java - 需要帮助显示来自 url 或文件选择器的图像

Question

我在使用 URL 或文件选择器显示图像时遇到问题。我已经实现了从 URL 或 PC 中提取文件的方法，只是不确定如何显示这些图像。

这里是我调用从 url 中提取的方法的地方:

@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 url: http://24.media.tumblr.com/tumblr_llmbvhAcsF1qg20muo1_500.gif

这是我的显示类:

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(); 
    }
}

创建了 Display 和 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);

}

如何将图像添加到 Pane 并调用 start 方法来显示场景？我知道我可以在 Display 类中创建 ImageView 的实例，然后将图像添加到 Pane 中，尽管我无法从 button0Action 方法中提取包含 url 的变量 cat 。此刻陷入困境，不知道该去哪里。这几天一直在努力尝试不同的方法，但没有运气。有什么想法吗？

这是迄今为止我的更改:

显示类别:

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(); 
    }
}

此处发生错误:此处不允许“void”类型

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

这是 FileChooser 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:

显示方式:

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:
因为我已经无法真正追随你了 尝试理解这个例子(它完全有效)。
这应该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);
   }
}