I found this Question multiple times but none of the Solutions seemed to work.
I have the following in the manifest:
<receiver android:name=".noactivity.Airplane">
<intent-filter>
<action android:name="android.intent.action.AIRPLANE_MODE_CHANGED"/>
</intent-filter>
</receiver>
And the following class:
public class Airplane extends BroadcastReceiver {
public Airplane(){
}
#Override
public void onReceive(Context context, Intent intent) {
Log.d("AirplaneMode", "Service state changed");
Toast.makeText(context,"Airplane mode changed",Toast.LENGTH_LONG).show();
}}
But if I change the Airplane mode nothing happens. To be sure I also added:
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
registerReceiver(new Airplane(), new IntentFilter("android.intent.action.AIRPLANE_MODE_CHANGED"));
}}
What also didn't work.
Do any of you know what I'm doing wrong?
I use this successfully without adding the receiver in manifest.
In you activity add this:
#Override
protected void onResume() {
//register receiver for air plane mode states
IntentFilter airPlaneModeFilter = new IntentFilter(Intent.ACTION_AIRPLANE_MODE_CHANGED);
registerReceiver(airPlaneModeReceiver, airPlaneModeFilter);
super.onResume();
}
private BroadcastReceiver airPlaneModeReceiver = new BroadcastReceiver() {#Override
public void onReceive(Context context, Intent intent) {
boolean airPlaneModeEnabled = intent.getBooleanExtra("state", false);
if (airPlaneModeEnabled) {
} else {
}
}
};
#Override
protected void onPause() {
if (airPlaneModeReceiver != null) unregisterReceiver(airPlaneModeReceiver);
super.onPause();
}
Related
I was learning broadcast receiver concept, so I tried making demo apps for sending broadcast and receiving custom private broadcast
This is my Broadcast Sender App code :
public class MainActivity extends AppCompatActivity {
TextView senderTextView;
Button sendButton;
private int counter;
//This is our anonymous class which will receive broadcast when sent from send button and set our text view
private final BroadcastReceiver innerReceiverAnonymousClass = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
//if our (com.example.PRIVATE_BROADCAST) broadcast equals to the intent received here from intent filter
if("com.example.PRIVATE_BROADCAST".equals(intent.getAction())){
//counter variable for tracking no. of times broadcast is sent
counter++;
//then this means broadcast has been sent in mobile
//set text
senderTextView.setText("Broadcast Sent " + counter + " times");
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//initializing views
senderTextView = findViewById(R.id.senderTextView);
sendButton = findViewById(R.id.sendButton);
//Setting onClick Listener on sendButton
sendButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
//Calling Broadcast Method
Broadcast();
}
});
}
//Broadcast Method
private void Broadcast(){
//Creating private broadcast event
Intent intent = new Intent("com.example.PRIVATE_BROADCAST");
//Adding String to our intent
intent.putExtra("BROADCAST_EXTRA_DATA","This is Private Broadcast");
//Sending our private broadcast to our android mobile
sendBroadcast(intent);
}
#Override
protected void onStart() {
super.onStart();
//Intent filter will filter out intent from all the broadcasts happening in mobile
// on basis of action and pass it to innerReceiverAnonymousClass
IntentFilter intentFilter = new IntentFilter("com.example.PRIVATE_BROADCAST");
registerReceiver(innerReceiverAnonymousClass,intentFilter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(innerReceiverAnonymousClass);
}
This is my Broadcast Receiver app :
public class MainActivity extends AppCompatActivity {
TextView receiverTextView;
//Our anonymous private broadcast receiver class
//We can also make a separate class java class that will extend BroadcastReceiver class
//But we are using an anonymous so that we can get control of text view i.e. UI
private final BroadcastReceiver privateBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if("com.example.PRIVATE_BROADCAST".equals(intent.getAction())){
Log.d("APP_LOGS", "Broadcast Received");
Toast.makeText(context, "Private Broadcast Received", Toast.LENGTH_SHORT).show();
String broadcastString = intent.getStringExtra("BROADCAST_EXTRA_DATA");
receiverTextView.setText("Broadcast Received : " + broadcastString);
}
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
receiverTextView = findViewById(R.id.receiverTextView);
}
#Override
protected void onStart() {
super.onStart();
IntentFilter intentFilter = new IntentFilter("com.example.PRIVATE_BROADCAST");
registerReceiver(privateBroadcastReceiver,intentFilter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(privateBroadcastReceiver);
}
When I press send Broadcast button textview inside sender activity sets to "Broadcast sent 1 times which means our intent is getting broadcasted but toast from my receiver app doesn't show which means I am not able to get broadcast there.
Can someone help me with this.
Thanks in advance.
I have codes in two classes
First class is ExampleBroadcastReceiver:
public class ExampleBroadcastReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false
);
if (noConnectivity) {
Toast.makeText(context, "Disconnected", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(context, "Connected", Toast.LENGTH_SHORT).show();
}
}
}
}
Second class is MainActivity:
public class MainActivity extends AppCompatActivity {
ExampleBroadcastReceiver exampleBroadcastReceiver = new ExampleBroadcastReceiver();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
protected void onStart() {
super.onStart();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(exampleBroadcastReceiver, filter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(exampleBroadcastReceiver);
}
}
How can I make the two classes into one by passing the code from the ExampleBroadcastReceiver class to MainActivity? Is it possible? Please don't ask why. Thanks.
Use java interface to handle an event in MainActivity that occurs in ExampleBroadcastReceiver. This way you don't have to merge classes to share an event based data.
public class ExampleBroadcastReceiver extends BroadcastReceiver {
public interface ConnectivityMonitorCallback {
void onConnectivityChanged(boolean connectivity);
}
public ConnectivityMonitorCallback callback;
public ExampleBroadcastReceiver(#NonNull ConnectivityMonitorCallback eventCallback) {
callback = eventCallback;
}
#Override
public void onReceive(Context context, Intent intent) {
if (ConnectivityManager.CONNECTIVITY_ACTION.equals(intent.getAction())) {
boolean noConnectivity = intent.getBooleanExtra(
ConnectivityManager.EXTRA_NO_CONNECTIVITY, false
);
callback.onConnectivityChanged(noConnectivity);
}
}
}
Finally in the MainActivity you handle the event.
public class MainActivity extends AppCompatActivity {
ExampleBroadcastReceiver exampleBroadcastReceiver;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Define event handling code here which occurs in ExampleBroadcastReceiver
exampleBroadcastReceiver = new ExampleBroadcastReceiver(new ExampleBroadcastReceiver.ConnectivityMonitorCallback {
#Override
void onConnectivityChanged(boolean connectivity) {
// Handle the event that occured in ExampleBroadcastReceiver
}
});
}
#Override
protected void onStart() {
super.onStart();
IntentFilter filter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
registerReceiver(exampleBroadcastReceiver, filter);
}
#Override
protected void onStop() {
super.onStop();
unregisterReceiver(exampleBroadcastReceiver);
}
}
I have declared my Service inside my Voice Activity's Voice.java that
public class Voice extends AppCompatActivity implements RecognitionListener {
#Override
protected void onCreate(Bundle savedInstanceState) {
startService(new Intent(Voice.this,task.class));
}
class task extends Service{
#Override
public void onCreate() {
//background code here
}
#Override
public void onDestroy() {
super.onDestroy();
}
#Nullable
#Override
public IBinder onBind(Intent intent) {
return null;
}
}
and my manifest showing
this error
Instantiatable attribute missing
In MainActivity I have a TextView: textV1. I also have a method in MainActivity that updates that textview:
public void updateTheTextView(final String t) {
MainActivity.this.runOnUiThread(new Runnable() {
public void run() {
TextView textV1 = (TextView) findViewById(R.id.textV1);
textV1.setText(t);
}
});
}
In a BroadcasrReceiver I need to update the text in textV1 in MainActivity.
public class NotifAlarm extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
// other things done here like notification
// NEED TO UPDATE TEXTV1 IN MAINACTIVITY HERE
}
}
How can this be done? The BroadcastReceiver is run from a service. This code I cannot change. Can I access and change textV1 in MainActivity from onReceive()? I've tried many things but all fail.
In your MainActivity initialize a variable of MainActivity class like below.
public class MainActivity extends Activity {
private static MainActivity ins;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ins = this;
}
public static MainActivity getInstace(){
return ins;
}
public void updateTheTextView(final String t) {
MainActivity.this.runOnUiThread(new Runnable() {
public void run() {
TextView textV1 = (TextView) findViewById(R.id.textV1);
textV1.setText(t);
}
});
}
}
public class NotifAlarm extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
try {
MainActivity .getInstace().updateTheTextView("String");
} catch (Exception e) {
}
}
}
#Use Interface
Another way to deal with this situation is by using an Interface. I will describe the advantage of this approach but first, let's see how it's done.
Follow these steps:
1) Create an interface
public interface MyBroadcastListener{
public void doSomething(String result);
}
2) Initialize the listener in BroadCastReceiver
public class NotifAlarm extends BroadcastReceiver {
private MyBroadcastListener listener;
#Override
public void onReceive(Context context, Intent intent) {
listener = (MyBroadcastListener)context;
// other things done here like notification
// NUPDATE TEXTV1 IN MAINACTIVITY HERE
listener.doSomething("Some Result");
}
}
3) Implement the interface in Activity and override the method
public YourActivity extends AppCompatActivity implements MyBroadcastListener{
// Your Activity code
public void updateTheTextView(String t) {
TextView textV1 = (TextView) findViewById(R.id.textV1);
textV1.setText(t);
}
#Override
public void doSomething(String result){
updateTheTextView(result); // Calling method from Interface
}
}
##Advantages of using the interface?
When you have BroadcastReceiver in a different file
Decoupled BroadcastReceiver
Using an interface makes BroadcastReceiver independent of any
Activity. Let's say in future you want to use this BroadCastReceiver
with another Activity which takes the result from BroadcastReceiver
and start a DetailActivity. This is completely a
different task but you will use the same BroadcastReceiver without even
a single code change inside BroadcastReceiver.
How to do that?
Implement the interface in the Activity and Override the method. That's it!
public ListActivity extends AppCompatActivity implements MyBroadcastListener{
// Your Activity code
public void startDetailActivity(String title) {
Intent i = new Intent(ListActivity,this, DetailActivity.class);
i.putExtra("Title", title);
startActivity(i);
}
#Override
public void doSomething(String result){
startDetailActivity(String title); // Calling method from Interface
}
}
create an instance of the class and then pass the value to the function that changes TextView value follow these steps please :
in your BroadcastReceiver overRide onReceive method and paste These lines or changes theme as you wish
private Handler handler = new Handler(); // Handler used to execute code on the UI thread
// Post the UI updating code to our Handler
handler.post(new Runnable() {
#Override
public void run() {
//Toast.makeText(context, "Toast from broadcast receiver", Toast.LENGTH_SHORT).show();
YourActivityToUpdate.updateTheTextView(message);
YourActivityToUpdateinst = YourActivityToUpdate.instance();
if(inst != null) { // your activity can be seen, and you can update it's context
inst.updateTheTextView(message);
}
}
});
now we explain the updateTheTextView and inst
in YourActivityToUpdate class Paste these Lines please
private static SignUpVerify mInst;
public static SignUpVerify instance() {
return mInst;
}
#Override
public void onStart() {
super.onStart();
mInst = this;
}
#Override
public void onStop() {
super.onStop();
mInst = null;
}
and this is the updateTheTextView method that should be placed in YourActivityToUpdate class
public void updateTheTextView(final String verifyCodeValue) {
Log.i("verifyCodeValue", verifyCodeValue);
YourTextViewToUpdate.setText(verifyCodeValue);
}
i think this is a better way thanks to "kevin-lynx"
If someone is searching this exact solution, but in Kotlin, do the following:
class MainActivity : AppCompatActivity() {
companion object {
var ins: MainActivity? = null
fun getInstance(): MainActivity? {
return ins
}
}
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
ins = this
}
fun updateTheTextView(t: String) {
this#MainActivity.runOnUiThread {
val textV1 = findViewById<TextView>(R.id.textV1)
textV1.text = t
}
}
}
class NotifAlarm : BroadcastReceiver() {
override fun onReceive(context: Context?, intent: Intent?) {
try {
MainActivity.getInstance()?.updateTheTextView("The String")
} catch (e: Exception) {
}
}
}
In your broadcastreceiver class send broadcast
public class mybroadcaster extends BroadcastReceiver{
#Override
public void onReceive(Context context, Intent intent) {
context.sendBroadcast(new Intent("updatetext"));
}
}
In your activity register your broadcastreceiver and call it, do your work at onReceive and unregister the broadcaster in onDestroy()
public class MyActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
registerReceiver(broadcastReceiver, new IntentFilter("updatetext"));
}
BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// do your work here
}
};
#Override
protected void onDestroy() {
super.onDestroy();
unregisterReceiver(broadcastReceiver);
}
}
Edit 1
I need to call a method from BroadcastReceiver and method exist in the Activity class mention below.
I tried this code and got NULL_POINTER_EXCEPTION where I create the reference the MainActivity class.
Correct me what I'm doing wrong ?
MainActivity.java
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void myTesting(){
Toast.makeText(MainActivity.this, "Welcome to Activity", Toast.LENGTH_SHORT).show();
}
}
BroadcastReceiver.java
public class BootCompeteReceiver extends BroadcastReceiver {
public Context mContext;
private MainActivity mainActivity;
#Override
public void onReceive(Context context, Intent intent) {
mContext = context;
try {
mainActivity = new MainActivity();
mainActivity.myTesting();
} catch (Exception e) {
Toast.makeText(context, ""+e, Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
Do something like that:
public class MainActivity extends Activity {
private BroadcastReceiver receiver = new BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
try {
MainActivity.this.myTesting();
} catch (Exception e) {
Toast.makeText(MainActivity.this, ""+e, Toast.LENGTH_LONG).show();
e.printStackTrace();
}
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
IntentFilter intFilt = new IntentFilter(Constants.YOUR_BROADCAST_RECEIVER_ACTION);
registerReceiver(receiver, intFilt);
}
public void myTesting(){
Toast.makeText(MainActivity.this, "Welcome to Activity", Toast.LENGTH_SHORT).show();
}
#Override
public void onDestroy() {
super.onDestroy();
unregisterReceiver(receiver);
}
}
You can startActivity in onReceive, and call myTesting in onCreate of your Activity.
You can try this:
public class MainActivity extends Activity {
private static volatile int INSTANCE_COUNTER = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
INSTANCE_COUNTER++;
IntentFilter intentFilter = new IntentFilter("com.your.package.ACTION");
registerReceiver(mWhateverReceiver, intentFilter);
if (getIntent().getBooleanExtra("fromYourReceiver", false)) {
myTesting();
}
}
private void myTesting() {
// Do something here
}
private BroadcastReceiver mWhateverReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
myTesting();
}
};
public static boolean isInstanceExist() {
return INSTANCE_COUNTER > 0;
}
#Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
INSTANCE_COUNTER--;
unregisterReceiver(mWhateverReceiver);
}
}
Your receiver
public class BootCompeteReceiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
if (MainActivity.isInstanceExist()) {
// There is already one instance of MainActivity, so broadcast this
// event to trigger the receiver inside MainActivity to do your task
Intent broadcastIntent = new Intent("com.your.package.ACTION");
context.sendBroadcast(broadcastIntent);
} else {
// There is no instances of MainActivity exist, so start a new one
// with the action that let the instance know what it should do
Intent activityIntent = new Intent(context, MainActivity.class);
activityIntent.putExtra("fromYourReceiver", true);
activityIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(activityIntent);
}
}
}