为什么上下文菜单不在ListView中显示？

问题描述：

我想显示一个上下文菜单长按，在搜索结果活动中的ListView项，我用“registerForContextMenu（View v）”函数，也重写了上下文菜单的创建方法，但是上下文菜单不是生成并且“onCreateContextMenu”方法没有被调用。请解释原因。这是我对含有ListView的活动Java代码：为什么上下文菜单不在ListView中显示？

public class WeatherSearch extends ListActivity implements WeatherServiceCallback { 

    private String query; 
    private OpenWeatherService service; 
    private ListView L; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_weather_search); 
     handleIntent(getIntent()); 
     Intent intent = getIntent(); 
     String query = intent.getStringExtra("query"); 
     service=new OpenWeatherService(this,getBaseContext(),"SEARCH",query,null); 
     service.refreshWeather(); 
     l=(ListView)findViewById(android.R.id.list); 
    } 

    @Override 
    protected void onNewIntent(Intent intent) { 
     handleIntent(intent); 
    } 

    private void handleIntent(Intent intent) { 
     try { 
      if (Intent.ACTION_SEARCH.equals(intent.getAction())) { 
       String query = intent.getStringExtra(SearchManager.QUERY); 
        //use the query to search 
      } 
     }catch(Exception e){ 
      e.printStackTrace();}; 
    } 

    @Override 
    public void serviceSuccess(JSONObject obj) { 
     searchResultParser prs=new searchResultParser(); 
     try { 
      prs.populate(obj); 
     }catch(Exception e){}; 
     WeatherAdapter adp = new  WeatherAdapter(this,R.layout.list,R.id.text,prs.getList()); 
     l.setAdapter(adp); 
     registerForContextMenu(l); 
    } 

    @Override 
    public void serviceFailure(Exception exp) { 
     Toast.makeText(getApplicationContext(), "Location Search Failed ! ", Toast.LENGTH_LONG).show(); 
    } 

    @Override 
    public void onCreateContextMenu(ContextMenu menu, View v,ContextMenu.ContextMenuInfo menuInfo) { 
    getMenuInflater().inflate(R.menu.menu_location_set_context, menu); 
     super.onCreateContextMenu(menu,v,menuInfo); 
     if (v.getId()==android.R.id.list) { 
      AdapterView.AdapterContextMenuInfo info = (AdapterView.AdapterContextMenuInfo)menuInfo; 
      menu.clearHeader(); 
      menu.add(Menu.NONE, 0, 0, "Set as Default Location"); 
     } 
    } 
    @Override 
    public boolean onContextItemSelected (MenuItem item){ 
     return true; 
    }}

这里为WeatherSearch活动我的XML代码：

<?xml version="1.0" encoding="utf-8"?> 
<RelativeLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:paddingLeft="@dimen/activity_horizontal_margin" 
    android:paddingRight="@dimen/activity_horizontal_margin" 
    android:paddingTop="@dimen/activity_vertical_margin" 
    android:paddingBottom="@dimen/activity_vertical_margin" 
    tools:context="com.example.adeel.openweatherprework.WeatherSearch" 
    android:background="@drawable/weather_bkg1"> 
    <LinearLayout 
     android:id="@+id/forecastLayout" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:orientation="vertical"> 
     <ListView 
      android:layout_width="match_parent" 
      android:layout_height="wrap_content" 
      android:id="@android:id/list" 
      android:layout_below="@+id/textView" 
      android:layout_marginTop="10dp" 
      android:layout_marginBottom="5dp" 
      android:layout_marginLeft="5dp" 
      android:layout_marginRight="5dp" 
      android:dividerHeight="2dp" 
      android:divider="#FFFFFF" /> 
    </LinearLayout> 
</RelativeLayout>

这里是自定义列表适配器使用的列表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="wrap_content" 
    android:clickable="true" 
    android:orientation="horizontal"> 

    <TextView xmlns:android="http://schemas.android.com/apk/res/android" 
     android:id="@+id/txt" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:clickable="true" 
     android:focusable="false" 
     android:focusableInTouchMode="false" 
     android:gravity="center_vertical" 
     android:onClick="clicked" 
     android:paddingBottom="12dp" 
     android:paddingTop="12dp" 
     android:textColor="#FFFFFF" 
     android:textSize="20dp" /> 
</RelativeLayout>

这里是上下文菜单XML：

<?xml version="1.0" encoding="utf-8"?> 
<menu xmlns:android="http://schemas.android.com/apk/res/android"> 
    <item android:id="@+id/context_menu" 
     android:title="@string/Loc_settings" /> 
</menu>

答

你夸大你的菜单第一

@Override 
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { 
getMenuInflater().inflate(R.menu.my_menu_context, menu); 
// Rest of your code goes here 
}

还需要太多的菜单：

my_menu_context.xml

<?xml version="1.0" encoding="utf-8"?> 
<menu 
xmlns:android="http://schemas.android.com/apk/res/android"> 
<item android:id="@+id/menu_item_delete" 
android:icon="@android:drawable/ic_menu_delete" 
android:title="@string/delete_item" /> 
</menu>

完成，仍然没有，代码也已经更新上面 –

你确定你的“serviceSuccess”是在onCreate的上下文中调用的？ –

不完全，ServiceSuccess在执行AsyncTask后作为回调函数执行。在OnCreate方法中，在第二个最后一行; service.refreshWeather（）启动一个AsyncTask作为一个新的线程，在此之后，serviceSuccess从传入的引用被回调。显然serviceSucess会在执行onCreate后调用 –

答

我longClick事件addedd这条线，并与我跑。 openContextMenu（adapterView）;

与此你可以处理onlongClick事件和onContextItemSelected。

建议添加一些上下文或示例代码来支持您的答案。 – ItamarG3

为什么上下文菜单不在ListView中显示？

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