Question

我想长按一下上下文菜单，在Search Result Activity中的ListView项目上，我使用了“registerForContextMenu（View v）”功能，并且还覆盖了上下文菜单创建方法，但是上下文菜单不是正在生成并且未调用“onCreateContextMenu”方法。请解释原因。这是我的包含ListView的活动的Java代码：

    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;
    }}

这里是WeatherSearch Activity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>

HERE是自定义列表适配器中使用的列表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>

Answer 1

你必须首先给菜单充气

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

你也需要一个菜单：

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>

Answer 2

我在longClick事件中添加了这一行，它与我一起运行。 openContextMenu（适配器视图）;

使用它可以处理onlongClick事件和onContextItemSelected。

为什么上下文菜单不会出现在ListView中？

2 个答案: