问题
I'm pretty new to java SWT, and while putting labels, it looks like i can't make the label background transparent. I'm using eclipse luna SWT desine form. this is what my window looks like:
as you can see,all the label backgrounds are white. What should i do so the label backgrounds will be the same as the window background(grey) by default (meaning - not by changing each label background at runtime, which does work for me).
it probably simple, but i just couldn't find on google how to do it. here is my code:
import java.awt.Color;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;
import org.eclipse.swt.SWT;
import org.eclipse.ui.forms.widgets.FormToolkit;
import org.eclipse.swt.widgets.Label;
import org.eclipse.wb.swt.SWTResourceManager;
import org.eclipse.swt.widgets.Combo;
import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.observable.value.IObservableValue;
import org.eclipse.jface.databinding.swt.WidgetProperties;
import org.eclipse.core.databinding.beans.PojoProperties;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.RowLayout;
import org.eclipse.swt.layout.RowData;
import org.eclipse.swt.layout.FormLayout;
import org.eclipse.swt.layout.FormData;
import org.eclipse.swt.layout.FormAttachment;
import org.eclipse.swt.widgets.Button;
import org.eclipse.swt.events.SelectionAdapter;
import org.eclipse.swt.events.SelectionEvent;
import org.eclipse.swt.widgets.Canvas;
public class WinApp2 {
private DataBindingContext m_bindingContext;
protected Shell shell;
private Text destenation_ip;
private final FormToolkit formToolkit = new FormToolkit(Display.getDefault());
private Label lblDestenationPortIp;
private Label lblNewLabel;
private Text ammount_of_packets;
private Label lblNewLabel_1;
private Text sorce_ip;
private Text destenation_port;
private Text sorce_port;
private Label lblNewLabel_2;
private Label label;
private Label label_1;
private Label ammount_of_packets_info;
/**
* Launch the application.
* @param args
*/
public static void main(String[] args) {
Display display = Display.getDefault();
Realm.runWithDefault(SWTObservables.getRealm(display), new Runnable() {
public void run() {
try {
WinApp2 window = new WinApp2();
window.open();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* 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.setBackgroundMode(SWT.INHERIT_DEFAULT);
shell.setSize(450, 306);
shell.setText("LAN Destroyer");
shell.setLayout(new FormLayout());
destenation_ip = new Text(shell, SWT.BORDER);
FormData fd_destenation_ip = new FormData();
destenation_ip.setLayoutData(fd_destenation_ip);
lblDestenationPortIp = new Label(shell, SWT.NONE);
lblDestenationPortIp.setAlignment(SWT.RIGHT);
FormData fd_lblDestenationPortIp = new FormData();
fd_lblDestenationPortIp.left = new FormAttachment(0, 351);
fd_lblDestenationPortIp.right = new FormAttachment(100, -10);
fd_lblDestenationPortIp.top = new FormAttachment(0, 35);
lblDestenationPortIp.setLayoutData(fd_lblDestenationPortIp);
lblDestenationPortIp.setBackground(SWTResourceManager.getColor(SWT.COLOR_LIST_SELECTION_TEXT));
formToolkit.adapt(lblDestenationPortIp, true, true);
lblDestenationPortIp.setText(":\u05E9\u05DC \u05D9\u05E2\u05D3 IP");
lblNewLabel = new Label(shell, SWT.NONE);
lblNewLabel.setAlignment(SWT.RIGHT);
FormData fd_lblNewLabel = new FormData();
fd_lblNewLabel.right = new FormAttachment(100, -10);
lblNewLabel.setLayoutData(fd_lblNewLabel);
formToolkit.adapt(lblNewLabel, true, true);
lblNewLabel.setText(":\u05DB\u05DE\u05D5\u05EA");
ammount_of_packets = new Text(shell, SWT.BORDER);
fd_destenation_ip.left = new FormAttachment(ammount_of_packets, 0, SWT.LEFT);
fd_destenation_ip.right = new FormAttachment(ammount_of_packets, -1, SWT.RIGHT);
FormData fd_ammount_of_packets = new FormData();
fd_ammount_of_packets.right = new FormAttachment(lblNewLabel, -68);
fd_ammount_of_packets.top = new FormAttachment(lblNewLabel, -3, SWT.TOP);
ammount_of_packets.setLayoutData(fd_ammount_of_packets);
formToolkit.adapt(ammount_of_packets, true, true);
Button nonstop_send = new Button(shell, SWT.CHECK);
fd_ammount_of_packets.left = new FormAttachment(0, 186);
nonstop_send.setAlignment(SWT.RIGHT);
nonstop_send.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent e) {
if(nonstop_send.getSelection()){
ammount_of_packets_info.setText("שולח ללא הפסקה");
ammount_of_packets_info.setBackground(SWTResourceManager.getColor(SWT.COLOR_DARK_GREEN));
ammount_of_packets.setEnabled(false);
}
else {
ammount_of_packets_info.setText("");
ammount_of_packets.setEnabled(true);
}
}
});
FormData fd_nonstop_send = new FormData();
fd_nonstop_send.top = new FormAttachment(lblNewLabel, 0, SWT.TOP);
fd_nonstop_send.right = new FormAttachment(ammount_of_packets, -9);
nonstop_send.setLayoutData(fd_nonstop_send);
formToolkit.adapt(nonstop_send, true, true);
nonstop_send.setText("\u05E9\u05DC\u05D7 \u05DC\u05DC\u05D0 \u05D4\u05E4\u05E1\u05E7\u05D4");
lblNewLabel_1 = new Label(shell, SWT.NONE);
fd_lblNewLabel.top = new FormAttachment(lblNewLabel_1, 6);
lblNewLabel_1.setAlignment(SWT.RIGHT);
FormData fd_lblNewLabel_1 = new FormData();
fd_lblNewLabel_1.right = new FormAttachment(100, -10);
fd_lblNewLabel_1.top = new FormAttachment(lblDestenationPortIp, 6);
lblNewLabel_1.setLayoutData(fd_lblNewLabel_1);
formToolkit.adapt(lblNewLabel_1, true, true);
lblNewLabel_1.setText(":\u05E9\u05DC \u05DE\u05E7\u05D5\u05E8 IP");
sorce_ip = new Text(shell, SWT.BORDER);
fd_destenation_ip.bottom = new FormAttachment(sorce_ip);
fd_lblNewLabel_1.left = new FormAttachment(sorce_ip, 29);
FormData fd_sorce_ip = new FormData();
fd_sorce_ip.top = new FormAttachment(0, 58);
fd_sorce_ip.left = new FormAttachment(0, 186);
fd_sorce_ip.right = new FormAttachment(100, -114);
sorce_ip.setLayoutData(fd_sorce_ip);
formToolkit.adapt(sorce_ip, true, true);
destenation_port = new Text(shell, SWT.BORDER);
fd_nonstop_send.left = new FormAttachment(destenation_port, 0, SWT.LEFT);
FormData fd_destenation_port = new FormData();
fd_destenation_port.top = new FormAttachment(0, 32);
fd_destenation_port.left = new FormAttachment(0, 40);
destenation_port.setLayoutData(fd_destenation_port);
formToolkit.adapt(destenation_port, true, true);
sorce_port = new Text(shell, SWT.BORDER);
sorce_port.setForeground(SWTResourceManager.getColor(SWT.COLOR_CYAN));
sorce_port.setBackground(SWTResourceManager.getColor(SWT.COLOR_YELLOW));
FormData fd_sorce_port = new FormData();
fd_sorce_port.top = new FormAttachment(lblNewLabel_1, -3, SWT.TOP);
fd_sorce_port.left = new FormAttachment(destenation_port, 0, SWT.LEFT);
sorce_port.setLayoutData(fd_sorce_port);
formToolkit.adapt(sorce_port, true, true);
lblNewLabel_2 = new Label(shell, SWT.NONE);
FormData fd_lblNewLabel_2 = new FormData();
fd_lblNewLabel_2.top = new FormAttachment(0, 35);
fd_lblNewLabel_2.left = new FormAttachment(destenation_port, 6);
lblNewLabel_2.setLayoutData(fd_lblNewLabel_2);
formToolkit.adapt(lblNewLabel_2, true, true);
lblNewLabel_2.setText(":\u05E4\u05D5\u05E8\u05D8");
label = new Label(shell, SWT.NONE);
label.setText(":\u05E4\u05D5\u05E8\u05D8");
FormData fd_label = new FormData();
fd_label.bottom = new FormAttachment(nonstop_send, -6);
fd_label.left = new FormAttachment(sorce_port, 6);
label.setLayoutData(fd_label);
formToolkit.adapt(label, true, true);
label_1 = new Label(shell, SWT.WRAP | SWT.SHADOW_IN);
FormData fd_label_1 = new FormData();
fd_label_1.top = new FormAttachment(ammount_of_packets, 20);
fd_label_1.left = new FormAttachment(0, 187);
label_1.setLayoutData(fd_label_1);
formToolkit.adapt(label_1, true, true);
label_1.setText(":\u05E1\u05D9\u05DB\u05D5\u05DD");
ammount_of_packets_info = new Label(shell, SWT.NONE);
ammount_of_packets_info.setBackground(SWTResourceManager.getColor(SWT.COLOR_DARK_MAGENTA));
FormData fd_ammount_of_packets_info = new FormData();
fd_ammount_of_packets_info.left = new FormAttachment(100, -158);
fd_ammount_of_packets_info.top = new FormAttachment(ammount_of_packets, 44);
fd_ammount_of_packets_info.right = new FormAttachment(100, -36);
ammount_of_packets_info.setLayoutData(fd_ammount_of_packets_info);
formToolkit.adapt(ammount_of_packets_info, true, true);
m_bindingContext = initDataBindings();
}
protected DataBindingContext initDataBindings() {
DataBindingContext bindingContext = new DataBindingContext();
//
return bindingContext;
}
}
thanks!
回答1:
Your problem is caused by FormToolkit#adapt(Control, boolean, boolean). Internally, this method sets the background color to the background color of the toolkit.
You can prevent that by calling:
formToolkit.setBackground(null);
Reference: Source of FormToolkit#adapt(Control, boolean, boolean)
回答2:
If you still want to have text, use the what I mentioned above: shell.setBackground(SWT.INHERIT_FORCE);. This makes it so that the background of your label will match the background color.
However, you can also do a simpler option. If you want to "hide" text, yet need to keep it for later and display it when you want to, you can set the text of a particular label to be null.
I often use this when I need text to disappear. The only thing is, is you need to store the text into an array (list) - or whatever you want (i.e. a database or someting similar) so you can save the text for later. You don't even need to use SWT.INHERIT_FORCE.This is a full example that might help:
package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.*;
/**
*
* @author Dylan
*/
public class Test {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
Display display = new Display();
Shell shell = new Shell(display);
shell.setLayout(new GridLayout(1, false));
shell.setText("Stackoverflow Test");
shell.setBackground(display.getSystemColor(SWT.COLOR_WHITE));
// shell.setBackgroundMode(SWT.INHERIT_FORCE);
Button button = new Button(shell, SWT.PUSH);
button.setText("Button that's fun to click - but there is no text :D");
Label label = new Label(shell, SWT.NONE);
label.setText("Horray, you entered text to stdin!!");
ArrayList<String> labelText = new ArrayList<>();
labelText.add(label.getText());
label.setText("");
shell.pack();
shell.open();
Boolean flag = false;
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
if (!flag) {
try(BufferedReader reader = new BufferedReader(new InputStreamReader(System.in))) {
System.out.println("Please enter some text");
char[] cbuf = new char[40];
String text = reader.readLine();
if (text.length()> 0) {
flag = true;
label.setText(labelText.remove(0));
button.setText(button.getText() + "... and now there is. Yay!");
shell.pack();
} else {
break;
}
} catch (IOException io) {
System.err.println(io.toString());
}
}
}
}
display.dispose();
}
}
来源：https://stackoverflow.com/questions/25188687/how-to-make-label-backgrounds-transparent-in-swt