java - actionbar下拉菜单的问题-PHP中文网问答

getMenuInflater().inflate(R.menu.options, menu);  


//搜索视窗，因为showAsAction="ifRoom"，所以图三中出现了搜索按钮  
 SearchView searchView = (SearchView) menu.findItem(R.id.menu_search)  
    .getActionView();  

//分享视窗，因为showAsAction="never"，所以只能在溢出菜单中才看见到  
ShareActionProvider mShareActionProvider = (ShareActionProvider) menu  
    .findItem(R.id.menu_share).getActionProvider();  
Intent shareIntent = new Intent(Intent.ACTION_SEND);  
shareIntent.setType("image/*");  
mShareActionProvider.setShareIntent(shareIntent);  

//设置视窗，MyActionProvider就是我们自定义的ActionProvider  
MyActionProvider myactionprovider = (MyActionProvider) menu.findItem(  
    R.id.menu_setting).getActionProvider();  
return super.onCreateOptionsMenu(menu);  

<?xml version="1.0" encoding="utf-8"?>

<item
    android:id="@+id/menu_search"
    android:actionViewClass="android.widget.SearchView"
    android:icon="@drawable/ic_menu_search"
    android:showAsAction="ifroom"
    android:title="搜索"/>
<item
    android:id="@+id/menu_share"
    android:actionProviderClass="android.widget.ShareActionProvider"
    android:showAsAction="never"
    android:title="分享"/>
<item
    android:id="@+id/menu_setting"
    android:actionProviderClass="com.example.tabdemo.MyActionProvider"
    android:showAsAction="never"
    android:title="设置">
    <menu>
        <item
            android:id="@+id/menu_theme"
            android:actionProviderClass="com.example.tabdemo.MyActionProvider"
            android:showAsAction="always|withText"
            android:title="更换主题"/>
        <item
            android:id="@+id/menu_system"
            android:actionProviderClass="com.example.tabdemo.MyActionProvider"
            android:showAsAction="always|withText"
            android:title="系统设置"/>
    </menu>
</item>

点击下拉菜单总是会出现null指针。经发现是mShareActionProvider。
另外为啥点击后不能触发事件。进入对应自定义的ActionProvider。
配置文件
android:actionProviderClass="com.example.tabdemo.MyActionProvider"
这个不起作用？

难道还要自己在onOptionsItemSelected触发事件？

@Override public boolean onOptionsItemSelected(MenuItem item) { FragmentManager manager = getSupportFragmentManager(); FragmentTransaction transaction = manager.beginTransaction(); switch (item.getItemId()) { case R.id.menu_share: transaction.replace(R.id.container, ShareFragment.newInstance()); transaction.commit(); return true; case R.id.menu_setting: transaction.replace(R.id.container, SettingFragment.newInstance()); transaction.commit(); return true; case R.id.menu_feedback: FeedbackAgent agent = new FeedbackAgent(this); agent.startFeedbackActivity(); transaction.commit(); return true; case R.id.menu_about: new AlertDialog.Builder(MainActivity.this) .setTitle("关于") .setMessage("") .setPositiveButton("确定", null) .show(); default: transaction.commit(); return super.onOptionsItemSelected(item); } }