相关疑难解决方法(0)

我刚刚实现了v7 AppCompat支持库,但在MenuItemCompat.getActionView我测试的每个Android版本中总是返回null(4.2.2,2.3.4 ....)

该SearchView显示在操作栏上,但它不响应触摸操作,不会展开,以显示其EditText与就像一个简单的图标.

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu, menu);

    MenuItem searchItem = menu.findItem(R.id.action_search);
    SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);
    if (searchView != null) {
        SearchViewCompat.setOnQueryTextListener(searchView, mOnQueryTextListener);
        searchView.setIconifiedByDefault(false);
        Log.d(TAG,"SearchView not null");
    } else
        Log.d(TAG, "SearchView is null");
    }
    return super.onCreateOptionsMenu(menu);
}

menu.xml文件

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto">

    <item android:id="@+id/action_search"
          app:showAsAction="always|collapseActionView"
          android:icon="@drawable/abc_ic_search"
          android:title="@string/action_bar_search"
          android:actionViewClass="android.support.v7.widget.SearchView"/>

    <item android:id="@+id/action_refresh"
          android:icon="@drawable/refresh"
          android:title="@string/action_bar_refresh"
          app:showAsAction="ifRoom"/>
</menu>

在我的活动中尝试将SearchView小部件添加到ActionBar时遇到了问题 - 在调用getActionView获取SearchView对象时,我得到一个空值.

我一直在关注Android开发者指南,并且还经历了大量的SO问题以及互联网上的其他一些链接; 一切都无济于事.它可能是一些简单的东西,但我无法弄明白 - 在我看来,我的代码基本上与谷歌相同(除了更改一些名称等),但它仍然无法正常工作.

任何帮助,将不胜感激.

下面包括代码的相关位.如果您不清楚是否有任何可能出错的问题,请告诉我.

活动代码:

    private ListView workflowListView;
    private DrawerLayout drawerLayout;
    private ListView drawerList;
    private ActionBarDrawerToggle drawerToggle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
        setContentView(R.layout.activity_workflow_list);

        workflowListView = (ListView) findViewById(R.id.workflowListView);
        drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawerList = (ListView) findViewById(R.id.drawer_list);

        drawerToggle = new ActionBarDrawerToggle(
             this,                  /* host Activity */
             drawerLayout,         /* DrawerLayout object */
             R.drawable.ic_launcher,  /* nav drawer icon to replace 'Up' caret */
             R.string.app_name,  /* "open drawer" description */
             R.string.app_name  /* "close drawer" description */
             ) …

我正在尝试将Search-ActionView添加到我的应用程序中(如http://developer.android.com/guide/topics/search/search-dialog.html#UsingSearchWidget中所述).不幸的是,我一直得到一个NullPointerException,我很难发现实际上出了什么问题.

我创建了一个可搜索的配置和一个可搜索的活动,如android页面所示.我的菜单.xml文件如下所示:

<menu xmlns:android="http://schemas.android.com/apk/res/android" >
    ...
    <item
        android:id="@+id/menu_item_search"
        android:actionViewClass="android.widget.SearchView"
        android:icon="@drawable/icon_search"
        android:showAsAction="always"
        android:title="@string/action_bar_button_search">
    </item>

</menu>

这是抛出异常的方法:

public boolean onCreateOptionsMenu( Menu menu )
{
    MenuInflater menuInflater = getMenuInflater();
    menuInflater.inflate( R.menu.action_bar, menu );

    SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    SearchView searchView = (SearchView) menu.findItem(R.id.menu_item_search).getActionView();

    // NullPointerException thrown here; searchView is null.
    searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
    searchView.setIconifiedByDefault(false);

    return super.onCreateOptionsMenu( menu );
}

完整的堆栈跟踪:

FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.activities.Test.onCreateOptionsMenu(Test.java:41)
at android.app.Activity.onCreatePanelMenu(Activity.java:2444)
at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:408)
at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java:759)
at com.android.internal.policy.impl.PhoneWindow$1.run(PhoneWindow.java:2997)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4507)
at …