显示java.lang.NullPointerException $ ExpandableAdapter.getGroupView

Question

我使用自定义BaseExpandableListAdapter与Fragment类，但我不知道为什么我得到的NullPointerException：

代码：

@Override 
public View getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) { 
    if (convertView == null) { 
     convertView = inflater.inflate(R.layout.group_list, null); <= NullPointerException 
    } 

    ((CheckedTextView) convertView).setText(parentItems.get(groupPosition)); 
    ((CheckedTextView) convertView).setChecked(isExpanded); 

    return convertView; 
} 

logcat的

05-02 13:00:52.219: E/AndroidRuntime(21979): FATAL EXCEPTION: main 
05-02 13:00:52.219: E/AndroidRuntime(21979): java.lang.NullPointerException 
05-02 13:00:52.219: E/AndroidRuntime(21979): at pro.businessbook.fragments.RechercheVilleSecteurFragment$ExpandableAdapter.getGroupView(RechercheVilleSecteurFragment.java:373) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:446) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.AbsListView.obtainView(AbsListView.java:2232) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.ListView.measureHeightOfChildren(ListView.java:1253) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.ListView.onMeasure(ListView.java:1162) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1411) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.measureVertical(LinearLayout.java:698) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.RelativeLayout.measureChild(RelativeLayout.java:666) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:477) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1411) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.measureVertical(LinearLayout.java:698) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.support.v4.widget.DrawerLayout.onMeasure(DrawerLayout.java:704) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.measureVertical(LinearLayout.java:850) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2193) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.View.measure(View.java:15775) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2212) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1291) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1486) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1181) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:4942) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:776) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.Choreographer.doCallbacks(Choreographer.java:579) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.Choreographer.doFrame(Choreographer.java:548) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:762) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.os.Handler.handleCallback(Handler.java:800) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.os.Handler.dispatchMessage(Handler.java:100) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.os.Looper.loop(Looper.java:194) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at android.app.ActivityThread.main(ActivityThread.java:5370) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at java.lang.reflect.Method.invokeNative(Native Method) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at java.lang.reflect.Method.invoke(Method.java:525) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:833) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600) 
05-02 13:00:52.219: E/AndroidRuntime(21979): at dalvik.system.NativeStart.main(Native Method) 
05-02 13:00:52.278: D/jdwp(21979): processIncoming 
05-02 13:00:52.278: D/jdwp(21979): handlePacket : cmd=0x1, cmdSet=0xB, len=0x13, id=0x101F, flags=0x0, dataLen=0x8 

group_list.xml

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:orientation="vertical" > 
    <ImageView 
     android:id ="@+id/label_indicator" 
     android:layout_width ="wrap_content" 
     android:layout_height ="wrap_content" 
     android:layout_alignParentLeft="true"/> 
    <TextView 
     android:id ="@+id/title" 
     android:layout_width ="wrap_content" 
     android:layout_height ="wrap_content" 
     android:layout_toRightOf="@id/label_indicator"/> 
    <CheckBox 
     android:id ="@+id/cb" 
     android:layout_width ="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_alignParentRight="true" 
     android:focusable="false"/> 


</RelativeLayout> 

Answer 1

这

((CheckedTextView) convertView).setText(parentItems.get(groupPosition)); 
((CheckedTextView) convertView).setChecked(isExpanded); 

随着

if (convertView == null) { 

    LayoutInflater infalInflater = (LayoutInflater)_context 
       .getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     convertView = infalInflater.inflate(R.layout.group_list, null); 
    } 

    TextView mGroupText = (TextView) convertView.findViewById(R.id.title); 
    mGroupText.setText(parentItems.get(groupPosition)); 

    CheckBox mCheckBox = (CheckBox) convertView.findViewById(R.id.cb); 
    mCheckBox.setChecked(isExpanded); 

您的应用程序崩溃这是你应该改变，因为在你的group_list.xml布局文件没有CheckedTextView。

Answer 2

你需要这些从

((CheckedTextView) convertView).setText(parentItems.get(groupPosition)); 
((CheckedTextView) convertView).setChecked(isExpanded); 

到

TextView txt= (TextView) convertView.findViewById(R.id.title); 
txt.setText(parentItems.get(groupPosition)); 

CheckBox chk = (CheckBox) convertView.findViewById(R.id.cb); 
chk.setChecked(isExpanded); 

Answer 3

你说你有例外，在这条线（这是很难在你的问题找到，顺便说一句）改变：

convertView = inflater.inflate(R.layout.group_list, null); 

这意味着您的inflater变量可能未被正确初始化。先检查一下。

---

在另一方面，你有@PiYusHGuPtA和@SimplePlan回答的另一个问题：setText()和setChecked()不能在膨胀的视图直接调用，但在（分别）的TextView和CheckBox那在您的convertView中包含包含。

为了让您的充气鉴于这些特定元素，使用convertView.findViewById()：

TextView title = (TextView) convertView.findViewById(R.id.title); 
title.setText(parentItems.get(groupPosition)); 

CheckBox cb = (CheckBox) convertView.findViewById(R.id.cb); 
cb.setChecked(isExpanded);