小菜最近遇到一个小需求，程序里面有个别页面，需要动态的调整某个页面的样式，包括一键变灰等效果。
      以前页面是用 shape 和 drawable 之类实现的效果。现在需要用 Kotlin/Java 代码实现动态修改。由于小菜技术浅浅，仅整理一下遇到一些坑。

日常应用的样式：

1. 圆角边框

默认 shape.xml 方式：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <stroke
        android:width="0.5dp"
        android:color="@color/colorAccent" />
    <corners android:radius="15dp" />
</shape>

现 Kotlin/Java 方式动态修改边框颜色：

var myGrad = tv2!!.getBackground() as GradientDrawable
myGrad.setStroke(1, resources.getColor(R.color.colorPrimary))

Tips: GradientDrawable 对象可设置 shape 边框属性(矩形/椭圆等)、stroke 边框宽度和颜色、cornerRadius 圆角角度、color 填充背景色。

2. 圆角边框填充颜色

默认 shape.xml 方式：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/colorAccent" />
    <stroke
        android:width="0.5dp"
        android:color="@color/colorAccent" />
    <corners android:radius="15dp" />
</shape>

现 Kotlin/Java 方式动态修改边框颜色及填充背景色：

var myGrad = tv3!!.getBackground() as GradientDrawable
myGrad.setStroke(1, resources.getColor(R.color.colorPrimary))
myGrad.setColor(resources.getColor(R.color.colorPrimary))

3. 圆角边框填充颜色，点击变更背景色

默认 shape.xml 方式：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/drawable_test1" android:state_pressed="true" />
    <item android:drawable="@drawable/drawable_test2" android:state_focused="false" android:state_pressed="false" />
    <item android:drawable="@drawable/drawable_test1" android:state_focused="true" />
    <item android:drawable="@drawable/drawable_test2" android:state_focused="false" />
</selector>

现 Kotlin/Java 方式动态修改边框颜色填充背景色，点击变更背景色：

var myGrad1 = GradientDrawable()
myGrad1.setStroke(1, resources.getColor(R.color.colorPrimary))
myGrad1.cornerRadius = 80.0f
myGrad1.setColor(resources.getColor(R.color.colorPrimary))
var myGrad2 = GradientDrawable()
myGrad2.setStroke(1, resources.getColor(R.color.colorPrimary))
myGrad2.cornerRadius = 80.0f
myGrad2.setColor(resources.getColor(R.color.white))

tv4!!.background = BitmapUtil.addStateDrawable1(context, myGrad3, myGrad4, myGrad4, myGrad4)

public static StateListDrawable addStateDrawable1(Context context, Drawable idNormal, Drawable idPressed, Drawable idFocused, Drawable idUnable) {
    StateListDrawable bg = new StateListDrawable();
    Drawable normal = idNormal;
    Drawable pressed = idPressed;
    Drawable focused = idFocused;
    Drawable unable = idUnable;
    // View.PRESSED_ENABLED_STATE_SET
    bg.addState(new int[] { android.R.attr.state_pressed, android.R.attr.state_enabled }, pressed);
    // View.ENABLED_FOCUSED_STATE_SET
    bg.addState(new int[] { android.R.attr.state_enabled, android.R.attr.state_focused }, focused);
    // View.ENABLED_STATE_SET
    bg.addState(new int[] { android.R.attr.state_enabled }, normal);
    // View.FOCUSED_STATE_SET
    bg.addState(new int[] { android.R.attr.state_focused }, focused);
    // View.WINDOW_FOCUSED_STATE_SET
    bg.addState(new int[] { android.R.attr.state_window_focused }, unable);
    // View.EMPTY_STATE_SET
    bg.addState(new int[] {}, normal);
    return bg;
}

Tips: StateListDrawable 设置 View 绘制不同状态背景图片，小菜测试中，发现需要设置点击事件或者 Pressed/Focused 状态，小菜认为如果只是设置 StateListDrawable 默认是 normal 样式，不会有点击效果。

4. 圆角边框填充颜色，点击变更背景色及文字颜色

默认 color.xml 方式：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="@color/colorAccent" android:state_selected="true" />
    <item android:color="@color/colorAccent" android:state_focused="true" />
    <item android:color="@color/colorAccent" android:state_pressed="true" />
    <item android:color="@color/white" />
</selector>

现 Kotlin/Java 方式动态修改边框颜色填充背景色，点击变更背景色及文字颜色：

tv5!!.setTextColor(BitmapUtil.createColorStateList(getResources().getColor(R.color.white), getResources().getColor(R.color.colorPrimary),
                getResources().getColor(R.color.colorPrimary), getResources().getColor(R.color.colorPrimary)));

public static ColorStateList createColorStateList(int normal, int pressed, int focused, int unable) {
    int[] colors = new int[] { pressed, focused, normal, focused, unable, normal };
    int[][] states = new int[6][];
    states[0] = new int[] { android.R.attr.state_pressed, android.R.attr.state_enabled };
    states[1] = new int[] { android.R.attr.state_enabled, android.R.attr.state_focused };
    states[2] = new int[] { android.R.attr.state_enabled };
    states[3] = new int[] { android.R.attr.state_focused };
    states[4] = new int[] { android.R.attr.state_window_focused };
    states[5] = new int[] {};
    ColorStateList colorList = new ColorStateList(states, colors);
    return colorList;
}

Tips: 小菜建议在编辑 color.xml 时，新建在 color 资源文件夹下。ColorStateList 对象设置文字点击时不同状态等文字效果。

5. 部分圆角边框填充颜色

默认 shape.xml 方式：

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="@color/colorAccent" />
    <stroke
        android:width="0.5dp"
        android:color="@color/colorAccent" />
    <corners
        android:bottomLeftRadius="15dp"
        android:topLeftRadius="15dp" />
</shape>

现 Kotlin/Java 方式动态修改部分圆角边框：

var myGrad = GradientDrawable()
var farr = floatArrayOf(80.0f, 80.0f, 0.0f, 0.0f, 0.0f, 0.0f, 80.0f, 80.0f)
myGrad.cornerRadii = farr
myGrad.setStroke(1, resources.getColor(R.color.colorPrimary))
myGrad.setColor(resources.getColor(R.color.colorPrimary))
tv6!!.background = myGrad

Tips: GradientDrawable 对象中，若设置四个圆角一致时，可设置 cornerRadius 属性；若设置部分圆角时，可设置 cornerRadii 属性，该属性包括 8 个 float 参数 (左上[X_Radius,Y_Radius],右上[X_Radius,Y_Radius],右下[X_Radius,Y_Radius],左下[X_Radius,Y_Radius]) 且只有设置 [X_Radius,Y_Radius] 两个参数时起作用。

6. 图标绘色

默认设置 tint 属性：

<ImageView
    android:id="@+id/drawable_iv3"
    android:layout_width="50dp"
    android:layout_height="50dp"
    android:layout_marginTop="20dp"
    android:src="@mipmap/icon_zan"
    android:tint="@color/colorAccent" />

现 Kotlin/Java 方式对图标绘色：

var plabit = BitmapUtil.drawableToBitmap3(resources.getDrawable(R.mipmap.icon_zan))
plabit = BitmapUtil.tintBitmap(plabit, resources.getColor(R.color.inactive_bottom_navigation))
iv2!!.setImageDrawable(BitmapDrawable(plabit))

public static Bitmap drawableToBitmap3(Drawable drawable) {
    Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
                drawable.getIntrinsicHeight(),
                drawable.getOpacity() != PixelFormat.OPAQUE ? Bitmap.Config.ARGB_8888
                        : Bitmap.Config.RGB_565);
    Canvas canvas = new Canvas(bitmap);
    drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    drawable.draw(canvas);
    return bitmap;
}

Tips: 用该方法绘制颜色时，建议不要设置图片的 tint 属性。

7. 图片灰度

设置 ColorMatrix 对象的 Saturation 属性：

val matrixpic = ColorMatrix()
matrixpic.setSaturation(0f)//饱和度 0灰色 100过度彩色，50正常
val filter = ColorMatrixColorFilter(matrixpic)
iv1!!.setColorFilter(filter)

GitHub 实例

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