Develop Reference

Android Change a variable in service from other app

the title says all, I need to change the variable of my service from a activity in my other app , what to finalize the service or not, this is possible?
I found the Message object , but I do not quite understand

The simplest solution would be to implement a BroadcastReceiver. Your Service listens for the Broadcast and the other App sends the Broadcast.
Example Reciever:
public class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// Get bundle from intent and use it to set your Variable in your Service
}
}
Example Broadcaster (courtesy of Vogella):
Intent intent = new Intent();
intent.setAction("de.vogella.android.mybroadcast");
sendBroadcast(intent);

Resume App from BroadcastReceiver

Is there a way to Resume an app from a BroadcastReceiver? (in the way that the Launcher Resumes or Starts an app)
I want to do this when the device is plugged in (don't worry, this isn't going in the Play store)
It seems like you must use FLAG_ACTIVITY_NEW_TASK or else you receive a RuntimeException for "Calling startActivity() from outside of an Activity context"
public class PowerReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals("android.intent.action.ACTION_POWER_CONNECTED")) {
final Intent newIntent = new Intent(context, FooActivity.class);
//newIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
newIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
context.startActivity(newIntent);
}
}
}

Multiple custom broadcasting (how to handle)

I want to add a custom broadcast receiver to my app. and I have 3 methods that should do the broadcast. and in my onReceive method i want to identify which method did the broadcast. I have 3 methods like this
public void method01(View v){
int flag = 1;
Intent intent = new Intent();
intent.addFlags(flag);
broadcastIntent(intent);
}
public void method02(){
int flag = 2;
Intent intent = new Intent();
intent.addFlags(flag);
broadcastIntent(intent);
}
public void method03(){
int flag = 3;
Intent intent = new Intent();
intent.addFlags(flag);
broadcastIntent(intent);
}
and this is my broadcastIntent method
public void broadcastIntent(Intent intent){
sendBroadcast(intent);
}
in my onReceive method i use getFlags() method to get the flag value from the intent and send it through a if, else. but this do not work. any suggestion for improvements are welcome.

You can also use Actions to identify each one of you Intent objects.
String action1 = "first_sender";
String action2 = "second_sender";
Intent createIntent01(){
Intent intent01 = new Intent();
intent01.setAction(action1);
return intent01;
}
Intent createIntent02(){
Intent intent02 = new Intent();
intent01.setAction(action2);
return intent02;
}
And in your onReceive method you can use the getAction() method of intents to check which action was sent. This is in case you're not already using Actions.
[[EDIT]]
To register a BroadcastReceiver you need to define an IntentFilter and register the actions you wish to receive this way:
mBroadcastReceiver broadcastReceiver = new mBroadcastReceiver();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(action1);
intentFilter.addAction(action2);
registerReceiver(broadcastReceiver,intentFilter);
class mBroadcastReceiver extends BroadcastReceiver{
public void onReceive(Context arg0, Intent arg1){
String action = arg1.getAction();
if(action.equals(action1)){
//do something
}else if(action.equals(action2)){
//do something else
}
}

The first problem is that ypu didn't specify a target for your intent. You can use intent filters and actions like rodkarom suggested or specify receiver's class directly (see in my example). In both cases you need either to declare your broadcast receiver in AndroidManifest.xml, or register it at runtime (see rodkarom's answer for a sample).
The method addFlags is used to specify some internal properties of Intent (like start activity corresponding to this intent in a new task) , so you cannot use it for your own data. The list of possible flags is in the documentation for setFlags method.
You can use putExtra to achieve your goal:
// an Activity is just an example
public class SenderActivity extends Activity {
// ...
void method01() {
int flag = 1;
Intent intent = new Intent(getApplicationContext(), Receiver.class); // any Context is acceptable here
intent.putExtra(MyReceiver.EXTRA_FLAG, flag); // any string will do well, you just need it to be the same here and in getExtra later
sendBroadcast(intent);
}
}
public class MyReceiver extends BroadcastReceiver {
public static final String EXTRA_FLAG = "your.package.name.EXTRA_FLAG";
// and in onReceive
public void onReceive (Context context, Intent intent) {
int flag = intent.getIntExtra(EXTRA_FLAG, someDefaultValue);
if (flag == 1) {
// ...
}
// ...
}
}

I found out the way to this and thought of sharing the code. this is the broadcasting done in my main activity for 2 different methods.
public void method1(View view){
Intent intent = new Intent();
intent.setAction("method1");
sendBroadcast(intent);
}
public void method2(View view){
Intent intent = new Intent();
intent.setAction("method2");
sendBroadcast(intent);
}
and this is how i receive it..
public class Receiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Toast.makeText(context, "Broadcast Intent Detected.",Toast.LENGTH_LONG).show();
}
this is how i registered it on manifest.
<receiver android:name="Receiver" >
<intent-filter>
<action android:name="method1" >
</action>
<action android:name="method2" >
</action>
</intent-filter>
</receiver>
Hope this will help if any one else came up with similar problem. and big thank you to every one who posted their answers here.

Updating Textview in an Activity with Local Service

I have an Activity with R.id.eventDistance and R.id.eventTime to display the distance & travel time based on current location. I calculate these values every 30 seconds using my Location Service class.
My question is: how do I update the TextView in Activity? I've tried looking up the question and found some possible solutions such as using a BroadcastReceiver and call TextView.setText() in the onReceive() method. I'm not sure how this is done. Am I supposed to pass in the Activity class like this:
public class MyReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
Intent i = new Intent(context, HomeActivity.class);
}
}
I'm not sure what to do after that. Any help is appreciated.

please see this flow.
1.in your LocationService class when you want to update UI. in your case it should be called every 30 seconds.
Intent i = new Intent("LOCATION_UPDATED");
i.putExtra("<Key>","text");
sendBroadcast(i);
2.in your UI (HomeActivity) class
in onCreate()
registerReceiver(uiUpdated, new IntentFilter("LOCATION_UPDATED"));
in class
private BroadcastReceiver uiUpdated= new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
TextView.setText(intent.getExtras().getString("<KEY>"))
}
};
in onDestroy()
unregisterReceiver(uiUpdated);

You should bind your Activity to your service so that they can directly communicate and message pass.
Ref
http://developer.android.com/guide/components/bound-services.html

Android - Broadcast Receiver launch a singletask Activity

I have a broadcast receiver which will launch an Activity onReceive.
When launched, this activity will perform a long task and call finish() at the end.
I do not want to trigger another launch of Activity when the previous Activity is still performing the long task. How can I launch only a singletask activity? I have set this in the manifest.
android:launchMode="singleTask"
In my onReceive method,
public void onReceive(Context context, Intent intent) {
Intent activity = new Intent(context, Preview.class);
activity.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(activity);
}
Don't seems to work.
The Activity class actually is a MediaRecorder which will record a video clip (say 10 sec). Thus I do not want to trigger another Activity while this recording is still incomplete.

You just need to have some way for your activity to communicate to your receiver to let it know whether or not it is already running. If you have that then you can make an if statement in the receiver that will keep it from launching multiples.
One option is a static boolean in your activity that indicates whether or not you are currently running. Then you can check that boolean from the receiver, and if it is true, then don't call startActivity().
your activity would need something like this:
public YourActivity extends Activity{
public static isRunning = false;
public void onStart(){
...
isRunning = true;
}
public void onStop(){
...
isRunning = false;
}
}
now in your receiver you can make a simple if statement that will check the value of isRunning:
public void onReceive(Context context, Intent intent) {
if(YourActivity.isRunning == false){
Intent activity = new Intent(context, Preview.class);
activity.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(activity);
}
}

Please add these flags.
public void onReceive(Context context, Intent intent) {
Intent activity = new Intent(context, Preview.class);
activity.addFlags(Intent.FLAG_ACTIVITY_REORDER_TO_FRONT | Intent.FLAG_ACTIVITY_CLEAR_TOP |Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
context.startActivity(activity);
}