小菜刚学习了 HarmonyOS 中 Button 的不同样式，其中背景效果主要是通过 shape 文件进行修改，对于渐变色等效果是通过 Java 的 ShapeElement 方式进行修改，小菜今天详细学习一下 ShapeElement 背景设置；
ShapeElement
与 Android 类似，HarmonyOS 同样可以使用 xml 和 Java 两种方式对组件样式进行绘制；
1. 引入 shape.xml 方式
小菜查看 ShapeElement 源码，有无参构造函数和两个参数的构造函数；带有参数的构造方法可以直接引入 shape.xml 文件，第一个参数是上下文环境，第二个参数是引入对应的 shape.xml 文件；
public ShapeElement(Context context, int xmlId) {
throw new RuntimeException("Stub!");
}
Component component01 = (Component) findComponentById(ResourceTable.Id_test_component1);
ShapeElement shapeElement = new ShapeElement(getContext(), ResourceTable.Graphic_shape_stroke);
component01.setBackground(shapeElement);
2. set/getShape 设置/获取样式
小菜查看源码，可以通过 set/getShape 方式设置和获取样式，包括：RECTANGLE 矩形、OVAL 圆形、PATH 路径、ARC 弧形、LINE 线形；
public void setShape(int shape) {
throw new RuntimeException("Stub!");
}
public int getShape() {
throw new RuntimeException("Stub!");
}
private ShapeElement shapeElement01(int shape) {
ShapeElement shapeElement = new ShapeElement();
shapeElement.setShape(shape);
shapeElement.setRgbColor(RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)));
return shapeElement;
}
Component component02 = (Component) findComponentById(ResourceTable.Id_test_component2);
component02.setBackground(shapeElement01(ShapeElement.RECTANGLE));
Component component03 = (Component) findComponentById(ResourceTable.Id_test_component3);
component03.setBackground(shapeElement01(ShapeElement.OVAL));
3. set/getRgbColor & set/getRgbColors 设置/获取颜色
ShapeElement 可以通过 setRgbColor 和 setRgbColors 两种方式设置背景色，setRgbColor 为设置单色，setRgbColors 用于添加颜色数组，设置渐变色；
public void setRgbColor(RgbColor color) {
throw new RuntimeException("Stub!");
}
public void setRgbColors(RgbColor[] colors) {
throw new RuntimeException("Stub!");
}
public RgbColor[] getRgbColors() {
throw new RuntimeException("Stub!");
}
public void setRgbColor(RgbColor color) {
throw new RuntimeException("Stub!");
}
private ShapeElement shapeElement02(int shape, boolean isRgbColor, RgbColor rgbColor, RgbColor[] rgbColors) {
ShapeElement shapeElement = new ShapeElement();
shapeElement.setShape(shape);
if (isRgbColor) {
shapeElement.setRgbColor(rgbColor);
} else {
shapeElement.setRgbColors(rgbColors);
}
return shapeElement;
}
Component component04 = (Component) findComponentById(ResourceTable.Id_test_component4);
component04.setBackground(shapeElement02(ShapeElement.RECTANGLE, true, RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)), null));
Component component05 = (Component) findComponentById(ResourceTable.Id_test_component5);
RgbColor[] rgbColors = new RgbColor[]{
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)),
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_center)),
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end))};
component05.setBackground(shapeElement02(ShapeElement.RECTANGLE, false, null, rgbColors));
4. setStroke 设置边框
可以通过 setStroke 设置边框样式，参数分别对应边框宽度和颜色；
public void setStroke(int width, RgbColor color) {
throw new RuntimeException("Stub!");
}
public int getStrokeWidth() {
throw new RuntimeException("Stub!");
}
public RgbColor getStrokeColor() {
throw new RuntimeException("Stub!");
}
private ShapeElement shapeElement03(int shape, int width, RgbColor rgbColor) {
ShapeElement shapeElement = new ShapeElement();
shapeElement.setShape(shape);
shapeElement.setRgbColor(RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)));
shapeElement.setStroke(width, rgbColor);
return shapeElement;
}
Component component06 = (Component) findComponentById(ResourceTable.Id_test_component6);
component06.setBackground(shapeElement03(ShapeElement.RECTANGLE, 4, RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end))));
Component component07 = (Component) findComponentById(ResourceTable.Id_test_component7);
component07.setBackground(shapeElement03(ShapeElement.RECTANGLE, 8, RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end))));
5. set/getCornerRadius & setCornerRadiiArray 设置圆角
ShapeElement 提供了两种设置圆角的方式，分别为 setCornerRadius 设置四角相同的圆角和 setCornerRadiiArray 分别设置四个圆角方式；其中 setCornerRadiiArray 需要设置 8 个 float 元素，角度分别从左上角顺时针分布；
public void setCornerRadius(float radius) {
throw new RuntimeException("Stub!");
}
public float getCornerRadius() {
throw new RuntimeException("Stub!");
}
public void setCornerRadiiArray(float[] radii) {
throw new RuntimeException("Stub!");
}
public float[] getCornerRadii() {
throw new RuntimeException("Stub!");
}
private ShapeElement shapeElement04(int shape, boolean isSameRadius, float radius, float[] radii) {
ShapeElement shapeElement = new ShapeElement();
shapeElement.setShape(shape);
shapeElement.setRgbColor(RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)));
shapeElement.setStroke(8, RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end)));
if (isSameRadius) {
shapeElement.setCornerRadius(radius);
} else {
shapeElement.setCornerRadiiArray(radii);
}
return shapeElement;
}
Component component08 = (Component) findComponentById(ResourceTable.Id_test_component8);
component08.setBackground(shapeElement04(ShapeElement.RECTANGLE, true, 20.0f, null));
Component component09 = (Component) findComponentById(ResourceTable.Id_test_component9);
float[] radii = {60.0f, 60.f, 20.f, 20.0f, 60.0f, 60.f, 20.f, 20.0f};
component09.setBackground(shapeElement04(ShapeElement.RECTANGLE, false, 0.0f, radii));
6. set/getGradientOrientation 设置/获取渐变色方向
对于渐变色的渐变方向，可以通过 setGradientOrientation 方式设置，可以按需求设置水平方向，或对角线方向等；
public void setGradientOrientation(ShapeElement.Orientation orientation) {
throw new RuntimeException("Stub!");
}
public ShapeElement.Orientation getGradientOrientation() {
throw new RuntimeException("Stub!");
}
private ShapeElement shapeElement05(int shape, ShapeElement.Orientation orientation) {
ShapeElement shapeElement = new ShapeElement();
shapeElement.setShape(shape);
RgbColor[] rgbColors = new RgbColor[]{
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_start)),
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_center)),
RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end))};
shapeElement.setRgbColors(rgbColors);
shapeElement.setStroke(8, RgbColor.fromArgbInt(getColor(ResourceTable.Color_color_btn_end)));
shapeElement.setCornerRadius(20.0f);
shapeElement.setGradientOrientation(orientation);
return shapeElement;
}
Component component10 = (Component) findComponentById(ResourceTable.Id_test_component10);
component10.setBackground(shapeElement05(ShapeElement.RECTANGLE, ShapeElement.Orientation.BOTTOM_RIGHT_TO_TOP_LEFT));
Component component11 = (Component) findComponentById(ResourceTable.Id_test_component11);
component11.setBackground(shapeElement05(ShapeElement.RECTANGLE, ShapeElement.Orientation.LEFT_TO_RIGHT));
Component component12 = (Component) findComponentById(ResourceTable.Id_test_component12);
component12.setBackground(shapeElement05(ShapeElement.RECTANGLE, ShapeElement.Orientation.TOP_END_TO_BOTTOM_START));
小菜对 ShapeElement 的方式还不够熟悉，还有几个方法需要深入研究；如有错误，请多多指导！
来源：阿策小和尚
