Java SWT 做計(jì)算器。

2019-11-15 00:33:52

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java SWT 做計(jì)算器。java -- swt - - 計(jì)算器

環(huán)境搭建安裝java、eclipse、以及對(duì)應(yīng)的swt插件。

開(kāi)始工程

建立工程：在java下建立一個(gè)在其他 —- WindowsBuilder —- SWTdesigner —- SWT/JFrame Java PRoject。建立好以后運(yùn)行將得到一個(gè)swt窗口。
設(shè)計(jì)界面：點(diǎn)擊代碼下的Design選項(xiàng)卡 —- 拖動(dòng)一個(gè)布局到窗口里 —- 然后自定義界面如果沒(méi)有發(fā)現(xiàn)Design選項(xiàng)卡的話在代碼編輯窗口內(nèi)右擊選擇打開(kāi)方式為: Windows Builder edit
碼代碼：獲取框里的文本：text.getText();設(shè)置文本：text.setText();很簡(jiǎn)單的函數(shù)。

Question & BUG　　TODO 處理按下 1 后顯示 01 的問(wèn)題　　FIXME 按下后變?yōu)?.1　　FIXME 直接按下 . 的話前面沒(méi)有變?yōu)?0 .　　TODO 字符串轉(zhuǎn) double　　TODO 處理浮點(diǎn)數(shù)運(yùn)算后結(jié)果多余顯示的“.0”

　　　　直接復(fù)制代碼或把代碼放到不同的計(jì)算器中運(yùn)行的話可能hi出現(xiàn)一大片紅色的錯(cuò)誤，是因?yàn)樵谛碌沫h(huán)境中沒(méi)有把需要的包給導(dǎo)入。

需要在項(xiàng)目上右擊 —- 屬性 —- 然后一步步把需要的包導(dǎo)入，很多簡(jiǎn)單，不懂就多試試。

　　　　在java中運(yùn)算浮點(diǎn)數(shù)的話會(huì)得不到準(zhǔn)確的值是因?yàn)橛?jì)算器中是用二進(jìn)制來(lái)存數(shù)據(jù)的，所以一個(gè)小數(shù)在計(jì)算機(jī)中會(huì)是無(wú)限循環(huán)的。

要處理這個(gè)BUG的話就需要使用java的BigDecimal類。

怎么把左上角的圖標(biāo)自定義？——–在Design里點(diǎn)擊窗口、在左邊的屬性框里找到Image。

怎么設(shè)置文本框里的文本出現(xiàn)在后邊？——也是在屬性框里找到Style 找到 align，設(shè)置。

怎么把工作空間導(dǎo)入eclipse？——–在工作空間那里（如果沒(méi)有這個(gè)窗口的話，在窗口那里找到它，把它顯示出來(lái)）右擊導(dǎo)入 —- General —- 現(xiàn)有項(xiàng)目到工作空間 —- 選擇根目錄 —-選項(xiàng)目文件夾的上層文件夾—- Finish

package com.java; * 計(jì)算器import org.eclipse.swt.widgets.Display;import org.eclipse.swt.widgets.Shell;import org.eclipse.swt.layout.GridLayout;import org.eclipse.swt.widgets.Button;import org.eclipse.swt.SWT;import org.eclipse.swt.layout.GridData;import org.eclipse.swt.widgets.Text;import org.eclipse.swt.events.SelectionAdapter;import org.eclipse.swt.events.SelectionEvent;import org.eclipse.wb.swt.SWTResourceManager;public class Test {    protected Shell shell;    private Text text;        private int op = 0;    private double num1;    private double num2;    private static final int op_ADD =1;    private static final int op_SUB =2;    private static final int op_MUL =3;    private static final int op_DIV =4;    /**     * Launch the application.     * @param args     */    public static void main(String[] args) {        try {            Test window = new Test();            window.open();        } catch (Exception e) {            e.printStackTrace();        }    }        //TODO 把文本設(shè)置在文本框的右邊：在 text 屬性的 style 的 align 里設(shè)置。    /**     * Open the window.     */    public void open() {        Display display = Display.getDefault();        createContents();        shell.open();        shell.layout();        while (!shell.isDisposed()) {            if (!display.readAndDispatch()) {                display.sleep();            }        }    }    /**     * Create contents of the window.     */    protected void createContents() {        shell = new Shell();        shell.setImage(SWTResourceManager.getImage("E://Design//nexus4full(96  96)//circle.png"));        shell.setSize(240, 297);        shell.setText("SWT Application");        shell.setLayout(new GridLayout(4, false));                text = new Text(shell, SWT.BORDER | SWT.RIGHT);        GridData gd_text = new GridData(SWT.FILL, SWT.FILL, true, false, 4, 1);        gd_text.heightHint = 36;        gd_text.widthHint = 424;        text.setLayoutData(gd_text);                Button button = new Button(shell, SWT.NONE);        button.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "7");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        GridData gd_button = new GridData(SWT.LEFT, SWT.CENTER, false, false, 1, 1);        gd_button.heightHint = 37;        gd_button.widthHint = 51;        button.setLayoutData(gd_button);        button.setText("7");                Button button_1 = new Button(shell, SWT.NONE);        button_1.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "8");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        GridData gd_button_1 = new GridData(SWT.LEFT, SWT.CENTER, false, false, 1, 1);        gd_button_1.heightHint = 37;        gd_button_1.widthHint = 51;        button_1.setLayoutData(gd_button_1);        button_1.setText("8");                Button button_2 = new Button(shell, SWT.NONE);        GridData gd_button_2 = new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1);        gd_button_2.heightHint = 37;        gd_button_2.widthHint = 51;        button_2.setLayoutData(gd_button_2);        button_2.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "9");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        button_2.setText("9");                Button button_10 = new Button(shell, SWT.NONE);        GridData gd_button_10 = new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1);        gd_button_10.widthHint = 46;        gd_button_10.heightHint = 40;        button_10.setLayoutData(gd_button_10);        button_10.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                op = op_ADD;                num1 =Double.parseDouble (text.getText() );                text.setText("0");            }        });        button_10.setText("+");        Button button_3 = new Button(shell, SWT.NONE);        button_3.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "4");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        GridData gd_button_3 = new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1);        gd_button_3.heightHint = 37;        gd_button_3.widthHint = 51;        button_3.setLayoutData(gd_button_3);        button_3.setText("4");                Button button_4 = new Button(shell, SWT.NONE);        button_4.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "5");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        GridData gd_button_4 = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);        gd_button_4.heightHint = 33;        button_4.setLayoutData(gd_button_4);        button_4.setText("5");                Button button_5 = new Button(shell, SWT.NONE);        button_5.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "6");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        GridData gd_button_5 = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);        gd_button_5.heightHint = 35;        button_5.setLayoutData(gd_button_5);        button_5.setText("6");                Button button_11 = new Button(shell, SWT.NONE);        button_11.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                op = op_SUB ;                num1 =Double.parseDouble (text.getText() );                //num1 = Integer.parseInt ( text.getText() );                text.setText("0");            }        });        button_11.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_11.setText("-");                Button button_6 = new Button(shell, SWT.NONE);        button_6.setFont(SWTResourceManager.getFont("微軟雅黑", 11, SWT.NORMAL));        button_6.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                                //TODO 處理按下 1 后顯示 01 的問(wèn)題                        text.setText (text.getText() + "1");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring (1, text.getText().length( ) ) ) ;                }                //FIXME 按下后變?yōu)?.1//                else if(text.getText().startsWith("0.")){//                    text.setText ( text.getText() +"1") ;//                }            }        });        GridData gd_button_6 = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);        gd_button_6.heightHint = 37;        gd_button_6.widthHint = 51;        button_6.setLayoutData(gd_button_6);        button_6.setText("1");                Button button_7 = new Button(shell, SWT.NONE);        button_7.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "2");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        button_7.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_7.setText("2");                Button button_8 = new Button(shell, SWT.NONE);        button_8.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "3");                if (text.getText().startsWith("0")){                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;                }            }        });        button_8.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_8.setText("3");                Button button_12 = new Button(shell, SWT.NONE);        button_12.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                op = op_MUL;                num1 =Double.parseDouble (text.getText() );                //num1 = Integer.parseInt ( text.getText() );                text.setText("0");            }        });        button_12.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_12.setText("/u00D7");                Button btnC = new Button(shell, SWT.NONE);        btnC.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText("0");            }        });        btnC.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        btnC.setText("C");                Button button_9 = new Button(shell, SWT.NONE);        button_9.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                text.setText(text.getText() + "0");//                if (text.getText().startsWith("0")){//                    text.setText ( text.getText().substring ( 1, text.getText().length( ) ) ) ;//                }            }        });        GridData gd_button_9 = new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1);        gd_button_9.heightHint = 37;        gd_button_9.widthHint = 51;        button_9.setLayoutData(gd_button_9);        button_9.setText("0");                Button button_14 = new Button(shell, SWT.NONE);        button_14.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                    text.setText (text.getText() + ".");                                    //FIXME 直接按下  .  的話前面沒(méi)有變?yōu)?0 .            }        });        button_14.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_14.setText(".");                Button button_13 = new Button(shell, SWT.NONE);        button_13.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                op = op_DIV;                num1 =Double.parseDouble (text.getText() );                //num1 = Integer.parseInt( text.getText() );                text.setText("0");            }        });        button_13.setLayoutData(new GridData(SWT.FILL, SWT.FILL, false, false, 1, 1));        button_13.setText("/u00F7");                Button button_15 = new Button(shell, SWT.NONE);        button_15.addSelectionListener(new SelectionAdapter() {            @Override            public void widgetSelected(SelectionEvent e) {                double  result ;                //TODO   字符串 轉(zhuǎn) double                num2 =Double.parseDouble ( text.getText() );                switch ( op) {                case op_ADD:                    result = num1+num2;                    text.setText( result +"");                                    //FIXME java中計(jì)算浮點(diǎn)數(shù)的時(shí)候不精確，如：0.3 * 3                    //需要使用 java 的大數(shù)類 BigDecimal。                                        //TODO 處理浮點(diǎn)數(shù)運(yùn)算后結(jié)果多余顯示的“.0”                    if (text.getText().endsWith("0"))                        text.setText(text.getText().substring(0,text.getText().length()-2));                    break;                case op_SUB:                     result = num1 - num2;                    text.setText( result +"");                    if (text.getText().endsWith("0"))                        text.setText(text.getText().substring(0,text.getText().length()-2));                    break;                case op_MUL:                    result = num1 * num2;                    text.setText( result +"");                    if (text.getText().endsWith("0"))                        text.setText(text.getText().substring(0,text.getText().length()-2));                    break;                case op_DIV:                    result = num1 / num2;                    text.setText( result +"");                    if (text.getText().endsWith("0"))                        text.setText(text.getText().substring(0,text.getText().length()-2));                    break;                default:                    break;                }            }        });        GridData gd_button_15 = new GridData(SWT.FILL, SWT.FILL, false, false, 4, 1);        gd_button_15.heightHint = 34;        button_15.setLayoutData(gd_button_15);        button_15.setText("=");    }}

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