Java tutorial
/* * Copyright (c) Gustavo Claramunt (AnderWeb) 2014. * * 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.adw.library.widgets.discreteseekbar.internal.drawable; import android.content.res.ColorStateList; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.Animatable; import android.os.SystemClock; import android.support.annotation.NonNull; import android.support.v4.view.animation.FastOutSlowInInterpolator; import android.view.animation.Interpolator; public class AlmostRippleDrawable extends StateDrawable implements Animatable { private static final long FRAME_DURATION = 1000 / 60; private static final int ANIMATION_DURATION = 250; private static final float INACTIVE_SCALE = 0f; private static final float ACTIVE_SCALE = 1f; private float mCurrentScale = INACTIVE_SCALE; private Interpolator mInterpolator; private long mStartTime; private boolean mReverse = false; private boolean mRunning = false; private int mDuration = ANIMATION_DURATION; private float mAnimationInitialValue; //We don't use colors just with our drawable state because of animations private int mPressedColor; private int mFocusedColor; private int mDisabledColor; private int mRippleColor; private int mRippleBgColor; public AlmostRippleDrawable(@NonNull ColorStateList tintStateList) { super(tintStateList); mInterpolator = new FastOutSlowInInterpolator(); setColor(tintStateList); } public void setColor(@NonNull ColorStateList tintStateList) { int defaultColor = tintStateList.getDefaultColor(); mFocusedColor = tintStateList.getColorForState( new int[] { android.R.attr.state_enabled, android.R.attr.state_focused }, defaultColor); mPressedColor = tintStateList.getColorForState( new int[] { android.R.attr.state_enabled, android.R.attr.state_pressed }, defaultColor); mDisabledColor = tintStateList.getColorForState(new int[] { -android.R.attr.state_enabled }, defaultColor); //The ripple should be partially transparent mFocusedColor = getModulatedAlphaColor(130, mFocusedColor); mPressedColor = getModulatedAlphaColor(130, mPressedColor); mDisabledColor = getModulatedAlphaColor(130, mDisabledColor); } private static int getModulatedAlphaColor(int alphaValue, int originalColor) { int alpha = Color.alpha(originalColor); int scale = alphaValue + (alphaValue >> 7); alpha = alpha * scale >> 8; return Color.argb(alpha, Color.red(originalColor), Color.green(originalColor), Color.blue(originalColor)); } @Override public void doDraw(Canvas canvas, Paint paint) { Rect bounds = getBounds(); int size = Math.min(bounds.width(), bounds.height()); float scale = mCurrentScale; int rippleColor = mRippleColor; int bgColor = mRippleBgColor; float radius = (size / 2); float radiusAnimated = radius * scale; if (scale > INACTIVE_SCALE) { if (bgColor != 0) { paint.setColor(bgColor); paint.setAlpha(decreasedAlpha(Color.alpha(bgColor))); canvas.drawCircle(bounds.centerX(), bounds.centerY(), radius, paint); } if (rippleColor != 0) { paint.setColor(rippleColor); paint.setAlpha(modulateAlpha(Color.alpha(rippleColor))); canvas.drawCircle(bounds.centerX(), bounds.centerY(), radiusAnimated, paint); } } } private int decreasedAlpha(int alpha) { int scale = 100 + (100 >> 7); return alpha * scale >> 8; } @Override public boolean setState(int[] stateSet) { int[] oldState = getState(); boolean oldPressed = false; for (int i : oldState) { if (i == android.R.attr.state_pressed) { oldPressed = true; } } super.setState(stateSet); boolean focused = false; boolean pressed = false; boolean disabled = true; for (int i : stateSet) { if (i == android.R.attr.state_focused) { focused = true; } else if (i == android.R.attr.state_pressed) { pressed = true; } else if (i == android.R.attr.state_enabled) { disabled = false; } } if (disabled) { unscheduleSelf(mUpdater); mRippleColor = mDisabledColor; mRippleBgColor = 0; mCurrentScale = ACTIVE_SCALE / 2; invalidateSelf(); } else { if (pressed) { animateToPressed(); mRippleColor = mRippleBgColor = mPressedColor; } else if (oldPressed) { mRippleColor = mRippleBgColor = mPressedColor; animateToNormal(); } else if (focused) { mRippleColor = mFocusedColor; mRippleBgColor = 0; mCurrentScale = ACTIVE_SCALE; invalidateSelf(); } else { mRippleColor = 0; mRippleBgColor = 0; mCurrentScale = INACTIVE_SCALE; invalidateSelf(); } } return true; } public void animateToPressed() { unscheduleSelf(mUpdater); if (mCurrentScale < ACTIVE_SCALE) { mReverse = false; mRunning = true; mAnimationInitialValue = mCurrentScale; float durationFactor = 1f - ((mAnimationInitialValue - INACTIVE_SCALE) / (ACTIVE_SCALE - INACTIVE_SCALE)); mDuration = (int) (ANIMATION_DURATION * durationFactor); mStartTime = SystemClock.uptimeMillis(); scheduleSelf(mUpdater, mStartTime + FRAME_DURATION); } } public void animateToNormal() { unscheduleSelf(mUpdater); if (mCurrentScale > INACTIVE_SCALE) { mReverse = true; mRunning = true; mAnimationInitialValue = mCurrentScale; float durationFactor = 1f - ((mAnimationInitialValue - ACTIVE_SCALE) / (INACTIVE_SCALE - ACTIVE_SCALE)); mDuration = (int) (ANIMATION_DURATION * durationFactor); mStartTime = SystemClock.uptimeMillis(); scheduleSelf(mUpdater, mStartTime + FRAME_DURATION); } } private void updateAnimation(float factor) { float initial = mAnimationInitialValue; float destination = mReverse ? INACTIVE_SCALE : ACTIVE_SCALE; mCurrentScale = initial + (destination - initial) * factor; invalidateSelf(); } private final Runnable mUpdater = new Runnable() { @Override public void run() { long currentTime = SystemClock.uptimeMillis(); long diff = currentTime - mStartTime; if (diff < mDuration) { float interpolation = mInterpolator.getInterpolation((float) diff / (float) mDuration); scheduleSelf(mUpdater, currentTime + FRAME_DURATION); updateAnimation(interpolation); } else { unscheduleSelf(mUpdater); mRunning = false; updateAnimation(1f); } } }; @Override public void start() { //No-Op. We control our own animation } @Override public void stop() { //No-Op. We control our own animation } @Override public boolean isRunning() { return mRunning; } }