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Android Studio back button activity

I've been trying to find out the back navigation button to lead to another activity.
Every time when I pressed the back button, it goes to the previous activity which is not what I want. I would like to set the back button that goes to another activity I want, instead of previous one.
For example, I have Activity 1, 2 and 3. I was in Activity 2 and just moved to Activity 3. But when I press the back button, it goes automatically to the previous activity which is Activity 2. I want to make it to Activity 1 and not Activity 2. Can anyone suggest me a solution please?

You can make the button to go to a specific activity, instead of having the default behavior that you described.
It can be something like this:
#Override
public void onClick(View v) {
Intent intent = new Intent(Activity2.this, Activity3.class);
intent.putExtra("variable", information); //this is optional, but can be useful if you need to send a specific info to the next activity
startActivity(intent);
}

Activity 2 is parliamonar, and Activity 3 is federalparliamentary. I replaced parliamonar with Activity 1, but it still didn't solve the problem.
public class federalparliamentary extends AppCompatActivity {
Button federal;
private Object parliamonar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_federalparliamentary);
federal = findViewById(R.id.back160);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), parliamonar.class);
startActivity(reserve);
}
});
federal = findViewById(R.id.next164);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), sar.class);
startActivity(reserve);
}
});
}
public void onClick(View V) {
Intent back = new Intent((Context) parliamonar, federalparliamentary.class);
startActivity(back);
}
}

public class federalparliamentary extends AppCompatActivity {
Button federal;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_federalparliamentary);
federal = findViewById(R.id.back160);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), parliamonar.class);
startActivity(reserve);
}
});
federal = findViewById(R.id.next164);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), sar.class);
startActivity(reserve);
}
});
}
public void Onclick(View v) {
Intent intent = new Intent(federalparliamentary.this, politicalsystem.class);
startActivity(intent);
}
}
Activity 1 is "politicalsystem".
I added with #Override method, but it says that I have to remove the method, so I added outside, then it says that I have to extract interface, so clicked on it, then it gave me a bunch of list. So I chose onClick(v:View ):void, but it still didn't solve the issue. I tried in another way without #Override, but nothing changed when I tested my app. I also tried inside onCreate method which did not modified the navigation as I desired.

Pass int to another Activity

Before you flame me:
I know there are uncountable tutorials out there, and I know myself how to pass data to another ACtivity, just like that.
In my case that's diffrent tho. "Usually" data is passed to another activity through Intents, Bundles ecc and the other Activity is started.
Here's my case:
I have an Item with 4 parameters (Image, String,String, int)
In an AdapterClass I have a PopUpView which retakes those 4 parameters.
What I'd like to achieve is the following:
With the click of a button, the 4th parameter, the int should be sent to the Main activity and inserted in a textView inside the MainActivity, without (here's the main diffrence between this and the other questions)launching the Main Activity.
How can this be done?
TIA.

use BroadcastReceiver to send that 4th int to MainActivity
in PopupView do these:
Intent intent = new Intent("SOMEACTION");
intent.putExtra("4th_int", value);
activity.sendBroadcast(intent);'
//In MainActivity:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
IntentFilter filter = new IntentFilter("SOMEACTION");
this.registerReceiver(mReceiver , filter);
}
#Override
public void onDestroy() {
super.onDestroy();
this.unregisterReceiver(this.mReceiver );
}
private BroadcastReceiver mReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction() == "SOMEACTION") {
// retrieve the 4th int value and update something in MainActivity
}
}
};

Android back button not working properly

When i push the back button on the phone it opens the pause activity as intended but it also goes to the previous activity(i can see this because pause activity style is Theme.AppCompat.Dialog. What i want is just open the pause activity but in the backround to be the current activity not the previous one.The code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_timer_2);
//...
}
//...
#Override
public void onBackPressed()
{
super.onBackPressed();
startActivity(new Intent(timer_2.this, timer_2_pause.class));
finish();
}

In case you wish to kill previous activity use this:
#Override
public void onBackPressed()
{
startActivity(new Intent(timer_2.this, timer_2_pause.class));
finish();
}
If you want to keep that activity in back stack use this:
#Override
public void onBackPressed()
{
startActivity(new Intent(timer_2.this, timer_2_pause.class));
}

Try this:
#Override
public void onBackPressed() {
Intent i=new Intent(timer_2.this,timer_2_pause.class);
startActivity(i);
finish();
super.onBackPressed();
}

Its because you are calling finish() to close the current activity.
Remove finish() and it wont close the current activity.

You should use onBackPress() like this :
#Override
public void onBackPressed()
{
// super.onBackPressed();
// finish();
startActivity(new Intent(timer_2.this, timer_2_pause.class));
}

Use this just...
#Override
public void onBackPressed()
{
//super.onBackPressed(); dont use this..
finish();
startActivity(new Intent(timer_2.this, timer_2_pause.class));
}

Call method of new activity from MainActivity

There are two Activities..
1. Open SecondActivity from MainActivity
2. When event comes into MainActivity, call testMethod of SecondActivity
But how to do call this testMethod?
public class MainActivity extends Activity implements someListener {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Launch SecondActivity here!!
Intent intent = new Intent();
intent.setClass(MainActivity.this, SecondActivity.class);
startActivityForResult(intent, ID_PlayerActivity);
}
//trigger by JNI, it's in the other thread, not main thread.
void onEventCome() {
//How to call testMethod() in SecondActivity?
}
}
public class SecondActivity extends Activity {
void testMethod() {
//execute something...
}
}

If you open the SecondActivity, your MainActivity becomes inactive. I don't believe it is a good idea to call some activity method from other inactive/stopped activity.
I suggest to use observer pattern. Create a global long-lived object like EventProducer and register all activities as observer. So your EventProducer can inform all Activities about new event.
Example:
public class SecondActivity extends Activity implements MyEventListener {
#Override
public void onResume(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EventProducer.instance().register(this);
}
#Override
public void onPause(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EventProducer.instance().unregister(this);
}
void testMethod(){
//just doit
}
#Override
void onMyEventCome() {
testMethod();
}
}

First you need an event aware listener that will capture such an event happening. Your class seems ill equipped to do so.
Since you have a valid question, here goes:
void onEventCome() {
SecondActivity secondActivity = new SecondActivity();
secondActivity.testMethod();
}

There are many ways.
For eg:
Create the method as static and use class name and call it.
public static void onEventCome() {
}
In MainActivity:
MainActivity.onEventCome();
This is one method. Another method is create an object for MainActivity.
public void onEventCome() {
}
MainActivity main;
main = new MainActivity();
main.onEventCome();

You don't have a content view for your second activity. If you don't need to see the operation happen, you could remove your
Intent intent = new Intent();
intent.setClass(MainActivity.this, SecondActivity.class);
startActivityForResult(intent, ID_PlayerActivity);
remove extends Activity in SecondActivity and add a constructor public SecondActivity(Context context) and invoke the test method from your first activity like #Dragan example:
void onEventCome() {
SecondActivity secondActivity = new SecondActivity(MainActivity.this);
secondActivity.testMethod();
}

NullPointerExceptoin when passing value from activity to broadcast receiver

I have an easy question.
I have declared text view in main activity, and created it from XML (findViewById). I would like to pass this value to a subclass of broadcast receiver. Following is my Broadcast constructor:
public Broadcast(TextView text_dBm) {
this.text_dBm = text_dBm;
}
In my main activity I create a new broadcast object and pass my textview value inside, like this:
new Broadcast(text_dBm);
But I'm still getting null pointer exception on my text_dBm. Is there anyway (besides static methods) to pass values between activites and broadcast receiver?
Oh and yes. My broadcast receiver is registered programmatically (in service), and its running perfectly.
Thank you for your time!
P.S: I already checked some threads here in SO, but i didn't find an answer:
How to pass value from an activity in an broadcast receiver?
Main activity class:
public class MainActivity extends Activity {
TextView text_dBm, text_time, text_rssi;
Intent startServiceFromActivity;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
text_dBm = (TextView) findViewById(R.id.textView_dBm);
new Broadcast(text_dBm);
startServiceFromActivity = new Intent(this, WifiService.class);
startService(startServiceFromActivity);
}
}
Broadcast receiver class:
public class Broadcast extends BroadcastReceiver {
WifiInfo wifiInfo;
WifiManager wifiManager_service;
TextView text_dBm;
public Broadcast(WifiManager wifiManager_service) {
this.wifiManager_service = wifiManager_service;
}
public Broadcast(TextView text_dBm) {
this.text_dBm = text_dBm;
}
#Override
public void onReceive(Context context, Intent intent) {
Log.d("RECEIVER", "Receiver running"); // LOG
text_dBm.setText("textview"); // nullpointerexception
}
}

You can't pass around views using Intents. To do what you want to do, you will need your broadcast receiver to be an inner class of your activity. The receiver should be registered when activity is started and unregistered when activity is stopped. Else you will leak memory. That means that you will only be able to receive your messages when actually on the activity screen itself.
If you need to be able to receive broadcasts outside the activity, you will need to:
register your receiver in the manifest for a given action (or in a service, but don't forget to unregister it)
start the activity and pass the message to show in the textview using an intent extra
when the activity starts, check if the intent contains anything to show in the textview and do the necessary
From your comment:
Create the receiver as an inner class of the activity (not a static one so it can access the activity's TextView instance)
register the receiver in onStart
unregister the receiver in onStop
In the onReceive method of your receiver do: textView.setText(intent.getStringExtra("dbm"));
Service sends the broadcast by passing an intent extra called "dbm" and containing the text you want to display
-
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dbmView = (TextView) findViewById(R.id.textView_dBm);
}
#Override
protected void onStart() {
super.onStart();
IntentFilter intentFilter = new IntentFilter("com.example.broadcasts.DBM_UPDATE");
registerReceiver(receiver, intentFilter);
}
#Override
protected void onStop() {
unregisterReceiver(receiver);
super.onStop();
}
private TextView dbmView;
private BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
dbmView.setText(intent.getStringExtra("dbm"));
}
}
}
In the service:
Intent i = new Intent("com.example.broadcasts.DBM_UPDATE");
i.putExtra("dbm", "it works!");
sendBroadcast(i);

Pass data Through intent
Activity -
Intent i = new Intent(Activity.this, Broadcast.class);
Bundle b = new Bundle();
b.putString("key", "value");
i.putExtras(b);
startActivity(i);
In your broadcast receiver class onReceive method
#Override
public void onReceive(Context context, Intent intent)
{
String result = intent.getString("key");
// your method
}