我正在开发一个jaxafx项目，用户输入该文件，然后通过另一种方法写入该文件。
所以我已将File和PrintWriter声明为静态全局变量。我也试过传递它们，但那也没有用，我知道全球性很糟糕。该文件打开并关闭正常，并在我打开它的方法内写入，但没有其他方法会写入它。
我已经尝试过大量的冲洗，但是我被卡住了。有任何想法吗？如果需要，我可以包括我的库;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import javafx.application.Application;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextField;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.text.Font;
import javafx.stage.Stage;
import uNumberLibrary.EnhancedUNumber;
import uNumberLibrary.InexactUNumber;
class Convert {
public boolean negative = false;
public EnhancedUNumber TheValue;
public boolean operandDefined = true;
public Label label_errOperand = new Label("");
public Convert() {
}
public Convert(String temp) {
if (temp.length() > 0 && temp.charAt(0) == '-')
TheValue = EnhancedUNumber.nextEnhancedUNumber(temp.substring(1), false);
else
TheValue = EnhancedUNumber.nextEnhancedUNumber(temp, true);
TheValue = new EnhancedUNumber(TheValue, 50);
}
}
public class Task3Solution extends Application {
// Constants used to parameterize the graphical user interface. We do not use a
// layout for
// this application. Rather we manually control the location of each graphical
// element.
Convert One = new Convert();
Convert Two = new Convert();
Convert OneErr = new Convert();
Convert TwoErr = new Convert();
Convert Size = new Convert();
private final double WINDOW_WIDTH = 600;
private final double WINDOW_HEIGHT = 400;
private final double BUTTON_SPACE = WINDOW_WIDTH / 6; // There are six gaps
private final double BUTTON_WIDTH = 60;;
private final double BUTTON_OFFSET = BUTTON_WIDTH / 2;
// These are the major application values not associated with the user interface
private EnhancedUNumber operand1;
private EnhancedUNumber operand2;
private EnhancedUNumber Erroperand1;
private EnhancedUNumber Erroperand2;
private Integer sizeD = 20;
boolean operandError = false;
boolean printing = false;
private double new_window_hieght = WINDOW_HEIGHT;
private int count=0;
// These are the application values required by the user interface
Label[] label = new Label[4];
Label[] labPM = new Label[3];
String texts[] = { "Inexact Printing Calculator", "First operand", "Second operand", "Result" };
String plusMinus[] = { "±", "±", "±" };
TextField text_Operand1 = new TextField();
TextField text_Operand2 = new TextField();
TextField Err_Operand1 = new TextField();
TextField Err_Operand2 = new TextField();
TextField text_Result = new TextField();
TextField Err_Result = new TextField();
TextField decimals = new TextField();
Label printLabel = new Label("");// new Label("Enter the file name here:");
Label printLabelErr = new Label("");// new Label("Replace existing file?");
Label printLabelNew = new Label("");// new Label("New file");
TextField PrintField = new TextField();
Label dec = new Label("Size (>7) ");
Label label_errOperand1 = new Label("");
Label label_errOperand2 = new Label("");
Button[] button = new Button[5];
String But_texts[] = { "+", "-", "x", "÷", "\u221A" };
Button printButton = new Button();
String Print_text[] = { "Enable Printing", "Disable Printing" };
Button printFileButton = new Button();
String Print_File_text[] = { "Set file for printing", "Replace file for printing", "Close the file!" };
static File file;
static PrintWriter printWriter;
/**********
* This method initializes all of the elements of the graphical user interface.
* These assignments determine the location, size, font, color, and change and
* event handlers for each GUI object.
*/
private void initializeTheGUIElements(Pane theRoot, Stage theStage) {
// Label theScene with the name of the calculator, centered at the top of the
// pane
int ypos[] = { 10, 40, 130, 220 };
int size[] = { 24, 18, 18, 18 };
for (int i = 0; i < texts.length; i++) {
label[i] = new Label(texts[i]);
Label l = label[i];
l.setFont(Font.font("Arial", size[i]));
l.setMinWidth(WINDOW_WIDTH - 10);
l.setLayoutX(0);
l.setLayoutY(ypos[i]);
}
int ypm[] = { 70, 160, 250 };
for (int i = 0; i < plusMinus.length; i++) {
labPM[i] = new Label(plusMinus[i]);
Label l = labPM[i];
l.setFont(Font.font("Arial", 24));
l.setMinWidth(WINDOW_WIDTH - 150);
l.setAlignment(Pos.BASELINE_RIGHT);
l.setLayoutX(0);
l.setLayoutY(ypm[i]);
}
// Establish the first text input operand field and when anything changes in
// operand 1,
// process both fields to ensure that we are ready to perform as soon as
// possible.
TextField t = text_Operand1;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(WINDOW_WIDTH - 200);
t.setMaxWidth(WINDOW_WIDTH - 200);
t.setAlignment(Pos.BASELINE_LEFT);
t.setLayoutX(10);
t.setLayoutY(70);
t.textProperty().addListener((observable, oldValue, newValue) -> {
One = new Convert(text_Operand1.getText());
operand1 = One.TheValue;
});
t.setOnAction((event) -> {
Err_Operand1.requestFocus();
});
t = Err_Operand1;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(120);
t.setMaxWidth(120);
t.setAlignment(Pos.BASELINE_LEFT);
t.setLayoutX(WINDOW_WIDTH - 130);
t.setLayoutY(70);
t.textProperty().addListener((observable, oldValue, newValue) -> {
OneErr = new Convert(Err_Operand1.getText());
Erroperand1 = OneErr.TheValue;
});
t.setOnAction((event) -> {
text_Operand2.requestFocus();
});
// Establish the second text input operand field and when anything changes in
// operand 2,
// process both fields to ensure that we are ready to perform as soon as
// possible.
t = text_Operand2;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(WINDOW_WIDTH - 200);
t.setMaxWidth(WINDOW_WIDTH - 200);
t.setAlignment(Pos.BASELINE_LEFT);
t.setLayoutX(10);
t.setLayoutY(160);
t.textProperty().addListener((observable, oldValue, newValue) -> {
Two = new Convert(text_Operand2.getText());
operand2 = Two.TheValue;
});
t.setOnAction((event) -> {
Err_Operand2.requestFocus();
});
t = Err_Operand2;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(120);
t.setMaxWidth(120);
t.setAlignment(Pos.BASELINE_LEFT);
t.setLayoutX(WINDOW_WIDTH - 130);
t.setLayoutY(160);
t.textProperty().addListener((observable, oldValue, newValue) -> {
TwoErr = new Convert(Err_Operand2.getText());
Erroperand2 = TwoErr.TheValue;
});
t.setOnAction((event) -> {
text_Result.requestFocus();
});
// Establish an error message for the first operand just above it with, right
// aligned
Label l = label_errOperand1;
l.setFont(Font.font("Arial", 18));
l.setTextFill(Color.RED);
l.setMinWidth(WINDOW_WIDTH - 10);
l.setAlignment(Pos.BASELINE_LEFT);
l.setLayoutX(400);
l.setLayoutY(45);
// Establish an error message for the second operand just above it with, right
// aligned
l = label_errOperand2;
l.setFont(Font.font("Arial", 18));
l.setTextFill(Color.RED);
l.setMinWidth(WINDOW_WIDTH - 10);
l.setAlignment(Pos.BASELINE_LEFT);
l.setLayoutX(400);
l.setLayoutY(135);
// Establish the result output field. It is not editable, so the text can be
// selected
// and copied, but it cannot be altered by the user.
t = text_Result;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(WINDOW_WIDTH - 200);
t.setMaxWidth(WINDOW_WIDTH - 200);
t.setAlignment(Pos.BASELINE_LEFT);
t.setEditable(false);
t.setLayoutX(10);
t.setLayoutY(250);
t = Err_Result;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(120);
t.setMaxWidth(120);
t.setAlignment(Pos.BASELINE_LEFT);
t.setEditable(false);
t.setLayoutX(WINDOW_WIDTH - 130);
t.setLayoutY(250);
printButton = new Button(Print_text[0]);
Button b = printButton;
b.setFont(Font.font("Symbol", 10));
b.setMinWidth(100);
b.setMaxWidth(100);
b.setMaxHeight(30);
b.setMinHeight(30);
b.setAlignment(Pos.BASELINE_LEFT);
b.setLayoutX(250);
b.setLayoutY(370);
b.setOnAction((event) -> {
if (printing) {
printButton.setText(Print_text[0]);
printing = false;// enables printing and sets button to disable enlarge window
theRoot.getChildren().remove(PrintField);
theRoot.getChildren().remove(printFileButton);
printLabel.setText("");
theStage.setHeight(new_window_hieght + 40); // change the hieght
} else {
printing = true;
printButton.setText(Print_text[1]);
theRoot.getChildren().add(PrintField);
theRoot.getChildren().add(printFileButton);
printLabel.setText("Enter the file name here:");
theStage.setHeight(new_window_hieght + 120); // change the hieght
}
});
t = PrintField;
t.setFont(Font.font("Arial", 18));
t.setMinWidth(320);
t.setMaxWidth(320);
t.setAlignment(Pos.BASELINE_LEFT);
t.setEditable(true);
t.setLayoutX(10);
t.setLayoutY(440);
t.textProperty().addListener((observable, oldValue, newValue) -> {
file = new File(PrintField.getText());
// PrintWriter file = new PrintWriter();
if (file.exists() && !file.isDirectory()) {
printFileButton.setText(Print_File_text[1]);
printLabelNew.setText("");
printLabelErr.setText("Replace existing file?");
} else {
printLabelNew.setText("New file");
printFileButton.setText(Print_File_text[0]);
printFileButton.setDisable(false);
printLabelErr.setText("");
}
//
//
// } catch (FileNotFoundException e) {
// printLabelErr.setText("Replace existing file?");
// //printLabelNew.setText("New file");
// //e.printStackTrace();
// }
});
l = printLabel;
l.setFont(Font.font("Arial", 18));
l.setTextFill(Color.BLACK);
l.setMinWidth(WINDOW_WIDTH - 200);
l.setAlignment(Pos.BASELINE_LEFT);
l.setLayoutX(10);
l.setLayoutY(410);
l = printLabelErr;
l.setFont(Font.font("Arial", 18));
l.setTextFill(Color.RED);
l.setMinWidth(200);
l.setAlignment(Pos.BASELINE_CENTER);
l.setLayoutX(350);
l.setLayoutY(410);
l = printLabelNew;
l.setFont(Font.font("Arial", 18));
l.setTextFill(Color.GREEN);
l.setMinWidth(200);
l.setAlignment(Pos.BASELINE_CENTER);
l.setLayoutX(350);
l.setLayoutY(410);
printFileButton = new Button(Print_File_text[0]);
b = printFileButton;
b.setFont(Font.font("Symbol", 12));
b.setMinWidth(200);
b.setMaxWidth(200);
b.setMaxHeight(30);
b.setMinHeight(30);
b.setAlignment(Pos.BASELINE_CENTER);
b.setLayoutX(350);
b.setLayoutY(440);
b.setDisable(true);
b.setOnAction((event) -> {
count++;
//PrintWriter printWriter = null;
printFileButton.setText(Print_File_text[2]);
printLabelNew.setText("");
printLabelErr.setText("Printing to file");
try {
printWriter = new PrintWriter(file);
PrintField.setDisable(true);
if (printFileButton.getText().equals(Print_File_text[2]) && count%2==0) {
printFileButton.setText(Print_File_text[0]);
printFileButton.setDisable(true);
PrintField.setDisable(false);
printLabelErr.setText("");
printWriter.close();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
}
//printWriter.println("printing right");
});
// this combines the four buttons into one loop
for (int i = 0; i < But_texts.length; i++) {
button[i] = new Button(But_texts[i]);
b = button[i];
b.setFont(Font.font("Symbol", 32));
b.setMinWidth(BUTTON_WIDTH);
b.setAlignment(Pos.BASELINE_LEFT);
b.setLayoutX((i + 1) * BUTTON_SPACE - BUTTON_OFFSET);
b.setLayoutY(300);
switch (i) {
case 0:
b.setOnAction((event) -> {
addOperands(printWriter);
printWriter.flush();
});
break;
case 1:
b.setOnAction((event) -> {
subOperands(printWriter);
printWriter.flush();
});
break;
case 2:
b.setOnAction((event) -> {
mpyOperands(printWriter);
});
break;
case 3:
b.setOnAction((event) -> {
divOperands(printWriter);
});
break;
case 4:
b.setOnAction((event) -> {
sqrtOperands(printWriter);
});
break;
default:
break;
}
}
}
/**********
* This is the start method that is call once the application has been loaded
* into memory and is ready to get to work.
*
* In designing this application I have elected to IGNORE all opportunities for
* automatic layout support and instead have elected to manually position each
* GUI element and its properties.
*
*/
public void start(Stage theStage) throws Exception {
theStage.setTitle("Amanda Martin"); // Label the stage (a window)
Pane theRoot = new Pane(); // Create a pane within the window
initializeTheGUIElements(theRoot, theStage); // Define all the GUI elements
theRoot.getChildren().addAll(label[0], label[1], label[2], label[3], text_Operand1, label_errOperand2,
label_errOperand1, text_Operand2, text_Result, button[0], button[1], button[2], button[3], button[4],
labPM[0], labPM[1], labPM[2], Err_Result, Err_Operand1, Err_Operand2, printButton, printLabelErr,
printLabelNew, printLabel);
Scene theScene = new Scene(theRoot, WINDOW_WIDTH, new_window_hieght + 10); // Create the scene with
// the required width and height
theStage.setScene(theScene); // Set the scene on the stage
theStage.setResizable(true);
theStage.show(); // Show the stage to the user
}
private boolean binaryOperandIssues() {
if (!One.operandDefined) { // Check operand 1 and set a
label_errOperand1.setText("Missing a valid value"); // missing value error
label_errOperand2.setText("");
}
if (!Two.operandDefined) { // Check operand 2 and set a
label_errOperand2.setText("Missing a valid value"); // missing value error
label_errOperand1.setText("");
}
if (operandError) // See if invalid input errors
return true; // return true if so
if (!One.operandDefined || !Two.operandDefined) // See if any missing input values
return true; // return true is so
label_errOperand1.setText("");
label_errOperand2.setText("");
return false; // Else okay input, return false
}
/*******************************************************************************************************
* This portion of the class defines the computation that takes place when the
* various calculator buttons (add, subtract, multiply, and divide) are pressed.
*/
/**********
* This is the add routine
*
*/
private void addOperands(PrintWriter printWriter) {
InexactUNumber Number1 = new InexactUNumber(operand1, Erroperand1);
InexactUNumber Number2 = new InexactUNumber(operand2, Erroperand2);
printWriter.println("Set Operand1 = "+Number1);
printWriter.flush();
printWriter.println("Set Operand2 = "+Number2);
printWriter.flush();
printWriter.println("Add ");
printWriter.flush();
if (binaryOperandIssues()) // If there is an operand error
return; // just return. Otherwise, reset
label_errOperand2.setText(""); // the "divide by zero error"
InexactUNumber result = new InexactUNumber(Number1);// create a new uNUmberMod to not overwrite operand 1
result.add(Number2); // perform the addition
text_Result.setText(Number1.toStringBestEstimate()); // Converts the result to string
label[3].setText("Sum"); // Specify the result is a sum
Number1.roundTo(Math.abs(Erroperand1.getDP()));
Err_Result.setText(Number1.toStringErrorTerm());
printWriter.println("Result= "+Number1);
printWriter.println();
}
/**********
* This is the subtract routine
*
*/
private void subOperands(PrintWriter printWriter) {
InexactUNumber Number2 = new InexactUNumber(operand2, Erroperand2);
InexactUNumber Number1 = new InexactUNumber(operand1, Erroperand1);
printWriter.println("Set Operand 1 = "+Number1);
printWriter.println("Set Operand 2 = "+Number2);
printWriter.println("Subtract ");
if (binaryOperandIssues()) // If there is an operand error
return; // just return. Otherwise, reset
InexactUNumber result = new InexactUNumber(Number1);// create a new uNUmberMod to not overwrite operand 1
result.sub(Number2); // perform the subtraction
text_Result.setText(Number1.toStringBestEstimate()); // Converts the result to string
label[3].setText("Difference"); // Specify the result is a difference
Number1.roundTo(Math.abs(Erroperand1.getDP()));
Err_Result.setText(Number1.toStringErrorTerm());
printWriter.println("Result= "+Number1);
printWriter.println();
}
/**********
* This is the multiply routine
*
*/
private void mpyOperands(PrintWriter printWriter) {
InexactUNumber Number2 = new InexactUNumber(operand2, Erroperand2);
InexactUNumber Number1 = new InexactUNumber(operand1, Erroperand1);
printWriter.println("Set Operand1 = "+Number1);
printWriter.println("Set Operand2 = "+Number2);
printWriter.println("Multiply ");
if (binaryOperandIssues()) // If there is an operand error
return; // just return. Otherwise, reset
InexactUNumber result = new InexactUNumber(Number1);// create a new uNUmberMod to not overwrite operand 1
result.mpy(Number2); // perform the product
text_Result.setText(Number1.toStringBestEstimate()); // Converts the result to string
label[3].setText("Product"); // Specify the result is a product
Number1.roundTo(Math.abs(Erroperand1.getDP()));
Err_Result.setText(Number1.toStringErrorTerm());
printWriter.println("Result= "+Number1);
printWriter.println();
}
/**********
* This is the divide routine. If the divisor is zero, the divisor is declared
* to be invalid.
*
*/
private void divOperands(PrintWriter printWriter) {
InexactUNumber Number2 = new InexactUNumber(operand2, Erroperand2);
InexactUNumber Number1 = new InexactUNumber(operand1, Erroperand1);
printWriter.println("Set Operand1 = "+Number1);
printWriter.println("Set Operand2 = "+Number2);
printWriter.println("Divide ");
if (binaryOperandIssues()) // If there is an operand error
return; // just return. Otherwise, reset
InexactUNumber result = new InexactUNumber(Number1);// create a new uNUmberMod to not overwrite operand 1
result.div(Number2); // perform the division
text_Result.setText(Number1.toStringBestEstimate()); // Converts the result to string
label[3].setText("Quotient"); // Specify the result is a sum
Number1.roundTo(Math.abs(Erroperand1.getDP()));
Err_Result.setText(Number1.toStringErrorTerm());
printWriter.println("Result= "+Number1);
printWriter.println();
}
private void sqrtOperands(PrintWriter printWriter) {
if (operand1.isNegative()) { // Check to see if the value is
label_errOperand1.setText("Square root of a negative value"); // negative. if so,
text_Result.setText(""); // display the error message
} else {
label_errOperand2.setText(""); // Reset the "divide by zero error"
// uNumberMod result = new uNumberMod(operand1,sizeD);
EnhancedUNumber result = new EnhancedUNumber(operand1);
EnhancedUNumber ErrResult = new EnhancedUNumber(Erroperand1);
printWriter.println("Set Operand1 = "+result+" ± "+ErrResult);
printWriter.println("Square Root ");
ErrResult = new EnhancedUNumber(ErrResult); // System.out.println(result);
result = new EnhancedUNumber(result); // System.out.println(result);
ErrResult.div(result);
result.squareRoot(); // Do the square root
ErrResult.mpy(result);
String theAnswer = result.toString(sizeD);// set theAnswer to the result with 8 characters
text_Result.setText(theAnswer); // Converts the result to string
label[3].setText("Square Root"); // Specify the result is a quotient
text_Operand2.setText("");
Erroperand1.div(new EnhancedUNumber("2", 1, true, Erroperand1.getDP()));
Erroperand1.mpy(result);
String theAnswerErr = Erroperand1.toString(sizeD);// set theAnswer to the result with 8 characters
Err_Result.setText(theAnswerErr);
printWriter.println("Result = "+result+" ± "+theAnswerErr);
}
}
public static void main(String[] args) {
launch(args); // for all JavaFX applications.
}
}
答案 0 :(得分：1)
您应该将您的printwriter对象作为追加模式。
printWriter = new PrintWriter(new BufferedWriter(new OutputStreamWriter(new FileOutputStream(file, true))), true);