Java实验(18) 幻灯片放映

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写一个程序，将54张扑克牌图片，按照每次1张，每张1秒的放映间隔，按顺序循环显示图片。并且要求：(1)向上箭头加快放映速度；向下箭头减缓放映速度；(2)双击鼠标左键暂停放映，再次双击则继续。

程序界面自定。

1、读取图片

a）用一个大小为55的ImagView数组存储读取的54张图片（0号位置不使用）。

ImageView []imag=new ImageView[55];

b）读取图片的方法：

public static ImageView readImageFromJar(Stringjarname, Stringpicname){

ImageView imageView =null;

try {

JarFile jarFile =new JarFile(jarname);

JarEntry entry =jarFile.getJarEntry(picname);

InputStream in =jarFile.getInputStream(entry);

imageView =new ImageView(new Image(in));

in.close();

jarFile.close();

}

catch (IOExceptione) {

System.err.println("read file error.");

}

return imageView;

}

c）读取图片到imag[]

for(int i=1;i<=54;i++){

String card=new String("cards/"+String.valueOf(i)+".png");

imag[i]=readImageFromJar("cards.jar",card);

}

2、事件

a）自动放映图片，事件间隔1s

EventHandler<ActionEvent> eventHandler =e->{

if(n==55)

n=1;

pane.getChildren().add(imag[n]);

n++;

};

Timeline animation =new Timeline(new KeyFrame(Duration.seconds(1),eventHandler));

animation.setCycleCount(Timeline.INDEFINITE);

animation.play();

b）双击暂停和开始

pane.setOnMouseClicked(e->{

if(animation.getStatus()==Animation.Status.PAUSED &&e.getClickCount()==2){

animation.play(); //双击原本暂停的开始

}

else if(e.getClickCount()==2){

animation.pause(); //双击暂停

}

});

c）加速(UP)和减速(DOWN)

pane.setOnKeyPressed(e->{

switch(e.getCode()){

case UP:animation.setRate(animation.getRate()+1);

case DOWN:animation.setRate(animation.getRate()-1);

}

});

3、补充说明

a）用一个全局变量n记录卡牌序号，当播放到第54张后返回1。

b）将焦点集中在pane上，可以根据鼠标指令进行相对的事件处理。

import java.io.IOException;import java.io.InputStream;import java.util.jar.JarEntry;import java.util.jar.JarFile;import javafx.animation.Animation;import javafx.animation.KeyFrame;import javafx.animation.Timeline;import javafx.application.Application;import javafx.event.ActionEvent;import javafx.event.EventHandler;import javafx.scene.Scene;import javafx.scene.image.Image;import javafx.scene.image.ImageView;import javafx.scene.layout.StackPane;import javafx.stage.Stage;import javafx.util.Duration;public class DisplayCards extends Application {    int n=1;    ImageView []imag=new ImageView[55];    public static ImageView readImageFromJar(String jarname, String picname){        ImageView imageView = null;        try {            JarFile jarFile = new JarFile(jarname);            JarEntry entry = jarFile.getJarEntry(picname);            InputStream in = jarFile.getInputStream(entry);            imageView = new ImageView(new Image(in));            in.close();            jarFile.close();        }         catch (IOException e) {            System.err.println("read file error.");        }        return imageView;    }    @Override    public void start(Stage primaryStage) {        StackPane pane = new StackPane();        for(int i=1;i<=54;i++){            String card=new String("cards/"+String.valueOf(i)+".png");            imag[i]=readImageFromJar("cards.jar",card);        }                EventHandler<ActionEvent> eventHandler = e->{            if(n==55)                n=1;            pane.getChildren().add(imag[n]);             n++;        };        Timeline animation = new Timeline(new KeyFrame(Duration.seconds(1),eventHandler));        animation.setCycleCount(Timeline.INDEFINITE);        animation.play();        pane.setOnMouseClicked(e->{            if(animation.getStatus()==Animation.Status.PAUSED && e.getClickCount()==2){                animation.play();            }            else if(e.getClickCount()==2){                animation.pause();            }        });        pane.setOnKeyPressed(e->{            switch(e.getCode()){                case UP:animation.setRate(animation.getRate()+1);                case DOWN:animation.setRate(animation.getRate()-1);            }        });                Scene scene = new Scene(pane, 300, 250);        primaryStage.setTitle("DisplayCards");        primaryStage.setScene(scene);        primaryStage.show();        pane.requestFocus();    }    public static void main(String[] args) {        launch(args);    }}

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