Quick Java Number pad problems

Basically I am trying to finish code for a simple GUI number pad and I am having issues with the very last bit. When I click the decimal Button(buttonDot) I want it to drop the default 0 after the decimal point, and then when I press another number button I want it to go where the 0 was.

Code Java:

public class ButtonListener implements ActionListener {   	
		public void actionPerformed(ActionEvent arg0) {
			JButton clickedOn = (JButton)arg0.getSource();
			String s=label1.getText();
			int length=s.length()-1;
			int d=0;
 
			if(decimal==false) {			
				if(clickedOn == buttonDot) {
					decimal=true;
				}
 
				else if(label1.getText()=="0.0"){
					label1.setText(clickedOn.getText()+".0");	
				} else {
					s=label1.getText();
					label1.setText(s.substring(0,length1)+clickedOn.getText()+s.substring(length-1,length+1));
					d++;
 
				}
			}
 
			if(decimal==true) {			
				if(clickedOn == buttonDot) {
					return;
				}
 
				if(label1.getText().substring(length-1,length)==".0"){
					label1.setText(s.substring(0,length-1)+clickedOn.getText());
					System.out.println("f");
				}
				else {
					label1.setText(s+clickedOn.getText());
					System.out.println("u");
				}
			}
			if(clickedOn == clear) {
				decimal=false;
				label1.setText("0.0");
 
 
 
		}
 
 
		}
 
 
	}
}

Thanks for any help you can give me.