I have a question regarding the awt Color class in Java.
I am currently using the class abbreviations such as Color.RED and Color.BLACK. I also have a list of three integers such as the following:
int var1 = 0
int var2 = 0
int var3 = 255
Is there a method to convert these integers into the appropriate Java Color name?
There is no way to do this with a single method in the Java core classes. However, you can fairly easily do this yourself in two ways.
First way
First, create a HashMap of Colors that contains all the colors you want:
HashMap<Color, String> colors = new HashMap<Color, String>();
colors.put(Color.BLACK, "BLACK");
colors.put(Color.BLUE, "BLUE");
colors.put(Color.CYAN, "CYAN");
colors.put(Color.DARK_GRAY, "DARK_GRAY");
colors.put(Color.GRAY, "GRAY");
colors.put(Color.GREEN, "GREEN");
colors.put(Color.LIGHT_GRAY, "LIGHT_GRAY");
colors.put(Color.MAGENTA, "MAGENTA");
colors.put(Color.ORANGE, "ORANGE");
colors.put(Color.PINK, "PINK");
colors.put(Color.RED, "RED");
colors.put(Color.WHITE, "WHITE");
colors.put(new Color(192, 0, 255), "PURPLE");
colors.put(new Color(0xBADA55), "BADASS_GREEN");
colors.put(new Color(0, 0, 128), "DARK_BLUE");
Then, create a new Color out of the RGB values you have:
Color color = new Color(var1, var2, var3);
Last, get the value in colors for the key color:
String colorName = colors.get(color);
Second way
This is potentially a less brittle way, but does have issues, and doesn't work as-is. You'll need to catch some exceptions, and maybe handle the case where a field isn't static and you can't just do f.get(null).
Create a new Color out of the RGB values you have:
Color color = new Color(var1, var2, var3);
Then
Get the Class object from the Color class with getClass().
Get the fields from that with getDeclaredFields().
Stream it using Arrays.stream()
Filter it by calling filter(), so it only contains all the enum constants that equal the color you made (there should be either one or zero).
Use toArray() to turn the stream into an array.
Get the first element of that array with [0]. This will throw an ArrayIndexOutOfBoundsException if there isn't a predefined color matching your color.
Get the name of that color with Enum's toString().
String colorName = Arrays.stream(Color.getClass().getDeclaredFields())
.filter(f -> f.get(null).equals(color))
.toArray()[0]
.toString();
There is no set function for this kind of behavior, but you could do something like this:
public static String getColorName(int r, int g, int b) {
String[] colorNames = new String[] {
"BLACK",
"BLUE",
"GREEN",
"CYAN",
"DARK_GRAY",
"GRAY",
"LIGHT_GRAY",
"MAGENTA",
"ORANGE",
"PINK",
"RED",
"WHITE",
"YELLOW"
};
Color userProvidedColor = new Color(r,g,b);
Color color;
Field field;
for (String colorName : colorNames) {
try {
field = Class.forName("java.awt.Color").getField(colorName);
color = (Color)field.get(null);
if (color.equals(userProvidedColor)) {
return colorName; // Or maybe return colorName.toLowerCase() for aesthetics
}
} catch (Exception e) {
}
}
Color someOtherCustomDefinedColorMaybePurple = new Color(128,0,128);
if (someOtherCustomDefinedColorMaybePurple.equals(userProvidedColor)) {
return "Purple";
}
return "Undefined";
}
There are a few options from here as well, maybe you want the nearest color? In which case you could try and resolve the distance somehow (here by distance from each r,g,b coordinate, admittedly not the best method but simple enough for this example, this wiki page has a good discussion on more rigorous methods)
// ...
String minColorName = "";
float minColorDistance = 10000000;
float thisColorDistance = -1;
for (String colorName : colorNames) {
try {
field = Class.forName("java.awt.Color").getField(colorName);
color = (Color)field.get(null);
thisColorDistance = ( Math.abs(color.red - userProvidedColor.red) + Math.abs(color.green - userProvidedColor.green) + Math.abs(color.blue - userProvidedColor.blue) );
if (thisColorDistance < minColorDistance) {
minColorName = colorName;
minColorDistance = thisColorDistance;
}
} catch (Exception e) {
// exception that should only be raised in the case color name is not defined, which shouldnt happen
}
}
if (minColorName.length > 0) {
return minColorName;
}
// Tests on other custom defined colors
This should outline how you would be able to compare to the built in colors from the Color library. You could use a Map to expand the functionality further to allow for you to define as many custom colors as you like (Something #TheGuywithTheHat suggests as well) which gives you more control over the return names of matched colors, and allows for you to go by more colors than just the predefined ones:
HashMap<String,Color> colorMap = new HashMap<String,Color>();
colorMap.put("Red",Color.RED);
colorMap.put("Purple",new Color(128,0,128));
colorMap.put("Some crazy name for a color", new Color(50,199,173));
// etc ...
String colorName;
Color color;
for (Map.Entry<String, Color> entry : colorMap.entrySet()) {
colorName = entry.getKey();
color= entry.getValue();
// Testing against users color
}
As far as i know, we don't have any such library to directly access the colors from the Constants.
But we can manage do it using Hex Color Library in Java.
References :
Hex
Color Class
Without any helping libraries I would say: No. Especially because not every RGB-Color has a specific name. However, you could of course build an own function, which tries to match some of the available colors and deliver something like "Unknown" if there is no match.
The matching attempt could theoretically be done using the Java reflection API...
Related
I wish to create an array of all the Colors predefined in java.awt.Color in order to randomly select one of them.
My current best attempt is:
` Color[] colors = Color.getClass().getEnumConstants();
which was suggested in the top answer to the question: Color Class in Java
but that generates the error:
Cannot make a static reference to the non-static method getClass() from the type Object
The constructor in which the erroneous call is made is below:
private Ball() {
Random initialSetter = new Random();
ballX = marginSize + initialSetter.nextInt(xSize - 2 * marginSize);
ballY = marginSize + initialSetter.nextInt(ySize - 2 * marginSize);
ballXV = initialSetter.nextInt(doubleMaxV) - doubleMaxV/2;
ballYV = initialSetter.nextInt(doubleMaxV) - doubleMaxV/2;
Color[] colors = Color.getClass().getEnumConstants();
color = colors[initialSetter.nextInt(colors.length)];
}
Replacing ".getClass().getEnumConstants()" with ".values()" generates much the same error (static reference to non-static method).
To fix your immediate error, you can do:
Color[] colors = Color.class.getEnumConstants();
But this only works if Color is an enum. According to your comments, Color refers to java.awt.Color, which is not an enum. The first way suggested by the linked answer is quite incorrect (Maybe it was 6 years ago?).
As far as I know, the best thing you can do here is to list them all out. There's not much - only 13. It's not like this number is going to change any time soon, as AWT is pretty old, they are unlikely to add new colours in at this stage.
For fun (this is only for fun), you can do it with reflection:
List<Color> colors = Arrays.stream(Color.class.getFields())
// fields of type Color, and in all caps, snake case
.filter(x -> x.getType() == Color.class && x.getName().matches("[A-Z_]+"))
.map(x -> {
try {
return (Color)x.get(null);
} catch (IllegalAccessException e) {
e.printStackTrace();
return Color.BLACK;
}
}).collect(Collectors.toList());
Note that reflection is really slow though, which is why your best choice is to hardcode it.
I would like to match color search results text with the checkbox text after clicking search button. See pic.
Currently I can view the Search Results text color but it doesn't match the checkbox text color after clicking search button. The code below is only for the Search Car Results text area and a class named CarBrand that matches the key of this HashMap carDetails. I am not sure how to compare and match its color using HashMap. Any suggestions would be great!
import java.awt.Color;
import java.swing.tree.DefaultTreeCellRenderer
public final class CarDetails extends DefaultTreeCellRenderer
{
private final Color defaultColor;
private final HashMap<String, Color> carDetails = new HashMap<>();
public CarDetails()
{
int i = 0;
defaultColor = getBackground(); //default color
int [][] rgb = {
{ 200, 000, 200 },
{ 000, 140, 000 },
{ 000, 200, 200 }
};
for (CarBrand car: CarModel.getCarBrandDetails()) {
carDetails.put(car.getCarBrand(), new Color(
rgb[i][0], rgb[i][1], rgb[i][2]));
i++;
// TODO this part is what I am not sure.
if (carDetails.containsKey(car.getCarBrand()) && carTable != null) {
for (Component c : carTable.getComponents()) {
if (c.getName().equals(car.getCarBrand())) {
c.setForeground(carDetails.containsObject(new
Color(rgb[i][0], rgb[i][1], rgb[i][2])));
}
}
}
}
}
}
I expect the output to match the color coding of the Search Car Results with the CheckBox text (Honda, Hundai, BMW) like the pic below.
I agree with Andrew Thompson a lot of code is missing to be able to reproduce your problem.
You should check if your conditions are correct (if statements).
The declaration of carTable is missing so we can't verify how it is build up. You use Component.getName(), are you sure this contains the value you expect ?
see what-is-java-awt-component-getname-and-setname-used-for
It is not filled by default so if you fill it before with the expected values, than it's fine to use.
Assuming c.getName() returns the name of the carBrand, you can do the following:
for (CarBrand car: CarModel.getCarBrandDetails()) {
carDetails.put(car.getCarBrand(), new Color(
rgb[i][0], rgb[i][1], rgb[i][2]));
i++;
}
if (carTable != null) {
for (Component c : carTable.getComponents()) {
if(carDetails.containsKey(c.getName()) {
c.setForeground(carDetails.get(c.getName())));
}
}
}
In your code you are not using the values from carDetails map you filled before. By calling ´carDetails.get()` method you reuse the created Color object.
I'm working on a homework project for an intro to java course. To practice calling methods and organizing tasks, we have to create two balloon objects s1 and s2 and modify their colors and altitudes using methods in a separate java class.
I have everything working fine, but not exactly to the requirements of the assignment. The sheet lists the method declarations and they cannot be changed, only the code within them can.
The method that is used to change a balloon's color is to be created as public void setColor(). This doesn't make sense to me, though. I'm using public void setColor(String color) for now.
How can I change the color property of a balloon object without passing anything to the setColor method?
I totally agree with #RealSkeptic but as your question says that changing the color without passing any value it means you need to generate the color each time your could use the following code. I'm not sure do this code is what you need.
public void setColor()
{
int red,green,blue;
red = green = blue = 0;
Random random = new Random();
int high = 255, low = 0;
red = random.nextInt(high-low)+low;
green = random.nextInt(high-low)+low;
blue = random.nextInt(high-low)+low;
color = new Color(red,green,blue);
//set this color to your balloon
}
Well, you can't specify any particular color without a parameter in the method. You can hardcode so that the color changes.
class Baloon {
private String[] colors = {"blue", "red" , "green"};
private int index = 0;
private String currentColor = colors[index];
public void setColor(){
index ++;
if (index = colors.length)
index = 0;
currentColor = colors[index];
}
}
I am working on a Java project. I want for the user to input a color for a Label. I want to do something like this, but with a String.
jLabel3.setForeground(Color.blue);
Here is what I tried, but didn't work:
String a = "blue";
jLabel3.setForeground(Color.a);
or:
String a = "blue";
jLabel3.setForeground(a);
Is there possibly another way to do this with a method? Any help would be great. Thank You.
Here is one way:
Map<String, Color> colors = new HashMap<String, Color>();
// ...
colors.put("blue", Color.BLUE);
colors.put("red", Color.RED);
colors.put("green", Color.GREEN);
// other colors
Then use it like:
String a = "blue";
jLabel3.setForeground(colors.get(a.toLowerCase()));
EDIT: Consider a color chooser. See How to Use Color Choosers.
Try reflection:
Color color;
try {
Field field = Class.forName("java.awt.Color").getField("yellow");
color = (Color)field.get(null);
} catch (final Exception e) {
e.printStackTrace();
}
Besides that you can create a map of colors and their names.
Not sure if there is a better way but you could do somthing like:
If("blue".equals(a)){
jLabel3.setForeground(Color.blue);
}
I'm trying to get colors by name, and I came across Converting a String to Color in Java, which suggests using java.awt.getColor.
I can't work out what to pass it as a string though. The following
System.out.println( java.awt.Color.getColor( "black", Color.red ) );
prints out
java.awt.Color[r=255,g=0,b=0]
i.e. it is going with the default color in there.
I've put this in a text box, and tried alternative capitalisations etc. The docs aren't very helpful here. Can anyone suggest what magic strings to put in?
The non-accepted answer uses Color.getColor. This method reads from system properties which may or may not be present. You should not use this method.
Instead, you should use the upvoted reflection method to find the static member of the Color class. Either this, or you should import your own color database which maps string names to RGB values.
Color color;
try {
Field field = Color.class.getField("yellow");
color = (Color)field.get(null);
} catch (Exception e) {
color = null; // Not defined
}