Java 适配器类

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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• java.awt。活动
• java.awt。哒哒
• java.swing。活动

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。

使用语法在 Java 中使用适配器类

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。

• java.awt。事件适配器类
• java.awt.dnd 适配器类
• java.摇摆。事件适配器类

1. java.awt。事件适配器类

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

适配器类

监听器接口

窗口适配器 窗口监听器 密钥适配器 按键监听器 鼠标适配器 鼠标监听器 MouseMotionAdapter MouseMotionListener 焦点适配器 焦点监听器 组件适配器 组件监听器 容器适配器 容器监听器 HierarchyBoundsAdapter HierarchyBoundsListener 表> WindowAdapter 类 下面的代码给出了 Adapter 类的语法，它让我们了解 WindowAdapter 类的外观和语法。

AdapterExample()
{
f=new Frame("Hello World");
f.addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
{
f.close();
}
}

语法：

KeyAdapter 类

下面的代码给出了 KeyAdapter 类的语法。

public abstract keyAdapter Class
extends Object
Implements KeyListener

语法：

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);
}

语法：

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);
}

语法：

FocusAdapter 类

下面的代码给出了 FocusAdapter 类的语法。

public abstract class FocusAdapter
extends Object
Implements FocusListener

语法：

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);
}
}

语法：

ContainerAdapter 类

下面的代码给出了 ContainerAdapter 类的语法。

public abstract class ContainerAdapter
extends Object
implements ContainerListener

语法：

HierarchyBoundsAdapter 类

下面的代码给出了 HierarchyBoundsAdapter 类的语法。

public abstract class HierarchyBoundsAdapter
extends Object
implements HierarchyBoundsListener 

语法：

Adapter Class	Listener Interface
DragSourceAdapter	DragSourceListener
DragTargetAdapter	DragTargetListener

2. java.awt.dnd 适配器类 下面是 awt.dnd 包中使用的一些适配器类。它们列在表格中。 适配器类 监听器接口 DragSourceAdapter DragSourceListener DragTargetAdapter DragTargetListener 表>

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.

DragSourceAdapter Class

The below code gives the syntax of the DragSourceAdapter class.

Syntax:

public abstract class DragSourceAdapter
extends Object
implements DragSourceAdapterListener

DragTargetAdapter Class

The below code gives the syntax of the DragTargetAdapter class.

Syntax:

public abstract class DragTargetAdapter
extends Object
implements DragTargetAdapterListener

3. java.swing. event Adapter Classes

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.

MouseInputAdapter Class

Below is the code which provides the syntax of the MouseInputAdapter class.

Syntax:

public abstract class MouseInputAdapter
extends MouseAdapter
implements MouseInputListener

InternalFrameAdapter Class

Below is the code which provides the syntax of the InternalFrameAdapter class.

Syntax:

public abstract class InternalFrameAdapter
extends Object
implements InternalFrameListener

Explanation

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.

Conclusion

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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