膨胀 View 时Android ListView NullPointerException

Question

我有一个带有自定义行的 ListView:detail_row1.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:orientation="horizontal" 
    android:layout_height="wrap_content"
    android:padding="6dip"
    **android:background="@drawable/item_background_selector"**  ---> line 7
    android:id="@+id/detail_linearLayout"
  >

<TextView 
    android:id="@+id/propName"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"   
    android:layout_weight="1"    
    android:textSize="16sp"
    android:textStyle="bold" 
    android:textColor="#000000"
    android:gravity="center_vertical|left"
    android:paddingTop="10sp"
    android:paddingBottom="10sp"
    android:paddingLeft="4sp"

/>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="2"
    android:id="@+id/propValue"       
    android:textColor="#000000"
    android:textSize="16sp"
    android:textStyle="bold"
    android:paddingTop="10sp"
    android:paddingBottom="10sp"
    android:paddingRight="4sp"
    android:gravity="center_vertical|right"
    />  

</LinearLayout>

我的/drawable/item_background_selector.xml(如果我将它放在 /color/item_background_selector.xml 下并在 detail_row1.xml 中正确引用它，则相同)

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_selected="false" android:color="#ACD52B">
    </item>
    <item android:state_selected="true" android:color="#0094CE">
    </item>
</selector>

当我尝试在我的 ListAdapter 中扩充此 View 时:

public View getView(int position, View convertView, ViewGroup parent) {
    View v=convertView;
    if(v==null) {
    LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        v=vi.inflate(R.layout.detail_row1, null); **--> NullPointerException**
   }
    .
    .

它抛出 NullPointerException。

如果我只是从 detail_row1.xml 中删除第 7 行(android/background)，情况就不是这样了

关于为什么会发生这种情况的任何线索/帮助(对 android 来说相当新)

提前致谢!

(编辑)Logcat:

**08-24 00:27:53.637: E/AndroidRuntime(15295): FATAL EXCEPTION: main**
08-24 00:27:53.637: E/AndroidRuntime(15295): android.view.InflateException: Binary XML file line #2: Error inflating class <unknown>
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.createView(LayoutInflater.java:613)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at com.android.internal.policy.impl.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:56)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.onCreateView(LayoutInflater.java:660)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:685)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:466)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:396)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at android.view.LayoutInflater.inflate(LayoutInflater.java:352)
08-24 00:27:53.637: E/AndroidRuntime(15295):    at **com.dhomes.steel.DetailActivity$1.getView(DetailActivity.java:101)**

(第二次编辑)

我的列表适配器:

lvProperties.setAdapter(new ListAdapter() {
//Section section=new Section();

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View v=convertView;

   if(v==null) {
   //LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   LayoutInflater vi =(LayoutInflater)DetailActivity.this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
   v=vi.inflate(R.layout.detail_row1, null);
   }

   TextView name=(TextView)v.findViewById(R.id.propName);
   TextView value=(TextView)v.findViewById(R.id.propValue);

   if(name!=null) {
       name.setText(section.propNames.get(position));
   }
   if(value!=null) {
       value.setText(section.propValues.get(position));
   }        
   return v;
}
.
.
.
}

Answer 1

LayoutInflater vi = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
v=vi.inflate(R.layout.detail_row1, null);

从，上面的行。你似乎只是在你的 customadapter 类中夸大它。所以，你从 Constructor 中得到了 context 对象，所以最好像下面这样使用它 -

...
LayoutInflater vi = (LayoutInflater)context.getSystemService(context.LAYOUT_INFLATER_SERVICE);
v=vi.inflate(R.layout.detail_row1, null);
...

并且，不要从您的 xml 文件中删除背景。只需尝试清理您的项目并在完成此更改后运行即可。