Slick2d，如何在屏幕上绘制字符串几秒钟？

Question

I've been trying to figure this out, all I want to do is be able to draw a string for longer than just a frame, but when I call it in the method I want it to flash up then disappear immediately, any advice would be appreciated :) I'm using something like this:

g.drawString("You got a Key!", 100, 100);

I'm doing this in a method which is called after an Item is picked up

public void addItemFound(Graphics g){
    ip.mainInventory[ip.getFirstEmptyStack()] = getItemStackFound();
    System.out.println(this.getItemFound() + " added");
    g.drawString("You Got a Key!", 100, 100);
}

That's the full method if you were interested :) Thanks!Also apologies for the dumb question, i'm a newbie to this :P

Answer 1

I believe that the best way to do this project would be to draw the scene at regular intervals eg 10 milliseconds using a Thread.sleep() . This way, you can simply add a variable to show the message for, say, 100 loops (1 second) like this:

private LinkedList<String> drawStringList= new LinkedList<>();
private LinkedList<Integer> drawStringTimeout= new LinkedList<>();
private LinkedList<Integer[]> drawStringPos= new LinkedList<>();


public void addText(String stringToWrite, int posX, int posY, int timeOut) {
    drawStringList.add(stringToWrite);
    int[] pos = new int[2];
    pos[0] = posX;
    pos[1] = posY;
    drawStringPos.add(pos);
    drawStringTimeout.add(timeOut);
}

private void mainLoop() {
...items to be drawn here...
for(int i=0;i<drawStringList.size();i++){
    g.drawString(drawStringList.get(i),drawStringPos.get(i)[0],drawStringPos.get(i)[1]);
    drawStringTimeout.set(i,drawStringTimeout.get(i)-1);
    if(drawStringTimeout.get(i)<=0) {
        drawStringList.remove(i);
        drawStringTimeout.remove(i);
        drawStringPos.remove(i);
    }
}
try { Thread.sleep(10); } catch (Exception e) {}
}

In this code, you must add the string you want to draw to drawStringList , add the number of loops you want it to stay for to drawStringTimeout and add the position you would like to draw it in to drawStringPos as an array (you could use a point if you wanted to). I have made a method to do this.

Answer 2

I don't know what Dan300 is trying to tell you to do but that's way, way, way over complicated. Slick2D works on gamestates:

http://slick.ninjacave.com/javadoc/org/newdawn/slick/state/GameState.html

The gamestate has a method called render(). The render() is called every single cycle of the loop to update your screen with drawing information. If you want to draw the text on the screen for a longer time you should be drawing the text somewhere within the stack space of this render() function.

What is happening now is you have a function with one specific purpose that only exists every so briefly: add an item to the player. The game comes across this statement and when adding an item within that 1 cycle the text will be drawn. But the next cycle when the player isn't picking up an item it won't come by that drawString statement and you won't have your string on your screen longer than 1 game cycle.