android群英传笔记--第三章--自定义控件四音频条形图

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mWidth = getWidth();
mRectHeight = getHeight();
mRectWidth = (int) (mWidth * 0.6 / mRectCount);
mLinearGradient = new LinearGradient(
0,
0,
mRectWidth,
mRectHeight,
Color.YELLOW,
Color.BLUE,
Shader.TileMode.CLAMP);
mPaint.setShader(mLinearGradient);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (int i = 0; i < mRectCount; i++) {
mRandom = Math.random();
float currentHeight = (float) (mRectHeight * mRandom);
canvas.drawRect(
(float) (mWidth * 0.4 / 2 + mRectWidth * i + offset),
currentHeight,
(float) (mWidth * 0.4 / 2 + mRectWidth * (i + 1)),
mRectHeight,
mPaint);
}
postInvalidateDelayed(300);
}