Android/Java Help

[Nickyyy]

Hello folks, need some help with a program I am trying to make in android

I hate programming so my skills are pretty null in it.

Anyways the App in question is a very basic app which converts kilometres to miles

So my GUI atm contains two text boxes, one to input kilometres, and the other to output the result as miles

I have a button called convert which when pressed I guess should have an on click listener, take the value from box 1 and multiply it by 1.6 and output it in the 2nd text box.

It's really simple only that I am crap at programming. if anyone has any pointers they could give me to implementing this it would be great. cheers.

 

[PaulStat]

Not Android, but Java code using Swing would be (I'm sure Android has it's own versions of this, just look through the API)

final JTextField inputField = new JTextField();
final JTextField outputField = new JTextField();

JButton convert = new JButton();

convert.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
        String miles = inputField.getText();
        double km = convertToKM(Integer.parseInt(miles));
        outputField.setText(String.valueOf(km));
    }
});
...
...
private double convertToKM(int miles) {
    return miles * 1.6;
}

Obviously missed out a few steps here like adding the components to your container, error checking etc.

 

[Nickyyy]

Thank you so much dude! Will give this a go later!

 

[PaulStat]

woops just noticed I was returning an int instead of a double in the convert method, two options in that case really

a) cast the return value like so, you will lose your decimal point

 return (int) miles * 1.6;

b) change the return type of the method to double, which is obviously better for a conversion like this.

It also assumed that the miles weren't a decimal value

 

[Nickyyy]

Cheers PaulStat[/b}

Nearly there I think could anyone help me with the last bit?


I think i've got the code sorted that it reads from the kilometer box and does the calculation, I need to display it in the miles box but it's not working.

package org.uuj;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.text.Editable;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;

public class Activity2<ActionEvent> extends Activity {
	
	  /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main2);  //calling my layout from R
        
        
        final EditText kilo = (EditText) findViewById(R.id.editText3); 
      
        
        
        /*instigating my XML buttons and edit 
        text boxes*/
        
        
        
        
        final EditText mile = (EditText) findViewById(R.id.editText2);
        
        final Button convert = (Button) findViewById(R.id.button1);
        Button back = (Button) findViewById(R.id.button2);
        
        
        // creating my back button's action listener to take you back to the start page
        back.setOnClickListener(new View.OnClickListener() {
			
			@Override
			public void onClick(View v) {
				Intent myIntent = new Intent (v.getContext(),AnroidsimpleappActivity.class);
				startActivityForResult(myIntent, 0);
				
				// TODO Auto-generated method stub
        
        
       // the onclick listener for the convert button, it takes values from the kilo box and 
			//	converts it to miles and outputs it to the miles box 
				
        convert.setOnClickListener(new View.OnClickListener() {
        	
    	   @SuppressWarnings("unused")
		public void actionPerformed(ActionEvent e) {
    		 
    		   Editable km1 = (Editable)kilo.getText();
    		   String km = km1.toString();
    		 
    		 int km2 = (Integer.parseInt(km));
    		 
    		 double answer = (km2/1.6);
    		 String answer1 = Double.toString(answer);
    		 
    		   mile.setText(answer1);
    		   
    		  
    		  
    		  
    	  }

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			
		}
    
    

    	  
    	  
       
    		 
    		  
    		  
    	  
    	   
       });
    }
    
    
        });
        
    }
    
}

I had to convert editable to string, then to an int, and then make the answer a double due to 1.6. then convert that to a string and then setText as the answer, but when I press the convert button nothing happens

Theres no syntax errors so I dunno

Anyone in Android development care to lend a hand? I'm stumped and my Lecturer isn't much help either.



That's what the app looks like.


Cheers for any input, its due in at 12PM tomorrow so any advice would be appreciated!

 

[PaulStat]

I'd be adding some debugging in around this code, i.e. print out the values it thinks it's got to the console

Editable km1 = (Editable)kilo.getText();
String km = km1.toString();
    		 
int km2 = (Integer.parseInt(km));
    		 
double answer = (km2/1.6);
String answer1 = Double.toString(answer);
    		 
mile.setText(answer1);