版權聲明:本文為部落客原創文章,未經部落客允許不得轉載。 https://blog.csdn.net/Hanniel/article/details/78877164
和其他的接口元件不同,FileChooser 不屬于javafx.scene.controls包,FileChooser 類在javafx.stage 包下,和其他主要的圖形元素在一起,比如:Stage,Window,以及Popup。
FileChooser提供了一個典型的界面功能:檔案系統導航。
打開檔案
檔案選擇器經常用來打開一個視窗來選擇檔案或者儲存檔案,最簡單是檔案選擇器的使用如下面代碼所示:
FileChooser fileChooser = new FileChooser();
fileChooser.setTitle("Open Resource File");
fileChooser.showOpenDialog(stage);
FileChooser最常用的還是讓我們點選一個按鈕後彈出檔案選擇器,看下面這個例子:
import java.awt.Desktop;
import java.awt.EventQueue;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
public final class FileChooserSample extends Application {
private final Desktop desktop = Desktop.getDesktop();
@Override
public void start(final Stage stage) {
stage.setTitle("File Chooser Sample");
final FileChooser fileChooser = new FileChooser();
final Button openButton = new Button("Open a Picture...");
final Button openMultipleButton = new Button("Open Pictures...");
openButton.setOnAction(
(final ActionEvent e) -> {
File file = fileChooser.showOpenDialog(stage);
if (file != null) {
openFile(file);
}
});
openMultipleButton.setOnAction(
(final ActionEvent e) -> {
List<File> list =
fileChooser.showOpenMultipleDialog(stage);
if (list != null) {
list.stream().forEach((file) -> {
openFile(file);
});
}
});
final GridPane inputGridPane = new GridPane();
GridPane.setConstraints(openButton, 0, 0);
GridPane.setConstraints(openMultipleButton, 1, 0);
inputGridPane.setHgap(6);
inputGridPane.setVgap(6);
inputGridPane.getChildren().addAll(openButton, openMultipleButton);
final Pane rootGroup = new VBox(12);
rootGroup.getChildren().addAll(inputGridPane);
rootGroup.setPadding(new Insets(12, 12, 12, 12));
stage.setScene(new Scene(rootGroup));
stage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
private void openFile(File file) {
EventQueue.invokeLater(() -> {
try {
desktop.open(file);
} catch (IOException ex) {
Logger.getLogger(FileChooserSample.
class.getName()).
log(Level.SEVERE, null, ex);
}
});
}
}
在該例子中,Open a Picture按鈕用來打開一個可以選擇一個圖檔的檔案選擇器,Open Pictures 按鈕可以打開一個可以選擇多個圖檔的檔案選擇器,setOnAction 方法定義了它們打開按鈕的方式。
- showOpenDialog 方法打開一個檔案選擇視窗。這個方法的傳回值就是使用者選擇的檔案,如果沒有選擇傳回null。
- showOpenMultipleDialog 方法打開一個可以多選的檔案視窗。這個方法傳回值是使用者選擇的多個檔案,如果沒有選擇傳回null,傳回的清單不能被修改,如果嘗試修改就會抛出UnsupportedOperationException 。
代碼運作效果如圖:
配置檔案選擇器
在下面的例子調用了initialDirectory 方法來初始化路徑,以及設定title屬性。
import java.awt.Desktop;
import java.awt.EventQueue;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
public final class FileChooserSample extends Application {
private final Desktop desktop = Desktop.getDesktop();
@Override
public void start(final Stage stage) {
stage.setTitle("File Chooser Sample");
final FileChooser fileChooser = new FileChooser();
final Button openButton = new Button("Open a Picture...");
final Button openMultipleButton = new Button("Open Pictures...");
openButton.setOnAction(
(final ActionEvent e) -> {
configureFileChooser(fileChooser);
File file = fileChooser.showOpenDialog(stage);
if (file != null) {
openFile(file);
}
}); openMultipleButton.setOnAction(
(final ActionEvent e) -> {
configureFileChooser(fileChooser);
List<File> list =
fileChooser.showOpenMultipleDialog(stage);
if (list != null) {
list.stream().forEach((file) -> {
openFile(file);
});
}
});
final GridPane inputGridPane = new GridPane();
GridPane.setConstraints(openButton, 0, 0);
GridPane.setConstraints(openMultipleButton, 1, 0);
inputGridPane.setHgap(6);
inputGridPane.setVgap(6);
inputGridPane.getChildren().addAll(openButton, openMultipleButton);
final Pane rootGroup = new VBox(12);
rootGroup.getChildren().addAll(inputGridPane);
rootGroup.setPadding(new Insets(12, 12, 12, 12));
stage.setScene(new Scene(rootGroup));
stage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
private static void configureFileChooser(final FileChooser fileChooser){
fileChooser.setTitle("View Pictures");
fileChooser.setInitialDirectory(
new File(System.getProperty("user.home"))
);
}
private void openFile(File file) {
EventQueue.invokeLater(() -> {
try {
desktop.open(file);
} catch (IOException ex) {
Logger.getLogger(FileChooserSample.
class.getName()).
log(Level.SEVERE, null, ex);
}
});
}
}
設定擴充過濾
import java.awt.Desktop;
import java.awt.EventQueue;
import java.io.File;
import java.io.IOException;
import java.util.List;
import java.util.logging.Level;
import java.util.logging.Logger;
import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Insets;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.FileChooser;
import javafx.stage.Stage;
public final class FileChooserSample extends Application {
private final Desktop desktop = Desktop.getDesktop();
@Override
public void start(final Stage stage) {
stage.setTitle("File Chooser Sample");
final FileChooser fileChooser = new FileChooser();
final Button openButton = new Button("Open a Picture...");
final Button openMultipleButton = new Button("Open Pictures...");
openButton.setOnAction(
(final ActionEvent e) -> {
configureFileChooser(fileChooser);
File file = fileChooser.showOpenDialog(stage);
if (file != null) {
openFile(file);
}
});
openMultipleButton.setOnAction(
(final ActionEvent e) -> {
configureFileChooser(fileChooser);
List<File> list =
fileChooser.showOpenMultipleDialog(stage);
if (list != null) {
list.stream().forEach((file) -> {
openFile(file);
});
}
});
final GridPane inputGridPane = new GridPane();
GridPane.setConstraints(openButton, 0, 1);
GridPane.setConstraints(openMultipleButton, 1, 1);
inputGridPane.setHgap(6);
inputGridPane.setVgap(6);
inputGridPane.getChildren().addAll(openButton, openMultipleButton);
final Pane rootGroup = new VBox(12);
rootGroup.getChildren().addAll(inputGridPane);
rootGroup.setPadding(new Insets(12, 12, 12, 12));
stage.setScene(new Scene(rootGroup));
stage.show();
}
public static void main(String[] args) {
Application.launch(args);
}
private static void configureFileChooser(
final FileChooser fileChooser) {
fileChooser.setTitle("View Pictures");
fileChooser.setInitialDirectory(
new File(System.getProperty("user.home"))
);
fileChooser.getExtensionFilters().addAll(
new FileChooser.ExtensionFilter("All Images", "*.*"),
new FileChooser.ExtensionFilter("JPG", "*.jpg"),
new FileChooser.ExtensionFilter("PNG", "*.png")
);
}
private void openFile(File file) {
EventQueue.invokeLater(() -> {
try {
desktop.open(file);
} catch (IOException ex) {
Logger.getLogger(FileChooserSample.
class.getName()).
log(Level.SEVERE, null, ex);
}
});
}
}
上面的代碼使用FileChooser.ExtensionFilter來設定了一個extension filter,它定義了這些檔案類型是可以選擇的:所有的圖檔檔案、JPG和PNG。
當你編譯、運作上面的代碼時,點選其中的一個按鈕,對應的擴充名過濾器将會出現在檔案選擇框窗體中。如果一個使用者選擇了JPG,那麼在檔案選擇框中将會僅顯示JPG類型的圖檔。
運作效果如圖:
儲存檔案
除了打開和過濾檔案之外,FileChooser 還提供了儲存檔案的能力。
FileChooser fileChooser = new FileChooser();
File file = fileChooser.showSaveDialog(stage);
if(file != null){
//将要寫入的内容寫到file檔案中
}
FileChooser類的showSaveDialog方法會打開一個儲存對話框窗體。與其他展示對話框的方法一樣,showSaveDialog方法傳回了被使用者選擇的檔案或者當沒有作出選擇時傳回null。