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/*
* 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.android.launcher3;
import android.animation.Animator;
import android.animation.ObjectAnimator;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
/**
* The fast scroller popup that shows the section name the list will jump to.
*/
public class BaseRecyclerViewFastScrollPopup {
private static final float FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR = 1.5f;
private static final int SHADOW_INSET = 3;
private static final int SHADOW_SHIFT_Y = 2;
private static final float SHADOW_ALPHA_MULTIPLIER = 0.67f;
private Resources mRes;
private BaseRecyclerView mRv;
private Bitmap mShadow;
private Paint mShadowPaint;
private Drawable mBg;
// The absolute bounds of the fast scroller bg
private Rect mBgBounds = new Rect();
private int mBgOriginalSize;
private Rect mInvalidateRect = new Rect();
private Rect mTmpRect = new Rect();
private String mSectionName;
private Paint mTextPaint;
private Rect mTextBounds = new Rect();
private float mAlpha;
private Animator mAlphaAnimator;
private boolean mVisible;
public BaseRecyclerViewFastScrollPopup(BaseRecyclerView rv, Resources res) {
mRes = res;
mRv = rv;
mBgOriginalSize = res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_size);
mBg = rv.getContext().getDrawable(R.drawable.container_fastscroll_popup_bg);
mBg.setBounds(0, 0, mBgOriginalSize, mBgOriginalSize);
mTextPaint = new Paint();
mTextPaint.setColor(Color.WHITE);
mTextPaint.setAntiAlias(true);
mTextPaint.setTextSize(res.getDimensionPixelSize(R.dimen.container_fastscroll_popup_text_size));
mShadowPaint = new Paint();
mShadowPaint.setAntiAlias(true);
mShadowPaint.setFilterBitmap(true);
mShadowPaint.setDither(true);
}
/**
* Sets the section name.
*/
public void setSectionName(String sectionName) {
if (!sectionName.equals(mSectionName)) {
mSectionName = sectionName;
mTextPaint.getTextBounds(sectionName, 0, sectionName.length(), mTextBounds);
// Update the width to use measureText since that is more accurate
mTextBounds.right = (int) (mTextBounds.left + mTextPaint.measureText(sectionName));
}
}
/**
* Updates the bounds for the fast scroller.
*
* @return the invalidation rect for this update.
*/
public Rect updateFastScrollerBounds(int lastTouchY) {
mInvalidateRect.set(mBgBounds);
if (isVisible()) {
// Calculate the dimensions and position of the fast scroller popup
int edgePadding = mRv.getMaxScrollbarWidth();
int bgPadding = (mBgOriginalSize - mTextBounds.height()) / 2;
int bgHeight = mBgOriginalSize;
int bgWidth = Math.max(mBgOriginalSize, mTextBounds.width() + (2 * bgPadding));
if (Utilities.isRtl(mRes)) {
mBgBounds.left = mRv.getBackgroundPadding().left + (2 * mRv.getMaxScrollbarWidth());
mBgBounds.right = mBgBounds.left + bgWidth;
} else {
mBgBounds.right = mRv.getWidth() - mRv.getBackgroundPadding().right -
(2 * mRv.getMaxScrollbarWidth());
mBgBounds.left = mBgBounds.right - bgWidth;
}
mBgBounds.top = lastTouchY - (int) (FAST_SCROLL_OVERLAY_Y_OFFSET_FACTOR * bgHeight);
mBgBounds.top = Math.max(edgePadding,
Math.min(mBgBounds.top, mRv.getVisibleHeight() - edgePadding - bgHeight));
mBgBounds.bottom = mBgBounds.top + bgHeight;
// Generate a bitmap for a shadow matching these bounds
mShadow = HolographicOutlineHelper.obtain(
mRv.getContext()).createMediumDropShadow(mBg, false /* shouldCache */);
} else {
mShadow = null;
mBgBounds.setEmpty();
}
// Combine the old and new fast scroller bounds to create the full invalidate rect
mInvalidateRect.union(mBgBounds);
return mInvalidateRect;
}
/**
* Animates the visibility of the fast scroller popup.
*/
public void animateVisibility(boolean visible) {
if (mVisible != visible) {
mVisible = visible;
if (mAlphaAnimator != null) {
mAlphaAnimator.cancel();
}
mAlphaAnimator = ObjectAnimator.ofFloat(this, "alpha", visible ? 1f : 0f);
mAlphaAnimator.setDuration(visible ? 200 : 150);
mAlphaAnimator.start();
}
}
// Setter/getter for the popup alpha for animations
public void setAlpha(float alpha) {
mAlpha = alpha;
mRv.invalidate(mBgBounds);
}
public float getAlpha() {
return mAlpha;
}
public int getHeight() {
return mBgOriginalSize;
}
public void draw(Canvas c) {
if (isVisible()) {
// Determine the alpha and prepare the canvas
final int alpha = (int) (mAlpha * 255);
int restoreCount = c.save(Canvas.MATRIX_SAVE_FLAG);
c.translate(mBgBounds.left, mBgBounds.top);
mTmpRect.set(mBgBounds);
mTmpRect.offsetTo(0, 0);
// Expand the rect (with a negative inset), translate it, and draw the shadow
if (mShadow != null) {
mTmpRect.inset(-SHADOW_INSET * 2, -SHADOW_INSET * 2);
mTmpRect.offset(0, SHADOW_SHIFT_Y);
mShadowPaint.setAlpha((int) (alpha * SHADOW_ALPHA_MULTIPLIER));
c.drawBitmap(mShadow, null, mTmpRect, mShadowPaint);
mTmpRect.inset(SHADOW_INSET * 2, SHADOW_INSET * 2);
mTmpRect.offset(0, -SHADOW_SHIFT_Y);
}
// Draw the background
mBg.setBounds(mTmpRect);
mBg.setAlpha(alpha);
mBg.draw(c);
// Draw the text
mTextPaint.setAlpha(alpha);
c.drawText(mSectionName, (mBgBounds.width() - mTextBounds.width()) / 2,
mBgBounds.height() - (mBgBounds.height() / 2) - mTextBounds.exactCenterY(),
mTextPaint);
c.restoreToCount(restoreCount);
}
}
public boolean isVisible() {
return (mAlpha > 0f) && (mSectionName != null);
}
}
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