com.coco.blinktextview.BlinkTextView.java Source code

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Here is the source code for com.coco.blinktextview.BlinkTextView.java

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package com.coco.blinktextview;

/*
 The MIT License (MIT)
    
 Copyright (c) 2014 justin
    
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in
 the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 the Software, and to permit persons to whom the Software is furnished to do so,
 subject to the following conditions:
    
 The above copyright notice and this permission notice shall be included in all
 copies or substantial portions of the Software.
    
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

import android.content.Context;
import android.content.res.ColorStateList;
import android.support.v4.view.ViewCompat;
import android.util.AttributeSet;
import android.util.Log;
import android.view.animation.LinearInterpolator;
import android.widget.Scroller;
import android.widget.TextView;

/**
 * Android blink text view with it's text repeatly fade in & fade out.
 */
public class BlinkTextView extends TextView {
    private static final String TAG = "BlinkTextView";
    private static final boolean DEBUG = false;

    private static void DEBUG_LOG(String msg) {
        if (DEBUG) {
            Log.v(TAG, msg);
        }
    }

    private static final int MIN_ALPHA = 0;
    private static final int MAX_ALPHA = 255;

    // options constant
    private static final int MIN_FADING_DURATION = 150; // ms
    private static final int DEFAULT_FADING_DURATION = 2000; // ms
    private static final int DEFAULT_DELAY_AFTER_FADEOUT = 300; // ms
    private static final int DEFAULT_DELAY_AFTER_FADEIN = 800; // ms

    // blink
    private ColorStateList mOriginalColors;
    private int mCurrentAlpha;

    // options
    private long mFadingDuration = DEFAULT_FADING_DURATION;
    private long mDelayAfterFadein = DEFAULT_DELAY_AFTER_FADEIN;
    private long mDelayAfterFadeout = DEFAULT_DELAY_AFTER_FADEOUT;

    private Scroller mScroller;
    private boolean mIsFadein;
    private boolean mBlinkStarted;

    private final Runnable mReverseFadingRunnable = new Runnable() {
        public void run() {
            mIsFadein = !mIsFadein;
            DEBUG_LOG("mReverseFadingRunnable mIsFadein=" + mIsFadein);
            startBlink();
        }
    };

    public BlinkTextView(Context context) {
        super(context);
        initBlinkTextView();
    }

    public BlinkTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initBlinkTextView();
    }

    public BlinkTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initBlinkTextView();
    }

    private void initBlinkTextView() {
        final Context context = getContext();
        mScroller = new Scroller(context, new LinearInterpolator());
        mCurrentAlpha = MAX_ALPHA;
    }

    @Override
    public void setEnabled(boolean enabled) {
        if (enabled == isEnabled()) {
            return;
        }
        super.setEnabled(enabled);
        if (enabled) {
            startBlink();
        } else {
            stopBlink();
        }
    }

    public long getFadingDuration() {
        return mFadingDuration;
    }

    public void setFadingDuration(long fadingDuration) {
        if (fadingDuration < MIN_FADING_DURATION) {
            fadingDuration = MIN_FADING_DURATION;
        }
        if (mFadingDuration != fadingDuration) {
            mFadingDuration = fadingDuration;
            resetBlink();
        }
    }

    public long getDelayAfterFadein() {
        return mDelayAfterFadein;
    }

    public void setDelayAfterFadein(long delayAfterFadein) {
        if (delayAfterFadein < 0) {
            delayAfterFadein = 0;
        }
        if (mDelayAfterFadein != delayAfterFadein) {
            mDelayAfterFadein = delayAfterFadein;
            resetBlink();
        }
    }

    public long getDelayAfterFadeout() {
        return mDelayAfterFadeout;
    }

    public void setDelayAfterFadeout(long delayAfterFadeout) {
        if (delayAfterFadeout < 0) {
            delayAfterFadeout = 0;
        }
        if (mDelayAfterFadeout != delayAfterFadeout) {
            mDelayAfterFadeout = delayAfterFadeout;
            resetBlink();
        }
    }

    @Override
    protected void onAttachedToWindow() {
        super.onAttachedToWindow();
        startBlink();
    }

    @Override
    protected void onDetachedFromWindow() {
        stopBlink();
        super.onDetachedFromWindow();
    }

    @Override
    public void onWindowFocusChanged(boolean hasWindowFocus) {
        super.onWindowFocusChanged(hasWindowFocus);
        DEBUG_LOG("onWindowFocusChanged hasWindowFocus=" + hasWindowFocus);
        if (hasWindowFocus) {
            startBlink();
        } else {
            stopBlink();
        }
    }

    @Override
    public void setTextAppearance(Context context, int resid) {
        super.setTextAppearance(context, resid);
        saveOriginalColor();
    }

    @Override
    public void setTextColor(ColorStateList colors) {
        super.setTextColor(colors);
        saveOriginalColor();
    }

    @Override
    public void setTextColor(int color) {
        super.setTextColor(color);
        saveOriginalColor();
    }

    private void saveOriginalColor() {
        mOriginalColors = getTextColors().withAlpha(mCurrentAlpha);
    }

    private void resetBlink() {
        if (mBlinkStarted) {
            startBlink();
        }
    }

    private void startBlink() {
        if (!isEnabled()) {
            return;
        }
        int sx;
        int dx;
        if (mIsFadein) {
            sx = mCurrentAlpha;
            dx = MAX_ALPHA - mCurrentAlpha;
        } else {
            sx = mCurrentAlpha;
            dx = -mCurrentAlpha;
        }
        final int duration = (int) (mFadingDuration * Math.abs(dx) / MAX_ALPHA);
        DEBUG_LOG("startBlink mIsFadein=" + mIsFadein + ", mCurrentAlpha=" + mCurrentAlpha + ", sx=" + sx + ", dx="
                + dx + ", duration=" + duration);
        mScroller.abortAnimation();
        mScroller.startScroll(sx, 0, dx, 0, duration);
        mBlinkStarted = true;
        ViewCompat.postInvalidateOnAnimation(this);
    }

    private void stopBlink() {
        mScroller.abortAnimation();
        if (getHandler() != null) {
            getHandler().removeCallbacks(mReverseFadingRunnable);
        }
        mBlinkStarted = false;
    }

    @Override
    public void computeScroll() {
        if (!isEnabled() || !mBlinkStarted) {
            return;
        }
        if (!mScroller.isFinished() && mScroller.computeScrollOffset()) {
            mCurrentAlpha = Math.max(MIN_ALPHA, Math.min(MAX_ALPHA, Math.abs(mScroller.getCurrX())));
            DEBUG_LOG("computeScroll mCurrentAlpha=" + mCurrentAlpha);
            super.setTextColor(mOriginalColors.withAlpha(mCurrentAlpha));

            // Keep on drawing until the animation has finished.
            ViewCompat.postInvalidateOnAnimation(this);
            return;
        }

        // Done with scroll, clean up state.
        stopBlink();
        final long delayMillis = mIsFadein ? mDelayAfterFadein : mDelayAfterFadeout;
        getHandler().postDelayed(mReverseFadingRunnable, delayMillis);
    }

}