问如何在android应用中激活“分享”按钮？

EN

private ShareActionProvider mShareActionProvider;

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.share_menu, menu);
    getMenuInflater().inflate(R.menu.main, menu);
    MenuItem item = menu.findItem(R.id.share_menu);
    mShareActionProvider = (ShareActionProvider) menu.findItem(R.id.share_menu).getActionProvider();
    mShareActionProvider.setShareIntent(getDefaultShareIntent());

    return true;
}

{
    Intent sharingIntent = new Intent(Intent.ACTION_SEND);
    sharingIntent.setType("text/plain");
    sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, "Text");
    sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Subject");
    startActivity(Intent.createChooser(sharingIntent, "Share using"));
}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/background_color"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context=".MainActivity$DummySectionFragment" >

<TextView
    android:id="@+id/section_label1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="@string/text"
    android:textColor="@color/text_color" />

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:src="@drawable/sprite" />