下面列出了android.graphics.drawable.PaintDrawable#setShaderFactory() 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
public static Drawable drawable(final int[] colorBoxes, final float[] position, final GradientAngle gradientAngle) {
ShapeDrawable.ShaderFactory shaderFactory = new ShapeDrawable.ShaderFactory() {
@Override
public Shader resize(int width, int height) {
AngleCoordinate ac = AngleCoordinate.getAngleCoordinate(gradientAngle, width, height);
LinearGradient linearGradient = new LinearGradient(ac.x1, ac.y1, ac.x2, ac.y2,
colorBoxes,
position,
Shader.TileMode.REPEAT);
return linearGradient;
}
};
PaintDrawable paint = new PaintDrawable();
paint.setShape(new RectShape());
paint.setShaderFactory(shaderFactory);
return paint;
}
/**
* 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(int baseColor, int numStops, int gravity) {
// Generate a cache key by hashing together the inputs, based on the method described in the Effective Java book
int cacheKeyHash = baseColor;
cacheKeyHash = 31 * cacheKeyHash + numStops;
cacheKeyHash = 31 * cacheKeyHash + gravity;
Drawable cachedGradient = cubicGradientScrimCache.get(cacheKeyHash);
if (cachedGradient != null) {
return cachedGradient;
}
numStops = Math.max(numStops, 2);
PaintDrawable paintDrawable = new PaintDrawable();
paintDrawable.setShape(new RectShape());
final int[] stopColors = new int[numStops];
int red = Color.red(baseColor);
int green = Color.green(baseColor);
int blue = Color.blue(baseColor);
int alpha = Color.alpha(baseColor);
for (int i = 0; i < numStops; i++) {
float x = i * 1f / (numStops - 1);
float opacity = MathUtil.constrain(0, 1, (float) Math.pow(x, 3));
stopColors[i] = Color.argb((int) (alpha * opacity), red, green, blue);
}
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) {
return new LinearGradient(
width * x0,
height * y0,
width * x1,
height * y1,
stopColors, null,
Shader.TileMode.CLAMP);
}
});
cubicGradientScrimCache.put(cacheKeyHash, paintDrawable);
return paintDrawable;
}
/**
* 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(int baseColor, int numStops, int gravity) {
// Generate a cache key by hashing together the inputs, based on the method described in the Effective Java book
int cacheKeyHash = baseColor;
cacheKeyHash = 31 * cacheKeyHash + numStops;
cacheKeyHash = 31 * cacheKeyHash + gravity;
Drawable cachedGradient = cubicGradientScrimCache.get(cacheKeyHash);
if (cachedGradient != null) {
return cachedGradient;
}
numStops = Math.max(numStops, 2);
PaintDrawable paintDrawable = new PaintDrawable();
paintDrawable.setShape(new RectShape());
final int[] stopColors = new int[numStops];
int red = Color.red(baseColor);
int green = Color.green(baseColor);
int blue = Color.blue(baseColor);
int alpha = Color.alpha(baseColor);
for (int i = 0; i < numStops; i++) {
float x = i * 1f / (numStops - 1);
float opacity = MathUtil.constrain(0, 1, (float) Math.pow(x, 3));
stopColors[i] = Color.argb((int) (alpha * opacity), red, green, blue);
}
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) {
return new LinearGradient(
width * x0,
height * y0,
width * x1,
height * y1,
stopColors, null,
Shader.TileMode.CLAMP);
}
});
cubicGradientScrimCache.put(cacheKeyHash, paintDrawable);
return paintDrawable;
}
/**
* 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(int baseColor, int numStops, int gravity) {
// Generate a cache key by hashing together the inputs, based on the method described in the Effective Java book
int cacheKeyHash = baseColor;
cacheKeyHash = 31 * cacheKeyHash + numStops;
cacheKeyHash = 31 * cacheKeyHash + gravity;
Drawable cachedGradient = cubicGradientScrimCache.get(cacheKeyHash);
if (cachedGradient != null) {
return cachedGradient;
}
numStops = Math.max(numStops, 2);
PaintDrawable paintDrawable = new PaintDrawable();
paintDrawable.setShape(new RectShape());
final int[] stopColors = new int[numStops];
int red = Color.red(baseColor);
int green = Color.green(baseColor);
int blue = Color.blue(baseColor);
int alpha = Color.alpha(baseColor);
for (int i = 0; i < numStops; i++) {
float x = i * 1f / (numStops - 1);
/* float opacity = MathUtil.constrain(0, 1, (float) Math.pow(x, 3));
stopColors[i] = Color.argb((int) (alpha * opacity), red, green, blue);*/
}
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;
}
});
cubicGradientScrimCache.put(cacheKeyHash, paintDrawable);
return paintDrawable;
}
/**
* 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;
}