无法实例化类：app.support.v7.widget.ShareActionProvider

Question

我正在尝试在DetailFragment类中使用ShareActionProvider。

public static class DetailFragment extends Fragment {

    private static final String LOG_TAG = DetailFragment.class.getSimpleName();
    private static final String FORECAST_SHARE_HASHTAG = " # SunshineApp";
    private String mForecastStr;

    public DetailFragment() {
        setHasOptionsMenu(true);
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {

       View rootView = inflater.inflate(R.layout.fragment_detail, container, false);
       Intent intent = getActivity().getIntent();

       if (intent != null && intent.hasExtra(Intent.EXTRA_TEXT)) {
            mForecastStr = intent.getStringExtra(Intent.EXTRA_TEXT);
            TextView info = (TextView)rootView.findViewById(R.id.info);
            Log.d(LOG_TAG, "mForecastStr is :  " + mForecastStr);
            info.setText(mForecastStr);
        }

       return rootView;
    }

    @Override
    public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
        inflater.inflate(R.menu.detailfragment, menu);
        MenuItem menuItem = menu.findItem(R.id.action_share);
        ShareActionProvider mShareActionProvider = (ShareActionProvider)MenuItemCompat.getActionProvider(menuItem);

        if (mShareActionProvider != null) {
            mShareActionProvider.setShareIntent(createShareForecastIntent());
        } else {
            Log.d(LOG_TAG, "Share Action Provider is null?");
        }
    }

    private Intent createShareForecastIntent() {
        Intent shareIntent = new Intent(Intent.ACTION_SEND);
        shareIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
        shareIntent.setType("text/plain");
        shareIntent.putExtra(Intent.EXTRA_TEXT, mForecastStr + FORECAST_SHARE_HASHTAG);
        return shareIntent;
    }
}

--EOF--

但我不仅可以获得null类而不是mShareActionProvider。错误消息在这里。

07-19 18:07:36.348: W/SupportMenuInflater(31261): Cannot instantiate class: app.support.v7.widget.ShareActionProvider
07-19 18:07:36.348: W/SupportMenuInflater(31261): java.lang.ClassNotFoundException: Didn't find class "app.support.v7.widget.ShareActionProvider" on path: DexPathList[[zip file "/data/app/com.example.project-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.project-1, /vendor/lib, /system/lib]]

似乎Android Studio无法找到app.support.v7.widget.ShareActionProvider。我已经安装了Android支持库。我该怎么办？

更新!!

这是我的build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"

    defaultConfig {
        applicationId "com.shinjaehun.sunshine"
        minSdkVersion 10
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        } 
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    compile 'com.android.support:support-v4:22.2.1'
    compile 'com.android.support:appcompat-v7:22.2.1'
}

--EOF---

我正在使用SDK构建工具版本22.0.1，但我的appcompat库版本是22.2.1。这就是我失败的原因，不是吗？我如何使用appcompat版本22.0.1？只有Android支持库Ver 22.2.1。