我有一些問題,我的歷史listview。對logcat 它聲明問題的原因是new_item。Logcat得到空指針異常?
這是我的代碼
c.mDbHelper.fetchAllNotes();
Item new_item;
for (i=0; i<c.getCount(); i++) {
new_item.set(c.getString(1), c.getString(2), c.getInt(4), Uri.parse(c.getString(5)));
item.add(new_item);
c.moveToNext();
}
產品是I類製成。這是set()方法。
public void set(String name, String code, int qty, Uri imageuri){
this.name = name;
this.code = code;
this.qty = qty;
this.imageuri = imageuri;
}
這是我的logcat
06-28 09:12:49.528: E/AndroidRuntime(818): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.avs.QRscanner/com.android.avs.QRscanner.ViewStock}: java.lang.NullPointerException
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.os.Handler.dispatchMessage(Handler.java:99)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.os.Looper.loop(Looper.java:123)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread.main(ActivityThread.java:3683)
06-28 09:12:49.528: E/AndroidRuntime(818): at java.lang.reflect.Method.invokeNative(Native Method)
06-28 09:12:49.528: E/AndroidRuntime(818): at java.lang.reflect.Method.invoke(Method.java:507)
06-28 09:12:49.528: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-28 09:12:49.528: E/AndroidRuntime(818): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-28 09:12:49.528: E/AndroidRuntime(818): at dalvik.system.NativeStart.main(Native Method)
06-28 09:12:49.528: E/AndroidRuntime(818): Caused by: java.lang.NullPointerException
06-28 09:12:49.528: E/AndroidRuntime(818): at com.android.avs.QRscanner.CustomAdapter.getCount(CustomAdapter.java:24)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.widget.ListView.setAdapter(ListView.java:454)
06-28 09:12:49.528: E/AndroidRuntime(818): at com.android.avs.QRscanner.ViewStock.onCreate(ViewStock.java:36)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
06-28 09:12:49.528: E/AndroidRuntime(818): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
06-28 09:12:49.528: E/AndroidRuntime(818): ... 11 more
DbHelper有5列,內搭字符串,字符串,字符串,整數,字符串(用於存儲URI)
在此先感謝您的幫助。
編輯:添加NEW_ITEM到列表項
.........你需要初始化'new_item' ........... –
請給我們你的LogCat錯誤堆棧 –