/*
* Copyright (C) 2015 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.allattentionhere.fabulousfilter.viewpagerbottomsheet;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.design.widget.CoordinatorLayout;
import android.support.v4.os.ParcelableCompat;
import android.support.v4.os.ParcelableCompatCreatorCallbacks;
import android.support.v4.view.AbsSavedState;
import android.support.v4.view.MotionEventCompat;
import android.support.v4.view.NestedScrollingChild;
import android.support.v4.view.VelocityTrackerCompat;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPagerUtils;
import android.support.v4.widget.ViewDragHelper;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import com.allattentionhere.fabulousfilter.R;
import java.lang.ref.WeakReference;
public class ViewPagerBottomSheetBehavior<V extends View> extends CoordinatorLayout.Behavior<V> {
/**
* Callback for monitoring events about bottom sheets.
*/
public abstract static class BottomSheetCallback {
public abstract void onStateChanged(View bottomSheet, int newState);
public abstract void onSlide(View bottomSheet, float slideOffset);
}
/**
* The bottom sheet is dragging.
*/
public static final int STATE_DRAGGING = 1;
/**
* The bottom sheet is settling.
*/
public static final int STATE_SETTLING = 2;
public static final int STATE_EXPANDED = 3;
public static final int STATE_COLLAPSED = 4;
public static final int STATE_HIDDEN = 5;
public @interface State {
}
public static final int PEEK_HEIGHT_AUTO = -1;
private static final float HIDE_THRESHOLD = 0.5f;
private static final float HIDE_FRICTION = 0.1f;
private float mMaximumVelocity;
private int mPeekHeight;
private boolean mPeekHeightAuto;
private int mPeekHeightMin;
int mMinOffset;
int mMaxOffset;
boolean mHideable;
private boolean mSkipCollapsed;
int mState = STATE_COLLAPSED;
ViewDragHelper mViewDragHelper;
private boolean mIgnoreEvents;
private int mLastNestedScrollDy;
private boolean mNestedScrolled;
int mParentHeight;
WeakReference<V> mViewRef;
WeakReference<View> mNestedScrollingChildRef;
private BottomSheetCallback mCallback;
private VelocityTracker mVelocityTracker;
int mActivePointerId;
private int mInitialY;
boolean mTouchingScrollingChild;
public ViewPagerBottomSheetBehavior() {
}
public ViewPagerBottomSheetBehavior(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray a = context.obtainStyledAttributes(attrs,
R.styleable.BottomSheetBehavior_Layout);
TypedValue value = a.peekValue(R.styleable.BottomSheetBehavior_Layout_behavior_peekHeight);
if (value != null && value.data == PEEK_HEIGHT_AUTO) {
setPeekHeight(value.data);
} else {
setPeekHeight(a.getDimensionPixelSize(
R.styleable.BottomSheetBehavior_Layout_behavior_peekHeight, PEEK_HEIGHT_AUTO));
}
setHideable(a.getBoolean(R.styleable.BottomSheetBehavior_Layout_behavior_hideable, false));
setSkipCollapsed(a.getBoolean(R.styleable.BottomSheetBehavior_Layout_behavior_skipCollapsed,
false));
a.recycle();
ViewConfiguration configuration = ViewConfiguration.get(context);
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
}
@Override
public Parcelable onSaveInstanceState(CoordinatorLayout parent, V child) {
return new SavedState(super.onSaveInstanceState(parent, child), mState);
}
@Override
public void onRestoreInstanceState(CoordinatorLayout parent, V child, Parcelable state) {
SavedState ss = (SavedState) state;
super.onRestoreInstanceState(parent, child, ss.getSuperState());
// Intermediate states are restored as collapsed state
if (ss.state == STATE_DRAGGING || ss.state == STATE_SETTLING) {
mState = STATE_COLLAPSED;
} else {
mState = ss.state;
}
}
@Override
public boolean onLayoutChild(CoordinatorLayout parent, V child, int layoutDirection) {
if (ViewCompat.getFitsSystemWindows(parent) && !ViewCompat.getFitsSystemWindows(child)) {
ViewCompat.setFitsSystemWindows(child, true);
}
int savedTop = child.getTop();
// First let the parent lay it out
parent.onLayoutChild(child, layoutDirection);
// Offset the bottom sheet
mParentHeight = parent.getHeight();
int peekHeight;
if (mPeekHeightAuto) {
if (mPeekHeightMin == 0) {
mPeekHeightMin = parent.getResources().getDimensionPixelSize(
R.dimen.design_bottom_sheet_peek_height_min);
}
peekHeight = Math.max(mPeekHeightMin, mParentHeight - parent.getWidth() * 9 / 16);
} else {
peekHeight = mPeekHeight;
}
mMinOffset = Math.max(0, mParentHeight - child.getHeight());
mMaxOffset = Math.max(mParentHeight - peekHeight, mMinOffset);
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);
} else if (mState == STATE_DRAGGING || mState == STATE_SETTLING) {
ViewCompat.offsetTopAndBottom(child, savedTop - child.getTop());
}
if (mViewDragHelper == null) {
mViewDragHelper = ViewDragHelper.create(parent, mDragCallback);
}
mViewRef = new WeakReference<>(child);
mNestedScrollingChildRef = new WeakReference<>(findScrollingChild(child));
return true;
}
@Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, V child, MotionEvent event) {
if (!child.isShown()) {
mIgnoreEvents = true;
return false;
}
int action = MotionEventCompat.getActionMasked(event);
// Record the velocity
if (action == MotionEvent.ACTION_DOWN) {
reset();
}
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
switch (action) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mTouchingScrollingChild = false;
mActivePointerId = MotionEvent.INVALID_POINTER_ID;
// Reset the ignore flag
if (mIgnoreEvents) {
mIgnoreEvents = false;
return false;
}
break;
case MotionEvent.ACTION_DOWN:
int initialX = (int) event.getX();
mInitialY = (int) event.getY();
View scroll = mNestedScrollingChildRef.get();
if (scroll != null && parent.isPointInChildBounds(scroll, initialX, mInitialY)) {
mActivePointerId = event.getPointerId(event.getActionIndex());
mTouchingScrollingChild = true;
}
mIgnoreEvents = mActivePointerId == MotionEvent.INVALID_POINTER_ID &&
!parent.isPointInChildBounds(child, initialX, mInitialY);
break;
}
if (!mIgnoreEvents && mViewDragHelper.shouldInterceptTouchEvent(event)) {
return true;
}
// We have to handle cases that the ViewDragHelper does not capture the bottom sheet because
// it is not the top most view of its parent. This is not necessary when the touch event is
// happening over the scrolling content as nested scrolling logic handles that case.
View scroll = mNestedScrollingChildRef.get();
return action == MotionEvent.ACTION_MOVE && scroll != null &&
!mIgnoreEvents && mState != STATE_DRAGGING &&
!parent.isPointInChildBounds(scroll, (int) event.getX(), (int) event.getY()) &&
Math.abs(mInitialY - event.getY()) > mViewDragHelper.getTouchSlop();
}
@Override
public boolean onTouchEvent(CoordinatorLayout parent, V child, MotionEvent event) {
if (!child.isShown()) {
return false;
}
int action = MotionEventCompat.getActionMasked(event);
if (mState == STATE_DRAGGING && action == MotionEvent.ACTION_DOWN) {
return true;
}
if (mViewDragHelper == null) {
mViewDragHelper = ViewDragHelper.create(parent, mDragCallback);
}
mViewDragHelper.processTouchEvent(event);
// Record the velocity
if (action == MotionEvent.ACTION_DOWN) {
reset();
}
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
// The ViewDragHelper tries to capture only the top-most View. We have to explicitly tell it
// to capture the bottom sheet in case it is not captured and the touch slop is passed.
if (action == MotionEvent.ACTION_MOVE && !mIgnoreEvents) {
if (Math.abs(mInitialY - event.getY()) > mViewDragHelper.getTouchSlop()) {
mViewDragHelper.captureChildView(child, event.getPointerId(event.getActionIndex()));
}
}
return !mIgnoreEvents;
}
@Override
public boolean onStartNestedScroll(CoordinatorLayout coordinatorLayout, V child,
View directTargetChild, View target, int nestedScrollAxes) {
mLastNestedScrollDy = 0;
mNestedScrolled = false;
return (nestedScrollAxes & ViewCompat.SCROLL_AXIS_VERTICAL) != 0;
}
@Override
public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, V child, View target, int dx,
int dy, int[] consumed) {
View scrollingChild = mNestedScrollingChildRef.get();
if (target != scrollingChild) {
return;
}
int currentTop = child.getTop();
int newTop = currentTop - dy;
if (dy > 0) { // Upward
if (newTop < mMinOffset) {
consumed[1] = currentTop - mMinOffset;
ViewCompat.offsetTopAndBottom(child, -consumed[1]);
setStateInternal(STATE_EXPANDED);
} else {
consumed[1] = dy;
ViewCompat.offsetTopAndBottom(child, -dy);
setStateInternal(STATE_DRAGGING);
}
} else if (dy < 0) { // Downward
if (!ViewCompat.canScrollVertically(target, -1)) {
if (newTop <= mMaxOffset || mHideable) {
consumed[1] = dy;
ViewCompat.offsetTopAndBottom(child, -dy);
setStateInternal(STATE_DRAGGING);
} else {
consumed[1] = currentTop - mMaxOffset;
ViewCompat.offsetTopAndBottom(child, -consumed[1]);
setStateInternal(STATE_COLLAPSED);
}
}
}
dispatchOnSlide(child.getTop());
mLastNestedScrollDy = dy;
mNestedScrolled = true;
}
@Override
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;
} 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;
}
if (mViewDragHelper.smoothSlideViewTo(child, child.getLeft(), top)) {
setStateInternal(STATE_SETTLING);
ViewCompat.postOnAnimation(child, new SettleRunnable(child, targetState));
} else {
setStateInternal(targetState);
}
mNestedScrolled = false;
}
@Override
public boolean onNestedPreFling(CoordinatorLayout coordinatorLayout, V child, View target,
float velocityX, float velocityY) {
return target == mNestedScrollingChildRef.get() &&
(mState != STATE_EXPANDED ||
super.onNestedPreFling(coordinatorLayout, child, target,
velocityX, velocityY));
}
void invalidateScrollingChild() {
final View scrollingChild = findScrollingChild(mViewRef.get());
mNestedScrollingChildRef = new WeakReference<>(scrollingChild);
}
public final void setPeekHeight(int peekHeight) {
boolean layout = false;
if (peekHeight == PEEK_HEIGHT_AUTO) {
if (!mPeekHeightAuto) {
mPeekHeightAuto = true;
layout = true;
}
} else if (mPeekHeightAuto || mPeekHeight != peekHeight) {
mPeekHeightAuto = false;
mPeekHeight = Math.max(0, peekHeight);
mMaxOffset = mParentHeight - peekHeight;
layout = true;
}
if (layout && mState == STATE_COLLAPSED && mViewRef != null) {
V view = mViewRef.get();
if (view != null) {
view.requestLayout();
}
}
}
public final int getPeekHeight() {
return mPeekHeightAuto ? PEEK_HEIGHT_AUTO : mPeekHeight;
}
public void setHideable(boolean hideable) {
mHideable = hideable;
}
public boolean isHideable() {
return mHideable;
}
public void setSkipCollapsed(boolean skipCollapsed) {
mSkipCollapsed = skipCollapsed;
}
public boolean getSkipCollapsed() {
return mSkipCollapsed;
}
public void setBottomSheetCallback(BottomSheetCallback callback) {
mCallback = callback;
}
public final void setState(final int state) {
if (state == mState) {
return;
}
if (mViewRef == null) {
// The view is not laid out yet; modify mState and let onLayoutChild handle it later
if (state == STATE_COLLAPSED || state == STATE_EXPANDED ||
(mHideable && state == STATE_HIDDEN)) {
mState = state;
}
return;
}
final V child = mViewRef.get();
if (child == null) {
return;
}
// Start the animation; wait until a pending layout if there is one.
ViewParent parent = child.getParent();
if (parent != null && parent.isLayoutRequested() && ViewCompat.isAttachedToWindow(child)) {
child.post(new Runnable() {
@Override
public void run() {
startSettlingAnimation(child, state);
}
});
} else {
startSettlingAnimation(child, state);
}
}
public final int getState() {
return mState;
}
void setStateInternal(int state) {
if (mState == state) {
return;
}
mState = state;
View bottomSheet = mViewRef.get();
if (bottomSheet != null && mCallback != null) {
mCallback.onStateChanged(bottomSheet, state);
}
}
private void reset() {
mActivePointerId = ViewDragHelper.INVALID_POINTER;
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
boolean shouldHide(View child, float yvel) {
if (mSkipCollapsed) {
return true;
}
if (child.getTop() < mMaxOffset) {
// It should not hide, but collapse.
return false;
}
final float newTop = child.getTop() + yvel * HIDE_FRICTION;
return Math.abs(newTop - mMaxOffset) / (float) mPeekHeight > HIDE_THRESHOLD;
}
private View findScrollingChild(View view) {
if (view instanceof NestedScrollingChild) {
return view;
}
if (view instanceof ViewPager) {
ViewPager viewPager = (ViewPager) view;
View currentViewPagerChild = ViewPagerUtils.getCurrentView(viewPager);
View scrollingChild = findScrollingChild(currentViewPagerChild);
if (scrollingChild != null) {
return scrollingChild;
}
} else if (view instanceof ViewGroup) {
ViewGroup group = (ViewGroup) view;
for (int i = 0, count = group.getChildCount(); i < count; i++) {
View scrollingChild = findScrollingChild(group.getChildAt(i));
if (scrollingChild != null) {
return scrollingChild;
}
}
}
return null;
}
private float getYVelocity() {
mVelocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
return VelocityTrackerCompat.getYVelocity(mVelocityTracker, mActivePointerId);
}
void startSettlingAnimation(View child, int state) {
int top;
if (state == STATE_COLLAPSED) {
top = mMaxOffset;
} 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));
}
}
private final ViewDragHelper.Callback mDragCallback = new ViewDragHelper.Callback() {
@Override
public boolean tryCaptureView(View child, int pointerId) {
if (mState == STATE_DRAGGING) {
return false;
}
if (mTouchingScrollingChild) {
return false;
}
if (mState == STATE_EXPANDED && mActivePointerId == pointerId) {
View scroll = mNestedScrollingChildRef.get();
if (scroll != null && ViewCompat.canScrollVertically(scroll, -1)) {
// Let the content scroll up
return false;
}
}
return mViewRef != null && mViewRef.get() == child;
}
@Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
dispatchOnSlide(top);
}
@Override
public void onViewDragStateChanged(int state) {
if (state == ViewDragHelper.STATE_DRAGGING) {
setStateInternal(STATE_DRAGGING);
}
}
@Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
int top;
int targetState;
if (yvel < 0) { // Moving up
top = mMinOffset;
targetState = STATE_EXPANDED;
} else if (mHideable && shouldHide(releasedChild, yvel)) {
top = mParentHeight;
targetState = STATE_HIDDEN;
} else if (yvel == 0.f) {
int currentTop = releasedChild.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;
}
if (mViewDragHelper.settleCapturedViewAt(releasedChild.getLeft(), top)) {
setStateInternal(STATE_SETTLING);
ViewCompat.postOnAnimation(releasedChild,
new SettleRunnable(releasedChild, targetState));
} else {
setStateInternal(targetState);
}
}
@Override
public int clampViewPositionVertical(View child, int top, int dy) {
return constrain(top, mMinOffset, mHideable ? mParentHeight : mMaxOffset);
}
private int constrain(int amount, int low, int high) {
return amount < low ? low : (amount > high ? high : amount);
}
@Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
return child.getLeft();
}
@Override
public int getViewVerticalDragRange(View child) {
if (mHideable) {
return mParentHeight - mMinOffset;
} else {
return mMaxOffset - mMinOffset;
}
}
};
void dispatchOnSlide(int top) {
View bottomSheet = mViewRef.get();
if (bottomSheet != null && mCallback != null) {
if (top > mMaxOffset) {
mCallback.onSlide(bottomSheet, (float) (mMaxOffset - top) /
(mParentHeight - mMaxOffset));
} else {
mCallback.onSlide(bottomSheet,
(float) (mMaxOffset - top) / ((mMaxOffset - mMinOffset)));
}
}
}
int getPeekHeightMin() {
return mPeekHeightMin;
}
private class SettleRunnable implements Runnable {
private final View mView;
private final int mTargetState;
SettleRunnable(View view, int targetState) {
mView = view;
mTargetState = targetState;
}
@Override
public void run() {
if (mViewDragHelper != null && mViewDragHelper.continueSettling(true)) {
ViewCompat.postOnAnimation(mView, this);
} else {
setStateInternal(mTargetState);
}
}
}
protected static class SavedState extends AbsSavedState {
final int state;
public SavedState(Parcel source) {
this(source, null);
}
public SavedState(Parcel source, ClassLoader loader) {
super(source, loader);
//noinspection ResourceType
state = source.readInt();
}
public SavedState(Parcelable superState, int state) {
super(superState);
this.state = state;
}
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeInt(state);
}
public static final Creator<SavedState> CREATOR = ParcelableCompat.newCreator(
new ParcelableCompatCreatorCallbacks<SavedState>() {
@Override
public SavedState createFromParcel(Parcel in, ClassLoader loader) {
return new SavedState(in, loader);
}
@Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
});
}
@SuppressWarnings("unchecked")
public static <V extends View> ViewPagerBottomSheetBehavior<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 ViewPagerBottomSheetBehavior)) {
throw new IllegalArgumentException(
"The view is not associated with ViewPagerBottomSheetBehavior");
}
return (ViewPagerBottomSheetBehavior<V>) behavior;
}
}
