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我嘗試使用一個月的天數來創建一個數組,但我在構建時得到了NullPointerException
。NullPointerException在陣列
這是我的源代碼:
Calendar gCal = new GregorianCalendar(2016, Calendar.JANUARY, 1);
int currentDay = gCal.get(Calendar.DAY_OF_WEEK);
lows = (GridView)findViewById(R.id.MonthView);
gCal.add(Calendar.DAY_OF_YEAR, Calendar.SUNDAY - currentDay);
for(int i=0;i<=34;i++){
lunas[i] = String.valueOf(gCal.get(Calendar.DAY_OF_MONTH));
gCal.add(Calendar.DAY_OF_YEAR, 1);
}
,這是我的logcat錯誤:
01-22 14:11:40.221: W/dalvikvm(19656): threadid=1: thread exiting with uncaught exception (group=0x41604898)
01-22 14:11:40.221: E/AndroidRuntime(19656): FATAL EXCEPTION: main
01-22 14:11:40.221: E/AndroidRuntime(19656): java.lang.RuntimeException: Unable to start activity ComponentInfo{ro.thich.programdetura/ro.thich.programdetura.MainActivity}: java.lang.NullPointerException
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2221)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2271)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread.access$600(ActivityThread.java:144)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1263)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.os.Handler.dispatchMessage(Handler.java:99)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.os.Looper.loop(Looper.java:137)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread.main(ActivityThread.java:5169)
01-22 14:11:40.221: E/AndroidRuntime(19656): at java.lang.reflect.Method.invokeNative(Native Method)
01-22 14:11:40.221: E/AndroidRuntime(19656): at java.lang.reflect.Method.invoke(Method.java:525)
01-22 14:11:40.221: E/AndroidRuntime(19656): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
01-22 14:11:40.221: E/AndroidRuntime(19656): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
01-22 14:11:40.221: E/AndroidRuntime(19656): at de.robv.android.xposed.XposedBridge.main(XposedBridge.java:132)
01-22 14:11:40.221: E/AndroidRuntime(19656): at dalvik.system.NativeStart.main(Native Method)
01-22 14:11:40.221: E/AndroidRuntime(19656): Caused by: java.lang.NullPointerException
01-22 14:11:40.221: E/AndroidRuntime(19656): at ro.thich.programdetura.MainActivity.onCreate(MainActivity.java:48)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.Activity.performCreate(Activity.java:5133)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
01-22 14:11:40.221: E/AndroidRuntime(19656): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2185)
01-22 14:11:40.221: E/AndroidRuntime(19656): ... 12 more
,這是我的線的MainActivity.java 48:
lunas[i] = String.valueOf(gCal.get(Calendar.DAY_OF_MONTH));
我不明白問題在哪裏。你可以幫我嗎?
你是否在實例化lunas?請告訴我們這個代碼。 – James
lunas在哪裏以及如何宣佈?請分享該代碼 –
已經創建了這樣的對象:private String [] lunas = new String [100]; –