How to catch a click event on a button?

Question

.NET Developer here just getting started with Eclipse and Android.

Can someone show me in the simplest way possible, with the absolute fewest lines of code, how to DO something when a button is clicked?

My button has id button1 and I just want to see where/how to write the onClick() handler.

So let's say I have imageview1 set to invisible. How would I make it visible when the button is clicked?

EDIT:

Thanks everyone, but since not a single one of your examples work for me, I'll try this: Can someone please post the ENTIRE code to make this work? Not just the method, because when I try to use ANY of your methods I get errors all over the place so obviously something else is missing. I need to see everything, beginning with all the imports.

Answer 1

/src/com/example/MyClass.java

package com.example  import android.app.Activity; import android.os.Bundle; import android.view.View; import android.view.View.OnClickListener; import android.widget.Button; import android.widget.ImageView;  public class MyClass extends Activity {    @Override   public void onCreate(Bundle savedInstanceState)   {     super.onCreate(savedInstanceState);     setContentView(R.layout.main);          Button button = (Button) findViewById(R.id.button1);      button.setOnClickListener(new OnClickListener()     {       public void onClick(View v)       {          ImageView iv = (ImageView) findViewById(R.id.imageview1);          iv.setVisibility(View.VISIBLE);       }     });    } } 

/res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?> <LinearLayout   xmlns:android="http://schemas.android.com/apk/res/android"   android:layout_width="fill_parent"   android:layout_height="fill_parent">     <Button        android:text="Button"       android:id="@+id/button1"       android:layout_width="wrap_content"        android:layout_height="wrap_content"     />     <ImageView        android:src="@drawable/image"        android:layout_height="wrap_content"        android:layout_width="wrap_content"        android:id="@+id/imageview1"       android:visibility="invisible"     /> </LinearLayout> 

Answer 2

The absolutely best way: Just let your activity implement View.OnClickListener, and write your onClick method like this:

public void onClick(View v) {     final int id = v.getId();     switch (id) {     case R.id.button1:         // your code for button1 here         break;     case R.id.button2:         // your code for button2 here         break;     // even more buttons here     } } 

Then, in your XML layout file, you can set the click listeners directly using the attribute android:onClick:

<Button     android:id="@+id/button1"     android:onClick="onClick"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="Button 1" /> 

That is the most cleanest way of how to do it. I use it in all of mine projects today, as well.