Java 中的适配器类并不是什么新鲜事。它们用于提供 Listener 接口的实现。适配器类的优点是节省代码。如果我们使用Adapter接口继承适配器类，我们就不会被迫实现所有监听器接口方法。 Java 适配器类位于三个包中。这三个套餐分别是：
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此外，适配器类的另一个优点是，当我们想要处理由特定事件侦听器接口处理的一些事件时，它们非常有用。
正如我们在简介中注意到的，我们在三个包中找到适配器类。我们现在将在所有三个包中看到相应适配器类的相应监听器接口。
下面是一些 Adapter 类及其相应的监听器接口。这些都存在于 Java 包的 Abstract Window Toolkit 中。
|
Adapter Class |
Listener Interface |
| WindowAdapter | WindowListener |
| KeyAdapter | KeyListener |
| MouseAdapter | MouseListener |
| MouseMotionAdapter | MouseMotionListener |
| FocusAdapter | FocusListener |
| ComponentAdapter | ComponentListener |
| ContainerAdapter | ContainerListener |
| HierarchyBoundsAdapter | HierarchyBoundsListener |
监听器接口
AdapterExample()
{
f=new Frame("Hello World");
f.addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
{
f.close();
}
}KeyAdapter 类
下面的代码给出了 KeyAdapter 类的语法。public abstract keyAdapter Class extends Object Implements KeyListener
MouseAdapter 类
下面的代码给出了 MouseAdapter 类的语法。MouseAdapterExample()
{
f=new Frame("Mouse Adapter");
f.addMouseListener(this);
f.setSize(100,100);
f.setLayout(null);
f.setVisible(false);
}MouseMotionAdapter 类
下面的代码给出了 MouseMotionAdapter 类的语法。MouseMotionAdapterExample()
{
f=new Frame("Adapter for Mouse Motion");
f.addMouseMotionListener(this);
f.setSize(100,100);
f.setLayout(null);
f.setVisible(false);
}
public void mouseDragged(MouseEvent e)
{
Graphics g=f.getGraphics();
g.setColor(Color.ORANGE);
g.fillOval(e.getX(),e.getY(),20,20);
}FocusAdapter 类
下面的代码给出了 FocusAdapter 类的语法。public abstract class FocusAdapter extends Object Implements FocusListener
ComponentAdapter 类
下面的代码给出了 ComponentAdapter 类的语法。class MyAdapter extends ComponentAdapter
{
public void componentMoved(ComponentEvent e)
{
int a = e.getComponent().getX();
int b = e.getComponent().getY();
System.out.println("Value of X " + a);
System.out.println("Value of Y: " + b);
}
}ContainerAdapter 类
下面的代码给出了 ContainerAdapter 类的语法。public abstract class ContainerAdapter extends Object implements ContainerListener
HierarchyBoundsAdapter 类
下面的代码给出了 HierarchyBoundsAdapter 类的语法。public abstract class HierarchyBoundsAdapter extends Object implements HierarchyBoundsListener
| Adapter Class | Listener Interface |
| DragSourceAdapter | DragSourceListener |
| DragTargetAdapter | DragTargetListener |
In this case, there are two Adapter classes under the respective package, which is called. We will see the syntax of the two Adapter classes and study the codes under the respective package.
The below code gives the syntax of the DragSourceAdapter class.
Syntax:
public abstract class DragSourceAdapter extends Object implements DragSourceAdapterListener
The below code gives the syntax of the DragTargetAdapter class.
Syntax:
public abstract class DragTargetAdapter extends Object implements DragTargetAdapterListener
Below are some of the classes which are used in the swing. event package. They are listed down in a table.
| Adapter Class | Listener Interface |
| MouseInputAdapter | MouseInputListener |
| InternalFrameAdapter | InternalFrameListener |
In this case, we notice two adapter classes along with their Listener Interface. The package javax. swing. event has two adapter classes which are respectively listed down in the table.
Below is the code which provides the syntax of the MouseInputAdapter class.
Syntax:
public abstract class MouseInputAdapter extends MouseAdapter implements MouseInputListener
Below is the code which provides the syntax of the InternalFrameAdapter class.
Syntax:
public abstract class InternalFrameAdapter extends Object implements InternalFrameListener
Adapter Classes are basically used in the case when the class is declared as abstract. Only the working is based on different functionalities, including the working of the Java classes, which are part of different Java packages. There are three packages in Java that have different Adapter classes and Listener Interfaces along with them. Adapter Classes are used in numerous cases where servers are used, and there is connectivity with the SQL database.
There are different functionalities, and mostly all of them are being used in Android programming as well. Adapter Classes are well-known functionality in Java programming, which helps coders get the idea of many applications that can be used via Swing methodology. There are many ideas that can be put forward to develop the Adapter Class methodology in Java. Loops can also be incorporated to develop some other types of functionality.
In this article, we see the working, and we see that there are three main packages that contain the adapter classes. We see the syntax of all the adapter classes which are present, as well as some of the codes of the working, are also provided. Adapter classes are basically unique in Java, and they are part of Swing functionality in Java.
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