diff options
Diffstat (limited to 'src/org/cyanogenmod/theme/widget/AutoSnapHorizontalScrollView.java')
-rw-r--r-- | src/org/cyanogenmod/theme/widget/AutoSnapHorizontalScrollView.java | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/src/org/cyanogenmod/theme/widget/AutoSnapHorizontalScrollView.java b/src/org/cyanogenmod/theme/widget/AutoSnapHorizontalScrollView.java new file mode 100644 index 0000000..29534f7 --- /dev/null +++ b/src/org/cyanogenmod/theme/widget/AutoSnapHorizontalScrollView.java @@ -0,0 +1,168 @@ +/* + * Copyright (C) 2016 Cyanogen, Inc. + * Copyright (C) 2016 The CyanogenMod 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 org.cyanogenmod.theme.widget; + +import android.content.Context; +import android.graphics.Rect; +import android.util.AttributeSet; +import android.view.MotionEvent; +import android.view.View; +import android.view.ViewGroup; +import android.widget.HorizontalScrollView; +import android.widget.LinearLayout; + +public class AutoSnapHorizontalScrollView extends HorizontalScrollView { + private static final int SNAP_ON_UP_DELAY = 250; + + private int mScrollPositionOnUp; + + enum EventStates { + SCROLLING, + FLING + } + + private EventStates mSystemState = EventStates.SCROLLING; + + public AutoSnapHorizontalScrollView(Context context) { + super(context); + } + + public AutoSnapHorizontalScrollView(Context context, AttributeSet attrs) { + super(context, attrs); + } + + public AutoSnapHorizontalScrollView(Context context, AttributeSet attrs, int defStyle) { + super(context, attrs, defStyle); + } + + Runnable mSnapRunnable = new Runnable(){ + @Override + public void run() { + snapItems(); + mSystemState = EventStates.SCROLLING; + } + }; + + /** + * Added runnable for snapping on an item when the user lifts up their finger and + * there is no scrolling taking place (i.e. no flinging) + */ + Runnable mSnapOnUpRunnable = new Runnable(){ + @Override + public void run() { + int scrollX = getScrollX(); + if (scrollX != mScrollPositionOnUp) { + mScrollPositionOnUp = scrollX; + postDelayed(mSnapOnUpRunnable, SNAP_ON_UP_DELAY); + } else { + snapItems(); + mSystemState = EventStates.SCROLLING; + } + } + }; + + @Override + public boolean onTouchEvent(MotionEvent ev) { + int action = ev.getAction(); + if (action == MotionEvent.ACTION_CANCEL || action == MotionEvent.ACTION_UP) { + mSystemState = EventStates.FLING; + removeCallbacks(mSnapRunnable); + mScrollPositionOnUp = getScrollX(); + postDelayed(mSnapOnUpRunnable, SNAP_ON_UP_DELAY); + } else if (action == MotionEvent.ACTION_DOWN) { + mSystemState = EventStates.SCROLLING; + removeCallbacks(mSnapRunnable); + removeCallbacks(mSnapOnUpRunnable); + } + return super.onTouchEvent(ev); + } + + private void snapItems() { + Rect parentBounds = new Rect(); + getDrawingRect(parentBounds); + Rect childBounds = new Rect(); + ViewGroup parent = (ViewGroup) getChildAt(0); + for (int i = 0; i < parent.getChildCount(); i++) { + View view = parent.getChildAt(i); + view.getHitRect(childBounds); + if (childBounds.right >= parentBounds.left && childBounds.left <= parentBounds.left) { + // First partially visible child + if ((childBounds.right - parentBounds.left) >= + (parentBounds.left - childBounds.left)) { + smoothScrollTo(Math.abs(childBounds.left), 0); + } else { + /** + * Added code to take into account dividers so that we do not see + * one on the edge of the screen when items snap in place. + */ + int dividerWidth = 0; + if (parent instanceof LinearLayout) { + dividerWidth = ((LinearLayout) parent).getDividerWidth(); + } + smoothScrollTo(Math.abs(childBounds.right) + dividerWidth, 0); + } + break; + } + } + } + + // Overwrite measureChildX as we want our child to be able to tell the + // parents width but do not impose any limits (AT_MOST; AT_MAX) + @Override + protected void measureChild(View child, int parentWidthMeasureSpec, + int parentHeightMeasureSpec) { + ViewGroup.LayoutParams lp = child.getLayoutParams(); + + int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, mPaddingTop + + mPaddingBottom, lp.height); + + int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec( + MeasureSpec.getSize(parentWidthMeasureSpec) - (mPaddingLeft + mPaddingRight), + MeasureSpec.UNSPECIFIED); + + child.measure(childWidthMeasureSpec, childHeightMeasureSpec); + } + + @Override + protected void measureChildWithMargins(View child, int parentWidthMeasureSpec, int widthUsed, + int parentHeightMeasureSpec, int heightUsed) { + MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams(); + + int childHeightMeasureSpec = getChildMeasureSpec(parentHeightMeasureSpec, + mPaddingTop + mPaddingBottom + lp.topMargin + lp.bottomMargin + + heightUsed, lp.height); + + int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec( + MeasureSpec.getSize(parentWidthMeasureSpec) - + (mPaddingLeft + mPaddingRight + lp.leftMargin + lp.rightMargin + + widthUsed), MeasureSpec.UNSPECIFIED); + + child.measure(childWidthMeasureSpec, childHeightMeasureSpec); + } + + @Override + protected void onScrollChanged(int l, int t, int oldl, int oldt) { + if (mSystemState == EventStates.SCROLLING) { + return; + } + if (Math.abs(l - oldl) <= 1 && mSystemState == EventStates.FLING) { + removeCallbacks(mSnapRunnable); + postDelayed(mSnapRunnable, 100); + } + } +} |