Question

我正在尝试设置TextView的文本，但每次尝试投射虚拟方法时，都会抛出NullPointerException。如您所见，小部件存在，我正在使用正确的id创建TextView变量。

<TextView
    android:id="@+id/searchDispensaryName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentStart="true"
    android:layout_alignTop="@+id/productPicture"
    android:layout_marginTop="13sp"
    android:layout_marginStart="13dp"
    android:text="TextView" />

TextView dispensaryName = (TextView) costumView.findViewById(R.id.searchDispensaryName);

以下是引发异常的地方：

dispensaryName.setText(object.get("dispensary_name").toString());

以下是例外文字：

    java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
                  at com.example.dragosandrei.greenkinexdorian.SearchCostumeAdapter.getView(SearchCostumeAdapter.java:47)
                  at android.widget.AbsListView.obtainView(AbsListView.java:2411)
                  at android.widget.ListView.makeAndAddView(ListView.java:1986)
                  at android.widget.ListView.fillDown(ListView.java:709)
                  at android.widget.ListView.fillFromTop(ListView.java:770)
                  at android.widget.ListView.layoutChildren(ListView.java:1749)
                  at android.widget.AbsListView.onLayout(AbsListView.java:2210)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.RelativeLayout.onLayout(RelativeLayout.java:1079)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.support.v4.widget.DrawerLayout.onLayout(DrawerLayout.java:1193)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
                  at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1762)
                  at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1606)
                  at android.widget.LinearLayout.onLayout(LinearLayout.java:1515)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
                  at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1762)
                  at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1606)
                  at android.widget.LinearLayout.onLayout(LinearLayout.java:1515)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.widget.FrameLayout.layoutChildren(FrameLayout.java:325)
                  at android.widget.FrameLayout.onLayout(FrameLayout.java:261)
                  at com.android.internal.policy.DecorView.onLayout(DecorView.java:774)
                  at android.view.View.layout(View.java:17688)
                  at android.view.ViewGroup.layout(ViewGroup.java:5631)
                  at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:2513)
                  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2228)
                  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1366)
                  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6768)
                  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:926)
                  at android.view.Choreographer.doCallbacks(Choreographer.java:735)
                  at android.view.Choreographer.doFrame(Choreographer.java:667)
                  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:912)
                  at android.os.Handler.handleCallback(Handler.java:761)
                  at android.os.Handler.dispatchMessage(Handler.java:98)
                  at android.os.Looper.loop(Looper.java:156)
                  at android.app.ActivityThread.main(ActivityThread.java:6523)
                  at java.lang.reflect.Method.invoke(Native Method)
                  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:942)
                  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:832)

实际上没有理由抛出这个异常！你能告诉我我错在哪里吗？

Answer 1

costumView.findViewById你确定它是如何工作的？尝试使用不带costumView的findViewById

TextView dispensaryName = (TextView) findViewById(R.id.searchDispensaryName);

NullPointerException无缘无故

1 个答案: