Class 'ActionMainFragmentToDetailFragment' is not abstract and does not implement abstract member public abstract fun getActionId(): Int defined in androidx.navigation.NavDirections
时间: 2024-03-29 14:40:20 浏览: 12
这错误通常表示 `ActionMainFragmentToDetailFragment` 没有正确实现 `getActionId()` 方法。这个方法是一个抽象方法,需要在 `ActionMainFragmentToDetailFragment` 中实现。你需要检查一下 `ActionMainFragmentToDetailFragment` 的实现是否有这个方法,如果没有,你需要添加这个方法并返回一个 `Int` 类型的值。此外,确保你的代码中没有重复定义同名的方法。如果问题仍然存在,你可以检查一下导航组件的配置是否正确。
相关问题
complete abstract class GraphicObject and implement subclasses Cone , Cuboid and Sphere based on the class GraphicObject .
Here is an example implementation of the abstract class GraphicObject and its subclasses Cone, Cuboid, and Sphere:
```java
abstract class GraphicObject {
protected int x, y;
public GraphicObject(int x, int y) {
this.x = x;
this.y = y;
}
abstract double area();
abstract double perimeter();
}
class Cone extends GraphicObject {
private int radius;
private int height;
public Cone(int x, int y, int radius, int height) {
super(x, y);
this.radius = radius;
this.height = height;
}
@Override
double area() {
return Math.PI * radius * (radius + Math.sqrt(Math.pow(height, 2) + Math.pow(radius, 2)));
}
@Override
double perimeter() {
return 2 * Math.PI * radius;
}
}
class Cuboid extends GraphicObject {
private int length;
private int width;
private int height;
public Cuboid(int x, int y, int length, int width, int height) {
super(x, y);
this.length = length;
this.width = width;
this.height = height;
}
@Override
double area() {
return 2 * (length * width + width * height + height * length);
}
@Override
double perimeter() {
return 4 * (length + width + height);
}
}
class Sphere extends GraphicObject {
private int radius;
public Sphere(int x, int y, int radius) {
super(x, y);
this.radius = radius;
}
@Override
double area() {
return 4 * Math.PI * Math.pow(radius, 2);
}
@Override
double perimeter() {
return 2 * Math.PI * radius;
}
}
```
The abstract class `GraphicObject` defines the common properties and methods that all subclasses must implement. The `Cone`, `Cuboid`, and `Sphere` classes extend the `GraphicObject` class and provide their own implementations of the `area()` and `perimeter()` methods.
For example, the `Cone` class calculates the surface area and circumference of a cone based on its radius and height, while the `Cuboid` class calculates the surface area and perimeter of a rectangular cuboid based on its length, width, and height. The `Sphere` class calculates the surface area and circumference of a sphere based on its radius.
Note that the `GraphicObject` class is abstract and cannot be instantiated directly. Instead, it provides a template for creating subclasses that represent specific types of geometric objects.
java.io.IOException: java.lang.RuntimeException: Class suc.vo.Person does not implement Serializable or externalizable是什么错误
这个错误发生在您尝试将一个未实现`Serializable`或`Externalizable`接口的对象序列化时。序列化是将对象转换为字节流以便于存储或传输的过程。
在Java中,要使一个类可序列化,需要实现`Serializable`接口。例如:
```java
import java.io.Serializable;
public class Person implements Serializable {
// 类的成员和方法
// ...
}
```
如果您尝试将一个未实现`Serializable`接口的对象序列化,就会出现上述错误。您需要确保要序列化的类实现了`Serializable`接口。这样,Java序列化机制才能正确地将对象转换为字节流。
如果您正在使用第三方库或框架,可能需要查看相关文档以确定是否需要实现其他接口或采取其他措施以使对象可序列化。