public class gradual extends View {
private int animatedValue;
private int colorEnd;
private int colorStart;
public gradual(Context context) {
super(context);
init();
}
public gradual(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
System.out.println(111);
init();
}
public void init() {
ValueAnimator animator=ValueAnimator.ofInt(0,255);
animator.setDuration(20000);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@RequiresApi(api = Build.VERSION_CODES.O)
@Override
public void onAnimationUpdate(ValueAnimator animation) {
animatedValue = (int) animation.getAnimatedValue();
colorStart = Color.rgb(255-animatedValue,animatedValue,255-animatedValue);
colorEnd = Color.rgb(animatedValue,animatedValue,255-animatedValue);
invalidate();
}
});
animator.start();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//获取View的宽高
int width = getWidth();
int height = getHeight();
Paint paint = new Paint();
LinearGradient backGradient = new LinearGradient(width, 0, 0, 0, new int[]{colorStart,colorEnd}, new float[]{0,1f}, Shader.TileMode.CLAMP);
paint.setShader(backGradient);
canvas.drawRect(0, 0, width, height, paint);
}
}
