Я делал домашнее задание для курса coursera, когда я улавливал NPE. Не удается исправить эту проблему в течение нескольких дней и не может продолжаться без фиксации. Google не помогает. ОБНОВЛЕНО КОД ВНИЗ СТРАНИЦА Вот мой код:ListView.setAdapter NullPointerException
MainActivity
List<Selfie> selfies = new ArrayList<Selfie>();
private CustomAdapter ADAPTER = new CustomAdapter(this, selfies);
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
@Override
protected void onResume() {
super.onResume();
File youDir = new File("/sdcard/DailySelfie/");
outer : for (File f : youDir.listFiles()) {
//try to find selfie in files
if (f.isFile()) {
for (Selfie selfie : selfies) {
if (selfie.getSelfieName() == f.getName()) {
continue outer;
}
else { continue;}
}
//code below works only if file doesn't exist in selfies.
Bitmap myBitmap = BitmapFactory.decodeFile(f.getAbsolutePath());
try {
selfies.add(new Selfie(f.getName(), myBitmap));
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
селфи:
public class Selfie {
private Bitmap selfieBitmap;
private String selfieName;
public Selfie(String selfieName, Bitmap selfieBitmap) {
this.selfieName = selfieName;
this.selfieBitmap = selfieBitmap;
}
public String getSelfieName() {
return selfieName;
}
public Bitmap getSelfieBitmap() {
return selfieBitmap;
}
}
CustomAdapter:
private Context context;
private List<Selfie> selfies = new ArrayList<Selfie>();
public CustomAdapter(Context context, List<Selfie> selfies) {
this.context = context;
this.selfies = selfies;
}
@Override
public int getCount() {
return selfies.size();
}
@Override
public Object getItem(int position) {
return selfies.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup viewGroup) {
Selfie selfie = selfies.get(position);
if (convertView == null) {
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View rowView = new View(context);
//get layout from row.xml
rowView = inflater.inflate(R.layout.row, null);
ImageView imageView = (ImageView) rowView.findViewById(R.id.imageView);
imageView.setImageBitmap(selfie.getSelfieBitmap());
TextView textView = (TextView) rowView.findViewById(R.id.text);
textView.setText(selfie.getSelfieName());
}
return convertView;
}
}
ADB:
04-27 13:17:58.792: E/AndroidRuntime(1979): FATAL EXCEPTION: main
04-27 13:17:58.792: E/AndroidRuntime(1979): java.lang.NullPointerException
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.AbsListView.obtainView(AbsListView.java:2179)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.ListView.makeAndAddView(ListView.java:1840)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.ListView.fillDown(ListView.java:675)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.ListView.fillFromTop(ListView.java:736)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.ListView.layoutChildren(ListView.java:1655)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.AbsListView.onLayout(AbsListView.java:2012)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.layoutHorizontal(LinearLayout.java:1660)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.onLayout(LinearLayout.java:1436)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.support.v7.internal.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:502)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1671)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1525)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.LinearLayout.onLayout(LinearLayout.java:1434)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.widget.FrameLayout.onLayout(FrameLayout.java:448)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.View.layout(View.java:14289)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewGroup.layout(ViewGroup.java:4562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:1976)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1730)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1004)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5481)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:749)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.Choreographer.doCallbacks(Choreographer.java:562)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.Choreographer.doFrame(Choreographer.java:532)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:735)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.os.Handler.handleCallback(Handler.java:730)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.os.Handler.dispatchMessage(Handler.java:92)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.os.Looper.loop(Looper.java:137)
04-27 13:17:58.792: E/AndroidRuntime(1979): at android.app.ActivityThread.main(ActivityThread.java:5103)
04-27 13:17:58.792: E/AndroidRuntime(1979): at java.lang.reflect.Method.invokeNative(Native Method)
04-27 13:17:58.792: E/AndroidRuntime(1979): at java.lang.reflect.Method.invoke(Method.java:525)
04-27 13:17:58.792: E/AndroidRuntime(1979): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
04-27 13:17:58.792: E/AndroidRuntime(1979): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-27 13:17:58.792: E/AndroidRuntime(1979): at dalvik.system.NativeStart.main(Native Method)
Похоже, что у меня есть NPE по адресу lv.setAdapter(ADAPTER);
. Находились те же проблемы в StackOverflow, но ни одно решение не помогло мне. UPDATE: переписал мой код, так что теперь
List<Selfie> selfies;
ListView lv;
private CustomAdapter ADAPTER;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
selfies = new ArrayList<Selfie>();
lv = (ListView) findViewById(R.id.listView);
ADAPTER = new CustomAdapter(this, selfies);
}
@Override
protected void onResume() {
super.onResume();
...
lv.setAdapter(ADAPTER);
}
еще такая же проблема - NPE. Я попытался пошевелиться «лев = ..; ADAPTER = ...» в onResume, пытался поставить его в начало onResume - это не помогает :(
Попробуйте переместить все в onResume() в OnCreate() – PPartisan
пробовал оба не помогают :( – Azi
Посмотрите на мой ответ ниже и обновите 'GetCount()' метода в адаптере соответственно. Это может быть из-за того, что ваш 'ArrayList' либо пуст, либо пуст. Кроме того, вы должны иметь возможность установить свой адаптер в' onCreate() ', поэтому попробуйте еще раз при тестировании моего ответа. – PPartisan