MiguelHincapieC MiguelHincapieC - 6 months ago 186
Android Question

Sliding up image with Official bottomSheet like google maps

I want to accomplish the same behavior that google maps has:



like you can see in this gif

I have already the Official bottomSheet working (even inside a tab and view pager).

What is making me going crazy is how to achieve the image behavior that come up from the BottomSheet when sliding up using official bottomSheet?.


I have tried using anchor like FAB with no success.

I read something about using a scroll listener but ppl said its not smooth and faster like google maps.



My XML (I don't think its going to help but anyway):



<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.MasterActivity">

<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">

<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/AppTheme.PopupOverlay"
app:layout_scrollFlags="scroll|enterAlways|snap">

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="?android:attr/borderlessButtonStyle"
android:text="Departure"
android:layout_gravity="center"
android:id="@+id/buttonToolBar"
/>


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

<android.support.design.widget.TabLayout
android:id="@+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabBackground="@android:color/white"
app:tabTextColor="@color/colorAccent"
app:tabSelectedTextColor="@color/colorAccent"/>

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

<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />


<android.support.v4.widget.NestedScrollView
android:id="@+id/asdf"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
app:behavior_peekHeight="100dp"
android:fitsSystemWindows="true"
app:layout_behavior="android.support.design.widget.BottomSheetBehavior">

<LinearLayout
android:id="@+id/qwert"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="16dp"
android:background="@android:color/white"
android:padding="15dp">

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="BOOTOMSHEET TITLE"
android:textAppearance="@style/TextAppearance.AppCompat.Title" />

<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Button1"/>

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="text 2"
android:layout_margin="10dp"/>

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="text 3"
android:layout_margin="10dp"/>

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="text 4"
android:layout_margin="10dp"/>


<FrameLayout
android:layout_width="match_parent"
android:layout_height="320dp"
android:background="@color/colorAccent">

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Your remaining content here"
android:textColor="@android:color/white" />

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


<android.support.design.widget.FloatingActionButton
android:layout_height="wrap_content"
android:layout_width="wrap_content"
app:layout_anchor="@id/asdf"
app:layout_anchorGravity="top|right|end"
android:src="@drawable/abc_ic_search_api_mtrl_alpha_copy"
android:layout_margin="@dimen/fab_margin"
android:clickable="true"/>

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

Answer

You can do it modifying default Behavior for BottomSheet, ImageView, ToolBars and FAB.

First of all you need to add one more state to BottomSheetBehavior. You can do it with following steps:

  1. Create a Java class and extend it from CoordinatorLayout.Behavior<V>
  2. Copy paste code from default BottomSheetBehavior file to your new one.
  3. Modify the method clampViewPositionVertical with the following code:

    @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. Add a new state

    public static final int STATE_ANCHOR_POINT = X;

  5. Modify the next methods: onLayoutChild, onStopNestedScroll, BottomSheetBehavior<V> from(V view) and setState (optional)



I'm going to add those modified methods and a link to the example project in where you can see all Custom Behaviors

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;
}



You can even use callbacks with behavior.setBottomSheetCallback(new BottomSheetBehaviorGoogleMapsLike.BottomSheetCallback() {....

And here is how its looks like:
[CustomBottomSheetBehavior]