Curious to know the reason behind not allowing updating UI elements from background thread in Android. Will main thread does something more (probably interacting with framework) after updating the UI elements so that changes can be seen on the screen? Is it the same case with other GUI tool kits?
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My purpose is very simple : each 1second, I want to redraw an object on different place on background. I do not know where my error on this code below. Here is my code:
public class My_View extends View{ private Bitmap mBackground_img;
private Drawable mMoveObject; private int mObjectw,mObjecth; private int Dx,Dy;
private Handler myHandler = new Handler(); private long lasttime;
public My_View(Context context,AttributeSet ats,int ds) {
super(context,ats,ds); init(context);
} public My_View(Context context,AttributeSet ats) { super(context,ats);
init(context); } public My_View(Context context) { super(context);
init(context); } public void change() { invalidate();
} private void init(Context context) {
Resources res = context.getResources();
mMoveObject = res.getDrawable (R.drawable.lander_firing);
mBackground_img = BitmapFactory.decodeResource(res, R.drawable.my_pic);
mObjectw = mMoveObject.getIntrinsicWidth();
mObjecth = mMoveObject.getIntrinsicHeight();
Dx = Dy = 0; lasttime = System.currentTimeMillis() + 1000;
Thread mthread = new Thread(null,doBackground,"Background");
mthread.start(); } private Runnable doBackground = new Runnable() {
public void run() { long now = System.currentTimeMillis();
if(lasttime < now ) { Dx = Dx + 10; Dy = Dy + 10;
lasttime = now + 1000; myHandler.post(change_view);
} } }; private Runnable change_view = new Runnable() {
public void run() { change();
} };
@Override public void onDraw(Canvas canvas) {
canvas.drawBitmap(mBackground_img,0 ,0 , null);
mMoveObject.setBounds(Dx, Dy, Dx+mObjectw, Dy+mObjecth);
mMoveObject.draw(canvas);
} }
I have a separate thread running to get data from the internet. After that, I would like to update the ListView in the main thread by calling adapter.notifyDataSetChanged(). But it does not work. Any workaround for that?
View 1 Replies View RelatedI try to make several connection in a class and update the multiple progressbar in the main screen. But I've got the following error trying to use thread in android : Code: 05-06 13:13:11.092: ERROR/ConnectionManager(22854): ERROR:Can't create handler inside thread that has not called Looper.prepare() Here is a small part of my code in the main Activity.
public class Act_Main extends ListActivity
{ private ConnectionManager cm;
public void onCreate(Bundle savedInstanceState)
{ super.onCreate(savedInstanceState);
// Set up the window layout
requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
setContentView(R.layout.main);
getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title); }
public void startConnection() { ......
I am writing an application in which i need to handle messages between the main thread(the deafult UI related thread) and the user created Gamethread.
The requirement is like this.
An activity(say "Activity_X") is setting the view by "setContentView(some "View_Y")". In "Activity_X" i have implemeted "onCreateOptionsMenu()" and "onOptionsItemSelected()" fucntions for creating menus & a switch case for action to be taken on selecting those menus.Menu has items like "resume/pause/zoom/" .
All action to be take on selecting these menus are implemented in "View_Y" in a separate Gamethread by extending "Thread" class.
So whenever a menu is selected in "Activity_X" i need to send a message to "View_Y". And on receiving this ,a particular action/method should be called in View_Y(GameThread).
How can i achieve this using Handlers?Is there any other way of doing this? Please do share with me some code snippets for these.
I am seeing some weird issues and looking to see if anyone knows what is going on. I have a BroadcastReceiver which updates some views on receiving an event. Some psudo code is shown below. What happens is the function runs fine and the app seems to update the textviews BUT when i then try to clear the textviews parent and add new textviews the linearlayout(parent) blanks out and will now draw any of it's children.
View 2 Replies View RelatedThe Android doc says "Like activities and the other components, services run in the main thread of the application process." Is the main thread here the same thing as UI thread?
View 3 Replies View RelatedAre the UI threads for each Activity and Service in an app separate threads, or is there actually 1 underlying UI thread per app that processes the UI message queue for each Activity and Service?
View 2 Replies View RelatedI have htc evo 4G with sprint and this is the software information
droid 2.1-update1
baseband: 2.05.00
Kernel: 2.6.29
software number: 1.47
PRL version: 60667
and i've been trying to root this so i can use other application and wifi tether however everytime i tried i always get this error " MAIN FOLDER IS OLDER , MAIN UPDATE FAIL!"
I used unrevoked - does not work then i restore to factory setting THEN i tried simpleroot get message Main Folder is older, main update fail!. I also have tried to do Restart the PHONE and press the power button and hold the volume button up (but i have upload the PC36IMG.ZIP before i reboot) THIS does not work either get same message.
IF anyone can help me with this root and PM me your PAYPAL i willing to pay $10 to give me detail instruction (step by step how to get this root)
After rooter i need to know if possible to update somehow to get my FLASH working or it have to be update to droid 2.2 (if i update to 2.2 after rooted, will it lose all my rooted previously assuming its already successfully rooted)
Can someone advise the am command (for adb shell) to run junit tests in the main thread please? The following shows onStart etc running in the test runner thread. am instrument -w -e class co.uk.telesense. tests.MyTest co.uk.telesense.tests/android.test.InstrumentationTestRunner Ewan Benfield ttp://www.telesense.co .uk tel: 0845 643 5691 (+44 845 643 5691) mob: +44 (0) 77859 26477
View 2 Replies View RelatedI was define a new thread for a task, but when task is complete, I must to refresh my listview, however I will get the error for just can use main thread to change view,
View 5 Replies View RelatedThere are a lot of Android SDK APIs where callback handlers are registered. For a concrete example, with MediaPlayer you can set an onCompletionListener callback. Will these callbacks be called from the main (UI) thread? If the answer is "it depends", then I'm looking for some general rules for what callbacks will be called from the main thread versus another thread. The SDK documentation doesn't seem to spell it out. (Maybe I missed it) It seems important to know, because if I'm guaranteed main thread callbacks, then I can skip some thread synchronization on data shared between different places in code. If I'm forced to be pessimistic out of ignorance, then I have to write extra synch block code and worry about deadlocks, data integrity, and reduced performance.
View 4 Replies View RelatedSay that a user clicks on a Button. Is the resulting onClick() function invoked on the main UI thread of the activity?
View 1 Replies View RelatedI want to cancel a Toast to show the next one. This is the description of the behavious I want, when I select one element in the menu i display a toast from the actuel menu element, but if i switch from one element to an other quickly i'm creating a list of Toast to display. So i need to cancel the previous one but i never succed. This is an extract of my code: public class MainActivity extends TabActivity
private Toast toast; private String toastMsg;
private void toast(){ if(toast!=null){ toast.cancel(); } toast = Toast.makeText(MainActivity.this, toastMsg,Toast.LENGTH_SHORT);
toast.show(); } }
Hi, I've noticed that on android, the call to pthread_join does not suspend the calling thread. I've a number (6) of new thread created using pthread_create and pthread_join is called on each thread. But It does not suspend the main (calling) thread. I believe this relates to the port of pthread lib to android.
View 2 Replies View RelatedI am trying to connect to a database, and I understand that it has to be outside of the main thread but i thought that this is what my code was doing...apparently not because i keep getting the error: android.os.NetworkOnMainThreadException.
package com.example.dbtesting;
import java.sql.*;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.TextView;
[code]....
Are we guaranteed that Application.onCreate() runs in the UI/main thread? I want to assume so but I can't find any information to make me 100 % sure. When I receive a broadcast I want to post a message onto the UI/main thread. Currently I've added a function in my Application class to return a handler (created in it's onCreate), is this a good solution? If not, what would be a better solution?
View 3 Replies View RelatedI am trying to start an error-reporting activty if unhandled exception detected. The problem is with exceptions thrown from main thread. Is there any way to start an activity if main thread crashed?
View 3 Replies View RelatedI have an app with a two threads - main and data loader. When data loader finishes it posts a Runnable object to the main thread (as described in the DevGuide), but it never gets delivered and run. Here's the basic code:
class MyApp extends Application{
public void onCreate()
{LoaderThread t = new LoaderThread();
t.start(); }
private class LoaderThread extends Thread {
public void run()
{ SystemClock.sleep(2000);
boolean res = m_handler.post(m_runnable);
if(res)
Log.d(TAG, "Posted Runnable"); } ............
In my game when the user completes a stage, I want the main game thread to pause/sleep/wait and a new activity to be launched called StageClear that displays information about points scored etc. After this has been displayed and the user has pressed continue I want the original game thread to resume where it left off. I have tried to implement this but have so far been unsuccessful, probably because I'm new to dealing with multiple threads and also the idea of synchronizing them. I most recently tried to implement a shared package-visible object that could notify after wait was called on itself, but I am getting errors in eclipse so it won't even compile, I think because though the object is declared public in an inner class, it cannot be seen or recognised by my activity elsewhere in a file in the package. I have already built both activities but my issue is getting the main game one to launch the other, and pause whilst it waits for this activity to finish, before the main game thread continues execution.
View 1 Replies View RelatedHow would I force the current thread to wait until another has finished before continuing. In my program the user selects a MODE from an AlertDialog, I want to halt executing of the program before continuing as the mode holds important configuration for the gameplay.
new AlertDialog.Builder(this)
.setItems(R.array.game_modes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case 0:
setMode(TRAINING_MODE);
case 1:
setMode(QUIZ_MODE);
default:
setMode(TRAINING_MODE);
break; ............
//continue loading the rest of onCreate();
contineOnCreate(); } })
.create().show();
If this is impossible can anyone give a possible solution?
I read somewhere that iPhone UI is so smooth because the thread which renders the UI has the REALTIME priority... so is that possible to mod android's UI thread priority?
View 2 Replies View RelatedI am trying to figure out how to add a child view to a parent view so I can use the MotionEvent.ACTION_MOVE feature to move from one child view to the next. Is this possible?
View 4 Replies View RelatedI want to slowly fade out my main view Xml and go to another XML?Please anyone give me an example with a sample code.
View 1 Replies View RelatedHow could i inflate my custom view using the main.xml file?
View 2 Replies View RelatedSince I got the original 2.2 update for my Droid, whenever I get a new text message and slide down the notification bar and select the new message, it takes me to the main text message window rather than the actual thread to reply to the person. It is really annoying because it requires an extra step. I figured it would be fixed with the second 2.2 update but it didn't. I called Verizon and they called Motorola and nobody knew of the problem so they shipped me out a new phone and it still does it! I am not sure if I am the only one experiencing this or if its normal. It doesn't do it 100% of the time but closer to 90% probably.
View 1 Replies View RelatedI have successed regarding storing of Custom field in Contact database, i also viewed my data through LogCat by printing it using "Cursor". Can we view our Custom field from Main Contacts Application?
View 2 Replies View Related<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
</LinearLayout>
Since the root element is a LinearLayout, which extends ViewGroup, why does main.xml get turned into a View instead of a ViewGroup? For example, in my main Activity class, I try to get the number of subviews that the LinearLayout contains like this:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
ViewGroup vg = (ViewGroup) findViewById(R.layout.main);
Log.v("myTag", "num children: " + vg.getChildCount());
but it crashes when i call vg.getChildCount(). What is the right way of doing it?
Am creating a small application In View Page am doing update and delete operation from database am displaying data s in the top (ex 10 records) and bottom i have 2 buttons Edit and delete if user clicks Edit button it redirects to Edit page In Edit page i am displaying content for editing also i have 2 buttons update and cancel if user click update again am redirecting(using start activity) to view page It is not displaying new records. i went back to main page and then i clicked view page now it is updated How to solve this ??? Another problem is At the same if user clicks back button it is going all page which i went (through redirected page)
For example First i clicked view page from main page in view page am doing edit and delete operation after completing this it goes to view page Here i am clicking back button it is going previous page that is edit or delete page which i have performed last I need to go main page from view (after performing edit or delete op) How to do this ?
I want to create a grid of images with text right below the images.
I created in a xml file a image_text item which basically is a linearlayout with and imageview and a textview right below.
I created a tablelayout and I want to add my custom image_text.xml to the table row. But I dont know how to reference my xml file inside. If I use the include statament, how do I pass the image id and text to my item_text.xml? code...