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java - 按属性值动态过滤 ObservableList

转载 作者:行者123 更新时间:2023-12-02 10:17:25 26 4
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我正在使用 JavaFX 编写日志读取器应用程序,并且我想根据所选属性实现基于搜索的过滤。 Application screenshot组合框中的值表示填充表的对象字段的名称。现在,我只想显示属性包含键入文本的行(对象)。

填充表格的对象如下所示:

public class LogEvent {

private final SimpleStringProperty timestamp = new SimpleStringProperty("");
private final SimpleStringProperty level = new SimpleStringProperty("");
private final SimpleStringProperty emitter = new SimpleStringProperty("");
private final SimpleStringProperty message = new SimpleStringProperty("");
private final SimpleStringProperty thread = new SimpleStringProperty("");
private final SimpleStringProperty mdc = new SimpleStringProperty("");
private final SimpleStringProperty stackTrace = new SimpleStringProperty("");

public LogEvent(String timestamp, String level, String emitter, String message, String thread, String mdc, String stackTrace) {
this.timestamp.set(timestamp);
this.level.set(level);
this.emitter.set(emitter);
this.message.set(message);
this.stackTrace.set(stackTrace);
this.thread.set(thread);
this.mdc.set(mdc);
}

public String getTimestamp() {
return timestamp.get();
}

public String getLevel() {
return level.get();
}

public String getEmitter() {
return emitter.get();
}

public String getMessage() {
return message.get();
}

public String getStackTrace() {
return stackTrace.get();
}

public String getThread() {
return thread.get();
}

public String getMdc() {
return mdc.get();
}

}

现在,为了过滤事件,我正在尝试执行以下操作:

private void filterEvents(String text) {
String property = filterCombo.getSelectionModel().getSelectedItem().toLowerCase();
if (!property.isEmpty() && text != null) {
FilteredList<LogEvent> filteredList = new FilteredList<>(events);
filteredList.setPredicate(event -> event.getProperty(property).contains(text));
tableView.setItems(filteredList);
tableView.refresh();
}
}

当然没有这样的方法。我知道我可以使用反射,或者编写一些开关,但这似乎不是一个好主意。有没有一些更清洁的方法来实现这一目标?例如,类似于我使用 PropertyValueFactory 动态创建表列的方式:

for (String keyword : keywords) {
TableColumn<LogEvent, String> column = new TableColumn<>(keyword);
column.setCellValueFactory(new PropertyValueFactory<>(keyword.toLowerCase()));
tableView.getColumns().add(column);
}

每一行都根据其级别严重性进行颜色编码。

tableView.setRowFactory(tableView -> new TableRow<>() {
@Override
protected void updateItem(LogEvent item, boolean empty) {
super.updateItem(item, empty);
if (item != null) {
switch (item.getLevel()) {
case LogLevel.ERROR:
setStyle("-fx-background-color: indianred;");
break;
case LogLevel.INFO:
setStyle("-fx-background-color: cornflowerblue;");
break;
case LogLevel.WARN:
setStyle("-fx-background-color: orange;");
break;
case LogLevel.DEBUG:
setStyle("-fx-background-color: lightblue;");
break;
case LogLevel.TRACE:
setStyle("-fx-background-color: ivory");
break;
case LogLevel.FATAL:
setStyle("-fx-background-color: firebrick");
break;
default:
setStyle("-fx-backgound-color: white;");
break;
}
}
}
}

);

最佳答案

我确信您有几个选择,但这里是使用反射的一个选择。您确实说过您知道可以这样做,但我不确定是否有解决方法。

全面披露:我无论如何都不是 Java 专家,因此这可能不是最好的方法。不过,它确实有效。

<小时/>

首先,我们需要更新 LogEvent 类以包含几个辅助方法:

import javafx.beans.property.SimpleStringProperty;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

public class LogEvent {

private final SimpleStringProperty timestamp = new SimpleStringProperty("");
private final SimpleStringProperty level = new SimpleStringProperty("");
private final SimpleStringProperty emitter = new SimpleStringProperty("");
private final SimpleStringProperty message = new SimpleStringProperty("");
private final SimpleStringProperty thread = new SimpleStringProperty("");

public LogEvent(String timestamp, String level, String emitter, String message, String thread) {
this.timestamp.set(timestamp);
this.level.set(level);
this.emitter.set(emitter);
this.message.set(message);
this.thread.set(thread);

}

// Allows our filter functionality to retrieve a list of this object's Property objects
public static List<String> getPropertiesList() {
List<String> list = new ArrayList<>();

// Let's loop through all our methods, looking for any that end in "Property"
for (Method method : LogEvent.class.getMethods()) {
String name = method.getName();

// If it's a Property, return just the name of the property
if (name.endsWith("Property")) {
list.add(name.replace("Property", ""));
}
}
return list;
}

public Object getPropertyByName(String propertyName) throws Exception {
Method method = this.getClass().getMethod(propertyName + "Property", (Class[]) null);
return method.invoke(this);
}

public String getTimestamp() {
return timestamp.get();
}

public SimpleStringProperty timestampProperty() {
return timestamp;
}

public void setTimestamp(String timestamp) {
this.timestamp.set(timestamp);
}

public String getLevel() {
return level.get();
}

public SimpleStringProperty levelProperty() {
return level;
}

public void setLevel(String level) {
this.level.set(level);
}

public String getEmitter() {
return emitter.get();
}

public SimpleStringProperty emitterProperty() {
return emitter;
}

public void setEmitter(String emitter) {
this.emitter.set(emitter);
}

public String getMessage() {
return message.get();
}

public SimpleStringProperty messageProperty() {
return message;
}

public void setMessage(String message) {
this.message.set(message);
}

public String getThread() {
return thread.get();
}

public SimpleStringProperty threadProperty() {
return thread;
}

public void setThread(String thread) {
this.thread.set(thread);
}
}
<小时/>

现在是一个简单的程序来演示(代码中的注释):

import javafx.application.Application;
import javafx.beans.property.StringProperty;
import javafx.collections.FXCollections;
import javafx.collections.ObservableList;
import javafx.collections.transformation.FilteredList;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.ComboBox;
import javafx.scene.control.TableColumn;
import javafx.scene.control.TableView;
import javafx.scene.control.TextField;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

public class FilteredTableViewSample extends Application {

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

@Override
public void start(Stage primaryStage) {

// First, let's create some sample LogEvent data
ObservableList<LogEvent> events = FXCollections.observableArrayList();
events.add(new LogEvent("4:02 pm", "Warning", "Emitter #1", "You're gonna need a bigger boat!", "Thread-03"));
events.add(new LogEvent("3:34 am", "Info", "Emitter #1", "Who you gonna call?", "Thread-05"));
events.add(new LogEvent("4:02", "Warning", "Emitter #1", "Be excellent to each other!", "Thread-JFX"));
events.add(new LogEvent("4:02", "Warning", "Emitter #1", "What we have here is a failure to communicate.", "Thread-JFX"));

// Simple interface
VBox root = new VBox(5);
root.setPadding(new Insets(10));
root.setAlignment(Pos.CENTER);

// Add our ComboBox and filter TextField
HBox filterPane = new HBox(5);
filterPane.setPadding(new Insets(5));

ComboBox<String> cboProperty = new ComboBox<>();
cboProperty.setPromptText("Filter By...");
cboProperty.setItems(FXCollections.observableList(LogEvent.getPropertiesList()));

TextField txtFilter = new TextField();
HBox.setHgrow(txtFilter, Priority.ALWAYS);
filterPane.getChildren().addAll(cboProperty, txtFilter);

// Just a standard TableView
TableView<LogEvent> tableView = new TableView<>();
TableColumn<LogEvent, String> colTimestamp = new TableColumn<>("Timestamp");
TableColumn<LogEvent, String> colLevel = new TableColumn<>("Level");
TableColumn<LogEvent, String> colEmitter = new TableColumn<>("Emitter");
TableColumn<LogEvent, String> colMessage = new TableColumn<>("Message");
TableColumn<LogEvent, String> colThread = new TableColumn<>("Thread");
tableView.getColumns().addAll(colTimestamp, colLevel, colEmitter, colMessage, colThread);

// Setup our CellValueFactories
colTimestamp.setCellValueFactory(tv -> tv.getValue().timestampProperty());
colLevel.setCellValueFactory(tv -> tv.getValue().levelProperty());
colEmitter.setCellValueFactory(tv -> tv.getValue().emitterProperty());
colMessage.setCellValueFactory(tv -> tv.getValue().messageProperty());
colThread.setCellValueFactory(tv -> tv.getValue().threadProperty());

FilteredList<LogEvent> filteredList = new FilteredList<>(events);
tableView.setItems(filteredList);

// Finally, we create our filter functionality
txtFilter.textProperty().addListener((observable, oldValue, newValue) -> {

final String searchString = newValue.toUpperCase();
filteredList.setPredicate(logEvent -> {

// If the search field is empty or no Filtered By value is selected, show all LogEvents
if (searchString.isEmpty() || cboProperty.getSelectionModel().getSelectedItem() == null) {
return true;
}

// Now we just add our checks for each possible search field
String filterBy = cboProperty.getSelectionModel().getSelectedItem();

// We retrieve the text for the property we're looking for
String targetString = "";
try {
targetString = ((StringProperty) logEvent.getPropertyByName(filterBy)).getValue();
} catch (Exception e) {
e.printStackTrace();
}

// Now, return true if there's a match
return targetString.toUpperCase().contains(searchString.toUpperCase());

});

});

root.getChildren().addAll(filterPane, tableView);

// Show the Stage
primaryStage.setWidth(600);
primaryStage.setHeight(300);
primaryStage.setScene(new Scene(root));
primaryStage.show();
}
}
<小时/>

The Result:

screenshot

关于java - 按属性值动态过滤 ObservableList,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/54580649/

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