Java tutorial
/* * Copyright (C) 2014 MyMenu, Inc. * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see [http://www.gnu.org/licenses/]. */ package ca.mymenuapp.ui.widgets; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PixelFormat; import android.graphics.Rect; import android.graphics.drawable.Drawable; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.ViewCompat; import android.support.v4.widget.ViewDragHelper; import android.util.AttributeSet; import android.util.Log; import android.view.Gravity; import android.view.MotionEvent; import android.view.SoundEffectConstants; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewGroup; import android.view.accessibility.AccessibilityEvent; import ca.mymenuapp.R; public class SlidingUpPanelLayout extends ViewGroup { private static final String TAG = SlidingUpPanelLayout.class.getSimpleName(); /** * Default peeking out panel height */ private static final int DEFAULT_PANEL_HEIGHT = 68; // dp; /** * Default height of the shadow above the peeking out panel */ private static final int DEFAULT_SHADOW_HEIGHT = 4; // dp; /** * If no fade color is given by default it will fade to 80% gray. */ private static final int DEFAULT_FADE_COLOR = 0x99000000; /** * Default Minimum velocity that will be detected as a fling */ private static final int DEFAULT_MIN_FLING_VELOCITY = 400; // dips per second /** * Default attributes for layout */ private static final int[] DEFAULT_ATTRS = new int[] { android.R.attr.gravity }; /** * Minimum velocity that will be detected as a fling */ private int mMinFlingVelocity = DEFAULT_MIN_FLING_VELOCITY; /** * The fade color used for the panel covered by the slider. 0 = no fading. */ private int mCoveredFadeColor = DEFAULT_FADE_COLOR; /** * The paint used to dim the main layout when sliding */ private final Paint mCoveredFadePaint = new Paint(); /** * Drawable used to draw the shadow between panes. */ private Drawable mShadowDrawable; /** * The size of the overhang in pixels. */ private int mPanelHeight = -1; /** * The size of the shadow in pixels. */ private int mShadowHeight = -1; /** * True if the collapsed panel should be dragged up. */ private boolean mIsSlidingUp; /** * True if a panel can slide with the current measurements */ private boolean mCanSlide; /** * If provided, the panel can be dragged by only this view. Otherwise, the entire panel can be * used for dragging. */ private View mDragView; /** * If provided, the panel can be dragged by only this view. Otherwise, the entire panel can be * used for dragging. */ private int mDragViewResId = -1; /** * The child view that can slide, if any. */ private View mSlideableView; /** * Current state of the slideable view. */ private enum SlideState { EXPANDED, COLLAPSED, ANCHORED } private SlideState mSlideState = SlideState.COLLAPSED; /** * How far the panel is offset from its expanded position. * range [0, 1] where 0 = expanded, 1 = collapsed. */ private float mSlideOffset; /** * How far in pixels the slideable panel may move. */ private int mSlideRange; /** * A panel view is locked into internal scrolling or another condition that * is preventing a drag. */ private boolean mIsUnableToDrag; /** * Flag indicating that sliding feature is enabled\disabled */ private boolean mIsSlidingEnabled; /** * Flag indicating if a drag view can have its own touch events. If set * to true, a drag view can scroll horizontally and have its own click listener. * * Default is set to false. */ private boolean mIsUsingDragViewTouchEvents; /** * Threshold to tell if there was a scroll touch event. */ private final int mScrollTouchSlop; private float mInitialMotionX; private float mInitialMotionY; private float mAnchorPoint = 0.f; private PanelSlideListener mPanelSlideListener; private final ViewDragHelper mDragHelper; /** * Stores whether or not the pane was expanded the last time it was slideable. * If expand/collapse operations are invoked this state is modified. Used by * instance state save/restore. */ private boolean mFirstLayout = true; private final Rect mTmpRect = new Rect(); /** * Listener for monitoring events about sliding panes. */ public interface PanelSlideListener { /** * Called when a sliding pane's position changes. * * @param panel The child view that was moved * @param slideOffset The new offset of this sliding pane within its range, from 0-1 */ public void onPanelSlide(View panel, float slideOffset); /** * Called when a sliding pane becomes slid completely collapsed. The pane may or may not * be interactive at this point depending on if it's shown or hidden * * @param panel The child view that was slid to an collapsed position, revealing other panes */ public void onPanelCollapsed(View panel); /** * Called when a sliding pane becomes slid completely expanded. The pane is now guaranteed * to be interactive. It may now obscure other views in the layout. * * @param panel The child view that was slid to a expanded position */ public void onPanelExpanded(View panel); public void onPanelAnchored(View panel); } /** * No-op stubs for {@link PanelSlideListener}. If you only want to implement a subset * of the listener methods you can extend this instead of implement the full interface. */ public static class SimplePanelSlideListener implements PanelSlideListener { @Override public void onPanelSlide(View panel, float slideOffset) { } @Override public void onPanelCollapsed(View panel) { } @Override public void onPanelExpanded(View panel) { } @Override public void onPanelAnchored(View panel) { } } public SlidingUpPanelLayout(Context context) { this(context, null); } public SlidingUpPanelLayout(Context context, AttributeSet attrs) { this(context, attrs, 0); } public SlidingUpPanelLayout(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); if (attrs != null) { TypedArray defAttrs = context.obtainStyledAttributes(attrs, DEFAULT_ATTRS); if (defAttrs != null) { int gravity = defAttrs.getInt(0, Gravity.NO_GRAVITY); if (gravity != Gravity.TOP && gravity != Gravity.BOTTOM) { throw new IllegalArgumentException("layout_gravity must be set to either top or bottom"); } mIsSlidingUp = gravity == Gravity.BOTTOM; } defAttrs.recycle(); TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.SlidingUpPanelLayout); if (ta != null) { mPanelHeight = ta.getDimensionPixelSize(R.styleable.SlidingUpPanelLayout_collapsedHeight, -1); mShadowHeight = ta.getDimensionPixelSize(R.styleable.SlidingUpPanelLayout_shadowHeight, -1); mMinFlingVelocity = ta.getInt(R.styleable.SlidingUpPanelLayout_flingVelocity, DEFAULT_MIN_FLING_VELOCITY); mCoveredFadeColor = ta.getColor(R.styleable.SlidingUpPanelLayout_fadeColor, DEFAULT_FADE_COLOR); mDragViewResId = ta.getResourceId(R.styleable.SlidingUpPanelLayout_dragView, -1); } ta.recycle(); } final float density = context.getResources().getDisplayMetrics().density; if (mPanelHeight == -1) { mPanelHeight = (int) (DEFAULT_PANEL_HEIGHT * density + 0.5f); } if (mShadowHeight == -1) { mShadowHeight = (int) (DEFAULT_SHADOW_HEIGHT * density + 0.5f); } setWillNotDraw(false); mDragHelper = ViewDragHelper.create(this, 0.5f, new DragHelperCallback()); mDragHelper.setMinVelocity(mMinFlingVelocity * density); mCanSlide = true; mIsSlidingEnabled = true; ViewConfiguration vc = ViewConfiguration.get(context); mScrollTouchSlop = vc.getScaledTouchSlop(); } /** * Set the Drag View after the view is inflated */ @Override protected void onFinishInflate() { super.onFinishInflate(); if (mDragViewResId != -1) { mDragView = findViewById(mDragViewResId); } } /** * Set the color used to fade the pane covered by the sliding pane out when the pane * will become fully covered in the expanded state. * * @param color An ARGB-packed color value */ public void setCoveredFadeColor(int color) { mCoveredFadeColor = color; invalidate(); } /** * @return The ARGB-packed color value used to fade the fixed pane */ public int getCoveredFadeColor() { return mCoveredFadeColor; } /** * Set the collapsed panel height in pixels * * @param val A height in pixels */ public void setPanelHeight(int val) { mPanelHeight = val; requestLayout(); } /** * @return The current collapsed panel height */ public int getPanelHeight() { return mPanelHeight; } public void setPanelSlideListener(PanelSlideListener listener) { mPanelSlideListener = listener; } /** * Set the draggable view portion. Use to null, to allow the whole panel to be draggable * * @param dragView A view that will be used to drag the panel. */ public void setDragView(View dragView) { mDragView = dragView; } /** * Set an anchor point where the panel can stop during sliding * * @param anchorPoint A value between 0 and 1, determining the position of the anchor point * starting from the top of the layout. */ public void setAnchorPoint(float anchorPoint) { if (anchorPoint > 0 && anchorPoint < 1) mAnchorPoint = anchorPoint; } /** * Set the shadow for the sliding panel */ public void setShadowDrawable(Drawable drawable) { mShadowDrawable = drawable; } void dispatchOnPanelSlide(View panel) { if (mPanelSlideListener != null) { mPanelSlideListener.onPanelSlide(panel, mSlideOffset); } } void dispatchOnPanelExpanded(View panel) { if (mPanelSlideListener != null) { mPanelSlideListener.onPanelExpanded(panel); } sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED); } void dispatchOnPanelCollapsed(View panel) { if (mPanelSlideListener != null) { mPanelSlideListener.onPanelCollapsed(panel); } sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED); } void dispatchOnPanelAnchored(View panel) { if (mPanelSlideListener != null) { mPanelSlideListener.onPanelAnchored(panel); } sendAccessibilityEvent(AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED); } void updateObscuredViewVisibility() { if (getChildCount() == 0) { return; } final int leftBound = getPaddingLeft(); final int rightBound = getWidth() - getPaddingRight(); final int topBound = getPaddingTop(); final int bottomBound = getHeight() - getPaddingBottom(); final int left; final int right; final int top; final int bottom; if (mSlideableView != null && hasOpaqueBackground(mSlideableView)) { left = mSlideableView.getLeft(); right = mSlideableView.getRight(); top = mSlideableView.getTop(); bottom = mSlideableView.getBottom(); } else { left = right = top = bottom = 0; } View child = getChildAt(0); final int clampedChildLeft = Math.max(leftBound, child.getLeft()); final int clampedChildTop = Math.max(topBound, child.getTop()); final int clampedChildRight = Math.min(rightBound, child.getRight()); final int clampedChildBottom = Math.min(bottomBound, child.getBottom()); final int vis; if (clampedChildLeft >= left && clampedChildTop >= top && clampedChildRight <= right && clampedChildBottom <= bottom) { vis = INVISIBLE; } else { vis = VISIBLE; } child.setVisibility(vis); } void setAllChildrenVisible() { for (int i = 0, childCount = getChildCount(); i < childCount; i++) { final View child = getChildAt(i); if (child.getVisibility() == INVISIBLE) { child.setVisibility(VISIBLE); } } } private static boolean hasOpaqueBackground(View v) { final Drawable bg = v.getBackground(); if (bg != null) { return bg.getOpacity() == PixelFormat.OPAQUE; } return false; } @Override protected void onAttachedToWindow() { super.onAttachedToWindow(); mFirstLayout = true; } @Override protected void onDetachedFromWindow() { super.onDetachedFromWindow(); mFirstLayout = true; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { final int widthMode = MeasureSpec.getMode(widthMeasureSpec); final int widthSize = MeasureSpec.getSize(widthMeasureSpec); final int heightMode = MeasureSpec.getMode(heightMeasureSpec); final int heightSize = MeasureSpec.getSize(heightMeasureSpec); if (widthMode != MeasureSpec.EXACTLY) { throw new IllegalStateException("Width must have an exact value or MATCH_PARENT"); } else if (heightMode != MeasureSpec.EXACTLY) { throw new IllegalStateException("Height must have an exact value or MATCH_PARENT"); } int layoutHeight = heightSize - getPaddingTop() - getPaddingBottom(); int panelHeight = mPanelHeight; final int childCount = getChildCount(); if (childCount > 2) { Log.e(TAG, "onMeasure: More than two child views are not supported."); } else if (getChildAt(1).getVisibility() == GONE) { panelHeight = 0; } // We'll find the current one below. mSlideableView = null; mCanSlide = false; // First pass. Measure based on child LayoutParams width/height. for (int i = 0; i < childCount; i++) { final View child = getChildAt(i); final LayoutParams lp = (LayoutParams) child.getLayoutParams(); int height = layoutHeight; if (child.getVisibility() == GONE) { lp.dimWhenOffset = false; continue; } if (i == 1) { lp.slideable = true; lp.dimWhenOffset = true; mSlideableView = child; mCanSlide = true; } else { height -= panelHeight; } int childWidthSpec; if (lp.width == LayoutParams.WRAP_CONTENT) { childWidthSpec = MeasureSpec.makeMeasureSpec(widthSize, MeasureSpec.AT_MOST); } else if (lp.width == LayoutParams.MATCH_PARENT) { childWidthSpec = MeasureSpec.makeMeasureSpec(widthSize, MeasureSpec.EXACTLY); } else { childWidthSpec = MeasureSpec.makeMeasureSpec(lp.width, MeasureSpec.EXACTLY); } int childHeightSpec; if (lp.height == LayoutParams.WRAP_CONTENT) { childHeightSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.AT_MOST); } else if (lp.height == LayoutParams.MATCH_PARENT) { childHeightSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(lp.height, MeasureSpec.EXACTLY); } child.measure(childWidthSpec, childHeightSpec); } setMeasuredDimension(widthSize, heightSize); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { final int paddingLeft = getPaddingLeft(); final int paddingTop = getPaddingTop(); final int slidingTop = getSlidingTop(); final int childCount = getChildCount(); if (mFirstLayout) { switch (mSlideState) { case EXPANDED: mSlideOffset = mCanSlide ? 0.f : 1.f; break; case ANCHORED: mSlideOffset = mCanSlide ? mAnchorPoint : 1.f; break; default: mSlideOffset = 1.f; break; } } for (int i = 0; i < childCount; i++) { final View child = getChildAt(i); if (child.getVisibility() == GONE) { continue; } final LayoutParams lp = (LayoutParams) child.getLayoutParams(); final int childHeight = child.getMeasuredHeight(); if (lp.slideable) { mSlideRange = childHeight - mPanelHeight; } final int childTop; if (mIsSlidingUp) { childTop = lp.slideable ? slidingTop + (int) (mSlideRange * mSlideOffset) : paddingTop; } else { childTop = lp.slideable ? slidingTop - (int) (mSlideRange * mSlideOffset) : paddingTop + mPanelHeight; } final int childBottom = childTop + childHeight; final int childLeft = paddingLeft; final int childRight = childLeft + child.getMeasuredWidth(); child.layout(childLeft, childTop, childRight, childBottom); } if (mFirstLayout) { updateObscuredViewVisibility(); } mFirstLayout = false; } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { super.onSizeChanged(w, h, oldw, oldh); // Recalculate sliding panes and their details if (h != oldh) { mFirstLayout = true; } } /** * Set sliding enabled flag * * @param enabled flag value */ public void setSlidingEnabled(boolean enabled) { mIsSlidingEnabled = enabled; } /** * Set if the drag view can have its own touch events. If set * to true, a drag view can scroll horizontally and have its own click listener. * * Default is set to false. */ public void setEnableDragViewTouchEvents(boolean enabled) { mIsUsingDragViewTouchEvents = enabled; } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { final int action = MotionEventCompat.getActionMasked(ev); if (!mCanSlide || !mIsSlidingEnabled || (mIsUnableToDrag && action != MotionEvent.ACTION_DOWN)) { mDragHelper.cancel(); return super.onInterceptTouchEvent(ev); } if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { mDragHelper.cancel(); return false; } final float x = ev.getX(); final float y = ev.getY(); boolean interceptTap = false; switch (action) { case MotionEvent.ACTION_DOWN: { mIsUnableToDrag = false; mInitialMotionX = x; mInitialMotionY = y; if (isDragViewUnder((int) x, (int) y) && !mIsUsingDragViewTouchEvents) { interceptTap = true; } break; } case MotionEvent.ACTION_MOVE: { final float adx = Math.abs(x - mInitialMotionX); final float ady = Math.abs(y - mInitialMotionY); final int dragSlop = mDragHelper.getTouchSlop(); // Handle any horizontal scrolling on the drag view. if (mIsUsingDragViewTouchEvents) { if (adx > mScrollTouchSlop && ady < mScrollTouchSlop) { return super.onInterceptTouchEvent(ev); } // Intercept the touch if the drag view has any vertical scroll. // onTouchEvent will determine if the view should drag vertically. else if (ady > mScrollTouchSlop) { interceptTap = isDragViewUnder((int) x, (int) y); } } if ((ady > dragSlop && adx > ady) || !isDragViewUnder((int) x, (int) y)) { mDragHelper.cancel(); mIsUnableToDrag = true; return false; } break; } } final boolean interceptForDrag = mDragHelper.shouldInterceptTouchEvent(ev); return interceptForDrag || interceptTap; } @Override public boolean onTouchEvent(MotionEvent ev) { if (!mCanSlide || !mIsSlidingEnabled) { return super.onTouchEvent(ev); } mDragHelper.processTouchEvent(ev); final int action = ev.getAction(); boolean wantTouchEvents = true; switch (action & MotionEventCompat.ACTION_MASK) { case MotionEvent.ACTION_DOWN: { final float x = ev.getX(); final float y = ev.getY(); mInitialMotionX = x; mInitialMotionY = y; break; } case MotionEvent.ACTION_UP: { final float x = ev.getX(); final float y = ev.getY(); final float dx = x - mInitialMotionX; final float dy = y - mInitialMotionY; final int slop = mDragHelper.getTouchSlop(); View dragView = mDragView != null ? mDragView : mSlideableView; if (dx * dx + dy * dy < slop * slop && isDragViewUnder((int) x, (int) y)) { dragView.playSoundEffect(SoundEffectConstants.CLICK); if (!isExpanded() && !isAnchored()) { expandPane(mAnchorPoint); } else { collapsePane(); } break; } break; } } return wantTouchEvents; } private boolean isDragViewUnder(int x, int y) { View dragView = mDragView != null ? mDragView : mSlideableView; if (dragView == null) return false; int[] viewLocation = new int[2]; dragView.getLocationOnScreen(viewLocation); int[] parentLocation = new int[2]; this.getLocationOnScreen(parentLocation); int screenX = parentLocation[0] + x; int screenY = parentLocation[1] + y; return screenX >= viewLocation[0] && screenX < viewLocation[0] + dragView.getWidth() && screenY >= viewLocation[1] && screenY < viewLocation[1] + dragView.getHeight(); } private boolean expandPane(View pane, int initialVelocity, float mSlideOffset) { if (mFirstLayout || smoothSlideTo(mSlideOffset, initialVelocity)) { return true; } return false; } private boolean collapsePane(View pane, int initialVelocity) { if (mFirstLayout || smoothSlideTo(1.f, initialVelocity)) { return true; } return false; } private int getSlidingTop() { if (mSlideableView != null) { return getMeasuredHeight() - getPaddingBottom() - mSlideableView.getMeasuredHeight(); } return getMeasuredHeight() - getPaddingBottom(); } /** * Collapse the sliding pane if it is currently slideable. If first layout * has already completed this will animate. * * @return true if the pane was slideable and is now collapsed/in the process of collapsing */ public boolean collapsePane() { return collapsePane(mSlideableView, 0); } /** * Expand the sliding pane if it is currently slideable. If first layout * has already completed this will animate. * * @return true if the pane was slideable and is now expanded/in the process of expading */ public boolean expandPane() { return expandPane(0); } /** * Partially expand the sliding pane up to a specific offset * * @param mSlideOffset Value between 0 and 1, where 0 is completely expanded. * @return true if the pane was slideable and is now expanded/in the process of expading */ public boolean expandPane(float mSlideOffset) { if (!isPaneVisible()) { showPane(); } return expandPane(mSlideableView, 0, mSlideOffset); } /** * Check if the layout is completely expanded. * * @return true if sliding panels are completely expanded */ public boolean isExpanded() { return mSlideState == SlideState.EXPANDED; } /** * Check if the layout is anchored in an intermediate point. * * @return true if sliding panels are anchored */ public boolean isAnchored() { return mSlideState == SlideState.ANCHORED; } /** * Check if the content in this layout cannot fully fit side by side and therefore * the content pane can be slid back and forth. * * @return true if content in this layout can be expanded */ public boolean isSlideable() { return mCanSlide; } public boolean isPaneVisible() { if (getChildCount() < 2) { return false; } View slidingPane = getChildAt(1); return slidingPane.getVisibility() == View.VISIBLE; } public void showPane() { if (getChildCount() < 2) { return; } View slidingPane = getChildAt(1); slidingPane.setVisibility(View.VISIBLE); requestLayout(); } public void hidePane() { if (mSlideableView == null) { return; } mSlideableView.setVisibility(View.GONE); requestLayout(); } private void onPanelDragged(int newTop) { final int topBound = getSlidingTop(); mSlideOffset = mIsSlidingUp ? (float) (newTop - topBound) / mSlideRange : (float) (topBound - newTop) / mSlideRange; dispatchOnPanelSlide(mSlideableView); } @Override protected boolean drawChild(Canvas canvas, View child, long drawingTime) { final LayoutParams lp = (LayoutParams) child.getLayoutParams(); boolean result; final int save = canvas.save(Canvas.CLIP_SAVE_FLAG); boolean drawScrim = false; if (mCanSlide && !lp.slideable && mSlideableView != null) { // Clip against the slider; no sense drawing what will immediately be covered. canvas.getClipBounds(mTmpRect); if (mIsSlidingUp) { mTmpRect.bottom = Math.min(mTmpRect.bottom, mSlideableView.getTop()); } else { mTmpRect.top = Math.max(mTmpRect.top, mSlideableView.getBottom()); } canvas.clipRect(mTmpRect); if (mSlideOffset < 1) { drawScrim = true; } } result = super.drawChild(canvas, child, drawingTime); canvas.restoreToCount(save); if (drawScrim) { final int baseAlpha = (mCoveredFadeColor & 0xff000000) >>> 24; final int imag = (int) (baseAlpha * (1 - mSlideOffset)); final int color = imag << 24 | (mCoveredFadeColor & 0xffffff); mCoveredFadePaint.setColor(color); canvas.drawRect(mTmpRect, mCoveredFadePaint); } return result; } /** * Smoothly animate mDraggingPane to the target X position within its range. * * @param slideOffset position to animate to * @param velocity initial velocity in case of fling, or 0. */ boolean smoothSlideTo(float slideOffset, int velocity) { if (!mCanSlide) { // Nothing to do. return false; } final int topBound = getSlidingTop(); int y = mIsSlidingUp ? (int) (topBound + slideOffset * mSlideRange) : (int) (topBound - slideOffset * mSlideRange); if (mDragHelper.smoothSlideViewTo(mSlideableView, mSlideableView.getLeft(), y)) { setAllChildrenVisible(); ViewCompat.postInvalidateOnAnimation(this); return true; } return false; } @Override public void computeScroll() { if (mDragHelper.continueSettling(true)) { if (!mCanSlide) { mDragHelper.abort(); return; } ViewCompat.postInvalidateOnAnimation(this); } } @Override public void draw(Canvas c) { super.draw(c); if (mSlideableView == null) { // No need to draw a shadow if we don't have one. return; } final int right = mSlideableView.getRight(); final int top; final int bottom; if (mIsSlidingUp) { top = mSlideableView.getTop() - mShadowHeight; bottom = mSlideableView.getTop(); } else { top = mSlideableView.getBottom(); bottom = mSlideableView.getBottom() + mShadowHeight; } final int left = mSlideableView.getLeft(); if (mShadowDrawable != null) { mShadowDrawable.setBounds(left, top, right, bottom); mShadowDrawable.draw(c); } } /** * Tests scrollability within child views of v given a delta of dx. * * @param v View to test for horizontal scrollability * @param checkV Whether the view v passed should itself be checked for scrollability (true), * or just its children (false). * @param dx Delta scrolled in pixels * @param x X coordinate of the active touch point * @param y Y coordinate of the active touch point * @return true if child views of v can be scrolled by delta of dx. */ protected boolean canScroll(View v, boolean checkV, int dx, int x, int y) { if (v instanceof ViewGroup) { final ViewGroup group = (ViewGroup) v; final int scrollX = v.getScrollX(); final int scrollY = v.getScrollY(); final int count = group.getChildCount(); // Count backwards - let topmost views consume scroll distance first. for (int i = count - 1; i >= 0; i--) { final View child = group.getChildAt(i); if (x + scrollX >= child.getLeft() && x + scrollX < child.getRight() && y + scrollY >= child.getTop() && y + scrollY < child.getBottom() && canScroll(child, true, dx, x + scrollX - child.getLeft(), y + scrollY - child.getTop())) { return true; } } } return checkV && ViewCompat.canScrollHorizontally(v, -dx); } @Override protected ViewGroup.LayoutParams generateDefaultLayoutParams() { return new LayoutParams(); } @Override protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) { return p instanceof MarginLayoutParams ? new LayoutParams((MarginLayoutParams) p) : new LayoutParams(p); } @Override protected boolean checkLayoutParams(ViewGroup.LayoutParams p) { return p instanceof LayoutParams && super.checkLayoutParams(p); } @Override public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) { return new LayoutParams(getContext(), attrs); } @Override protected Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ss.mSlideState = mSlideState; return ss; } @Override protected void onRestoreInstanceState(Parcelable state) { SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); mSlideState = ss.mSlideState; } private class DragHelperCallback extends ViewDragHelper.Callback { @Override public boolean tryCaptureView(View child, int pointerId) { if (mIsUnableToDrag) { return false; } return ((LayoutParams) child.getLayoutParams()).slideable; } @Override public void onViewDragStateChanged(int state) { int anchoredTop = (int) (mAnchorPoint * mSlideRange); if (mDragHelper.getViewDragState() == ViewDragHelper.STATE_IDLE) { if (mSlideOffset == 0) { if (mSlideState != SlideState.EXPANDED) { updateObscuredViewVisibility(); dispatchOnPanelExpanded(mSlideableView); mSlideState = SlideState.EXPANDED; } } else if (mSlideOffset == (float) anchoredTop / (float) mSlideRange) { if (mSlideState != SlideState.ANCHORED) { updateObscuredViewVisibility(); dispatchOnPanelAnchored(mSlideableView); mSlideState = SlideState.ANCHORED; } } else if (mSlideState != SlideState.COLLAPSED) { dispatchOnPanelCollapsed(mSlideableView); mSlideState = SlideState.COLLAPSED; } } } @Override public void onViewCaptured(View capturedChild, int activePointerId) { // Make all child views visible in preparation for sliding things around setAllChildrenVisible(); } @Override public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) { onPanelDragged(top); invalidate(); } @Override public void onViewReleased(View releasedChild, float xvel, float yvel) { int top = mIsSlidingUp ? getSlidingTop() : getSlidingTop() - mSlideRange; if (mAnchorPoint != 0) { int anchoredTop; float anchorOffset; if (mIsSlidingUp) { anchoredTop = (int) (mAnchorPoint * mSlideRange); anchorOffset = (float) anchoredTop / (float) mSlideRange; } else { anchoredTop = mPanelHeight - (int) (mAnchorPoint * mSlideRange); anchorOffset = (float) (mPanelHeight - anchoredTop) / (float) mSlideRange; } if (yvel > 0 || (yvel == 0 && mSlideOffset >= (1f + anchorOffset) / 2)) { top += mSlideRange; } else if (yvel == 0 && mSlideOffset < (1f + anchorOffset) / 2 && mSlideOffset >= anchorOffset / 2) { top += mSlideRange * mAnchorPoint; } } else if (yvel > 0 || (yvel == 0 && mSlideOffset > 0.5f)) { top += mSlideRange; } mDragHelper.settleCapturedViewAt(releasedChild.getLeft(), top); invalidate(); } @Override public int getViewVerticalDragRange(View child) { return mSlideRange; } @Override public int clampViewPositionVertical(View child, int top, int dy) { final int topBound; final int bottomBound; if (mIsSlidingUp) { topBound = getSlidingTop(); bottomBound = topBound + mSlideRange; } else { bottomBound = getPaddingTop(); topBound = bottomBound - mSlideRange; } return Math.min(Math.max(top, topBound), bottomBound); } } public static class LayoutParams extends ViewGroup.MarginLayoutParams { private static final int[] ATTRS = new int[] { android.R.attr.layout_weight }; /** * True if this pane is the slideable pane in the layout. */ boolean slideable; /** * True if this view should be drawn dimmed * when it's been offset from its default position. */ boolean dimWhenOffset; Paint dimPaint; public LayoutParams() { super(MATCH_PARENT, MATCH_PARENT); } public LayoutParams(int width, int height) { super(width, height); } public LayoutParams(android.view.ViewGroup.LayoutParams source) { super(source); } public LayoutParams(MarginLayoutParams source) { super(source); } public LayoutParams(LayoutParams source) { super(source); } public LayoutParams(Context c, AttributeSet attrs) { super(c, attrs); final TypedArray a = c.obtainStyledAttributes(attrs, ATTRS); a.recycle(); } } static class SavedState extends BaseSavedState { SlideState mSlideState; SavedState(Parcelable superState) { super(superState); } private SavedState(Parcel in) { super(in); try { mSlideState = Enum.valueOf(SlideState.class, in.readString()); } catch (IllegalArgumentException e) { mSlideState = SlideState.COLLAPSED; } } @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeString(mSlideState.toString()); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }; } }