Programmatically changing background

Question

I have this code that changes the background when you click a button however, I want to change the background every 10 seconds, and I want to switch between files img1.png, img2.png and img3.png and when the cycle is completed start all over again. Thanks in advance. Here is the code: In 'MainActivity.java'

package lucas.app_2001;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.LinearLayout;


public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    Button button;
    LinearLayout mainLayout;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mainLayout=(LinearLayout)findViewById(R.id.myLayout);
        button=(Button)findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                mainLayout.setBackgroundResource(R.drawable.yellowgradient);
            }
        });
    }
}

'MainActivity.xml':

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/myLayout"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="64dp"
        android:layout_marginTop="71dp"
        android:text="Shout!" />

</LinearLayout>

take a look at this SO question: [How to set background drawable programmatically...](http://stackoverflow.com/questions/12523005) — Bö macht Blau, Nov 05 '15 at 17:49

score 0 · Answer 1 · answered Nov 05 '15 at 17:49

0

Use a while loop to repeat.

To delay it for 10 seconds try something like this:

//wait 10 seconds
        Button.postDelayed(new Runnable() {

            @Override
            public void run() {
                Button.setClickable(true);                        
            }
        }, 10000);

answered Nov 05 '15 at 17:49

ImperialCode

3
6

The thing is I don't want a button I just want to be able to change between the images with out the users interaction – lucas rodriguez Nov 05 '15 at 17:51
Im sry, then you should use a handler and put the code in onCreate – ImperialCode Nov 05 '15 at 17:53

Hiren Patel · Accepted Answer · 2015-11-07T05:08:58.433

0

You can do this way:

private Handler mHandler;
private Runnable mRunnable;
private int i = 0;

MainActivity.java:

public class MainActivity extends Activity {
    /** Called when the activity is first created. */
    Button button;
    LinearLayout mainLayout;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mainLayout=(LinearLayout)findViewById(R.id.myLayout);
        button=(Button)findViewById(R.id.button1);
        button.setOnClickListener(new View.OnClickListener() {

            public void onClick(View arg0) {
                mainLayout.setBackgroundResource(R.drawable.yellowgradient);
            }
        });

        mHandler = new Handler();
        mRunnable = new Runnable(){
        @Override
        public void run() {
             i++;
             if(i==1){
             mainLayout.setBackgroundResource(R.drawable.image_one);
              }else if(i==2){
             mainLayout.setBackgroundResource(R.drawable.image_two);
              }else if(i==3){
             mainLayout.setBackgroundResource(R.drawable.image_three);
               i ==0;
              }

             mHandler.postDelayed(mRunnable , 10000);
            }
         }; 
        mHandler .post(mRunnable);
    }
}

on onStop():

if(mHandler!=null){
  mHandler.removeCallbacks(mRunnable);
}

Done

edited Nov 07 '15 at 05:08

answered Nov 05 '15 at 17:51

Hiren Patel

52,124
21
173
151

It crashes on the emulator... Any idea why? – lucas rodriguez Nov 05 '15 at 18:10
On **onCreate** I get this error: Missing Super Call Some methods, such as View#onDetachedFromWindow, require that you also call the super implementation as part of your method. – lucas rodriguez Nov 05 '15 at 18:24
added this line of code ´super.onCreate(savedInstanceState);´ but it still crashes – lucas rodriguez Nov 05 '15 at 20:30
@lucasrodriguez, I have edited my answer, please check it. You have to put your code on onclick of Button. – Hiren Patel Nov 06 '15 at 03:44
the thing is I don't want to use a button at all – lucas rodriguez Nov 06 '15 at 11:54
@lucasrodriguez, you want on start of activity ? – Hiren Patel Nov 06 '15 at 12:51
Yes when the app opens i want it to display an image and then start changing every 10 s – lucas rodriguez Nov 06 '15 at 14:18

Programmatically changing background

2 Answers2