尝试在空对象引用上调用虚拟方法'android.graphics.Bitmap android.graphics.drawable.BitmapDrawable.getBitmap（）'

Question

我正在尝试从 CategoriesSpinnerAdapter 获得位图值。Java，但工作室说位图为空。当我放置 android：src =“ @ drawable / defaultimg” 时，错误消失了，但是他获取的值是我的可绘制对象中的“ defaultimg”吗？如何在 CategoriesSpinnerAdapter 中获得位图值？顺便说一下，我解码来自realmdatabase的图像，因为它仅支持byte []。

NewExpenseFragment.java

 public void onSaveExpense() {

    ImageView imageViewer;
    View viewer;
    LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    viewer = inflater.inflate(R.layout.spinner_ui,null);

    //TODO - BITMAP EXPENSE ICONS


    if (mCategoriesSpinnerAdapter.getCount() > 0 ) {
        if (!Util.isEmptyField(etTotal)) {
            Category currentCategory = (Category) spCategory.getSelectedItem();
            String total = etTotal.getText().toString();
            String description = etDescription.getText().toString();

            imageViewer = (ImageView) viewer.findViewById(R.id.spinnerimg);
            Bitmap bitmap = ((BitmapDrawable)imageViewer.getDrawable()).getBitmap();
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            bitmap.compress(Bitmap.CompressFormat.PNG, 100, baos);
            byte[] expenseIcons = baos.toByteArray();


            if (mUserActionMode == IUserActionsMode.MODE_CREATE) {
                RealmManager.getInstance().save(new Expense(description, selectedDate,expenseIcons, mExpenseType, currentCategory, Float.parseFloat(total)), Expense.class);
            } else {
                Expense editExpense = new Expense();
                editExpense.setId(mExpense.getId());
                editExpense.setTotal(Float.parseFloat(total));
                editExpense.setDescription(description);
                editExpense.setIconViewer(expenseIcons);
                editExpense.setCategory(currentCategory);
                editExpense.setDate(selectedDate);
                RealmManager.getInstance().update(editExpense);
            }
            // update widget if the expense is created today
            if (DateUtils.isToday(selectedDate)) {
                Intent i = new Intent(getActivity(), ExpensesWidgetProvider.class);
                i.setAction(ExpensesWidgetService.UPDATE_WIDGET);
                getActivity().sendBroadcast(i);
            }
            getTargetFragment().onActivityResult(getTargetRequestCode(), Activity.RESULT_OK, null);
            dismiss();
        } else {
            DialogManager.getInstance().showShortToast(getString(R.string.error_total));
        }
    } else {
        DialogManager.getInstance().showShortToast(getString(R.string.no_categories_error));
    }
}

新更新---这是我的错误日志

Process: com.jmnapps.expensetracker, PID: 6610
java.lang.NullPointerException: Attempt to invoke virtual method 'android.graphics.Bitmap android.graphics.drawable.BitmapDrawable.getBitmap()' on a null object reference
    at com.jmnapps.expensetracker.ui.expenses.NewExpenseFragment.onSaveExpense(NewExpenseFragment.java:195)
    at com.jmnapps.expensetracker.ui.expenses.NewExpenseFragment.onClick(NewExpenseFragment.java:163)
    at android.view.View.performClick(View.java:6294)
    at android.view.View$PerformClick.run(View.java:24770)
    at android.os.Handler.handleCallback(Handler.java:790)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6494)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

spinner_ui

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="center">
    <ImageView
        android:layout_marginLeft="10dp"
        android:id="@+id/spinnerimg"
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:layout_gravity="center_vertical"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="@dimen/dimen_20dp"
        android:text="text"
        android:id="@+id/spinnertext"
        android:padding="5dip"
        android:fontFamily="sans-serif-light"/>
</LinearLayout>

CategoriesSpinnerAdapter

public class CategoriesSpinnerAdapter extends ArrayAdapter<Category> {


Category[] categoriesList = null;
LayoutInflater inflater;

public CategoriesSpinnerAdapter(Activity context, Category[] categoriesList) {
    super(context, R.layout.spinner_ui, categoriesList);
    this.categoriesList = categoriesList;
    this.inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public View getDropDownView(int position, View convertView, ViewGroup parent) {
    return getCustomView(position, convertView, parent);
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return getCustomView(position, convertView, parent);
}

public View getCustomView(int position, View convertView, ViewGroup parent) {
    View row = inflater.inflate(R.layout.spinner_ui, parent, false);
    Category category = categoriesList[position];
    Bitmap bitmap = BitmapFactory.decodeByteArray(category.getImgico(),0,category.getImgico().length);
    ImageView imgview = (ImageView)row.findViewById(R.id.spinnerimg);
    TextView title = (TextView)row.findViewById(R.id.spinnertext);
    title.setText(category.getName());
    imgview.setImageBitmap(bitmap);
    return row;
}

}