      c.drawCircle(yellowball.getX(), yellowball.getY(),yellowball.getRadius(), yellowball.getPaint()); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      c.drawCircle(magentaball.getX(), magentaball.getY(),magentaball.getRadius(), magentaball.getPaint()); 
      break; 

     case 7: 
      myball.bounce(c); 
      greenball.bounce(c); 
      redball.bounce(c); 
      cyanball.bounce(c); 
      yellowball.bounce(c); 
      magentaball.bounce(c); 
      greyball.bounce(c); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      c.drawCircle(yellowball.getX(), yellowball.getY(),yellowball.getRadius(), yellowball.getPaint()); 
      c.drawCircle(myball.getX(), myball.getY(),myball.getRadius(), myball.getPaint()); 
      c.drawCircle(greenball.getX(), greenball.getY(),greenball.getRadius(), greenball.getPaint()); 
      c.drawCircle(redball.getX(), redball.getY(),redball.getRadius(), redball.getPaint()); 
      c.drawCircle(cyanball.getX(), cyanball.getY(),cyanball.getRadius(), cyanball.getPaint()); 
      c.drawCircle(magentaball.getX(), magentaball.getY(),magentaball.getRadius(), magentaball.getPaint()); 
      c.drawCircle(greyball.getX(), greyball.getY(),greyball.getRadius(), greyball.getPaint()); 
      break; 
     default:System.out.println("invalid value"); 
     } 

h.postDelayed(r, FRAME_RATE); 

    } 
    private Runnable r=new Runnable() 
    { public void run() 
    { invalidate(); 
    } 
    }; 
    }

로그 캣 오류 메시지

그것이 이제까지에서는 setString()에 대한 호출에 의해 초기화되기 전에 당신의 생성자에서

4-08 19:34:59.610: E/AndroidRuntime(660): FATAL EXCEPTION: main 
04-08 19:34:59.610: E/AndroidRuntime(660): java.lang.NullPointerException 
04-08 19:34:59.610: E/AndroidRuntime(660): at com.example.preliminarytest.AnimationView.onDraw(AnimationView.java:164) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13458) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13342) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.drawChild(ViewGroup.java:2929) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13340) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.drawChild(ViewGroup.java:2929) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13461) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.widget.FrameLayout.draw(FrameLayout.java:467) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13342) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.drawChild(ViewGroup.java:2929) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13340) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.drawChild(ViewGroup.java:2929) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewGroup.dispatchDraw(ViewGroup.java:2799) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.View.draw(View.java:13461) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.widget.FrameLayout.draw(FrameLayout.java:467) 
04-08 19:34:59.610: E/AndroidRuntime(660): at com.android.internal.policy.impl.PhoneWindow$DecorView.draw(PhoneWindow.java:2183) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl.drawSoftware(ViewRootImpl.java:2258) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl.draw(ViewRootImpl.java:2153) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2021) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1832) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4214) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:725) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.Choreographer.doCallbacks(Choreographer.java:555) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.Choreographer.doFrame(Choreographer.java:525) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:711) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.os.Handler.handleCallback(Handler.java:615) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.os.Handler.dispatchMessage(Handler.java:92) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.os.Looper.loop(Looper.java:137) 
04-08 19:34:59.610: E/AndroidRuntime(660): at android.app.ActivityThread.main(ActivityThread.java:4745) 
04-08 19:34:59.610: E/AndroidRuntime(660): at java.lang.reflect.Method.invokeNative(Native Method) 
04-08 19:34:59.610: E/AndroidRuntime(660): at java.lang.reflect.Method.invoke(Method.java:511) 
04-08 19:34:59.610: E/AndroidRuntime(660): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
04-08 19:34:59.610: E/AndroidRuntime(660): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
04-08 19:34:59.610: E/AndroidRuntime(660): at dalvik.system.NativeStart.main(Native Method)

activity_two.xml

<LinearLayout 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" 
    tools:context=".MainActivity" > 

    <com.example.preliminarytest.AnimationView 
     android:id= "@+id/animationView" 
     android:layout_width="match_parent" 
    android:layout_height="match_parent"/> 

</LinearLayout>

출처

2014-04-08 Anonymous

Logcat에 들어있는 스택 추적을 게시하십시오. –

코드가 너무 많으므로 UR 문제에 대한 정확한 의견을 게시하십시오 –

당신은 명확 치에 액세스 할 수 있습니다. 그건 널 포인터 예외를 생성합니다! 모든 초기화 논리를 사용하여 switch 문을 setString() 내부에서 호출되는 함수로 이동합니다. setString()이 아직 호출되지 않은 경우 onDraw()가 무언가를하는지 확인하십시오.

출처

2014-04-08 14:17:01 RobP

감사합니다. –

문제가 변수 '값이'예, 간접적으로

스위치

를 호출하기 전에 초기화되지 않는 것입니다입니다. 귀하의 logcat은 어딘가의 AnimationView.java 라인 164에 NullPointerException을 명확하게 보여줍니다. value 자체는 NullPointerException을 반환 할 수 없으며 기본 유형이며 기본값 (0)을가집니다. 이 인 라인을 지정하지 않았지만

, 나는 그것이 myball.bounce(c);

생성자의 스위치가 "잘못된 값"인쇄 기본 케이스를 가지고 추측하고있다. 당신은 logcat에서 이것을 볼 수 있습니까?

생성자가 호출되기 전에 setString()을 호출 할 수 없기 때문에 은 생성자에서 스위치를 켜면 필연적으로 0이 될 것이므로 myball은 초기화되지 않습니다.

출처

2014-04-08 14:20:36

스위치 케이스가 작동하지 않습니다

답변

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