Прокрутка Smooth ImageView в CoordinatorLayout

Question

У меня проблема с плавной прокруткой в ​​CoordinatorLayout в моем приложении.

Я пытаюсь добиться этого: http://wstaw.org/m/2015/10/02/google-scroll.gif

, но мой лучший результат: http://wstaw.org/m/2015/10/02/my-scroll.gif

<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    android:id="@+id/main_content" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:isScrollContainer="true"> 

    <android.support.design.widget.AppBarLayout 
     android:id="@+id/appbar" 
     android:layout_width="match_parent" 
     android:layout_height="wrap_content" 
     android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"> 

     <ImageView 
      android:id="@+id/imageView" 
      android:layout_width="match_parent" 
      android:layout_height="@dimen/detail_image_height" 
      android:background="?attr/colorPrimary" 
      android:fitsSystemWindows="true" 
      android:adjustViewBounds="true" 
      android:scaleType="centerCrop" 
      app:layout_scrollFlags="scroll|exitUntilCollapsed" /> 

     <android.support.v7.widget.Toolbar 
      android:id="@+id/toolbar" 
      android:layout_width="match_parent" 
      android:layout_height="?attr/actionBarSize" 
      android:background="?attr/colorPrimary" 
      app:popupTheme="@style/ThemeOverlay.AppCompat.Light" /> 

     <RelativeLayout 
      android:id="@+id/relativeLayout" 
      android:layout_width="fill_parent" 
      android:layout_height="wrap_content" 
      android:layout_centerVertical="true" 
      android:layout_marginLeft="@dimen/activity_horizontal_margin" 
      android:layout_marginRight="@dimen/activity_horizontal_margin" 
      android:background="?attr/colorPrimary" 
      android:minHeight="80dp"> 

      (...) 

     </RelativeLayout> 

    </android.support.design.widget.AppBarLayout> 

    <android.support.v4.widget.NestedScrollView 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" 
     android:layout_centerHorizontal="true" 
     app:layout_behavior="@string/appbar_scrolling_view_behavior"> 

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

      (...) 

     </LinearLayout> 
    </android.support.v4.widget.NestedScrollView> 

</android.support.design.widget.CoordinatorLayout> 

Что я делаю неправильно? Заранее спасибо.

Answer 1

Я не смог полностью исправить это поведение, но нашел что-то, что помогло с прокруткой вверх. Он основан на this answer в потоке SO о том, что он бросает координаторLayout. Сначала создайте класс, который расширяет AppBarLayout.Behavior.

/** 
* This "fixes" the weird scroll behavior with CoordinatorLayouts with NestedScrollViews when scrolling up. 
* This is based on https://stackoverflow.com/questions/30923889/flinging-with-recyclerview-appbarlayout 
*/ 
@SuppressWarnings("unused") 
public class CoordinatorFlingBehavior extends AppBarLayout.Behavior { 
    private static final String TAG = "CoordinatorFling"; 

    public CoordinatorFlingBehavior() { 
    } 

    public CoordinatorFlingBehavior(Context context, AttributeSet attrs) { 
     super(context, attrs); 
    } 

    @Override 
    public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child, View target, float velocityX, float velocityY, boolean consumed) { 
     // Passing false for consumed will make the AppBarLayout fling everything and pull down the expandable stuff 
     if (target instanceof NestedScrollView && velocityY < 0) { 
      final NestedScrollView scrollView = (NestedScrollView) target; 
      int scrollY = scrollView.getScrollY(); 

      // Note the ! in front 
      consumed = !(scrollY < target.getContext().getResources().getDimensionPixelSize(R.dimen.flingThreshold) // if below threshold, fling 
       || isScrollingUpFast(scrollY, velocityY)); // Or if moving quickly, fling 

      Log.v(TAG, "onNestedFling: scrollY = " + scrollY + ", velocityY = " + velocityY + ", flinging = " + !consumed); 
     } 
     return super.onNestedFling(coordinatorLayout, child, target, velocityX, velocityY, consumed); 
    } 

    /** 
    * This uses the log of the velocity because constants make it too easy to uncouple the CoordinatorLayout - the AppBarLayout and the NestedScrollView - when scrollPosition is small. 
    * 
    * @param scrollPosition - of the NestedScrollView target 
    * @param velocityY  - Y velocity. Should be negative, because scrolling up is negative. However, a positive value won't crash this method. 
    * @return true if scrolling up fast 
    */ 
    private boolean isScrollingUpFast(int scrollPosition, float velocityY) { 
     float positiveVelocityY = Math.abs(velocityY); 

     double calculation = scrollPosition * Math.log(positiveVelocityY); 

     return positiveVelocityY > calculation; 
    } 

} 

Затем добавьте следующую строку в XML-блок AppBarLayout (заменяющий CompanyName и пакеты с что вы используете):

app:layout_behavior="com.companyname.packages.CoordinatorFlingBehavior"