I have some questions about android ui api.
Give a example, that I want to implement.
Main_UI_Thread.java. code...
I know the message passing can be do that;
But I want the ui program is be implemented in DisplayClass.java. Is it possible?
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I'm just getting into Android development, and I have a question about communicating between a receiver class and an activity class. I'm very new to JAVA and Android so I hope I don't sound too stupid. I'm developing an application where I intercept an SMS message and then based on various elements of that SMS I might delete it once it's been saved to the inbox. I have a receiver class that intercepts the txt message, and I am also able to delete messages from my inbox with code in the activity class using a button at the moment. The problem I have is communicating between the receiver class and the activity class where the code to delete a message resides. I tried putting that code directly into the receiver class but as I'm sure most of you already know the BroadcastReceiver class doesn't seem to support what I need to delete messages. I've been searching for an answer to this for a while, but haven't been able to find anything. Honestly I'm not sure I know enough about JAVA and Android to even recognize a solution if I saw it.
View 2 Replies View RelatedI'm new to Java and android development. In my application I need data which is accessible for a few activities. I've read that a good solution is to use Application class for this. So I use it like this:
public class MyApplication extends Application {
private String str;
public String getStr(){
return str;
}
public void setStr(String s){
str = s;
}
}
and I can access this variable from activity like this:........................................
I have just started android. I just want to know that how can i call activity class from other java class. i just want to pass class object to activity class.
public class GsonParser extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MagazineThread thread=new MagazineThread();
thread.start();
}
public GsonParser(JsonMagazineParser Obj)
{
}
}
and i am just doing like from other class. GsonParser obj=new GsonParser(this);passing obj to activity class.how can i achieve that.
What is the difference when a class extend from Handler and Thread?
As described in developer.android.com
...
Each Handler instance is associated with a single thread and that thread's message queue.
...
Does the thread has no message queue ?
Any benefit for a class extend from Handler?
When I put the setContentView in thread as below, it crashes while running in emulator. code...
View 2 Replies View RelatedAn activity can be called from existing activity through *startActivity(intent); *
Is t possible to call an activity from non Activity class ? and how?
Is there a reason why the Thread class in the SDK LunarLander and JetBoy examples are not each in a separate java file, rather than being inside the View file?
It would make things a bit clearer, IMHO. Am I missing something?
In Virgil Dobjanschi's talk, "Developing Android REST client applications" (link here), he said a few things that took me by surprise. Including:
Don't run http queries in threads spawned by your activities. Instead, communicate with a service to do them, and store the information in a ContentProvider.
Use a ContentObserver to be notified of changes.
Always perform long running tasks in a Service, never in your Activity.
Stop your Service when you're done with it.
I understand that he was talking about a REST API, but I'm trying to make it fit with some other ideas I've had for apps. One of APIs I've been using uses long-polling for their chat interface. There is a loop http queries, most of which will time out. This means that, as long as the app hasn't been killed by the OS, or the user hasn't specifically turned off the chat feature, I'll never be done with the Service, and it will stay open forever. This seems less than optimal.
Long question short:
For a chat application that uses long polling to simulate push and immediate response, is it still best practice to use a Service to perform the HTTP queries, and store the information in a ContentProvider?
My problem is: Activity A called Activity B, and in Activity B, it start a background thread to do some client-server work. But it maybe takes too much time. So i add a cancel button to call the stop() method to stop the thread, and call finish() to finish the Activity B and go back to Activity A. Although it is back to Activity A, the thread isn't stop immediately. Can i just call the finish() to go back to Activity A, and leave the thread to exit by itself? If it is not the right way, which is?
View 10 Replies View RelatedI have a class defined as
public class viewGroups extends ListActivity
Somewhere in the class I have
objItem = new clsContactGroups(context);
I am wondering what is advised to be used here? Which context?
I know four choices, but maybe there are others...
this
this.getApplicationContext()
this.getBaseContext()
this.getParent()
I use this Context to show a Toast. So I would like to show on the front-most view visible.
I have three classes one main-activity(named MainMap), one non-activity class(named MyItemizedOverlay), and one activity class(named AudioStream). I want to start AudioStream activity from non-activity class but i don't know how to.
View 1 Replies View RelatedIf I want to send an event, e.g. OnClick, to an activity from a thread? The expected work flow is below:public class HelloAndroid extends Activity {public void onCreate(Bundle savedInstanceState)Code...
View 4 Replies View RelatedI am want to pass data back from a Thread to Activity (which created the thread). So I am doing like described on Android documentation.Only one thing I am missing here - where and how should be defined mResults so I could access it from both Activity and Thread, and also would be able to modify as needed? If I define it as final in MyActivity, I can't change it anymore in Thread - as it is shown in example.
View 1 Replies View RelatedHow can I kill Android activity from asynchronous thread? In my android application, I start another activity using startActivity. Is there anyway for me to kill that activity I started after several minutes?Or is there any way beside using thread?
View 2 Replies View RelatedSuppose my activity ui-thread spawns a separate thread at some point. Is it safe for that new thread to fire off an Intent for launching a new activity?
View 1 Replies View RelatedI have an Android app modeled after the LunarLander example by Google.
I am debugging it on a real device, (Motorola Droid) with Android 2.0.
When the orientation changes, the program crashes on a null pointer Exception.
Logcat from just before crash:
CODE:.............
The first line that worries me is "Something wrong here" at 24:38.620. I have no idea what it means, But I think its due to me not reacting properly to the screen change.
Next I get a debug message that I printed myself from within my own method surfaceChanged() about the new surface dimensions.
Then I print out debug message about whether flies was null. flies is the field that eventually causes the NullPointerException. Its created once, and never written to again for the rest of the program. I know that it was not null before the crash, because it was read several times.
Does anyone have a clue how my private member variable came to be null just by these clues?
I would include code but there is a lot of it and I don't know what would be relevant.
I have an activity class(Application Class ) which calls a service class(Service Class) and closes. The service class takes about 5 seconds to complete its task and calls a method which is present in another class(Callback Class). Now according to the result, the callback needs to notify the Application class.Once i get the callback from the service, I tried calling a method defined in the Application class. In this method i create a new intent of Application class and call startActivity(Application Class). But this is not working. Can anyone tell where i am going wrong and what can I do to solve this issue.
View 5 Replies View RelatedI must be overlooking something because I am unable to get my TabHost to display in my Activity class.I am getting the dreaded force close when I try to run the app.It will work if I extend TabActivity, but I can't do that [details at the bottom] because once I move the code from my prototype project its going to be in a custom class that inherits from Activity.
View 2 Replies View RelatedI wrote successfully TTS with some references in Activity.
However, I want to call this TTS in my own class as below.
CODE:............
Can i call method of Listactivity from Activity class? I have creates Intent object of myListActivity class and called startIntent() from myActivity class.
View 3 Replies View RelatedI've got two activities, one of them is called MyActivity. I want both of them to be able to use a function located in a class othat we may call MyClass. In MyClass, I try to use an intent to launch the activity AnotherActivity. Since the constructor takes a context as parameter, I simply tried to store a context from the activity in the constructor, and then use it when I try to create my intent.However, even thought none of the arguments are null (checked that with a simple if-statement), intent seems to be null and a NullPointerException is thrown. Why does it not work, and what can I do to solve the problem?
I'm quite new to Android and Java development, so please explain it as basic as you can.
I am new to Android, and I haven't developed any app regarding databases on Android yet. So I have a few basic questions. I am after a good database class sample, that will let me to run the CRUD operations. I would like to use it as a static class
like: clsDB->Select("select * from clients");
or objClient->Delete(clientid);
I am wondering if someone, can share his database classes, if more people share the best. Also I have in mind to reuse this class in multiple ways, I will have services, activities etc...
I've adapted the GridInputProcessor-class of the 3D-Gallery ( http://android.git.kernel.org/?p=platform/packages/apps/Gallery3D.git;a=blob;f=src/com/cooliris/media/GridInputProcessor.java;h=91dfd4783be6b21ec8ff2518a5c244752570e90d;hb=HEAD ) so that it detects upward/downward swipes.
The detection of swipes works, but I now want to start another activity (or draw a bitmap on the currently displayed activity), but I seemingly can't use startActivity(mContext, myIntent), because the class declaration is public final class GridInputProcessor implements GestureDetector.OnGestureListener, GestureDetector.OnDoubleTapListener {so it doesn't extend Activity...
Can I still start an Activity through this class, or how would I go about doing this? I have also tried sending a broadcast, but this is also not "implemented".
This is vinod i have been saving problem while i am starting Activity in receiver so i would know this is the way or not for start activity in receiver
View 3 Replies View RelatedFor example, I have an activity that uses a utility class. I would like to be able to start an activity from the utility class and have the activity result sent back to the utility class.
The only way I could think of starting the activity was to pass the original activity to the utility class, so that the utility class could use the original activity to start the activity. The problem with this is that the activity is sent to the original activity, rather than the utility class.
I also thought of actually making the utility class an activity itself, but that would make using the utility class much more complicated.
How to can call one activity from Dialog.
View 3 Replies View RelatedI am quite new to Android and Java
I am looking for example of how to use this class:
SingleLaunchActivityTestCase
Till now I am using class InstrumentationTestCase but the problem is that for each launched test case Android calling onSetup() and TearDown()
Is it possible to retrieve the contacts without using Activity class?
I'm using LWUIT for developing android application. I need to retrieve the contacts from android phonebook. How its possible?
Because normally retrieve contacts process achieved in inside of extend Activity class. ( I seen some examples).
In LWUIT, They created own Activity class.
So i need to achieve some other class not in activity class.
How its possible?
How to create a class which not extended Activity & how can i use it class?
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