NullPointerException in Android code

The error is:

java.lang.NullPointerException.onCreateOptionsMenu(AddMyMarketsActivity.java:44)

My code is:

41 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
42          SearchManager searchManager = (SearchManager) getSystemService(Context.SEARCH_SERVICE);
43          SearchView searchView = (SearchView) menu.findItem(R.id.menu_search).getActionView();       
44          searchView.setSearchableInfo(searchManager.getSearchableInfo(getComponentName()));
            Log.i("searchView", "set searchable configuration for searchView ");

What could be the problem with my code?

回答1:

If you're using androids support libary to display your action bar, be sure you use the right actionViewClass in your SearchView declaration.

Should be app:actionViewClass="android.support.v7.widget.SearchView".

After that you can use as replacement for your code trying to get the ActionView:

MenuItem searchItem = menu.findItem(R.id.search_view);
SearchView searchView = (SearchView) MenuItemCompat.getActionView(searchItem);

Be sure to call getMenuInfalter().inflate(...) before calling this.

More information: http://developer.android.com/guide/topics/ui/actionbar.html#ActionView

回答2:

I had the same error and it was removed by changing:

android:actionViewClass="android.widget.SearchView"

app:actionViewClass="android.widget.SearchView"

from menu.xml file

i.e change android: to app:

回答3:

I'm describing the whole procedure of adding search view to action bar.This snippets of code worked for me.

Add search view in menu:add the following item in the menu layout of the activity in which you require search view.

<item
android:id="@+id/search"
android:title="@string/search_title"
android:icon="@drawable/ic_action_search"
app:showAsAction="collapseActionView|ifRoom"
app:actionViewClass="android.support.v7.widget.SearchView"/>

Note: menu layout file should contain following schema. xmlns:app="http://schemas.android.com/apk/res-auto"

Create a Searchable Configuration: create a file searchable.xml in the directory res/xml. copy the following code into it.

<?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" />

Modify onCreateOptionsMenu() method: In the onCreateOptionsMenu() method of your activity, associate the searchable configuration with the SearchView by calling setSearchableInfo(SearchableInfo): Your onCreateOptionsMenu should look like this.

public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu_display_cards, menu);
    // Associate searchable configuration with the SearchView
    SearchManager searchManager =
            (SearchManager) getSystemService(Context.SEARCH_SERVICE);
    //SearchView searchView =
     //       (SearchView) menu.findItem(R.id.search).getActionView();
    MenuItem mSearchMenuItem = menu.findItem(R.id.search);
    SearchView searchView =
    (SearchView)MenuItemCompat.getActionView(mSearchMenuItem);         
    searchView.setSearchableInfo(searchManager.getSearchableInfo(
            new ComponentName(getApplicationContext(), 
            SearchResultsActivity.class)));
    return true;
}

Make an activity SearchResultsActivity to show the results of your search. In the manifest file ,add the following

<activity
        android:name=".SearchResultsActivity"
        android:label="@string/title_activity_search_results" >
        <intent-filter>
            <action android:name="android.intent.action.SEARCH" />
        </intent-filter>
        <meta-data
            android:name="android.app.searchable"
            android:resource="@xml/searchable"
            android:value=".SearchResultsActivity"/>
 </activity>

Your SearchResultsActivity should implement the following methods

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

private void handleIntent(Intent intent) {

    if (Intent.ACTION_SEARCH.equals(intent.getAction())) {
        String query = intent.getStringExtra(SearchManager.QUERY);
        //use the query to search your data and show it in 
        //SearchResultsActivity
    }
}

Note:You should call the following from onCreate method of SearchResultsActivity