Android - 操作栏中 SearchView 上的 NullPointerException [英] Android - NullPointerException on SearchView in Action Bar
问题描述
我在尝试将 SearchView 小部件添加到我的 Activity 中的 ActionBar 时遇到问题 - 在调用 getActionView 以获取我的 SearchView 对象时得到一个空值.
I've got a problem trying to add a SearchView widget to the ActionBar in my activity - I get a null value when calling getActionView to get my SearchView object.
我一直在关注 Android 开发者指南，还浏览了大量 SO 问题以及互联网上的其他一些链接；一切都无济于事.这可能很简单，但我无法弄清楚 - 在我看来，我的代码与谷歌的代码基本相同(除了更改一些名称等)，但它仍然无法工作.
I've been following the Android Developer guide and also went through a ton of SO questions as well as some other links on the Internet; all to no avail. It could be something simple but I wasn't able to figure it out - it seems to me my code is basically the same as that from google (apart from changing some names etc.) but it still won't work.
任何帮助将不胜感激.
下面是代码的相关部分.如果您对可能的错误有任何想法，请让我知道是否有任何不清楚的地方.
Included below are relevant bits of the code. Please let me know if anything's unclear of if you have any idea as to what could possibly be wrong.
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 */
) {
/** Called when a drawer has settled in a completely closed state. */
public void onDrawerClosed(View view) {
// getActionBar().setTitle("Closed drawer");
}
/** Called when a drawer has settled in a completely open state. */
public void onDrawerOpened(View drawerView) {
// getActionBar().setTitle("Open drawer");
}
};
drawerLayout.setDrawerListener(drawerToggle);
ActionBar actionBar = getActionBar();
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setDisplayHomeAsUpEnabled(true);
actionBar.setHomeButtonEnabled(true);
actionBar.setIcon(android.R.color.transparent);
String[] testData = {"a", "b", "c", "d"};
ArrayList<String> workflowList = new ArrayList<String>();
for (String s : testData) {
workflowList.add(s);
}
ArrayAdapter<String> workflowAdapter = new ArrayAdapter<String>(this.getApplicationContext(), R.layout.workflow_list_item, workflowList);
workflowListView.setAdapter(workflowAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.workflow_list, menu);
inflater.inflate(R.menu.options_menu, menu);
// Associate searchable configuration with the SearchView
SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
// The below line returned null even though it was used in Google sample code
SearchView searchView = (SearchView) menu.findItem(R.id.search).getActionView();
searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
return super.onCreateOptionsMenu(menu);
}
xml/searchable.xml:
xml/searchable.xml:
<?xml version="1.0" encoding="utf-8"?>
<searchable xmlns:android="http://schemas.android.com/apk/res/android"
android:label="@string/app_name"
android:hint="@string/search_hint"
android:includeInGlobalSearch="false" />
menu/options_menu.xml:
menu/options_menu.xml:
<?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/search"
android:title="@string/search_title"
android:icon="@drawable/ic_action_search"
android:showAsAction="always|collapseActionView"
android:actionViewClass="android.support.v7.widget.SearchView" />
</menu>
推荐答案
尝试将失败的行替换为:
Try to replace the failing line with:
mSearchMenuItem = menu.findItem(R.id.action_search);
mSearchView = (EnglishVerbSearchView) MenuItemCompat.getActionView(mSearchMenuItem);
其中 R.id.action_search 是菜单中搜索项的 ID.
Where R.id.action_search is the id of your search item in the menu.
编辑
您的清单应如下所示:
<activity
android:name="com.bronzelabs.twc.activities.WorkflowListActivity"
android:label="@string/app_name"
android:theme="@style/Theme.AppCompat.Light" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity
android:name=".activities.SearchResultActivity"
android:theme="@style/Theme.AppCompat.Light"
android:launchMode="singleTop">
<intent-filter>
<action android:name="android.intent.action.SEARCH" />
</intent-filter>
<meta-data android:name="android.app.searchable" android:resource="@xml/searchable"
android:value=".activities.SearchResultActivity" />
</activity>
你调用 setSearchableInfo 的方式是:
mSearchView.setSearchableInfo(searchManager.getSearchableInfo(
new ComponentName(getApplicationContext(), SearchResultActivity.class)));
编辑 2
确保您的菜单 xml 文件是这样的(注意带有 yourapp 命名空间的这 2 个属性 - 当您使用 compat 库时需要这样做):
Make sure your menu xml file is like that (pay attention to those 2 attributes with yourapp namespace - this is needed when you use the compat library):
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:yourapp="http://schemas.android.com/apk/res-auto" >
<item android:id="@+id/action_search"
android:title="@string/action_search"
android:icon="@drawable/action_search"
yourapp:showAsAction="always|collapseActionView"
yourapp:actionViewClass="android.support.v7.widget.SearchView" />
</menu>
这篇关于Android - 操作栏中 SearchView 上的 NullPointerException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
