Develop Reference

How to schedule different images to change in design background

I'm currently working on a weather project in Android Studio where I want to schedule image changes in my design background every 5 seconds, I have all the image resources in my #drawable directory. I watched a basic tutorial where they explained some things in the demo but it only helped a little and didn't quite suit me, I'm still confused because I'm getting a lot of errors but I've currently tried these few codes:
HomeActivity.java:
public class HomeActivity extends AppCompatActivity {
public static int count=0;
int[] drawablearray=new int[]{R.drawable.burj_khalifa,R.drawable.central_bank_of_nigeria,R.drawable.eiffel_tower,R.drawable.hong_kong,R.drawable.statue_of_liberty};
Timer _t;
ImageView imageView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
imageView = findViewById(R.id.imageView);
ImageView = (ConstraintLayout) findViewById(R.id.lnMain);
_t = new Timer();
_t.scheduleAtFixedRate(new TimerTask); {
public void run(); {
runOnUiThread(new Runnable() { // run on ui thread
#Override
public void run() {
if (count < drawablearray.length) {
lnMain.setBackgroundDrawable(drawablearray[count]);
count = (count + 1) % drawablearray.length;
}
}
});
}
}, 5000, 5000);
}
}
Any Idea on how to Organize it to suit the design?

final Handler h = new Handler();
Runnable r = new Runnable() {
public void run() {
Home.this.getWindow.setBackgroundDrawableResource(drawableArray[count]);
cout += (count + 1) % drawableArray.length;
h.postDelayed(this, 5000);
}
};

final Runnable r = new Runnable() {
public void run() {
imageView.setBackgroundDrawableResource(drawablearray[count]);
count += (count+1)%(drawablearray.length);
handler.postDelayed(this, 5000);
}
};
And the call is like this:
handler.postDelayed(r,0);
This will call the runnable to execute and handle.postDelayed will run the method every 5000 millsec.

I already fixed the error by using constraintlayout in place of imageview and inmain. I also got id for the layout:
constraintLayout = findViewById(R.id.layout);
constraintLayout.setBackgroundResource(R.drawable.burj_khalifa);
_t = new Timer();
_t.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() { // run on ui thread
#Override
public void run() {
if (count < drawable.length) {
constraintLayout.setBackgroundResource(drawable[count]);
count = (count + 1) % drawable.length;
}
}
});
}
}, 5000, 5000);
}
}

Image view image need to change periodically in android

I have an image view. So in the image view i want to change the images after a certain time period. Images are coming from an array list. Now when the no of images are 3 or more than 3, it is working perfect. But when it is 2, my logic is not working. Second image is visible for a moment and then again changed to first image here is my code:
r = new Runnable(){
int i = 0;
public void run(){
iv.setImageBitmap(alBmps.get(i));
i++;
if(i >= alBmps.size()){
i = 0;
}
iv.postDelayed(r, 5000); //set to go off again in 5 seconds.
}
};
iv.postDelayed(r, 1000);
Can any one help me what changes i need on the above code?
Thanks.

Try this
declare variables
static int i=0;
private Timer myTimer;
in your onCreate or on button click where you want to call and start the methods
myTimer = new Timer();
myTimer.schedule(new TimerTask()
{
#Override
public void run()
{
TimerMethod();
}
}, 500, 5000);
add these methods to your class
private void TimerMethod()
{
this.runOnUiThread(Timer_Tick);
}
private Runnable Timer_Tick = new Runnable()
{
public void run()
{
if(i<alBmps.size())
{
iv.setImageBitmap(alBmps.get(i));
}
else
{
i=0;
iv.setImageBitmap(alBmps.get(i));
}
i++;
}
};

Alternate image in a imageview of screen

I have two images in my drawable folder and I desire to alternate the two images in my view every x time.
I try to use a Asynctask but don't work and I can't found the solution.
My xml Code
<ImageView
android:id="#+id/imageload"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:layout_marginBottom="64dp"
android:adjustViewBounds="false"
android:baselineAlignBottom="false"
android:contentDescription="#string/imatge"
android:cropToPadding="false"
android:fitsSystemWindows="false"
android:focusable="false"
android:focusableInTouchMode="false"
android:src="#drawable/hdtitol2" />
I call the class with:
new ModifyImage().execute(null,null,null);
The main class contains de class with async code
public class ModifyImage extends AsyncTask<Void, Void, Void> {
ImageView img= (ImageView)findViewById(R.id.imageload);
#Override
protected void onPreExecute(){
}
#Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
int i = 0;
boolean opt = true;
boolean exit = false;
while(!exit){
if(i == 1000){
i = 0;
if(!opt){
img.setImageResource(R.drawable.blackhdtitol2);
opt =true;
}else{
opt = false;
img.setImageResource(R.drawable.hdtitol2);
}
}
i++;
}
return null;
}
#Override
protected void onPostExecute(Void i){
}
}

Do this,
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
Integer tag = (Integer) img.getTag();
if(tag == R.drawable.blackhdtitol2){
img.setImageResource(R.drawable.blackhdtitol2);
img.setTag(R.drawable.blackhdtitol2);
}else{
img.setImageResource(R.drawable.hdtitol2);
img.setTag(R.drawable.hdtitol2);
}
}
}, 60*1000);

In the end I found a possible solution descarting all de java code that I had about this problem.
The solution that I found is to create a new class
public class RepeatingThread implements Runnable {
private final Handler mHandler = new Handler();
public RepeatingThread() {
}
#Override
public void run() {
final ImageView img = (ImageView) findViewById(R.id.imageload);
if(img.getVisibility() == View.INVISIBLE ){
img.setVisibility(View.VISIBLE);
}else{
img.setVisibility(View.INVISIBLE);
}
mHandler.postDelayed(this, 1000);
}
}
And the code in the function on create:
final Thread t = new Thread(new RepeatingThread());
t.start();

Make android screen change color once per second

I am a beginner to android, with some java under my belt. I have completed the make my first app tutorial only.
Next I want to make an app to use simple 2D graphics
To start, I want to find a way of flashing the screen between two colors (red and green) in an infinite loop
wait int seconds;
make screen red;
wait int seconds;
make screen green;
loop forever;
Could anyone please point me to a tutorial(s) or source code(s) that may help?
Many Thanks

How about you make a layout which fills the screen, lets call it llayout.
put this in the code:
static final int[] COLORS = {0xff0000, 0x00ff00};
static final int WAITTIME = 1000;
int currentColor = 0;
public void onCreate(Bundle b) {
setContentView(R.layout.mylayout);
final LinearLayout llayout = (LinearLayout) findViewById(R.id.llayout);
new Thread() {
public void run() {
while(true) {
Thread.sleep(WAITTIME);
currentColor++;
if (currentColor > COLORS.length)
currentColor = 0;
YourActivity.this.runOnUiThread(new Runnable() {
public void run() {
llayout.setBackgroundColor(COLORS[currentColor]);
}
});
}
}
}.start();
}
This should work. Using this code, you can add additional colors to the array COLORS.

Thanks for the input,
This code seems to work OK
package biz.consett.mydraw;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
/* Flash the screen between red and green each second */
public class MainActivity extends Activity {
final static int INTERVAL = 1000; // 1000=1sec
private static View myView = null;
boolean whichColor = true;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myView = (View) findViewById(R.id.my_view);
myView.setBackgroundColor(Color.RED);// set initial colour
new Thread(new Runnable() {
public void run() {
while (true) {
try {
Thread.sleep(INTERVAL);
}
catch (InterruptedException e) {
e.printStackTrace();
}
updateColor();
whichColor = !whichColor;
}
}
}).start();
}
private void updateColor() {
runOnUiThread(new Runnable() {
#Override
public void run() {
if (whichColor)
myView.setBackgroundColor(Color.RED);
else
myView.setBackgroundColor(Color.GREEN);
}
});
}
}
Layout, activity_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<View
android:id="#+id/my_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</View>
</RelativeLayout>

You already got a lot of solutions but just adding my own...
You will need a timer
#Override
protected void onCreate(Bundle bundle)
{
...
Timer timer = new Timer();
TimerTask updateColor = new SwitchColorTask();
timer.scheduleAtFixedRate(updateColor, 100, 100);
...
}
A timer task.
private boolean colorSwitched;
class SwitchColorTask extends TimerTask {
public void run() {
LinearLayout main = (LinearLayout)findViewById(R.id.main);
if(colorSwitched){
main.setBackgroundColor (Color.GREEN)
}
else{
main.setBackgroundColor (Color.RED)
}
colorSwitched=!colorSwitched
}
}

Taken from this post and edited for your case:
private int m_interval = 1000; // 1 second by default, can be changed later
private Handler m_handler;
private Layout mYourMainLayout //dont know what type of layout you use
private boolean which;
#Override
protected void onCreate(Bundle bundle)
{
...
mYourMainLayout = (Layout) this.findViewById(R.id.yourMainLayout);
m_handler = new Handler();
}
Runnable m_colorChanger = new Runnable()
{
#Override
public void run() {
if(which){
mYourMainLayout.setBackgroundColor(Color.GREEN)
}
else {
mYourMainLayout.setBackgroundColor(Color.RED)
}
which=!which
m_handler.postDelayed( m_colorChanger, m_interval);
}
};

This code implements the array of colors and works fine - many thanks.
(uses same manifest and layout)
package biz.consett.mydraw;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
/*
* Simple use of Android Thread
* Flash the screen between an array of colours at an interval
*
*/
public class MainActivity extends Activity
static final int[] COLORS =
{AColor.RED, AColor.BLUE, AColor.GREEN};// colour array
// Colour Red Green Blue
// Index [0] [1] [2]
private int currentColor = 0;
private View MYVIEW = null;
//boolean whichColor = true;
final int interval = 100; // 0.6 second static final?
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
MYVIEW = (View) findViewById(R.id.my_view);
MYVIEW.setBackgroundColor(Color.RED);// set initial colour
new Thread(new Runnable()
{
// #Override
public void run()
{
while (true)
{
try
{
Thread.sleep(interval); // sleep for interval
}
catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
updateColor();
} // end of while true loop
}// end of run
}).start(); // end of runnable
} // end of onCreate bundle
private void updateColor()
{
runOnUiThread(new Runnable()
{
#Override
public void run()
{
if (currentColor > COLORS.length - 1)
{
currentColor = 0;
}
MYVIEW.setBackgroundColor(COLORS[currentColor]);
currentColor++;
}// end of run
});
}
}// -------------END OF MainActivity extends Activity-----------------------
package biz.consett.mydraw;
public class AColor
{
final static int RED = 0xFFFF0000; // hex alpha_R_G_B
final static int GREEN = 0xFF00FF00;
final static int BLUE = 0xFF0000FF;
final static int PURPLE = 0xFFAA00AA;
}

Animation, delay

I would like to make an animation, I have 10 images of a ball and I want to do:
Image1 visible, all the other images hidden
Image2 visible all the other images hidden
...
Image10 visible all the other images hidden
Should I do that in one animation (how?) or should I create a java method showImage(String pathimage) which would show the image located at pathimage and hide the others? Could I put any idea of time delay with using
handler.postDelayed(new Runnable() {
public void run() { }
}
EDIT, here is my code
The problem is that run() is always called in what seems to be an infinite loop. But I don't see where is my error
GAMEACTIVITY
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
.....
ImageView image2 = (ImageView) findViewById(R.id.imageView3);
image2.setOnTouchListener(new OnTouchListener(){
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
myAsyncRunnable mar = new myAsyncRunnable(GameActivity.this);
mar.execute(null);
PhotoTask photoTask = new PhotoTask(camera,surfaceCamera,isPreview,holder,GameActivity.this);
photoTask.execute(null);
Log.w("GAMEACTIVITY","PHOTOTASK");
return false;
}
});
}
My Async Task
public class myAsyncRunnable extends AsyncTask<Void, Boolean, Void> {
GameActivity gameactivity;
#Override
protected Void doInBackground(Void... params) {
pull();
return null;
}
public myAsyncRunnable(GameActivity gameactivity) {
super();
this.gameactivity = gameactivity;
}
public void pull() {
final ImageView image3 = (ImageView) gameactivity.findViewById(R.id.imageView3);
final int drawables[] = new int[] {R.drawable.pull2,R.drawable.pull3,R.drawable.pull4,R.drawable.pull5,R.drawable.pull6,R.drawable.pull7};
Runnable runnable = new Runnable() {
#Override
public void run() {
for (int i=0;i<drawables.length;i++) {
image3.setImageResource(drawables[i]);
gameactivity.handler.postDelayed(this, 500);
Log.w("asyncrunnable","run"+i);
}
}
};
gameactivity.handler.post(runnable);
}
}

You should not create 10 ImageViews to do such animation.
Only one ImageView should suffice! Use a handler to update the Image using any flavor of setImage every x milliseconds or so.
Initialize the images in an array and the current image in an integer :
int drawables[] = new int[] {R.drawable.image1, R.drawable.image2, ...};
int mCurrent = 0;
Then initialize your updater:
Runnable runnable = new Runnable() {
#Override
public void run() {
if(mCurrent>=drawables.length)mCurrent=0;
imageView.setImageResource(drawables[mCurrent]);
mHandler.postDelayed(this, 3000); //every 3 seconds
}
};
Finally when you want to start, just post the runnable:
mHandler.post(runnable);
Your code is wrong:
Try this pull function (although i do not really approve the whole code style but no time to fix that)
public void pull() {
final ImageView image3 = (ImageView) gameactivity.findViewById(R.id.imageView3);
final int drawables[] = new int[] {R.drawable.pull2,R.drawable.pull3,R.drawable.pull4,R.drawable.pull5,R.drawable.pull6,R.drawable.pull7};
for (int i=0;i<drawables.length;i++) {
final int j = i;
Runnable runnable = new Runnable() {
#Override
public void run() {
image3.setImageResource(drawables[j]);
}
};
gameactivity.handler.postDelayed(this, 500 * i);
Log.w("asyncrunnable","run"+i);
}
}
}