Thread: drag and drop word to match image

Originally Posted by Norm

It looks like the code will call the reject method more than one time. Once in the else and once after that.

Where is the if statement that tests if the dropped String is to be accepted?

The accept works... heres the code:

The {}s are missing for the else block.

What is the variable: string2 for?

The variable: string1 should be defined as a class instance variable, not as a local variable in a method. The next step in the test program will be to pass into the class the String that it is supposed to accept.

Originally Posted by Norm

The {}s are missing for the else block.

What is the variable: string2 for?

The variable: string1 should be defined as a class instance variable, not as a local variable in a method. The next step in the test program will be to pass into the class the String that it is supposed to accept.

this code i have just changed it works... is this correct now?? or do i need change what u have suggested above?

The accept String needs to be defined outside of the method. Make it a parameter to the class's constructor.

What part of post#89 are you asking about.

Do you know what the definition of a method is? For example, what variables are defined inside a method and what variables are defined outside of a method.

like so??

That looks like the definition of a method.

Did you have a question about the contents of that method?

One poor coding technique is putting more than one } on the same line like at the end of the method. Each } should be on its own line.

how do i string more than one label to be accepted??

Use an OR condition in the if statement for all the Strings to be accepted.

Have you changed the test program to show two images, each with a label area and with different Strings that they accept?

To show an image with its own label, create a panel, use the Gridlayout, add the image and label to the panel and then add the panel to the frame.
For the panel, Have the drop target extend JPanel and pass its constructor the image and the accept String.

When that test version works, you can think about copying the logic to the big program.

Originally Posted by Norm

Use an OR condition in the if statement for all the Strings to be accepted.

Is this correct for the OR Condition?

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Is this correct for the OR Condition?

Did you test it? Does it work?

Don't be in a hurry to move the testing code into the main program. It will be easier to work out the techniques in the test program.

Change the test program to show two images, each with a label area and with different Strings that they accept.

To show an image with its own label, create a panel, use the Gridlayout, add the image and label to the panel and then add the panel to the frame.
For the panel, Have the drop target extend JPanel and pass its constructor the image and the accept String.

i have added the images to the panel.

--- Update ---

Have the drop target extend JPanel and pass its constructor the image and the accept String.

i did change it but then i got errors, please see error below.
Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException: Uncompilable source code - Erroneous sym type: javaapplication24.DragAndDropExample.DropTargetTex tArea.setText
at javaapplication24.DragAndDropExample$DropTargetTex tArea.drop(DragAndDropExample.java:178)
at java.awt.dnd.DropTarget.drop(DropTarget.java:450)
at sun.awt.dnd.SunDropTargetContextPeer.processDropMe ssage(SunDropTargetContextPeer.java:537)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatch er.dispatchDropEvent(SunDropTargetContextPeer.java :851)
at sun.awt.dnd.SunDropTargetContextPeer$EventDispatch er.dispatchEvent(SunDropTargetContextPeer.java:775 )
at sun.awt.dnd.SunDropTargetEvent.dispatch(SunDropTar getEvent.java:48)
at java.awt.Component.dispatchEventImpl(Component.jav a:4716)
at java.awt.Container.dispatchEventImpl(Container.jav a:2287)
at java.awt.Component.dispatchEvent(Component.java:46 87)
at java.awt.LightweightDispatcher.retargetMouseEvent( Container.java:4832)
at java.awt.LightweightDispatcher.processDropTargetEv ent(Container.java:4566)
at java.awt.LightweightDispatcher.dispatchEvent(Conta iner.java:4417)
at java.awt.Container.dispatchEventImpl(Container.jav a:2273)
at java.awt.Window.dispatchEventImpl(Window.java:2719 )
at java.awt.Component.dispatchEvent(Component.java:46 87)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.j ava:723)
at java.awt.EventQueue.access$200(EventQueue.java:103 )
at java.awt.EventQueue$3.run(EventQueue.java:682)
at java.awt.EventQueue$3.run(EventQueue.java:680)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:87)
at java.awt.EventQueue$4.run(EventQueue.java:696)
at java.awt.EventQueue$4.run(EventQueue.java:694)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPri vilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java: 693)
at java.awt.EventDispatchThread.pumpOneEventForFilter s(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(E ventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarch y(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispa tchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThre ad.java:91)

Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException: Uncompilable source code - Erroneous sym type: javaapplication24.DragAndDropExample.DropTargetTex tArea.setText
at javaapplication24.DragAndDropExample$DropTargetTex tArea.drop(DragAndDropExample.java:178)

The error message points to the setText() used at line 178. I'm not familiar with what the IDE is saying. Can you use the javac command to get a better compiler error message?

Other problems:
What are the variables: string1, string2 and string3 for? They should not be there. The accept String(s) should be passed to the class in the constructor

The images should be passed to the drop class.

Originally Posted by Norm

The error message points to the setText() used at line 178. I'm not familiar with what the IDE is saying. Can you use the javac command to get a better compiler error message?

Other problems:
What are the variables: string1, string2 and string3 for? They should not be there. The accept String(s) should be passed to the class in the constructor

The images should be passed to the drop class.

i dont understand i thought i need the string1, string2

The String variables: string1, string2 and string3 should NOT be defined and given values inside of the method.
The accept String(s) should be passed to the class's constructor and saved in a class variable for use in the if test to determine if the dropped String is to be accepted or not.

Do you know how to create and use class constructors? See the tutorial:
Providing Constructors for Your Classes (The Java™ Tutorials > Learning the Java Language > Classes and Objects)

Please explain what your current problem is.

There are two parts. The first part: remove the definitions from the class
What problem do you have with that? Select the lines in the editor and press the Delete button.

Passing a value to a class using a constructor:
This is really VERY BASIC java.
What don't you understand about how to code a constructor that takes an argument?
From the tutorial:

public Bicycle(int startCadence, int startSpeed, int startGear) {
    gear = startGear;
    cadence = startCadence;
    speed = startSpeed;
}

That code passes 3 values in the constructor. The 3 values are saved into class variables.