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      1 /*
      2  * Copyright (C) 2008 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package com.android.calculator2;
     18 
     19 import android.content.Context;
     20 import android.content.res.Resources;
     21 import android.graphics.Canvas;
     22 import android.graphics.Paint;
     23 import android.graphics.Paint.Style;
     24 import android.util.AttributeSet;
     25 import android.view.View.OnClickListener;
     26 import android.view.View;
     27 import android.view.MotionEvent;
     28 import android.widget.Button;
     29 
     30 /**
     31  * Button with click-animation effect.
     32  */
     33 class ColorButton extends Button implements OnClickListener {
     34     int CLICK_FEEDBACK_COLOR;
     35     static final int CLICK_FEEDBACK_INTERVAL = 10;
     36     static final int CLICK_FEEDBACK_DURATION = 350;
     37 
     38     float mTextX;
     39     float mTextY;
     40     long mAnimStart;
     41     OnClickListener mListener;
     42     Paint mFeedbackPaint;
     43 
     44     public ColorButton(Context context, AttributeSet attrs) {
     45         super(context, attrs);
     46         Calculator calc = (Calculator) context;
     47         init(calc);
     48         mListener = calc.mListener;
     49         setOnClickListener(this);
     50     }
     51 
     52     public void onClick(View view) {
     53         mListener.onClick(this);
     54     }
     55 
     56     private void init(Calculator calc) {
     57         Resources res = getResources();
     58 
     59         CLICK_FEEDBACK_COLOR = res.getColor(R.color.magic_flame);
     60         mFeedbackPaint = new Paint();
     61         mFeedbackPaint.setStyle(Style.STROKE);
     62         mFeedbackPaint.setStrokeWidth(2);
     63         getPaint().setColor(res.getColor(R.color.button_text));
     64 
     65         mAnimStart = -1;
     66     }
     67 
     68 
     69     @Override
     70     public void onSizeChanged(int w, int h, int oldW, int oldH) {
     71         measureText();
     72     }
     73 
     74     private void measureText() {
     75         Paint paint = getPaint();
     76         mTextX = (getWidth() - paint.measureText(getText().toString())) / 2;
     77         mTextY = (getHeight() - paint.ascent() - paint.descent()) / 2;
     78     }
     79 
     80     @Override
     81     protected void onTextChanged(CharSequence text, int start, int before, int after) {
     82         measureText();
     83     }
     84 
     85     private void drawMagicFlame(int duration, Canvas canvas) {
     86         int alpha = 255 - 255 * duration / CLICK_FEEDBACK_DURATION;
     87         int color = CLICK_FEEDBACK_COLOR | (alpha << 24);
     88 
     89         mFeedbackPaint.setColor(color);
     90         canvas.drawRect(1, 1, getWidth() - 1, getHeight() - 1, mFeedbackPaint);
     91     }
     92 
     93     @Override
     94     public void onDraw(Canvas canvas) {
     95         if (mAnimStart != -1) {
     96             int animDuration = (int) (System.currentTimeMillis() - mAnimStart);
     97 
     98             if (animDuration >= CLICK_FEEDBACK_DURATION) {
     99                 mAnimStart = -1;
    100             } else {
    101                 drawMagicFlame(animDuration, canvas);
    102                 postInvalidateDelayed(CLICK_FEEDBACK_INTERVAL);
    103             }
    104         } else if (isPressed()) {
    105             drawMagicFlame(0, canvas);
    106         }
    107 
    108         CharSequence text = getText();
    109         canvas.drawText(text, 0, text.length(), mTextX, mTextY, getPaint());
    110     }
    111 
    112     public void animateClickFeedback() {
    113         mAnimStart = System.currentTimeMillis();
    114         invalidate();
    115     }
    116 
    117     @Override
    118     public boolean onTouchEvent(MotionEvent event) {
    119         boolean result = super.onTouchEvent(event);
    120 
    121         switch (event.getAction()) {
    122             case MotionEvent.ACTION_UP:
    123                 if (isPressed()) {
    124                     animateClickFeedback();
    125                 } else {
    126                     invalidate();
    127                 }
    128                 break;
    129             case MotionEvent.ACTION_DOWN:
    130             case MotionEvent.ACTION_CANCEL:
    131                 mAnimStart = -1;
    132                 invalidate();
    133                 break;
    134         }
    135 
    136         return result;
    137     }
    138 }
    139