drawImage won't work, but drawRect does?

Question

It's really weird... I was following this video tutorial for parts of my game, and when I used

package dashiesgame;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;

public class Cell extends Rectangle {
    private static final long serialVersionUID = 1L;
    public int[] id = {0,0};
    public Cell(Rectangle size, int[] id) {
        setBounds(size);
        this.id = id;
    }
public void render(Graphics g){
    g.setColor(new Color(255,100,100));
    g.fillRect(x,y,width,height);

}
}

it worked. I had some red squares on the bottom of my screen. I wanted to replace the red squared with a cell-type thing that I created in GIMP and exported to png, so I replaced the end of the code above with

 public void render(Graphics g){
    g.drawImage(Block.cell, x, y, width, height, null);

}

In the video, that was exactly what the guy did, and it worked out fine. However, it doesn't seem to show up for me. I've tried changing it to this instead of null, but then it makes me implement ImageObserver, which gives me a ton of errors when I try to run the code. Any help would be appreciated!

Also, sorry if I seem a bit ignorant about this or something... this is my first time coding and I'm learning as I go, so please be a bit patient.... I can also give some more code from other parts if anyone needs to see that to help me figure out what's wrong....

This is where Block.cell is defined: (it's the class block, and then cell is the image. I also took out the other images to save space because there are a bunch, but you get the idea.)

package dashiesgame;

import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;

public class Block {
    public static int tileSize = 20;
    public static int invLength = 6;
    public static int invCellSize = 40;
    public static int invCell = 8;
    public static int invCellSpace = 4;
    public static int invBorderSpace = 4;

    public static final int[] air1 = {-1, -1};
    public static final int[] TwilightBlock1 = {0,0};
    public static final int[] DashieBlock1 = {1,0};
    public static final int[] ApplejackBlock1 = {2,0};
    public static final int[] RarityBlock1 = {3,0};
    public static final int[] FluttershyBlock1 = {4,0};
    public static final int[] PinkieBlock1 = {5,0};


    public static BufferedImage cell ;
    {


    try {
        Block.cell = ImageIO.read(new File("cell.png"));
    } catch (IOException e) {
        e.printStackTrace();
    }
    }   
}

Then this is [robably important as well....

package dashiesgame;

import java.awt.Graphics;
import java.awt.Rectangle;

public class Inventory {
    public Cell[] invBar = new Cell[Block.invLength];
    public Inventory(){
        for (int i=0;i<invBar.length;i++){
            invBar[i] = new Cell(new Rectangle((Game.pixel.width / 2) - ((Block.invLength * (Block.invCellSize + Block.invCellSpace))/2) + (i * (Block.invCellSize + Block.invCellSpace)), Game.size.height - (Block.invCellSize + Block.invCellSpace), Block.invCellSize, Block.invCellSize), Block.air1 );
        }
    };
    public void render(Graphics g){
        for (int i=0;i<invBar.length;i++){
            invBar[i].render(g);
    }
}
}

Answer 1

drawImage, unlike fillRect, has a strange property: it might not finish. It returns true if it does finish. Otherwise, it returns false, and the drawing is not completed until some later call to paintComponent.

While this would not be thread-safe for a large image, here's one workaround:

while (!g.drawImage(...)) {
  // Loop body empty -- wait for drawImage to return true
}