FloatActionButton无形

Question

在点击相机按钮之前，它看起来像： 单击相机按钮并选择图像后，相机按钮变为隐形或图库按钮隐藏它 我的布局xml文件：          

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:fitsSystemWindows="true">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:layout_scrollFlags="scroll|enterAlways" />
    </android.support.design.widget.AppBarLayout>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        tools:listitem="@layout/item_recycler_images" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/camera"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="end|bottom"
        android:layout_marginBottom="10dp"
        android:layout_marginEnd="10dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="10dp"
        android:src="@drawable/ic_camera" />
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab_invisible"
        android:layout_width="15dp"
        android:layout_height="15dp"
        android:layout_gravity="top|end"
        android:layout_margin="15dp"
        android:visibility="invisible"
        app:layout_anchor="@id/camera"
        app:layout_anchorGravity="top" />
    <android.support.design.widget.FloatingActionButton
        android:id="@+id/gallery"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="top|end"
        app:layout_anchor="@id/fab_invisible"
        app:layout_anchorGravity="top"
        android:layout_marginBottom="10dp"
        android:layout_marginTop="10dp"
        android:src="@drawable/ic_gallery" />
</android.support.design.widget.CoordinatorLayout>

我使用过支持版：'27 .0.0'。 在三星Galaxy S3（Android版本5.0.1）上观察到此错误。 在三星galaxy Tab S上没有观察到这个bug。 我处理点击事件的代码

public class ScanDocumentActivity extends AppCompatActivity implements Adapter.OnCloseClickListener {
    private static final int REQUEST_CAMERA_PERMISSION = 111;
    private static final int REQUEST_IMAGE_CAMERA = 99;
    public static final int SCAN_REQUEST = 330;

    @BindView(R.id.recyclerView)
    RecyclerView recyclerView;
    @BindView(R.id.gallery)
    FloatingActionButton gallery;
    @BindView(R.id.camera)
    FloatingActionButton camera;
    @BindView(R.id.toolbar)
    Toolbar toolbar;
    @BindView(R.id.coordinator)
    CoordinatorLayout coordinatorLayout;

    Adapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan_document);
        ButterKnife.bind(this);
        setSupportActionBar(toolbar);
        toolbar.setTitle("Salom");
        adapter = new Adapter(this);
        recyclerView.setLayoutManager(new GridLayoutManager(this, 3));
        recyclerView.setAdapter(adapter);
        gallery.setOnClickListener(view -> galleryIntent());
        gallery.setBackgroundTintList(ColorStateList.valueOf(ContextCompat.getColor(this, R.color.colorPrimary)));
        camera.setOnClickListener(view -> cameraIntent());
    }
    public void cameraIntent() {
        Intent intent = new Intent(this, ScanActivity.class);
        intent.putExtra(ScanConstants.OPEN_INTENT_PREFERENCE, ScanConstants.OPEN_CAMERA);
        startActivityForResult(intent, REQUEST_IMAGE_CAMERA);
    }
    public void galleryIntent() {
        Intent intent = new Intent(this, ScanActivity.class);
        intent.putExtra(ScanConstants.OPEN_INTENT_PREFERENCE, ScanConstants.OPEN_MEDIA);
        startActivityForResult(intent, REQUEST_IMAGE_CAMERA);
    }