可扩展列表适配器不断崩溃活动

请原谅我可能是最不问题的问题，但我不知道是什么原因导致我的应用崩溃（这次）。我只是试图膨胀一个XML布局文件到可扩展列表视图。可扩展列表适配器不断崩溃活动

package com.anthonyce.mcathomie; 

import android.app.Activity; 
import android.content.Context; 
import android.os.Bundle; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.BaseExpandableListAdapter; 
import android.widget.ExpandableListView; 
import android.widget.TextView; 

public class PlayoptionsActivity extends Activity { 

ExpandableListView Mtopics; 
ExpandableAdapter MtopicsAdapter; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_playoptions); 
    //set up adapter 
    MtopicsAdapter = new ExpandableAdapter(); 
    Mtopics = (ExpandableListView) findViewById(R.id.mtopicsListView); 
    Mtopics.setAdapter(MtopicsAdapter); 
    //Mtopics.setGroupIndicator(null); 
} 

public class ExpandableAdapter extends BaseExpandableListAdapter { 
    private Context context; 
    private String[] groups = { "People Names", "Dog Names", "Cat Names", 
      "Fish Names" }; 
    private String[][] children = { { "Arnold" }, { "Ace" }, { "Fluffy" }, 
      { "Goldy" } }; 

    public Object getChild(int groupPosition, int childPosition) { 
      return children[groupPosition][childPosition]; 
    } 

    public long getChildId(int groupPosition, int childPosition) { 
      return childPosition; 
    } 

    public View getChildView(int groupPosition, int childPosition, 
      boolean isLastChild, View convertView, ViewGroup parent) { 
     View childView; 
     LayoutInflater childInflate = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     childView = childInflate.inflate(R.layout.mtopics_childrow, parent, false); 

     TextView childtxt = (TextView)childView.findViewById(R.id.mtopicchildtext); 
     childtxt.setText(getChild(groupPosition, childPosition).toString()); 

     return childView; 

    } 

    public int getChildrenCount(int groupPosition) { 
     return children[groupPosition].length; 
    } 

    public Object getGroup(int groupPosition) { 
     return groups[groupPosition]; 
    } 

    public int getGroupCount() { 
     return groups.length; 
    } 

    public long getGroupId(int groupPosition) { 
     return groupPosition; 
    } 

    public View getGroupView(int groupPosition, boolean isExpanded, 
      View convertView, ViewGroup parent) { 
     View groupView; 
     groupView = new View(context); 
     LayoutInflater groupInflate = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     groupView = groupInflate.inflate(R.layout.mtopics_grouprow, parent, false); 

     TextView grouptxt = (TextView)groupView.findViewById(R.id.mtopicgrouptext); 
     grouptxt.setText(getGroup(groupPosition).toString()); 

     return groupView; 
    } 

    public boolean hasStableIds() { 
     return true; 
    } 

    public boolean isChildSelectable(int groupPosition, int childPosition) { 
     return true; 
    } 
} 
}

这里是组布局的XML，我试图夸大

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/mtopicgrouplin" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:gravity="fill"> 

    <TextView 
     android:gravity="left" 
     android:id="@+id/mtopicgrouptext" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     android:layout_weight="1" 
     android:ems="10" 
     android:textStyle="bold" /> 



    <CheckBox 
     android:id="@+id/checkBoxgroup" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" /> 

</LinearLayout>

这是工作之前，但没有文字显示是现在有了这个代码，它只是崩溃。我不认为这个问题将在childrow，但在这里不用

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/mtopicchildlin" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:gravity="fill"> 

    <CheckBox 
     android:paddingLeft="10dp" 
     android:id="@+id/checkBoxchild" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content"/> 

    <TextView 
     android:id="@+id/mtopicchildtext" 
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content" 
     /> 
</LinearLayout>

这里是logcat的是我发现漶

09-05 17:09:33.919: E/AndroidRuntime(429): FATAL EXCEPTION: main 
09-05 17:09:33.919: E/AndroidRuntime(429): java.lang.NullPointerException 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewConfiguration.get(ViewConfiguration.java:228) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.<init>(View.java:1878) 
09-05 17:09:33.919: E/AndroidRuntime(429): at com.anthonyce.mcathomie.PlayoptionsActivity$ExpandableAdapter.getGroupView(PlayoptionsActivity.java:118) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.ExpandableListConnector.getView(ExpandableListConnector.java:445) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.AbsListView.obtainView(AbsListView.java:1430) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.ListView.measureHeightOfChildren(ListView.java:1216) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.ListView.onMeasure(ListView.java:1127) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.measure(View.java:8313) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.LinearLayout.measureVertical(LinearLayout.java:386) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.measure(View.java:8313) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.measure(View.java:8313) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.LinearLayout.measureVertical(LinearLayout.java:531) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.measure(View.java:8313) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.View.measure(View.java:8313) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewRoot.performTraversals(ViewRoot.java:839) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.view.ViewRoot.handleMessage(ViewRoot.java:1859) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.os.Handler.dispatchMessage(Handler.java:99) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.os.Looper.loop(Looper.java:123) 
09-05 17:09:33.919: E/AndroidRuntime(429): at android.app.ActivityThread.main(ActivityThread.java:3683) 
09-05 17:09:33.919: E/AndroidRuntime(429): at java.lang.reflect.Method.invokeNative(Native Method) 
09-05 17:09:33.919: E/AndroidRuntime(429): at java.lang.reflect.Method.invoke(Method.java:507) 
09-05 17:09:33.919: E/AndroidRuntime(429): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
09-05 17:09:33.919: E/AndroidRuntime(429): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
09-05 17:09:33.919: E/AndroidRuntime(429): at dalvik.system.NativeStart.main(Native Method)

来源

2012-09-05 mango

你从来就不是一个值设置为context变量，所以当你做groupView = new View(context)时，上下文为空并且抛出一个NullPointerException。

使用，而不是当前的活动背景：

groupView = new View(PlayoptionsActivity.this);

你也可以创建一个构造函数：

ExpandableAdapter(Context context) 
{ 
    this.context = context; 
}

来源

2012-09-05 17:24:40 Dalmas

这可能是因为你在其他行上使用'context'。使用构造函数，它不应该崩溃。 – Dalmas

有什么意思！即使凝视几个小时，我也完全错过了。不幸的是纠正这个问题没有做到。我甚至试图删除线路，它仍然崩溃。是否我的布局充气器环境也需要定义？（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）; – mango

是的，这条线也会引发异常。 – Dalmas

删除

groupView = new View(context);

和运行程序。

来源

2012-09-05 17:30:25 Chet

可扩展列表适配器不断崩溃活动

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