Implement pseudo 3d overscroll for tab switcher
Bug: 5255100
Change-Id: Id756e36bba2644cc1be1a699f80dbd78119ec56f
diff --git a/src/com/android/browser/NavTabScroller.java b/src/com/android/browser/NavTabScroller.java
new file mode 100644
index 0000000..03bf595
--- /dev/null
+++ b/src/com/android/browser/NavTabScroller.java
@@ -0,0 +1,516 @@
+/*
+ * Copyright (C) 2011 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.android.browser;
+
+
+import android.animation.Animator;
+import android.animation.AnimatorListenerAdapter;
+import android.animation.AnimatorSet;
+import android.animation.ObjectAnimator;
+import android.content.Context;
+import android.database.DataSetObserver;
+import android.graphics.Canvas;
+import android.util.AttributeSet;
+import android.view.Gravity;
+import android.view.View;
+import android.view.ViewGroup;
+import android.view.animation.DecelerateInterpolator;
+import android.widget.BaseAdapter;
+import android.widget.LinearLayout;
+
+import com.android.browser.view.ScrollerView;
+
+/**
+ * custom view for displaying tabs in the nav screen
+ */
+public class NavTabScroller extends ScrollerView {
+
+ static final int INVALID_POSITION = -1;
+ static final float[] PULL_FACTOR = { 2.5f, 0.9f };
+
+ interface OnRemoveListener {
+ public void onRemovePosition(int position);
+ }
+
+ interface OnLayoutListener {
+ public void onLayout(int l, int t, int r, int b);
+ }
+
+ private ContentLayout mContentView;
+ private BaseAdapter mAdapter;
+ private OnRemoveListener mRemoveListener;
+ private OnLayoutListener mLayoutListener;
+ private int mGap;
+ private int mGapPosition;
+ private ObjectAnimator mGapAnimator;
+
+ // after drag animation velocity in pixels/sec
+ private static final float MIN_VELOCITY = 1500;
+ private Animator mAnimator;
+
+ private float mFlingVelocity;
+ private boolean mNeedsScroll;
+ private int mScrollPosition;
+
+ DecelerateInterpolator mCubic;
+ int mPullValue;
+
+ public NavTabScroller(Context context, AttributeSet attrs, int defStyle) {
+ super(context, attrs, defStyle);
+ init(context);
+ }
+
+ public NavTabScroller(Context context, AttributeSet attrs) {
+ super(context, attrs);
+ init(context);
+ }
+
+ public NavTabScroller(Context context) {
+ super(context);
+ init(context);
+ }
+
+ private void init(Context ctx) {
+ mCubic = new DecelerateInterpolator(1.5f);
+ mGapPosition = INVALID_POSITION;
+ setHorizontalScrollBarEnabled(false);
+ setVerticalScrollBarEnabled(false);
+ mContentView = new ContentLayout(ctx, this);
+ mContentView.setOrientation(LinearLayout.HORIZONTAL);
+ addView(mContentView);
+ mContentView.setLayoutParams(
+ new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
+ // ProGuard !
+ setGap(getGap());
+ mFlingVelocity = getContext().getResources().getDisplayMetrics().density
+ * MIN_VELOCITY;
+ }
+
+ protected int getScrollValue() {
+ return mHorizontal ? mScrollX : mScrollY;
+ }
+
+ protected void setScrollValue(int value) {
+ scrollTo(mHorizontal ? value : 0, mHorizontal ? 0 : value);
+ }
+
+ protected NavTabView getTabView(int pos) {
+ return (NavTabView) mContentView.getChildAt(pos);
+ }
+
+ /**
+ * define a visual gap in the list of items
+ * the gap is rendered in front (left or above)
+ * the given position
+ * @param position
+ * @param gap
+ */
+ public void setGapPosition(int position, int gap) {
+ mGapPosition = position;
+ mGap = gap;
+ }
+
+ public void setGap(int gap) {
+ if (mGapPosition != INVALID_POSITION) {
+ mGap = gap;
+ postInvalidate();
+ }
+ }
+
+ public int getGap() {
+ return mGap;
+ }
+
+ protected boolean isHorizontal() {
+ return mHorizontal;
+ }
+
+ public void setOrientation(int orientation) {
+ mContentView.setOrientation(orientation);
+ if (orientation == LinearLayout.HORIZONTAL) {
+ mContentView.setLayoutParams(
+ new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT));
+ } else {
+ mContentView.setLayoutParams(
+ new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
+ }
+ super.setOrientation(orientation);
+ }
+
+ @Override
+ protected void onMeasure(int wspec, int hspec) {
+ super.onMeasure(wspec, hspec);
+ calcPadding();
+ }
+
+ private void calcPadding() {
+ if (mAdapter.getCount() > 0) {
+ View v = mContentView.getChildAt(0);
+ if (mHorizontal) {
+ int pad = (getMeasuredWidth() - v.getMeasuredWidth()) / 2 + 2;
+ mContentView.setPadding(pad, 0, pad, 0);
+ } else {
+ int pad = (getMeasuredHeight() - v.getMeasuredHeight()) / 2 + 2;
+ mContentView.setPadding(0, pad, 0, pad);
+ }
+ }
+ }
+
+ public void setAdapter(BaseAdapter adapter) {
+ setAdapter(adapter, 0);
+ }
+
+
+ public void setOnRemoveListener(OnRemoveListener l) {
+ mRemoveListener = l;
+ }
+
+ public void setOnLayoutListener(OnLayoutListener l) {
+ mLayoutListener = l;
+ }
+
+ protected void setAdapter(BaseAdapter adapter, int selection) {
+ mAdapter = adapter;
+ mAdapter.registerDataSetObserver(new DataSetObserver() {
+
+ @Override
+ public void onChanged() {
+ super.onChanged();
+ handleDataChanged();
+ }
+
+ @Override
+ public void onInvalidated() {
+ super.onInvalidated();
+ }
+ });
+ handleDataChanged(selection);
+ }
+
+ protected ViewGroup getContentView() {
+ return mContentView;
+ }
+
+ protected int getRelativeChildTop(int ix) {
+ return mContentView.getChildAt(ix).getTop() - mScrollY;
+ }
+
+ protected void handleDataChanged() {
+ handleDataChanged(INVALID_POSITION);
+ }
+
+ protected void handleDataChanged(int newscroll) {
+ int scroll = getScrollValue();
+ if (mGapAnimator != null) {
+ mGapAnimator.cancel();
+ }
+ mContentView.removeAllViews();
+ for (int i = 0; i < mAdapter.getCount(); i++) {
+ View v = mAdapter.getView(i, null, mContentView);
+ LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
+ LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
+ lp.gravity = (mHorizontal ? Gravity.CENTER_VERTICAL : Gravity.CENTER_HORIZONTAL);
+ mContentView.addView(v, lp);
+ if ((mGapPosition > INVALID_POSITION) && (i >= mGapPosition)) {
+ adjustViewGap(v, mGap);
+ }
+ }
+ if (newscroll > INVALID_POSITION) {
+ newscroll = Math.min(mAdapter.getCount() - 1, newscroll);
+ mNeedsScroll = true;
+ mScrollPosition = newscroll;
+ requestLayout();
+ } else {
+ setScrollValue(scroll);
+ }
+ if (mGapPosition > INVALID_POSITION) {
+ mGapAnimator = ObjectAnimator.ofInt(this, "gap", mGap, 0);
+ mGapAnimator.setDuration(250);
+ mGapAnimator.addListener(new AnimatorListenerAdapter() {
+ @Override
+ public void onAnimationEnd(Animator a) {
+ mGap = 0;
+ adjustGap();
+ mGapPosition = INVALID_POSITION;
+ mGapAnimator = null;
+ mContentView.requestLayout();
+ }
+ });
+ mGapAnimator.start();
+ }
+
+ }
+
+ protected void finishScroller() {
+ mScroller.forceFinished(true);
+ }
+
+ @Override
+ protected void onLayout(boolean changed, int l, int t, int r, int b) {
+ super.onLayout(changed, l, t, r, b);
+ if (mNeedsScroll) {
+ mScroller.forceFinished(true);
+ snapToSelected(mScrollPosition, false);
+ mNeedsScroll = false;
+ }
+ if (mLayoutListener != null) {
+ mLayoutListener.onLayout(l, t, r, b);
+ mLayoutListener = null;
+ }
+ }
+
+ void adjustGap() {
+ for (int i = 0; i < mContentView.getChildCount(); i++) {
+ if (i >= mGapPosition) {
+ final View child = mContentView.getChildAt(i);
+ adjustViewGap(child, mGap);
+ }
+ }
+ }
+
+ private void adjustViewGap(View view, int gap) {
+ if (mHorizontal) {
+ view.setTranslationX(gap);
+ } else {
+ view.setTranslationY(gap);
+ }
+ }
+
+
+ void clearTabs() {
+ mContentView.removeAllViews();
+ }
+
+ void snapToSelected(int pos, boolean smooth) {
+ if (pos < 0) return;
+ View v = mContentView.getChildAt(pos);
+ int sx = 0;
+ int sy = 0;
+ if (mHorizontal) {
+ sx = (v.getLeft() + v.getRight() - getWidth()) / 2;
+ } else {
+ sy = (v.getTop() + v.getBottom() - getHeight()) / 2;
+ }
+ if ((sx != mScrollX) || (sy != mScrollY)) {
+ if (smooth) {
+ smoothScrollTo(sx,sy);
+ } else {
+ scrollTo(sx, sy);
+ }
+ }
+ }
+
+ protected void animateOut(View v) {
+ if (v == null) return;
+ animateOut(v, -mFlingVelocity);
+ }
+
+ private void animateOut(final View v, float velocity) {
+ float start = mHorizontal ? v.getTranslationY() : v.getTranslationX();
+ animateOut(v, velocity, start);
+ }
+
+ private void animateOut(final View v, float velocity, float start) {
+ if ((v == null) || (mAnimator != null)) return;
+ final int position = mContentView.indexOfChild(v);
+ int target = 0;
+ if (velocity < 0) {
+ target = mHorizontal ? -getHeight() : -getWidth();
+ } else {
+ target = mHorizontal ? getHeight() : getWidth();
+ }
+ int distance = target - (mHorizontal ? v.getTop() : v.getLeft());
+ long duration = (long) (Math.abs(distance) * 1000 / Math.abs(velocity));
+ if (mHorizontal) {
+ mAnimator = ObjectAnimator.ofFloat(v, TRANSLATION_Y, start, target);
+ } else {
+ mAnimator = ObjectAnimator.ofFloat(v, TRANSLATION_X, start, target);
+ }
+ mAnimator.setDuration(duration);
+ mAnimator.addListener(new AnimatorListenerAdapter() {
+ public void onAnimationEnd(Animator a) {
+ if (mRemoveListener != null) {
+ boolean needsGap = position < (mAdapter.getCount() - 1);
+ if (needsGap) {
+ setGapPosition(position, mHorizontal ? v.getWidth() : v.getHeight());
+ }
+ mRemoveListener.onRemovePosition(position);
+ mAnimator = null;
+ }
+ }
+ });
+ mAnimator.start();
+ }
+
+ @Override
+ public void draw(Canvas canvas) {
+ super.draw(canvas);
+ if (mGapPosition > INVALID_POSITION) {
+ adjustGap();
+ }
+ }
+
+ @Override
+ protected View findViewAt(int x, int y) {
+ x += mScrollX;
+ y += mScrollY;
+ final int count = mContentView.getChildCount();
+ for (int i = count - 1; i >= 0; i--) {
+ View child = mContentView.getChildAt(i);
+ if (child.getVisibility() == View.VISIBLE) {
+ if ((x >= child.getLeft()) && (x < child.getRight())
+ && (y >= child.getTop()) && (y < child.getBottom())) {
+ return child;
+ }
+ }
+ }
+ return null;
+ }
+
+ @Override
+ protected void onOrthoDrag(View v, float distance) {
+ if ((v != null) && (mAnimator == null)) {
+ offsetView(v, distance);
+ }
+ }
+
+ @Override
+ protected void onOrthoDragFinished(View downView) {
+ if (mAnimator != null) return;
+ if (mIsOrthoDragged && downView != null) {
+ // offset
+ float diff = mHorizontal ? downView.getTranslationY() : downView.getTranslationX();
+ if (Math.abs(diff) > (mHorizontal ? downView.getHeight() : downView.getWidth()) / 2) {
+ // remove it
+ animateOut(downView, Math.signum(diff) * mFlingVelocity, diff);
+ } else {
+ // snap back
+ offsetView(downView, 0);
+ }
+ }
+ }
+
+ @Override
+ protected void onOrthoFling(View v, float velocity) {
+ if (v == null) return;
+ if (mAnimator == null && Math.abs(velocity) > mFlingVelocity / 2) {
+ animateOut(v, velocity);
+ } else {
+ offsetView(v, 0);
+ }
+ }
+
+ private void offsetView(View v, float distance) {
+ if (mHorizontal) {
+ v.setTranslationY(distance);
+ } else {
+ v.setTranslationX(distance);
+ }
+ }
+
+ private float ease(DecelerateInterpolator inter, float value, float start, float dist, float duration) {
+ return start + dist * inter.getInterpolation(value / duration);
+ }
+
+ @Override
+ protected void onPull(int delta) {
+ boolean layer = false;
+ int count = 2;
+ if (delta == 0 && mPullValue == 0) return;
+ if (delta == 0 && mPullValue != 0) {
+ // reset
+ for (int i = 0; i < count; i++) {
+ View child = mContentView.getChildAt((mPullValue < 0)
+ ? i
+ : mContentView.getChildCount() - 1 - i);
+ if (child == null) break;
+ ObjectAnimator trans = ObjectAnimator.ofFloat(child,
+ mHorizontal ? "translationX" : "translationY",
+ mHorizontal ? getTranslationX() : getTranslationY(),
+ 0);
+ ObjectAnimator rot = ObjectAnimator.ofFloat(child,
+ mHorizontal ? "rotationY" : "rotationX",
+ mHorizontal ? getRotationY() : getRotationX(),
+ 0);
+ AnimatorSet set = new AnimatorSet();
+ set.playTogether(trans, rot);
+ set.setDuration(100);
+ set.start();
+ }
+ mPullValue = 0;
+ } else {
+ if (mPullValue == 0) {
+ layer = true;
+ }
+ mPullValue += delta;
+ }
+ final int height = mHorizontal ? getWidth() : getHeight();
+ int oscroll = Math.abs(mPullValue);
+ int factor = (mPullValue <= 0) ? 1 : -1;
+ for (int i = 0; i < count; i++) {
+ View child = mContentView.getChildAt((mPullValue < 0)
+ ? i
+ : mContentView.getChildCount() - 1 - i);
+ if (child == null) break;
+ if (layer) {
+ }
+ float k = PULL_FACTOR[i];
+ float rot = -factor * ease(mCubic, oscroll, 0, k * 2, height);
+ int y = factor * (int) ease(mCubic, oscroll, 0, k*20, height);
+ if (mHorizontal) {
+ child.setTranslationX(y);
+ } else {
+ child.setTranslationY(y);
+ }
+ if (mHorizontal) {
+ child.setRotationY(-rot);
+ } else {
+ child.setRotationX(rot);
+ }
+ }
+ }
+
+ static class ContentLayout extends LinearLayout {
+
+ NavTabScroller mScroller;
+
+ public ContentLayout(Context context, NavTabScroller scroller) {
+ super(context);
+ mScroller = scroller;
+ }
+
+ @Override
+ protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
+ super.onMeasure(widthMeasureSpec, heightMeasureSpec);
+ if (mScroller.getGap() > 0) {
+ View v = getChildAt(0);
+ if (v != null) {
+ if (mScroller.isHorizontal()) {
+ int total = v.getMeasuredWidth() + getMeasuredWidth();
+ setMeasuredDimension(total, getMeasuredHeight());
+ } else {
+ int total = v.getMeasuredHeight() + getMeasuredHeight();
+ setMeasuredDimension(getMeasuredWidth(), total);
+ }
+ }
+
+ }
+ }
+
+ }
+
+}
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