java.lang.NullPointerException：name为null
@Override
public View getView(int position, View convertView, ViewGroup parent) {
Holder holder;
if (convertView == null) {
holder = new Holder();
LayoutInflater vi = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
convertView = vi.inflate(R.layout.history_item, parent, false);
holder.tvCat = (TextView)convertView.findViewById(R.id.tv_category);
holder.tvAmt = (TextView)convertView.findViewById(R.id.tv_amount);
holder.tvDate = (TextView)convertView.findViewById(R.id.tv_date);
holder.img = (ImageView)convertView.findViewById(R.id.iv);
convertView.setTag(holder);
}
holder=(Holder)convertView.getTag();
//Holder holder = new Holder();
//View rowView;
HistoryItem historyItem;
//rowView=inflater.inflate(R.layout.history_item,null);
historyItem = historyItems.get(position);
holder.tvCat.setText(historyItem.getCategory());
holder.tvAmt.setText(historyItem.getAmount()+"");
DateFormat df = new SimpleDateFormat("yyyy/MM/dd kk:mm:ss");
Calendar c = Calendar.getInstance();
c.setTimeInMillis(historyItem.getTimestamp());
Date day = c.getTime();
holder.tvDate.setText(df.format(day));
Resources res = context.getResources();
String mDrawableName = iconMapper.get(historyItem.getCategory());
//This line is giving the null pointer exception...
int resID = res.getIdentifier(mDrawableName , "drawable", context.getPackageName());
holder.img.setImageResource(resID);
return convertView;
}
我检查了mDrawableName，它保存了正确的值 此外，上下文来自我的ListView类 任何帮助将不胜感激。
Logcat：
java.lang.NullPointerException: name is null
at android.content.res.ResourcesImpl.getIdentifier(ResourcesImpl.java:214)
at android.content.res.Resources.getIdentifier(Resources.java:1866)
at com.example.sharang.wheresmymoney.HistoryCustomAdapter.getView(HistoryCustomAdapter.java:92)
at com.baoyz.swipemenulistview.SwipeMenuAdapter.getView(SwipeMenuAdapter.java:49)
at android.widget.AbsListView.obtainView(AbsListView.java:2369)
at android.widget.ListView.makeAndAddView(ListView.java:1970)
at android.widget.ListView.fillDown(ListView.java:704)
at android.widget.ListView.fillFromTop(ListView.java:765)
at android.widget.ListView.layoutChildren(ListView.java:1744)
at android.widget.AbsListView.onLayout(AbsListView.java:2161)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.support.v7.widget.ActionBarOverlayLayout.onLayout(ActionBarOverlayLayout.java:433)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1741)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1585)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1494)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:323)
at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:724)
at android.view.View.layout(View.java:17526)
at android.view.ViewGroup.layout(ViewGroup.java:5612)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2342)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2069)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1246)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6307)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:871)
at android.view.Choreographer.doCallbacks(Choreographer.java:683)
at android.view.Choreographer.doFrame(Choreographer.java:619)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:857)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
答案 0 :(得分：0)
您可以将context替换为getContext()
确保在创建适配器时不使用getApplicationContext
您必须弄清楚为什么iconMapper不包含historyItem类别值
如果全部失败，则在设置图像资源
周围添加空检查答案 1 :(得分：0)
用getContext（）替换上下文或将上下文传递给适配器。 这样的事情。
public Adapter(Context context, boolean isGrid, ArrayList<Recipe> data){
this.context = context;
this.recipes = data;
this.isGrid = isGrid;
}