需要帮助显示来自url或filechooser的图像

Question

我无法使用url或filechooser显示图像。我已经实现了方法来从URL或从PC拉文件只是不知道如何显示这些图像。

这里就是我所说的，从一个网址拉法：

@FXML 
private void button0Action (ActionEvent event) throws IOException { 

     catdog c = new catdog(); 
     String cat = c.cat();   
     System.out.println(cat); 

输出对话框返回的网址： http://24.media.tumblr.com/tumblr_llmbvhAcsF1qg20muo1_500.gif

这里是我的Display类：

package screensaver; 

import javafx.application.Application; 
import javafx.geometry.Pos; 
import javafx.scene.Scene; 
import javafx.scene.layout.GridPane; 
import javafx.stage.Stage; 

public class Display extends Application { 
    @Override // Override the start method in the Application class 
    public void start(Stage primaryStage) { 
     GridPane pane = new GridPane(); 
     pane.setAlignment(Pos.CENTER); 
     pane.setHgap(0); 
     pane.setVgap(0); 

     Scene scene = new Scene(pane); 
     primaryStage.setTitle("imageViewer"); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } 
} 

创建Display and ImageView的新实例：

@FXML 
private void button0Action (ActionEvent event) throws IOException { 

     catdog c = new catdog(); 
     String cat = c.cat();   
     System.out.println(cat); 

     Display catDisplay = new Display(); 
     ImageView catImage = new ImageView(cat); 

} 

我该如何将图像添加到窗格并调用start方法来显示场景？我知道我可以在Display类中创建一个ImageView实例，然后将图像添加到窗格中，但我无法从button0Action方法中拉出包含url的变量cat。目前陷入困境，不知道该从哪里出发。过去几天一直在努力尝试不同的方法，但没有运气。有任何想法吗？

这里是我的变化，到目前为止：

显示类：发生

package screensaver; 

import java.io.IOException; 
import javafx.geometry.Pos; 
import javafx.scene.Scene; 
import javafx.scene.image.ImageView; 
import javafx.scene.layout.GridPane; 
import javafx.stage.Stage; 

public class Display { 
public void showImage0 (String url) throws IOException { 

    Stage stage = new Stage(); 
    GridPane pane = new GridPane(); 
    pane.setAlignment(Pos.CENTER); 
    pane.setHgap(0); 
    pane.setVgap(0); 

    Catdog c = new Catdog(); 
    pane.getChildren().add(new ImageView(c.cat())); 

    Scene scene = new Scene(pane); 
    stage.setTitle("imageViewer"); 
    stage.setScene(scene); 
    stage.show(); 
} 

public void showImage1 (String url) throws IOException { 

    Stage stage = new Stage(); 
    GridPane pane = new GridPane(); 
    pane.setAlignment(Pos.CENTER); 
    pane.setHgap(0); 
    pane.setVgap(0); 

    Catdog d = new Catdog(); 
    pane.getChildren().add(new ImageView(d.dog())); 

    Scene scene = new Scene(pane); 
    stage.setTitle("imageViewer"); 
    stage.setScene(scene); 
    stage.show(); 
} 

public void showImage2 (String url) throws IOException { 

    Stage stage = new Stage(); 
    GridPane pane = new GridPane(); 
    pane.setAlignment(Pos.CENTER); 
    pane.setHgap(0); 
    pane.setVgap(0); 

    LandscapeImage lI = new LandscapeImage(); 
    pane.getChildren().add(new ImageView(lI.imageSource)); 

    Scene scene = new Scene(pane); 
    stage.setTitle("imageViewer"); 
    stage.setScene(scene); 
    stage.show(); 
} 

public void showImage3 (String file) throws IOException { 

    Stage stage = new Stage(); 
    GridPane pane = new GridPane(); 
    pane.setAlignment(Pos.CENTER); 
    pane.setHgap(0); 
    pane.setVgap(0); 

    FileChooser fc3 = new FileChooser(); 

    pane.getChildren().add(new ImageView(fc3.fileChoice())); 

    Scene scene = new Scene(pane); 
    stage.setTitle("imageViewer"); 
    stage.setScene(scene); 
    stage.show(); 
    } 
} 

错误这里为 '无效' 类型此处不允许

pane.getChildren().add(new ImageView(fc3.fileChoice())); 

这里的文件选择器类：

/* 
* To change this license header, choose License Headers in Project Properties. 
* To change this template file, choose Tools | Templates 
* and open the template in the editor. 
*/ 
package screensaver; 

import java.io.File; 
import java.io.IOException; 
import javafx.scene.control.Alert; 
import javafx.scene.control.ButtonType; 

/** 
* 
* @author Jacob 
*/ 
public class FileChooser { 
void fileChoice() throws IOException{ 
    javafx.stage.FileChooser fc3 = new javafx.stage.FileChooser(); 
    File selectedFile = fc3.showOpenDialog(null); 

    fc3.getExtensionFilters().addAll(
     new javafx.stage.FileChooser.ExtensionFilter("Image Files", "*.png", "*.jpg", "*.gif")); 


    if (selectedFile != null) { 

     String location = (selectedFile.getAbsoluteFile().toURI().toString()); 
     System.out.println(location); 

     Display ownDisplay = new Display(); 
     ownDisplay.showImage3(location); 
    } else { 

     Alert alert = new Alert(Alert.AlertType.CONFIRMATION,"No file was selected"); 

     alert.showAndWait() 
     .filter(response -> response == ButtonType.OK) 
     .ifPresent((ButtonType response) -> { 
      System.out.println("OK"); 
     }); 
    } 
} 
} 

最新代码：

显示方法：

public void showImage3 (String file) throws IOException, Exception { 

    Stage stage = new Stage(); 
    GridPane pane = new GridPane(); 
    pane.setAlignment(Pos.CENTER); 
    pane.setHgap(0); 
    pane.setVgap(0); 

    pane.getChildren().add(new ImageView(file)); 

    Scene scene = new Scene(pane); 
    stage.setTitle("imageViewer"); 
    stage.setScene(scene); 
    stage.show(); 
    } 

button3Action方法：

@FXML 
private void button3Action(ActionEvent event) throws IOException, Exception { 

     FileChooser fc3 = new FileChooser(); 
     File selectedFile = fc3.showOpenDialog(null); 

     fc3.getExtensionFilters().addAll(
     new ExtensionFilter("Image Files", "*.png", "*.jpg", "*.gif")); 


    if (selectedFile != null) { 

     String location = (selectedFile.getAbsoluteFile().toURI().toString()); 
     System.out.println(location); 
     Display fileChoice = new Display(); 
     fileChoice.showImage3(location); 

    } else { 

     Alert alert = new Alert(AlertType.CONFIRMATION,"No file was selected"); 

     alert.showAndWait() 
     .filter(response -> response == ButtonType.OK) 
     .ifPresent((ButtonType response) -> { 
      System.out.println("OK"); 
     }); 

    } 
    } 

Answer 1

编辑2：
因为我真的不能跟着你了， 试着去了解这个例子（它完全正常）。
这将有助于解决您的问题：

public class TestClass extends javafx.application.Application 
{ 
    @Override 
    public void start(javafx.stage.Stage primaryStage) 
    { 
     javafx.scene.control.Button button = new javafx.scene.control.Button("click me"); 
     button.setOnAction((javafx.event.ActionEvent event) -> { chooseImageAndDisplay(); }); 

     javafx.scene.layout.BorderPane pane = new javafx.scene.layout.BorderPane(); 
     pane.setCenter(button); 
     pane.setPrefSize(300, 200); 
     javafx.scene.Scene scene = new javafx.scene.Scene(pane); 
     primaryStage.setTitle("imageViewer"); 
     primaryStage.setScene(scene); 
     primaryStage.show(); 
    } 

    private void chooseImageAndDisplay() 
    { 
     javafx.stage.FileChooser fc = new javafx.stage.FileChooser(); 
     fc.getExtensionFilters().addAll(new javafx.stage.FileChooser.ExtensionFilter("Image Files", "*.png", "*.jpg", "*.gif")); 

     java.io.File selectedFile = fc.showOpenDialog(null); 

     if (selectedFile != null) 
     { 
     String location = (selectedFile.getAbsoluteFile().toURI().toString()); 

     javafx.scene.layout.BorderPane pane = new javafx.scene.layout.BorderPane(); 
     pane.setPrefSize(300, 200); 
     javafx.scene.image.ImageView iw = new javafx.scene.image.ImageView(location); 
     pane.setCenter(iw); 

     javafx.scene.Scene scene = new javafx.scene.Scene(pane); 
     javafx.stage.Stage stage = new javafx.stage.Stage(); 
     stage.setTitle("imageViewer"); 
     stage.setScene(scene); 
     stage.show(); 
     } 
    } 

    public static void main(String[] args) 
    { 
     launch(args); 
    } 
}