Java 如何在Combox ListView中显示动态变化的文本
我想在加载列表内容时,在组合框列表中显示动态变化的加载文本。在获取内容时显示一些文本不是问题。问题是如何使文本动态更改。此代码将动态更改消息显示为Java 如何在Combox ListView中显示动态变化的文本,java,text,dynamic,javafx,combobox,Java,Text,Dynamic,Javafx,Combobox,我想在加载列表内容时,在组合框列表中显示动态变化的加载文本。在获取内容时显示一些文本不是问题。问题是如何使文本动态更改。此代码将动态更改消息显示为标签: import javafx.animation.KeyFrame; import javafx.animation.Timeline; import javafx.application.Application; import javafx.event.Event; import javafx.event.EventHandler; impor
标签
:
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class SSCCE extends Application {
@Override
public void start(Stage stage) {
VBox root = new VBox();
final Label message = new Label("Loading");
final Timeline timeline = new Timeline(new KeyFrame(
Duration.ZERO, new EventHandler() {
@Override
public void handle(Event event) {
String messageText = message.getText();
message.setText(("Loading . . ."
.equals(messageText)) ? "Loading ."
: messageText + " .");
}
}), new KeyFrame(Duration.millis(500)));
timeline.setCycleCount(Timeline.INDEFINITE);
root.getChildren().add(message);
timeline.play();
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
}
但问题是,因为将节点
对象放入项目列表是(而且看起来很奇怪)。我需要把它们放在别的东西里
我想我通过使用SimpleStringProperty
解决了这个问题,因为它实现了Observable
:
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.SimpleStringProperty;
import javafx.event.Event;
import javafx.event.EventHandler;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;
public class SSCCE2 extends Application {
@Override
public void start(Stage stage) {
VBox root = new VBox();
final SimpleStringProperty message = new SimpleStringProperty("Loading");
final Timeline timeline = new Timeline(new KeyFrame(
Duration.ZERO, new EventHandler() {
@Override
public void handle(Event event) {
String messageText = message.getValue();
message.setValue(("Loading . . ."
.equals(messageText)) ? "Loading ."
: messageText + " .");
}
}), new KeyFrame(Duration.millis(500)));
timeline.setCycleCount(Timeline.INDEFINITE);
ComboBox<SimpleStringProperty> comboBox = new ComboBox<SimpleStringProperty>();
comboBox.getItems().add(message);
timeline.play();
root.getChildren().add(comboBox);
Scene scene = new Scene(root);
stage.setScene(scene);
stage.show();
}
public static void main(String[] args) {
launch();
}
}
导入javafx.animation.KeyFrame;
导入javafx.animation.Timeline;
导入javafx.application.application;
导入javafx.beans.property.SimpleStringProperty;
导入javafx.event.event;
导入javafx.event.EventHandler;
导入javafx.scene.scene;
导入javafx.scene.control.ComboBox;
导入javafx.scene.layout.VBox;
导入javafx.stage.stage;
导入javafx.util.Duration;
公共类SSCCE2扩展了应用程序{
@凌驾
公众假期开始(阶段){
VBox root=新的VBox();
最终SimpleStringProperty消息=新SimpleStringProperty(“加载”);
最终时间线=新时间线(新关键帧(
Duration.ZERO,新的EventHandler(){
@凌驾
公共无效句柄(事件){
字符串messageText=message.getValue();
message.setValue((“正在加载…”
.equals(messageText))?“正在加载。”
:messageText+“);
}
}),新的关键帧(持续时间.millis(500));
timeline.setCycleCount(timeline.unfinite);
ComboBox ComboBox=新建ComboBox();
comboBox.getItems().add(消息);
timeline.play();
root.getChildren().add(组合框);
场景=新场景(根);
舞台场景;
stage.show();
}
公共静态void main(字符串[]args){
发射();
}
}
但它不起作用。它只是一直显示“加载”。是的。ComboBox
当前显示了SimpleStringProperty
的toString()
方法,但是可以通过设置ComboBox
的单元格工厂或转换器轻松修复。我没有在这里添加这一部分,因为我想让示例尽可能小。同样,这种方法会显示SimpleStringProperty的getValue(),它是不可观察的,我们又回到了原点
无论如何。在这个例子中,什么都没有发生。这对我来说很奇怪,因为SimpleStringProperty
实现了Observable
,这意味着将显示任何更改。要在组合框本身中显示动画的“加载”消息,请创建一个列表单元格
,并从时间线更新它;然后将其设置为组合框的按钮cell
:
import java.util.Arrays;
import java.util.List;
import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ComboBoxWithLoadingMessage extends Application {
@Override
public void start(Stage primaryStage) {
ComboBox<String> combo = new ComboBox<>();
// mock loading task:
Task<List<String>> loadingTask = new Task<List<String>>() {
@Override
public List<String> call() throws Exception {
// mimic long loading process:
Thread.sleep(5000);
return Arrays.asList("One", "Two", "Three", "Four", "Five");
}
};
loadingTask.setOnSucceeded(e ->
combo.getItems().setAll(loadingTask.getValue()));
ListCell<String> buttonCell = new ListCell<String>() {
@Override
public void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
State state = loadingTask.getState() ;
if (state == State.SUCCEEDED ) {
if (empty) {
setText(null);
} else {
setText(item);
}
}
}
};
Timeline timeline = new Timeline(
new KeyFrame(Duration.ZERO, e -> buttonCell.setText("Loading .")),
new KeyFrame(Duration.millis(500), e -> buttonCell.setText("Loading . .")),
new KeyFrame(Duration.millis(1000), e -> buttonCell.setText("Loading . . .")),
new KeyFrame(Duration.millis(1500))
);
timeline.setCycleCount(Animation.INDEFINITE);
loadingTask.stateProperty().addListener((obs, oldState, newState) -> {
if (newState == State.RUNNING) {
timeline.play();
} else {
timeline.stop();
if (buttonCell.isEmpty()) {
buttonCell.setText(null);
} else {
buttonCell.setText(buttonCell.getItem());
}
}
});
combo.setButtonCell(buttonCell);
new Thread(loadingTask).start();
StackPane root = new StackPane(combo);
Scene scene = new Scene(root, 350, 120);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
使用此选项可以使动画看起来更好
.combo-box .placeholder {
-fx-alignment: center-left ;
-fx-padding: 5 ;
}
在外部样式表中
您也可以考虑将占位符设置为<代码> PraseScRebug < /C> >省略时间线等,这将是一个更简单的选择。
< P>在组合框中显示动画“加载”消息,创建一个<代码> ListCys<代码>,并从时间线中更新它;然后将其设置为组合框的按钮cell
:
import java.util.Arrays;
import java.util.List;
import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ComboBoxWithLoadingMessage extends Application {
@Override
public void start(Stage primaryStage) {
ComboBox<String> combo = new ComboBox<>();
// mock loading task:
Task<List<String>> loadingTask = new Task<List<String>>() {
@Override
public List<String> call() throws Exception {
// mimic long loading process:
Thread.sleep(5000);
return Arrays.asList("One", "Two", "Three", "Four", "Five");
}
};
loadingTask.setOnSucceeded(e ->
combo.getItems().setAll(loadingTask.getValue()));
ListCell<String> buttonCell = new ListCell<String>() {
@Override
public void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
State state = loadingTask.getState() ;
if (state == State.SUCCEEDED ) {
if (empty) {
setText(null);
} else {
setText(item);
}
}
}
};
Timeline timeline = new Timeline(
new KeyFrame(Duration.ZERO, e -> buttonCell.setText("Loading .")),
new KeyFrame(Duration.millis(500), e -> buttonCell.setText("Loading . .")),
new KeyFrame(Duration.millis(1000), e -> buttonCell.setText("Loading . . .")),
new KeyFrame(Duration.millis(1500))
);
timeline.setCycleCount(Animation.INDEFINITE);
loadingTask.stateProperty().addListener((obs, oldState, newState) -> {
if (newState == State.RUNNING) {
timeline.play();
} else {
timeline.stop();
if (buttonCell.isEmpty()) {
buttonCell.setText(null);
} else {
buttonCell.setText(buttonCell.getItem());
}
}
});
combo.setButtonCell(buttonCell);
new Thread(loadingTask).start();
StackPane root = new StackPane(combo);
Scene scene = new Scene(root, 350, 120);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
使用此选项可以使动画看起来更好
.combo-box .placeholder {
-fx-alignment: center-left ;
-fx-padding: 5 ;
}
在外部样式表中
您也可以考虑将占位符设置为<代码> PraseScRebug < /C> >省略时间线等,这将是一个更简单的选择。
< P>在组合框中显示动画“加载”消息,创建一个<代码> ListCys<代码>,并从时间线中更新它;然后将其设置为组合框的按钮cell
:
import java.util.Arrays;
import java.util.List;
import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ComboBoxWithLoadingMessage extends Application {
@Override
public void start(Stage primaryStage) {
ComboBox<String> combo = new ComboBox<>();
// mock loading task:
Task<List<String>> loadingTask = new Task<List<String>>() {
@Override
public List<String> call() throws Exception {
// mimic long loading process:
Thread.sleep(5000);
return Arrays.asList("One", "Two", "Three", "Four", "Five");
}
};
loadingTask.setOnSucceeded(e ->
combo.getItems().setAll(loadingTask.getValue()));
ListCell<String> buttonCell = new ListCell<String>() {
@Override
public void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
State state = loadingTask.getState() ;
if (state == State.SUCCEEDED ) {
if (empty) {
setText(null);
} else {
setText(item);
}
}
}
};
Timeline timeline = new Timeline(
new KeyFrame(Duration.ZERO, e -> buttonCell.setText("Loading .")),
new KeyFrame(Duration.millis(500), e -> buttonCell.setText("Loading . .")),
new KeyFrame(Duration.millis(1000), e -> buttonCell.setText("Loading . . .")),
new KeyFrame(Duration.millis(1500))
);
timeline.setCycleCount(Animation.INDEFINITE);
loadingTask.stateProperty().addListener((obs, oldState, newState) -> {
if (newState == State.RUNNING) {
timeline.play();
} else {
timeline.stop();
if (buttonCell.isEmpty()) {
buttonCell.setText(null);
} else {
buttonCell.setText(buttonCell.getItem());
}
}
});
combo.setButtonCell(buttonCell);
new Thread(loadingTask).start();
StackPane root = new StackPane(combo);
Scene scene = new Scene(root, 350, 120);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
使用此选项可以使动画看起来更好
.combo-box .placeholder {
-fx-alignment: center-left ;
-fx-padding: 5 ;
}
在外部样式表中
您也可以考虑将占位符设置为<代码> PraseScRebug < /C> >省略时间线等,这将是一个更简单的选择。
< P>在组合框中显示动画“加载”消息,创建一个<代码> ListCys<代码>,并从时间线中更新它;然后将其设置为组合框的按钮cell
:
import java.util.Arrays;
import java.util.List;
import javafx.animation.Animation;
import javafx.animation.KeyFrame;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.concurrent.Task;
import javafx.concurrent.Worker.State;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ListCell;
import javafx.scene.layout.StackPane;
import javafx.stage.Stage;
import javafx.util.Duration;
public class ComboBoxWithLoadingMessage extends Application {
@Override
public void start(Stage primaryStage) {
ComboBox<String> combo = new ComboBox<>();
// mock loading task:
Task<List<String>> loadingTask = new Task<List<String>>() {
@Override
public List<String> call() throws Exception {
// mimic long loading process:
Thread.sleep(5000);
return Arrays.asList("One", "Two", "Three", "Four", "Five");
}
};
loadingTask.setOnSucceeded(e ->
combo.getItems().setAll(loadingTask.getValue()));
ListCell<String> buttonCell = new ListCell<String>() {
@Override
public void updateItem(String item, boolean empty) {
super.updateItem(item, empty);
State state = loadingTask.getState() ;
if (state == State.SUCCEEDED ) {
if (empty) {
setText(null);
} else {
setText(item);
}
}
}
};
Timeline timeline = new Timeline(
new KeyFrame(Duration.ZERO, e -> buttonCell.setText("Loading .")),
new KeyFrame(Duration.millis(500), e -> buttonCell.setText("Loading . .")),
new KeyFrame(Duration.millis(1000), e -> buttonCell.setText("Loading . . .")),
new KeyFrame(Duration.millis(1500))
);
timeline.setCycleCount(Animation.INDEFINITE);
loadingTask.stateProperty().addListener((obs, oldState, newState) -> {
if (newState == State.RUNNING) {
timeline.play();
} else {
timeline.stop();
if (buttonCell.isEmpty()) {
buttonCell.setText(null);
} else {
buttonCell.setText(buttonCell.getItem());
}
}
});
combo.setButtonCell(buttonCell);
new Thread(loadingTask).start();
StackPane root = new StackPane(combo);
Scene scene = new Scene(root, 350, 120);
primaryStage.setScene(scene);
primaryStage.show();
}
public static void main(String[] args) {
launch(args);
}
}
使用此选项可以使动画看起来更好
.combo-box .placeholder {
-fx-alignment: center-left ;
-fx-padding: 5 ;
}
在外部样式表中
您也可以考虑将占位符设置为<代码>进度指示器< /代码>,省略时间线等,这将是一个更简单的选择。
这很好。但这并不是我想要的。是否可以在组合框
下拉列表中而不是按钮单元格中显示此加载消息?这在我的应用程序中是绝对必要的。是的,只需在电池工厂而不是按钮电池中进行。我将在几小时后回到计算机时更新答案。假设列表在加载完成之前是空的,实际上比这更简单:只需使用组合框。占位符
属性。使用该示例更新了代码。在我的实现中,我实例化了ComboBox,然后将实例发送到另一个类并在那里显示(我希望在启动应用程序后立即启动任务,但ComboBox显示在另一个窗口中)。但是,除非在将占位符发送到其他类之前将其添加到窗格中,否则占位符不会显示。你知道为什么吗?这很好。但这并不是我想要的。是否可以在组合框
下拉列表中而不是按钮单元格中显示此加载消息?这在我的应用程序中是绝对必要的。是的,只需在电池工厂而不是按钮电池中进行。我会在几小时后回到电脑前更新答案,假设列表是em