Discussions

It's only available as a printed book.

The reason it does not work is that once you remove 'this' from the world, the 'getWorld' method will return 'null'. Looking at your code, it appears that everything after that statement (getWorld().removeObject(this);) is useless nonesense (creating new objects and removing them from a world they are not in). Either remove or comment out everything after the removal statement or put a 'return;' statement immediately after it.

Why does it not help? In the Cannonball class act method, you should have code reflecting the following actions (at least): - move - if not targetHit and intersects target - show "HIT" message - option to remove cannonball or set flag targetHit (boolean field) - if at world edge - if not targetHit, show "MISSED" message - remove cannonball In your Cannon class, when you detect a "space" keypress and add a new cannonball into the world, show "" message.

Sorry about the Message thing. I though I had given you code for a Message class, but apparently it was someone else. Copy/paste the code for a Message class in this discussion post for your Message class.

use the move method of the smooth mover

Sent you an e-mail telling you my username on Skype.

Solved

This has new information (which would have helped, if I had known this previously). OK, we need to start over as far as 'adding/removing/deleting' dragons. You will need a field in the Dragon class, but it will need to be a 'static' field. It can hold either a Dragon object or be a boolean. Being a dragon object could make other coding easier. If holding a dragon object: It will hold the dragon object that IS alive. It should be changed to 'null' when the live dragon is killed. It should be check

Getting to your issues above (not in order): (4) Since you have now unbounded your world (put the extra parameter 'false' in your world 'super' constructor), this is not an issue. (3) You should allow passage over all possibilities of power. Incrementing is the way to go. (2) You will need to do two things to fix this. One set a minimum on the power to 30 and add a 'setPaintOrder' statement in your world constructor so that the cannonball is hidden behind the cannon while passing up the tube. (1) I addressed this earlier in the discussion.

It seems the new wav files aren't in a format your system can play directly - this happens sometimes. You may want to try converting them to mp3s (use Audacity) and try again.

The return needs to be cast to an Actor type. Use <Code Omitted>As an Object type, which is the type returned, it cannot be set to a field which holds an Actor type.

<Code Omitted>

@davmac Thanks so much, that's exactly what I needed!