I wrote code which can change the background every 3 second, but unfortunately it only change 1 time, I try using the count but it wont work, where did it went wrong?
public class MainActivity extends AppCompatActivity {
public static int count=0;
int images[] = new int[] {R.drawable.main, R.drawable.main2, R.drawable.main3, R.drawable.main4};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new Handler().postDelayed(new Runnable() {
public void run() {
if (count < images.length) {
RelativeLayout background = (RelativeLayout) findViewById(R.id.activity_main);
Random rand = new Random();
int index = rand.nextInt(images.length);
background.setBackgroundResource(images[index]);
count++;
}
else{
count = 0;
}
}
}, 3000);
}
};
Just call handler.postDelayed inside run() method to start it again, and modify your code like this:
public class MainActivity extends AppCompatActivity {
int images[] = new int[] {R.drawable.main, R.drawable.main2, R.drawable.main3, R.drawable.main4};
final Handler animHandler = new Handler();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RelativeLayout background = (RelativeLayout) findViewById(R.id.activity_main);
animHandler.post(new Runnable() {
#Override
public void run() {
Random rand = new Random();
int index = rand.nextInt(images.length);
background.setBackgroundResource(images[index]);
animHandler.postDelayed(this, 3000);
}
});
}
};
}
Related
The following code is showing the error of cannot resolve symbol post even if import android.os.Handler; is used. And also invalid method declaration, return type is required for Runnable object.
TextView tv = (TextView) this.findViewById(R.id.txt);
String[] str = new String[] { "72", "71", "70",
"73", "75", "74", "69", "76", "77", "78" };
final Handler h = new Handler();
h.post(new Runnable() {
#Override
public void run() {
Random generator = new Random();
final int random = generator.nextInt(str.length);
tv.setText(str[random]);
h.postDelayed(this, 1000);
}
});
The import is correct, the problem seem to be inside the runnable. If you want to run a rask with delay the direct method is postDelay. Two arguments, a runnable and the delay.
h.postDelay(new Runnable..., 1000);
This is because you're calling the method post() outside of a method in a class.
For example, if your code inside an Activity class,
This is wrong:
public class MainActivity extends AppCompatActivity {
final Handler h = new Handler();
// This is outside a method. It's wrong.
h.post(new Runnable() {
#Override
public void run() {
Random generator = new Random();
final int random = generator.nextInt(str.length);
tv.setText(str[random]);
h.postDelayed(this, 1000);
}
});
...
#Override
protected void onCreate(Bundle savedInstanceState) {
}
}
This is right:
public class MainActivity extends AppCompatActivity {
private void generateRandom() {
final Handler h = new Handler();
h.post(new Runnable() {
#Override
public void run() {
Random generator = new Random();
final int random = generator.nextInt(str.length);
tv.setText(str[random]);
h.postDelayed(this, 1000);
}
});
}
...
#Override
protected void onCreate(Bundle savedInstanceState) {
}
}
I am developing a simple android activity with a scrollable TextView. I am displaying numbers from 1-100 in my TextView with a time delay. However my desired output is not what I'm getting.
Current Output: 1 replaced by 2 replaced by 3....till 100.
Desired Output:
1
2
3
4
.
.
100
Here is my Activity code:
public class MainActivity extends ActionBarActivity {
private static int i = 0;
TextView textView;
Handler handler;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main_page);
textView = (TextView) findViewById(R.id.text_area);
new PrimeCalculation().execute();
handler = new Handler();
handler.post(updateView);
}
private Runnable updateView = new Runnable() {
#Override
public void run() {
if(i <= 100) {
textView.setText(Integer.toString(i));
i++;
handler.postDelayed(this, 1000);
}
}
};
}
How about this:
textView.setText(textView.getText() + "\n" + i);
Create a new String Array. Set the text view to the array.toString(); Every time that your timer runs out insert the most recent number into the array and repeat. The most recent number should be an int that increases when the timer runs out. Hope this helps!
Try this
private Handler mHandler = new Handler();
private int nCounter = 0;
View.OnClickListener mButtonStartListener = new OnClickListener() {
public void onClick(View v) {
try {
mHandler.removeCallbacks(hMyTimeTask);
// Parameters
// r The Runnable that will be executed.
// delayMillis The delay (in milliseconds) until the Runnable will be executed.
mHandler.postDelayed(hMyTimeTask, 1000); // delay 1 second
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
private Runnable hMyTimeTask = new Runnable() {
nCounter++;
hTextView.append("\n"+nCounter);
}
public void run() {
};
Hope this will help you
You can use following code......
public class MainActivity extends ActionBarActivity {
private static int i = 0;
TextView textView;
Handler handler;
String textViewText="";
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.text_area);
handler = new Handler();
handler.post(updateView);
}
private Runnable updateView = new Runnable() {
#Override
public void run() {
if(i <= 100) {
//
textViewText=textViewText+Integer.toString(i)+" ";
textView.setText(textViewText);
// textViewText=textViewText+textView.getText().toString();
i++;
handler.postDelayed(this, 1000);
}
}
};}
I hope it will help you....
i am creating a sample app in which i want to change a TextVeiw value every second.
TextView value should change continue every second.
to perform this task i tried this below code:
but this code is not changing text values continue, it only change on app start or screen rotate.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
Boolean b = true;
final TextView tv = (TextView) this.findViewById(R.id.textView1);
final String[] str = new String[] { "897451", "34232", "33432",
"46867", "54554", "6756", "56r7", "2345u8", "9654", "987650", };
Random generator = new Random();
final int random = generator.nextInt(str.length);
Thread t = new Thread() {
#Override
public void run() {
try {
while (b != false) {
Thread.sleep(1000);
runOnUiThread(new Runnable() {
#Override
public void run() {
// update TextView here!
tv.setText(str[random]);
}
});
}
} catch (InterruptedException e) {
}
}
};
t.start();
}
and i also tried this code:
but this code crash application
private Timer timer = new Timer();
private TimerTask timerTask;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
final TextView tv = (TextView) this.findViewById(R.id.textView1);
final String[] str = new String[] { "897451", "34232", "33432",
"46867", "54554", "6756", "56r7", "2345u8", "9654", "987650", };
Random generator = new Random();
final int random = generator.nextInt(str.length);
timerTask = new TimerTask() {
#Override
public void run() {
// refresh your textview
tv.setText(str[random]);
}
};
timer.schedule(timerTask, 0, 1000);
}
Try the following code snippet
final Handler h = new Handler();
h.post(new Runnable() {
#Override
public void run() {
long millis =(long)currentTime();
dateAndTime.setText(getDate(millis, "dd/MM/yyyy hh:mm:ss.SSS"));
h.postDelayed(this, 1000);
}
});
final TextView tv = (TextView) this.findViewById(R.id.textView1);
final String[] str = new String[] { "897451", "34232", "33432",
"46867", "54554", "6756", "56r7", "23458", "9654", "987650", };
// //
final Handler h = new Handler();
h.post(new Runnable() {
#Override
public void run() {
Random generator = new Random();
final int random = generator.nextInt(str.length);
tv.setText(str[random]);
h.postDelayed(this, 1000);
}
});
// //
i'm working on an Android application in which i want the background image to be changed after every 5 seconds. i have all the images in my drawable folder.
i am giving the code which i am using but i am not getting the output. As an output i am getting a still image which is not changing.
Please help
Thanks
[CODE]
public class Home extends Activity {
public static int count=0;
int[] drawablearray=new int[]{R.drawable.slider_1,R.drawable.slider_2,R.drawable.slider_3,R.drawable.slider_4,R.drawable.slider_5};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
new Handler().postDelayed(new Runnable() {
public void run() {
if(count<drawablearray.length){
Home.this.getWindow().
setBackgroundDrawableResource(drawablearray[count]);
count++; //<<< increment counter here
}
else{
// reset counter here
count=0;
}
}
}, 5000);
}
}
You can achieve this using Timer
public class Home extends Activity {
public static int count=0;
int[] drawablearray=new int[]{R.drawable.slider_1,R.drawable.slider_2,R.drawable.slider_3,R.drawable.slider_4,R.drawable.slider_5};
Timer _t;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
lnMain = (LinearLayout) findViewById(R.id.lnMain);
_t = new Timer();
_t.scheduleAtFixedRate(new TimerTask() {
#Override
public void run() {
runOnUiThread(new Runnable() // run on ui thread
{
public void run() {
if (count < drawablearray.length) {
lnMain.setBackgroundDrawable(drawablearray[count]);
count = (count + 1) % drawablearray.length;
}
}
});
}
}, 5000, 5000);
}
}
Why don't you have a look at the ViewFlipper class
http://developer.android.com/reference/android/widget/ViewFlipper.html
final Handler h = new Handler();
Runnable r = new Runnable() {
public void run() {
Home.this.getWindow().setBackgroundDrawableResource(drawablearray[count]);
count += (count+1)%drawablearray.length; //<<< increment counter here
h.postDelayed(this, 5000);
}
};
now call like
h.postDelayed(r, 5000);
I think that would be easier to work with the xmls. You can change the background of the main layout of the activity.
Try something like this:
public class Home extends Activity {
public static int count=0;
int[] drawablearray=new int[]{R.drawable.slider_1,R.drawable.slider_2,R.drawable.slider_3,R.drawable.slider_4,R.drawable.slider_5};
LinearLayout ll;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
ll = (LinearLayout) findViewByID(R.id.mainlayout) //It depends of the name that you gave to it
new Handler().postDelayed(new Runnable() {
public void run() {
ll.setBackgroundDrawable(drawablearray[count]);
// or ll.setBackgroundResource(resid) if you want.
count += (count+1)%drawablearray.length;
}
}, 5000);
}
}
I have a problem that I want to paste images on ImageView in Android and that images are periodically changed after some interval. Means one by one images shown in ImageView. I am doing this with the help of Thread in java but I got some problem that Thread is not attached and something. Please review my code given below and tell me the exact error and how to remove that error or give me some diffrent way for doing this.
package com.ex.thread;
import com.ex.thread.R;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;
public class thread extends Activity implements Runnable{
/** Called when the activity is first created. */
public static Integer[] mThumbIds = {
R.drawable.al1,R.drawable.al2,R.drawable.al3,R.drawable.al4,
};
Thread th;
ImageView iv;
public void run()
{
for(int i=0;i<3;i++)
{
iv.setImageResource(mThumbIds[i]);
System.out.println("Sanat Pandey");
try{
Thread.sleep(3000);
}catch(Exception e)
{
System.out.println(e);
}
}
}
public void create()
{
Thread th = new Thread(new thread());
th.start();
try{
Thread.sleep(3000);
}catch(Exception e)
{
System.out.println(e);
}
}
#Override
public void onCreate(Bundle savedInstace)
{
super.onCreate(savedInstace);
setContentView(R.layout.main);
create();
}
}
Try this..It works out well...
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);``
//
//
int []imageArray={R.drawable.img1,R.drawable.img2,R.drawable.img3};
final Handler handler = new Handler();
Runnable runnable = new Runnable() {
int i=0;
public void run() {
imageView.setImageResource(imageArray[i]);
i++;
if(i>imageArray.length-1)
{
i=0;
}
handler.postDelayed(this, 50); //for interval...
}
};
handler.postDelayed(runnable, 2000); //for initial delay..
}
You can't use things in the UI thread from a background one. So this call:
iv.setImageResource(mThumbIds[i]);
Has to be done in the main thread. In fact you probably don't need a background thread at all to get the effect you're looking for. You can make that just an activity, no need to implement runnable. and then do something like this:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
iv = (ImageView) findViewById(R.id.yourImageViewID);
int i = 0;
Runnable r = Runnable(){
public void run(){
iv.setImageResource(mThumbIds[i]);
i++;
if(i >= mThumbIds.length){
i = 0;
}
iv.postDelayed(r, 3000); //set to go off again in 3 seconds.
}
};
iv.postDelayed(r,3000); // set first time for 3 seconds
Try this
it's working
public class vv extends Activity {
int b[] = {R.drawable.a, R.drawable.m, R.drawable.b, R.drawable.j, R.drawable.er, R.drawable.chan, R.drawable.vv};
public ImageView i;
int z = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
i = (ImageView) findViewById(R.id.image);
i.setImageResource(b[0]);
Thread timer = new Thread() {
public void run() {
try {
sleep(2000);
for (z = 0; z < b.length + 2; z++) {
if (z < b.length) {
sleep(2000);
runOnUiThread(new Runnable() {
public void run() {
i.setImageResource(b[z]);
}
});
} else {
z = 0;
}
}
} catch (InterruptedException e) {
e.printStackTrace();
} finally {
System.out.println("finally");
}
}
};
timer.start();
}
}
try this code.the images was saved in drawable. please do insert a imageview in xml code. noted that the time interval for the following code is 1 sec.
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;
public class MainActivity extends AppCompatActivity {
public ImageView iv;
public static Integer[] mThumbIds = {
R.drawable.pic1,R.drawable.pic2,R.drawable.pic3,R.drawable.pic4};
int i;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.imageView);
i=0;
t.start();
}
Thread t = new Thread() {
#Override
public void run() {
try {
while (!isInterrupted()) {
Thread.sleep(1000);
runOnUiThread(new Runnable() {
#Override
public void run() {
iv.setImageResource(mThumbIds[i]);
i++;
if(i >= mThumbIds.length){
i = 0;
}}});}}
catch (InterruptedException e) {
}}};
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final int img[] = {R.drawable.flower1, R.drawable.flower2, R.drawable.flower3, R.drawable.flower4};
layout = (RelativeLayout) findViewById(R.id.activity_main);
final Handler handler=new Handler();
Runnable runnable = new Runnable() {
int i = 0;
#Override
public void run() {
layout.setBackgroundResource(img[i]);
i++;
if (i > img.length - 1) {
i = 0;
}
handler.postDelayed(this, 4000); //for interval 4s..
}
};handler.postDelayed(runnable, 100); //for initial delay..
}