Android: Running thread preventing animation from starting
I currently have an Android activity which manages some locally-stored RSS feeds. In this activity, these feeds are updated in their own thread via a private class. I'm also trying to include an "updating" icon that rotates with a RotateAnimation
while this thread is running.
The animation works by itself, but doesn't work while the thread is running despite the log entries stating the code is being executed. I suspect this is due to the thread not being entirely safe, and taking up most of the CPU time. However I'd just like to know if there's a better way of achieving this.
The function updateAllFeeds()
is called from a button press. Here's the relevant code:
/**
* Gets the animation properties for the rotation
*/
protected RotateAnimation getRotateAnimation() {
// Now animate it
Log.d("RSS Alarm", "Performing animation");
RotateAnimation anim = new RotateAnimation(359f, 0f, 16f, 21f);
anim.setInterpolator(new LinearInterpolator());
anim.setRepeatCount(Animation.INFINITE);
anim.setDuration(700);
return anim;
}
/**
* Animates the refresh icon with a rotate
*/
public void setUpdating() {
btnRefreshAll.startAni开发者_运维知识库mation(getRotateAnimation());
}
/**
* Reverts the refresh icon back to a still image
*/
public void stopUpdating() {
Log.d("RSS Alarm", "Stopping animation");
btnRefreshAll.setAnimation(null);
refreshList();
}
/**
* Updates all RSS feeds in the list
*/
protected void updateAllFeeds() {
setUpdating();
Updater updater = new Updater(channels);
updater.run();
}
/**
* Class to update RSS feeds in a new thread
* @author Michael
*
*/
private class Updater implements Runnable {
// Mode flags
public static final int MODE_ONE = 0;
public static final int MODE_ALL = 1;
// Class vars
Channel channel;
ArrayList<Channel> channelList;
int mode;
/**
* Constructor for singular update
* @param channel
*/
public Updater(Channel channel) {
this.mode = MODE_ONE;
this.channel = channel;
}
/**
* Constructor for updating multiple feeds at once
* @param channelList The list of channels to be updated
*/
public Updater(ArrayList<Channel> channelList) {
this.mode = MODE_ALL;
this.channelList = channelList;
}
/**
* Performs all the good stuff
*/
public void run() {
// Flag for writing problems
boolean write_error = false;
// Check if we have a singular or list
if(this.mode == MODE_ONE) {
// Updating one feed only
int updateStatus = channel.update(getApplicationContext());
// Check for error
if(updateStatus == 2) {
// Error - show dialog
write_error = true;
}
}
else {
// Iterate through all feeds
for(int i = 0; i < this.channelList.size(); i++) {
// Update this item
int updateStatus = channelList.get(i).update(getApplicationContext());
if(updateStatus == 2) {
// Error - show dialog
write_error = true;
}
}
}
// If we have an error, show the dialog
if(write_error) {
runOnUiThread(new Runnable(){
public void run() {
showDialog(ERR_SD_READ_ONLY);
}
});
}
// End updater
stopUpdating();
} // End run()
} // End class Updater
(I know the updateStatus == 2
bit is bad practice, that's one of the next things I plan to tidy up).
Any help is greatly appreciated, many thanks in advance.
Run the updater runnable in a separate thread. Do the following changes.
protected void updateAllFeeds() {
setUpdating();
new Thread( new Updater(channels)).start();
}
Call stopUpdating()
in runOnUiThread
block.
private class Updater implements Runnable {
.........
.........
.........
public void run() {
.........
.........
// End updater
runOnUiThread(new Runnable(){
public void run() {
stopUpdating();
}
});
} // End run()
} // End class Updater
Move anything that affects the UI off into its own Runnable
and then post it with your button
btnRefreshAll.post(new StopUpdating());
I managed to get this working last night using Android's AsyncTask class. It was surprisingly easy to implement, though the downside was I had to write one class for updating an individual feed, and another for updating all feeds. Here's the code for updating all feeds at once:
private class MassUpdater extends AsyncTask<ArrayList<Channel>, Void, Void> {
@Override
protected Void doInBackground(ArrayList<Channel>... channels) {
ArrayList<Channel> channelList = channels[0];
// Flag for writing problems
boolean write_error = false;
// Iterate through all feeds
for(int i = 0; i < channelList.size(); i++) {
// Update this item
int updateStatus = channelList.get(i).update(getApplicationContext());
if(updateStatus == FileHandler.STATUS_WRITE_ERROR) {
// Error - show dialog
write_error = true;
}
}
// If we have an error, show the dialog
if(write_error) {
runOnUiThread(new Runnable(){
public void run() {
showDialog(ERR_SD_READ_ONLY);
}
});
}
return null;
}
protected void onPreExecute() {
btnRefreshAll.setAnimation(getRotateAnimation());
btnRefreshAll.invalidate();
btnRefreshAll.getAnimation().startNow();
}
protected void onPostExecute(Void hello) {
btnRefreshAll.setAnimation(null);
refreshList();
}
}
Thanks for your answers guys. userSeven7s' reply also makes a lot of sense so I may use that as a backup should I run into any problems with AsyncTask.
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