Android shape动态修改颜色

package android.graphics.drawable;

import ...

/**
 * ...
 * @attr ref android.R.styleable#GradientDrawableStroke_color
 * ...
 */
public class GradientDrawable extends Drawable {
    ....
    private void updateGradientDrawableStroke(TypedArray a) {
        final GradientState st = mGradientState;

        // Account for any configuration changes.
        st.mChangingConfigurations |= a.getChangingConfigurations();

        // Extract the theme attributes, if any.
        st.mAttrStroke = a.extractThemeAttrs();

        // We have an explicit stroke defined, so the default stroke width
        // must be at least 0 or the current stroke width.
        final int defaultStrokeWidth = Math.max(0, st.mStrokeWidth);
        final int width = a.getDimensionPixelSize(
                R.styleable.GradientDrawableStroke_width, defaultStrokeWidth);
        final float dashWidth = a.getDimension(
                R.styleable.GradientDrawableStroke_dashWidth, st.mStrokeDashWidth);

        ColorStateList colorStateList = a.getColorStateList(
                R.styleable.GradientDrawableStroke_color);
        if (colorStateList == null) {
            colorStateList = st.mStrokeColors;
        }

        if (dashWidth != 0.0f) {
            final float dashGap = a.getDimension(
                    R.styleable.GradientDrawableStroke_dashGap, st.mStrokeDashGap);
            setStroke(width, colorStateList, dashWidth, dashGap);
        } else {
            setStroke(width, colorStateList);
        }
    }
    ....
    /**
     * 
Set the stroke width and color for the drawable. If width is zero,
     * then no stroke is drawn.
     * 
Note: changing this property will affect all instances
     * of a drawable loaded from a resource. It is recommended to invoke
     * {@link #mutate()} before changing this property.
     *
     * @param width The width in pixels of the stroke
     * @param color The color of the stroke
     *
     * @see #mutate()
     * @see #setStroke(int, int, float, float)
     */
    public void setStroke(int width, @ColorInt int color) {
        setStroke(width, color, 0, 0);
    }

    /**
     * 
Set the stroke width and color state list for the drawable. If width
     * is zero, then no stroke is drawn.
     * 
Note: changing this property will affect all instances
     * of a drawable loaded from a resource. It is recommended to invoke
     * {@link #mutate()} before changing this property.
     *
     * @param width The width in pixels of the stroke
     * @param colorStateList The color state list of the stroke
     *
     * @see #mutate()
     * @see #setStroke(int, ColorStateList, float, float)
     */
    public void setStroke(int width, ColorStateList colorStateList) {
        setStroke(width, colorStateList, 0, 0);
    }

    /**
     * 
Set the stroke width and color for the drawable. If width is zero,
     * then no stroke is drawn. This method can also be used to dash the stroke.
     * 
Note: changing this property will affect all instances
     * of a drawable loaded from a resource. It is recommended to invoke
     * {@link #mutate()} before changing this property.
     *
     * @param width The width in pixels of the stroke
     * @param color The color of the stroke
     * @param dashWidth The length in pixels of the dashes, set to 0 to disable dashes
     * @param dashGap The gap in pixels between dashes
     *
     * @see #mutate()
     * @see #setStroke(int, int)
     */
    public void setStroke(int width, @ColorInt int color, float dashWidth, float dashGap) {
        mGradientState.setStroke(width, ColorStateList.valueOf(color), dashWidth, dashGap);
        setStrokeInternal(width, color, dashWidth, dashGap);
    }

    /**
     * 
Set the stroke width and color state list for the drawable. If width
     * is zero, then no stroke is drawn. This method can also be used to dash
     * the stroke.
     * 
Note: changing this property will affect all instances
     * of a drawable loaded from a resource. It is recommended to invoke
     * {@link #mutate()} before changing this property.
     *
     * @param width The width in pixels of the stroke
     * @param colorStateList The color state list of the stroke
     * @param dashWidth The length in pixels of the dashes, set to 0 to disable dashes
     * @param dashGap The gap in pixels between dashes
     *
     * @see #mutate()
     * @see #setStroke(int, ColorStateList)
     */
    public void setStroke(
            int width, ColorStateList colorStateList, float dashWidth, float dashGap) {
        mGradientState.setStroke(width, colorStateList, dashWidth, dashGap);
        final int color;
        if (colorStateList == null) {
            color = Color.TRANSPARENT;
        } else {
            final int[] stateSet = getState();
            color = colorStateList.getColorForState(stateSet, 0);
        }
        setStrokeInternal(width, color, dashWidth, dashGap);
    }

}

还有其它的相关属性都可以根据源码中的实现和开放的api进行 *** 作。
不再一一列举，熟读源码即可。
或者参考文章尾部的官方Api文档。

https://developer.android.google.cn/reference/android/graphics/drawable/GradientDrawable