我正在使用firebase作爲我的後端的Android項目。我以url的形式將數據保存在數據庫中,並且正在嘗試使用Picasso library在應用中獲取圖像。但我無法檢索圖像表單數據庫。以下是我的代碼。如何檢索圖像url形式firebase數據庫andriod
片段類,我使用來獲取數據:
public class McaFirstSemSylabus extends Fragment {
public ImageView mcafirstsemsylbausimag;
Syllabus sl;
DatabaseReference loadmcafirstsylabus;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.activity_mca_first_sem_sylabus, container, false);
loadmcafirstsylabus = FirebaseDatabase.getInstance().getReference().child("Syllabus").child("McaSyllabus").child("Firstsem");
mcafirstsemsylbausimag = (ImageView) rootView.findViewById(R.id.mcasylabus_img);
String img = sl.getImg();
Picasso.with(getActivity().getApplicationContext()).load(img).into(mcafirstsemsylbausimag);
return rootView;
}
}
下面是POJO類由getter和setter:
public class Syllabus {
private String img;
public String getImg() {
return img;
}
public void setImg(String img) {
this.img = img;
}
public Syllabus(){
}
public Syllabus(String image) {
this.img = image;
}
}
這裏有什麼問題? 'sl.getImg();'的NullPointerException異常? –
是的,這是我的錯誤「空指針異常」 –
你明白這是什麼意思?如何解決它?請用logcat編輯。 –