final void update() {
if (mIsRunning) {
// Update the animated fraction
final long elapsed = SystemClock.uptimeMillis() - mStartTime;
final float linearFraction = MathUtils.constrain(elapsed / (float) mDuration, 0f, 1f);
mAnimatedFraction =
mInterpolator != null ? mInterpolator.getInterpolation(linearFraction) : linearFraction;
// If we're running, dispatch to the update listeners
dispatchAnimationUpdate();
// Check to see if we've passed the animation duration
if (SystemClock.uptimeMillis() >= (mStartTime + mDuration)) {
mIsRunning = false;
dispatchAnimationEnd();
}
}
if (mIsRunning) {
// If we're still running, post another delayed runnable
sHandler.postDelayed(mRunnable, HANDLER_DELAY);
}
}
/**
* Creates an approximated cubic gradient using a multi-stop linear gradient. See <a
* href="https://plus.google.com/+RomanNurik/posts/2QvHVFWrHZf">this post</a> for more details.
*/
public static Drawable makeCubicGradientScrimDrawable(
@ColorInt int baseColor, int numStops, int gravity) {
numStops = Math.max(numStops, 2);
PaintDrawable paintDrawable = new PaintDrawable();
paintDrawable.setShape(new RectShape());
final int[] stopColors = new int[numStops];
int alpha = Color.alpha(baseColor);
for (int i = 0; i < numStops; i++) {
float x = i * 1f / (numStops - 1);
float opacity = MathUtils.constrain(0, 1, (float) Math.pow(x, 3));
stopColors[i] = ColorUtils.modifyAlpha(baseColor, (int) (alpha * opacity));
}
final float x0, x1, y0, y1;
switch (gravity & Gravity.HORIZONTAL_GRAVITY_MASK) {
case Gravity.LEFT:
x0 = 1;
x1 = 0;
break;
case Gravity.RIGHT:
x0 = 0;
x1 = 1;
break;
default:
x0 = 0;
x1 = 0;
break;
}
switch (gravity & Gravity.VERTICAL_GRAVITY_MASK) {
case Gravity.TOP:
y0 = 1;
y1 = 0;
break;
case Gravity.BOTTOM:
y0 = 0;
y1 = 1;
break;
default:
y0 = 0;
y1 = 0;
break;
}
paintDrawable.setShaderFactory(
new ShapeDrawable.ShaderFactory() {
@Override
public Shader resize(int width, int height) {
LinearGradient linearGradient =
new LinearGradient(
width * x0,
height * y0,
width * x1,
height * y1,
stopColors,
null,
Shader.TileMode.CLAMP);
return linearGradient;
}
});
return paintDrawable;
}
