Android录制按钮源码解析

private void initParame(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.RButtonY, defStyleAttr, 0);
    //外圆和内部正方形之间的间距
    mCircleOutMarginSize = typedArray.getDimensionPixelSize(R.styleable.RButtonY_rby_circle_out_margin, 5);
    //外圆画笔的宽度
    mCircleWidth = typedArray.getDimensionPixelSize(R.styleable.RButtonY_rby_circle_width, 5);
    //外圆画笔的颜色
    mCirclePaintColor = typedArray.getColor(R.styleable.RButtonY_rby_circle_paint_color, Color.YELLOW);
    //内部正方形画笔的颜色
    mRectPaintColor = typedArray.getColor(R.styleable.RButtonY_rby_rect_paint_color, Color.RED);
    //内部正方形初始边长相对于外圆内切正方形边长比率 0-1 
    mRectRateStart = typedArray.getFloat(R.styleable.RButtonY_rby_rect_rate_start, 0.9f);
    //内部正方形结束边长相对于外圆内切正方形边长比率 0-1 
    mRectRateFinish = typedArray.getFloat(R.styleable.RButtonY_rby_rect_rate_fnish, 0.5f);
    //录制规定最短时间
    mShortest = typedArray.getInteger(R.styleable.RButtonY_rby_short_time, 3);
    //录制规定最长时间
    mLongest = typedArray.getInteger(R.styleable.RButtonY_rby_long_time, 10);
    typedArray.recycle();
}

// Paint.Style.FILL设置只绘制图形内容
// Paint.Style.STROKE设置只绘制图形的边
// Paint.Style.FILL_AND_STROKE设置都绘制
private void initPaint() {
    //外圆画笔
    mCirclePaint = new Paint();
    mCirclePaint.setAntiAlias(true);
    mCirclePaint.setColor(mCirclePaintColor);
    mCirclePaint.setStyle(Paint.Style.STROKE);
    mCirclePaint.setStrokeWidth(mCircleWidth);
    //内部正方形画笔
    mRectPaint = new Paint();
    mRectPaint.setAntiAlias(true);
    mRectPaint.setColor(mRectPaintColor);
    mRectPaint.setStyle(Paint.Style.FILL_AND_STROKE);
}

private void initRect() {
        mRectF = new RectF();
}

/**
 * 初始化动画
 * 这里对动画进行监听, 获取正方形边长随动画改变的值,然后重绘
 */
private void initAnimator() {
    mAnimator = new ValueAnimator();
    /**
     * onAnimationStart() - 当动画开始的时候调用.
     * onAnimationEnd() - 动画结束时调用.
     * onAnimationRepeat() - 动画重复时调用.
     * onAnimationCancel() - 动画取消时调用.取消动画也会调用onAnimationEnd，它不会关系动画是怎么结束的。
     */
    mAnimator.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            //动画结束
            isAnimRuning = false;
        }
        @Override
        public void onAnimationStart(Animator animation) {
            //动画开始
            isAnimRuning = true;
        }
    });
    //动画进度监听,获取正方形随动画变化的边长,然后重绘
    mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
        @Override
        public void onAnimationUpdate(ValueAnimator animation) {
            //动态获取正方形边长
            mTempRectSize = (float) animation.getAnimatedValue();
            invalidate();//重绘
        }
    });
}

 @Override
 protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
     super.onLayout(changed, left, top, right, bottom);
     int width = getWidth();
     int height = getHeight();
     //圆心坐标
     centerX = width / 2;
     centerY = height / 2;
     //半径
     radius = Math.min(centerX, centerY) - mCircleOutMarginSize / 2;
     //pow 平方，sqrt 开方
     //正方形开始边长,圆形直径的平方除以二再开放,为正方形边长.
     mRectStartSize = (int) (Math.sqrt(Math.pow(radius * 2, 2) / 2) * mRectRateStart);
     //正方形结束边长
     mRectEndSize = (int) (mRectStartSize * mRectRateFinish);
    //mTempRectSize == 0 时, 即第一创建该View.
    if (mTempRectSize == 0) {
        //如果屏幕旋转,onLayout将被回调,此时并不希望mTempRectSize被重新赋值为mRectStartSize(开始状态).
        //所以只有当第一次创建时,才需要为mTempRectSize赋值为mRectStartSize(开始状态)
        mTempRectSize = mRectStartSize;
    }
 }

@Override
 protected void onDraw(Canvas canvas) {
     super.onDraw(canvas);
     //外圆绘制
     canvas.drawCircle(centerX, centerY, radius, mCirclePaint);
     //正方形四点坐标
     int mLeftRectTemp = (int) (centerX - mTempRectSize / 2);
     int mRightRectTemp = (int) (centerX + mTempRectSize / 2);
     int mTopRectTemp = (int) (centerY + mTempRectSize / 2);
     int mButtonRectTemp = (int) (centerY - mTempRectSize / 2);
     //绘制正方形
     mRectF.set(mLeftRectTemp, mTopRectTemp, mRightRectTemp, mButtonRectTemp);
     //(float) Math.sqrt(radius): 圆角半径
     canvas.drawRoundRect(mRectF, (float) Math.sqrt(radius), (float) Math.sqrt(radius), mRectPaint);
 }

/**
 * 录制开始
 */
private void recordStart() {
    //正方形开始动画
    startAnimation(mRectStartSize, mRectEndSize);
    if (rbyCb != null) {
        //录制开始的回调
        rbyCb.startCb(String.valueOf(mCurrent));
    }
    //开始计时
    mHandler.sendEmptyMessage(0);
    //录制标识为开始
    up = true;
    mTempRectSize = mRectEndSize;
}
/**
 * 录制结束
 */
private void recordFinish() {
    //正方形结束动画
    startAnimation(mRectEndSize, mRectStartSize);
    if (rbyCb != null) {
        //结束时回调
        rbyCb.finishCb(String.valueOf(mCurrent));
    }
    //录制结束,当前时间归0
    mCurrent = 0;
    mHandler.removeCallbacksAndMessages(null);
    //录制标识为结束
    up = false;
    mTempRectSize = mRectStartSize;
}
/**
 * 开始动画
 *
 * @param startValue
 * @param endValue
 */
private void startAnimation(float startValue, float endValue)
    mAnimator.setFloatValues(startValue, endValue);
    mAnimator.setDuration(100);
    mAnimator.setInterpolator(new LinearInterpolator());
    mAnimator.start();
}

public interface RBYCallback {
    /**
     * 记录结束的回调
     *
     * @param current
     */
    void finishCb(String current);
    /**
     * 每一秒 都会触发该回调
     *
     * @param current
     */
    void eventCb(String current);
    /**
     * 开始记录的回调
     */
    void startCb(String current);
    /**
     * 录制时长小于录制最短要求时间之时,用户点击按钮时候,回调该方法
     */
    void lessShortTimeRecode(String current);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    switch (event.getAction()) {
        case MotionEvent.ACTION_UP:
            //如果正方形动画正在播放，就拒绝按钮点击
            if (isAnimRuning) return true;
            //up为false代表未开始记录,true 代表开始记录
            //未开始记录时,mCurrent是等于0
            if (!up && mCurrent == 0) {
                recordStart();
            }
            //已开始记录,并且当前录制时间大于或者等于所设置的最短记录时长,则按钮可以手动结束
            if (up && mCurrent >= mShortest) {
                recordFinish();
            }
            //已开始记录,当前录制时间小于所设置的最短记录时长,并且录制时间大于1,则回调方法通知当前还不能手动结束录制
            if (up && mCurrent < mShortest && mCurrent >= 1) {
                if (rbyCb != null) {
                    rbyCb.lessShortTimeRecode(String.valueOf(mCurrent));
                }
            }
            break;
    }
    return true;//消费事件
}

//屏幕旋转时候保存必要的数据
@Nullable
@Override
protected Parcelable onSaveInstanceState() {
    if (mCurrent != 0) {
        Bundle bundle = new Bundle();
        //保存系统其他原有的状态信息
        bundle.putParcelable("instance", super.onSaveInstanceState());
        //保存当前的一些状态
        bundle.putFloat("rect_size", mTempRectSize);//保存方形边长
        bundle.putBoolean("up", up);//当前录制状态
        bundle.putInt("mCurrent", mCurrent);//当前录制时间
        return bundle;
    } else {
        return super.onSaveInstanceState();
    }
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
    //判断state的类型是否为bundle,若是则从bundle中取数据
    if (state instanceof Bundle) {
        Bundle bundle = (Bundle) state;
        mTempRectSize = bundle.getFloat("rect_size");
        up = bundle.getBoolean("up");
        mCurrent = bundle.getInt("mCurrent");
        //开始计时
        mHandler.sendEmptyMessage(0);
        super.onRestoreInstanceState(bundle.getParcelable("instance"));
        return;
    }
    super.onRestoreInstanceState(state);
}

@SuppressLint("HandlerLeak")
private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(@NonNull Message msg) {
        super.handleMessage(msg);
        mCurrent++;
        if (rbyCb != null) {
            rbyCb.eventCb(String.valueOf(mCurrent));
        }
        if (mCurrent >= mLongest) {//当前记录时间大于或等于最大记录时间，将自动结束记录
            recordFinish();
        } else {
            mHandler.sendEmptyMessageDelayed(0, 1000);
        }
    }
};

//页面销毁,清空消息,防止内存泄漏
@Override
protected void onDetachedFromWindow() {
    super.onDetachedFromWindow();
    mHandler.removeCallbacksAndMessages(null);
    mHandler = null;
}