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目前我正在使用这个库中的底页，我想在滑动底页时实现像这个谷歌地图这样的图像动画 ，我想按照显示的图像一起滑动 imageview，我已经使用这个链接寻求帮助但没有得到. 我已经尝试了这么多小时，但找不到任何解决方案，任何帮助都将不胜感激。提前致谢..

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2 回答 2

20

您可以修改BehaviorBottomSheet、ImageView、ToolBars 和 FAB 的默认值。

首先，您需要向 BottomSheetBehavior 添加一个状态。您可以通过以下步骤来做到这一点：

  1. 创建一个 Java 类并从CoordinatorLayout.Behavior<V>
  2. 将粘贴代码从默认BottomSheetBehavior文件复制到新文件。

  3. clampViewPositionVertical使用以下代码修改方法：

    @Override
public int clampViewPositionVertical(View child, int top, int dy) {
    return constrain(top, mMinOffset, mHideable ? mParentHeight : mMaxOffset);
}
int constrain(int amount, int low, int high) {
return amount < low ? low : (amount > high ? high : amount);
}

  4. 添加新状态

    public static final int STATE_ANCHOR_POINT = X;

  5. 修改下一个方法：onLayoutChild、、onStopNestedScroll和BottomSheetBehavior<V> from(V view)（setState可选）



我将添加那些修改过的方法和示例项目的链接，您可以在其中看到所有自定义行为

public boolean onLayoutChild(CoordinatorLayout parent, V child, int layoutDirection) {
    // First let the parent lay it out
    if (mState != STATE_DRAGGING && mState != STATE_SETTLING) {
        if (ViewCompat.getFitsSystemWindows(parent) &&
                !ViewCompat.getFitsSystemWindows(child)) {
            ViewCompat.setFitsSystemWindows(child, true);
        }
        parent.onLayoutChild(child, layoutDirection);
    }
    // Offset the bottom sheet
    mParentHeight = parent.getHeight();
    mMinOffset = Math.max(0, mParentHeight - child.getHeight());
    mMaxOffset = Math.max(mParentHeight - mPeekHeight, mMinOffset);

    //if (mState == STATE_EXPANDED) {
    //    ViewCompat.offsetTopAndBottom(child, mMinOffset);
    //} else if (mHideable && mState == STATE_HIDDEN...
    if (mState == STATE_ANCHOR_POINT) {
        ViewCompat.offsetTopAndBottom(child, mAnchorPoint);
    } else if (mState == STATE_EXPANDED) {
        ViewCompat.offsetTopAndBottom(child, mMinOffset);
    } else if (mHideable && mState == STATE_HIDDEN) {
        ViewCompat.offsetTopAndBottom(child, mParentHeight);
    } else if (mState == STATE_COLLAPSED) {
        ViewCompat.offsetTopAndBottom(child, mMaxOffset);
    }
    if (mViewDragHelper == null) {
        mViewDragHelper = ViewDragHelper.create(parent, mDragCallback);
    }
    mViewRef = new WeakReference<>(child);
    mNestedScrollingChildRef = new WeakReference<>(findScrollingChild(child));
    return true;
}


public void onStopNestedScroll(CoordinatorLayout coordinatorLayout, V child, View target) {
    if (child.getTop() == mMinOffset) {
        setStateInternal(STATE_EXPANDED);
        return;
    }
    if (target != mNestedScrollingChildRef.get() || !mNestedScrolled) {
        return;
    }
    int top;
    int targetState;
    if (mLastNestedScrollDy > 0) {
        //top = mMinOffset;
        //targetState = STATE_EXPANDED;
        int currentTop = child.getTop();
        if (currentTop > mAnchorPoint) {
            top = mAnchorPoint;
            targetState = STATE_ANCHOR_POINT;
        }
        else {
            top = mMinOffset;
            targetState = STATE_EXPANDED;
        }
    } else if (mHideable && shouldHide(child, getYVelocity())) {
        top = mParentHeight;
        targetState = STATE_HIDDEN;
    } else if (mLastNestedScrollDy == 0) {
        int currentTop = child.getTop();
        if (Math.abs(currentTop - mMinOffset) < Math.abs(currentTop - mMaxOffset)) {
            top = mMinOffset;
            targetState = STATE_EXPANDED;
        } else {
            top = mMaxOffset;
            targetState = STATE_COLLAPSED;
        }
    } else {
        //top = mMaxOffset;
        //targetState = STATE_COLLAPSED;
        int currentTop = child.getTop();
        if (currentTop > mAnchorPoint) {
            top = mMaxOffset;
            targetState = STATE_COLLAPSED;
        }
        else {
            top = mAnchorPoint;
            targetState = STATE_ANCHOR_POINT;
        }
    }
    if (mViewDragHelper.smoothSlideViewTo(child, child.getLeft(), top)) {
        setStateInternal(STATE_SETTLING);
        ViewCompat.postOnAnimation(child, new SettleRunnable(child, targetState));
    } else {
        setStateInternal(targetState);
    }
    mNestedScrolled = false;
}

public final void setState(@State int state) {
    if (state == mState) {
        return;
    }
    if (mViewRef == null) {
        // The view is not laid out yet; modify mState and let onLayoutChild handle it later
        /**
         * New behavior (added: state == STATE_ANCHOR_POINT ||)
         */
        if (state == STATE_COLLAPSED || state == STATE_EXPANDED ||
                state == STATE_ANCHOR_POINT ||
                (mHideable && state == STATE_HIDDEN)) {
            mState = state;
        }
        return;
    }
    V child = mViewRef.get();
    if (child == null) {
        return;
    }
    int top;
    if (state == STATE_COLLAPSED) {
        top = mMaxOffset;
    } else if (state == STATE_ANCHOR_POINT) {
        top = mAnchorPoint;
    } else if (state == STATE_EXPANDED) {
        top = mMinOffset;
    } else if (mHideable && state == STATE_HIDDEN) {
        top = mParentHeight;
    } else {
        throw new IllegalArgumentException("Illegal state argument: " + state);
    }
    setStateInternal(STATE_SETTLING);
    if (mViewDragHelper.smoothSlideViewTo(child, child.getLeft(), top)) {
        ViewCompat.postOnAnimation(child, new SettleRunnable(child, state));
    }
}


public static <V extends View> BottomSheetBehaviorGoogleMapsLike<V> from(V view) {
    ViewGroup.LayoutParams params = view.getLayoutParams();
    if (!(params instanceof CoordinatorLayout.LayoutParams)) {
        throw new IllegalArgumentException("The view is not a child of CoordinatorLayout");
    }
    CoordinatorLayout.Behavior behavior = ((CoordinatorLayout.LayoutParams) params)
            .getBehavior();
    if (!(behavior instanceof BottomSheetBehaviorGoogleMapsLike)) {
        throw new IllegalArgumentException(
                "The view is not associated with BottomSheetBehaviorGoogleMapsLike");
    }
    return (BottomSheetBehaviorGoogleMapsLike<V>) behavior;
}



你甚至可以使用回调behavior.setBottomSheetCallback(new BottomSheetBehaviorGoogleMapsLike.BottomSheetCallback() {....

这是它的样子：
CustomBottomSheetBehavior

于 2016-05-27T03:20:25.710 回答
5

过去 Google 并未在其设计库中提供对 BottomSheet 的支持，但最近在其更新的 API 23.2 中，谷歌揭示了 BottomSheet 的 API。

检查此链接

更新

你的布局

<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:fitsSystemWindows="true">

    <android.support.design.widget.AppBarLayout>

        <android.support.design.widget.CollapsingToolbarLayout>

            <ImageView/>

            <android.support.v7.widget.Toolbar/>

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

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

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

        <LinearLayout>

            //.....

        </LinearLayout>


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

    <FrameLayout
        android:id="@+id/bottom_sheet"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:behavior_hideable="true"
        app:layout_behavior="android.support.design.widget.BottomSheetBehavior">

        //your bottom sheet layout

        </LinearLayout>
    </FrameLayout>


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

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

你的 Java 文件

CoordinatorLayout coordinatorLayout = (CoordinatorLayout) findViewById(R.id.main_content);
// The View with the BottomSheetBehavior
View bottomSheet = coordinatorLayout.findViewById(R.id.bottom_sheet);
final BottomSheetBehavior behavior = BottomSheetBehavior.from(bottomSheet);
behavior.setBottomSheetCallback(new BottomSheetBehavior.BottomSheetCallback() {
    @Override
    public void onStateChanged(@NonNull View bottomSheet, int newState) {
        // React to state change
        Log.e("onStateChanged", "onStateChanged:" + newState);
        if (newState == BottomSheetBehavior.STATE_EXPANDED) {
                fab.setVisibility(View.GONE);
            } else {
                fab.setVisibility(View.VISIBLE);
            }
    }

    @Override
    public void onSlide(@NonNull View bottomSheet, float slideOffset) {
        // React to dragging events
        Log.e("onSlide", "onSlide");
    }
});

behavior.setPeekHeight(100);
于 2016-03-04T10:39:35.647 回答