SetVisibility not working with ImageButton

So I've been looking around in forums for how to do this, but nothing I have found has worked. When I call setVisibility() on my image button, the button is unaffected. Below is my code that is in the onCreate method, and both buttons are showing up when I run the application. However, if I were to hardcode the attribute into the xml file, the visibility does change. Any ideas why this is happening?

super.onCreate(savedInstanceState);
    setCon开发者_高级运维tentView(R.layout.main);
    btn1 = new ImageButton(this);
    btn1.setVisibility(GONE);
    btn2 = new ImageButton(this);
    btn2.setVisibility(GONE);

Change your code to :

super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn1 = (ImageButton)findViewById(R.id.btn1);
btn1.setVisibility(View.GONE);
btn2 = (ImageButton)findViewById(R.id.btn2);
btn2.setVisibility(View.GONE);

and modify your main.xml:

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                  android:gravity="center_horizontal"
                  android:layout_width="fill_parent"
                  android:layout_height="fill_parent"
                  android:orientation="vertical"
                  >
        <Button android:id="@+id/btn1" android:layout_width="100dip" 
            android:layout_height="40dip" android:text="btn1"/>       
        <Button android:id="@+id/btn2" android:layout_width="100dip" 
            android:layout_height="40dip" android:text="btn2"/>

    </LinearLayout>

FIRST : you shoud use the method setVisibility like this :

btn1.setVisibility(VIEW.GONE),// not setVisibility(GONE);

SECONDE: you have created your buttons , but you didn't add them to your activity , ( the content of your activity is ( R.layout.main )

try this :

super.onCreate(savedInstanceState);

    btn1 = new ImageButton(this);
    setContentView(btn1);
    btn1.setVisibility(VIEW.GONE);
    try{
          Thread.sleep(3000);//pause 3 secondes 
    }catch(Exception e){}
    btn1.setVisibility(View.VISIBLE);

EDIT :

super.onCreate(savedInstanceState);

    LinearLayout layout = new LinearLayout(this);
    ImageButton btn1 = new ImageButton(this);
    ImageButton btn2 = new ImageButton(this);
    layout.addView(btn1);
    layout.addView(btn2);
    setContentView(layout);
    btn1.setVisibility(VIEW.GONE);
    btn2.setVisibility(VIEW.VISIBLE);
    try{
          Thread.sleep(3000);//pause 3 secondes 
    }catch(Exception e){}
    btn1.setVisibility(View.VISIBLE);
    btn2.setVisibility(VIEW.GONE);