OnClickListener NullPoinerException 오류?

StackOverflow https://stackoverflow.com/questions/5891663

  •  28-10-2019
  •  | 
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문제

청취자를 정리하려고 했는데 뭔가 잘못되었습니다.다음 방법을 사용하여 LogCat에서 일반적인 'NullPoinerException'이 발생합니다(이 방법을 처음 시도하는 경우).

도움이 필요하세요?감사합니다!

활동:

public class List_RegulatoryDocs extends Activity {

OnClickListener myClickListener = new OnClickListener() {
    @Override
    public void onClick(View v) {
        if (v == acItem) {
            Intent ACList = new Intent(List_RegulatoryDocs.this,
                    List_AC.class);
            startActivity(ACList);
        } else if (v == adItem) {
            // TODO
        }else if (v == cfrItem) {
            // TODO
        }//TODO + items
    }
};

/**
 * -- Called when the activity is first created
 * ===================================================================
 */
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.regulatory_docs_list);

    // Set the Click Listeners
    acItem.setOnClickListener(myClickListener);
    adItem.setOnClickListener(myClickListener);
    cfrItem.setOnClickListener(myClickListener);

}

/**
 * -- Local Variables
 * =====================================================================
 **/
RelativeLayout acItem = (RelativeLayout) findViewById(R.id.acItem);
RelativeLayout adItem = (RelativeLayout) findViewById(R.id.adItem);
 RelativeLayout cfrItem = (RelativeLayout) findViewById(R.id.cfrItem);
// RelativeLayout pmaItem = (RelativeLayout) findViewById(R.id.pmaItem);
// RelativeLayout saibItem = (RelativeLayout) findViewById(R.id.saibItem);
// RelativeLayout sfarItem = (RelativeLayout) findViewById(R.id.sfarItem);
// RelativeLayout stcItem = (RelativeLayout) findViewById(R.id.stcItem);
// RelativeLayout tsoItem = (RelativeLayout) findViewById(R.id.tsoItem);
// RelativeLayout tcdsItem = (RelativeLayout) findViewById(R.id.tcdsItem);
}

로그캣:

05-05 01:27:29.931: WARN/dalvikvm(13268): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268): FATAL EXCEPTION: main
05-05 01:27:29.971: ERROR/AndroidRuntime(13268): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.aeroTechnologies.flyDroid/com.aeroTechnologies.flyDroid.regList.List_RegulatoryDocs}: java.lang.NullPointerException
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.os.Handler.dispatchMessage(Handler.java:99)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.os.Looper.loop(Looper.java:123)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread.main(ActivityThread.java:4627)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at java.lang.reflect.Method.invokeNative(Native Method)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at java.lang.reflect.Method.invoke(Method.java:521)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at dalvik.system.NativeStart.main(Native Method)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268): Caused by: java.lang.NullPointerException
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.Activity.findViewById(Activity.java:1637)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at com.aeroTechnologies.flyDroid.regList.List_RegulatoryDocs.<init>(List_RegulatoryDocs.java:51)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at java.lang.Class.newInstanceImpl(Native Method)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at java.lang.Class.newInstance(Class.java:1429)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
05-05 01:27:29.971: ERROR/AndroidRuntime(13268):     ... 11 more
도움이 되었습니까?

해결책

acItem, adItem, cfrItem을 선언합니다 (원하는 경우 멤버 vars로). 그런 다음 onCreate (); 라코 디스

다른 팁

~ 안에 onCreate, 당신은 액세스하는 것 같습니다 acItem, adItem, 그리고 cfrItem 초기화하지 않고.

onCreate에서 초기화하지 않고 acItem, adItem 및 cfrItem에 액세스하는 것 같습니다.

잘했습니다. 저에게 효과적입니다.

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