Material 设计：如何为 Android 浮动操作按钮设置透明度

Question

我的问题与一个有关。

当我打开NavigationDrawer 时，Floating Button 在上面但必须在下面。

我试着这样做：

        @Override
        public void onDrawerSlide(View drawerView, float slideOffset) {
            Log.i(TAG , " inner onDrawerSlide");
            super.onDrawerSlide(drawerView, slideOffset);
            fabButton.setAlpha(25);
            float alpha = 0.2f;
            AlphaAnimation alphaUp = new AlphaAnimation(alpha, alpha);
            alphaUp.setFillAfter(true);
            fabButton.startAnimation(alphaUp);
            syncState();
        }

像那样：

            @Override
            public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerClosed(view);
                invalidateOptionsMenu();
                fabButton.setAlpha(255);
                syncState();
            }

对我没有任何作用。有什么解决办法？

我的布局：

<mobapply.freightexchange.customviews.FragmentNavigationDrawer
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    android:orientation="vertical">

    <!-- The ActionBar -->
    <include
        layout="@layout/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

    <!-- The main content view -->
    <FrameLayout
        android:id="@+id/flContent"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>
<!-- The navigation drawer -->
<ListView
    android:id="@+id/lvDrawer"
    android:layout_width="match_parent"
    android:divider="@null"
    android:dividerHeight="0dp"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:choiceMode="singleChoice"
    android:background="#FFFFFF"
    android:cacheColorHint="@android:color/transparent"
     />

FragmentNavigationDrawer 是自定义的 DrawerLayout

Answer 1

来自 Android documentation for setAlpha(float alpha)（自 API 11）：

Sets the opacity of the view. This is a value from 0 to 1, where 0 means the view is completely transparent and 1 means the view is completely opaque.

您正在尝试将其设置为值 25 或 255 :)

Answer 2

这应该用漂亮的动画隐藏它:

public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerSlide(drawerView, slideOffset);
                invalidateOptionsMenu();
                fabButton.setAlpha(1 - slideOffset);
                syncState();
            }

或者，您可以将其滑出视图：

public void onDrawerSlide(View drawerView, float slideOffset) {
                super.onDrawerSlide(drawerView, slideOffset);
                invalidateOptionsMenu();
                fabButton.setTranslationX(slideOffset * 100);
                syncState();
            }

Answer 3

如果 fab 的位置有问题，那么让它可以拖动。这是

的代码

private FloatingActionButton fab;
float dX;
float dY;
int lastAction;


fab = (FloatingActionButton) findViewById(R.id.fab);

    fab.setOnTouchListener(this);





@Override
public boolean onTouch(View view, MotionEvent event) {
    switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            dX = view.getX() - event.getRawX();
            dY = view.getY() - event.getRawY();
            lastAction = MotionEvent.ACTION_DOWN;
            break;

        case MotionEvent.ACTION_MOVE:
            view.setY(event.getRawY() + dY);
            view.setX(event.getRawX() + dX);
            lastAction = MotionEvent.ACTION_MOVE;
            break;

        case MotionEvent.ACTION_UP:
            if (lastAction == MotionEvent.ACTION_DOWN) {
                Intent intent = new Intent(Main.this, Cart.class);
                startActivity(intent);
                Toast.makeText(this, "Clicked!", Toast.LENGTH_SHORT).show();
            }
            break;

        default:
            return false;
    }
    return true;
}

Answer 4

我使用这行代码可以正常工作，但它可能与设备方向的变化有关。

public void onDrawerSlide(View drawerView, float slideOffset) {
            super.onDrawerSlide(drawerView, slideOffset);

            fab.setAlpha(1-slideOffset);
        }

Material 设计：如何为 Android 浮动操作按钮设置透明度

Material Design : how to set transparency for Android Floating Action Button

android

navigation-drawer

material-design

floating-action-button