Develop Reference

How to add Back Button from an Activity to a Fragment

I'm using a fragment because I used a nav drawer menu. After I click "Category" menu it will take me to "Category" fragment and in that fragment, I have added a floating action bar that will take you to "Add category" activity.
Since fragments can't be viewed in AndroidManifest.xml file, I can't make a fragment as a parent. What I want is to add a "Back Button" from "Add category" activity, display a toast message (If sure to leave without saving changes..etc) and will go back to "Category" fragment.
I have tried using "onBackPressed()" and "getSuppoerActionBar()" that will show a toast but when running the app, the toast message will just show up in a few seconds and will go back to "Category" fragment.
Please help. Thanks!
Here is my code.
CategoriesFragment.java
package com.example.devcash;
import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.design.widget.FloatingActionButton;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
/**
* A simple {#link Fragment} subclass.
*/
public class CategoriesFragment extends Fragment {
public CategoriesFragment() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_categories, container, false);
//add floating action button
FloatingActionButton categories_fab = view.findViewById(R.id.addcategories_fab);
categories_fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
// when add fab is pressed, go to add product activity
Intent addprod = new Intent(getActivity(), AddCategoryActivity.class);
startActivity(addprod);
}
});
return view;
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getActivity().setTitle("Categories");
}
}
AddCategoryActivity.java
package com.example.devcash;
import android.content.DialogInterface;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.MenuItem;
public class AddCategoryActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_category);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
#Override
public void onBackPressed() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Unsaved changes");
builder.setMessage("Are you sure you want to leave without saving changes?");
builder.setPositiveButton("LEAVE", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
AddCategoryActivity.super.onBackPressed();
}
});
builder.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
builder.show();
super.onBackPressed();
}
}

You need to remove below code from onBackPressed() as it is calling super class method and eventually destroying activity.
super.onBackPressed();
To handle toolbar back add following code
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// todo: goto back activity from here
onBackPressed();
default:
return super.onOptionsItemSelected(item);
}
}

Your AddCategoryActivity should be like this
public class AddCategoryActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_category);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
#Override
public void onBackPressed() {
quitActivity();
}
private void quitActivity() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Unsaved changes");
builder.setMessage("Are you sure you want to leave without saving changes?");
builder.setPositiveButton("LEAVE", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
finish();
}
});
builder.setNegativeButton("CANCEL", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
dialog.dismiss();
}
});
builder.show();
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId() == android.R.id.home) {
quitActivity();
return true;
} else
return super.onOptionsItemSelected(item);
}
}

you can use EventBus.
class Activity{
fun backToFragment(){
EventBus.postEvent(BackToFragmentEvent())
}
}
class HomeActivity{
EventBus.register{
fragmentmanager.replace(CategoriesFragment)
}
}

SignOut is not working in Fragment using Item Menu with firebase

This is my Profile fragment and I am having three of them in main Activity.
Here I am using Sign out functionality but it is not working.
package com.example.user.transroads;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.AlertDialog;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import com.google.firebase.auth.FirebaseAuth;
public class ProfileFragment extends Fragment {
private FirebaseAuth firebaseAuth;
public static ProfileFragment newInstance() {
ProfileFragment fragment = new ProfileFragment();
return fragment;
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
firebaseAuth = FirebaseAuth.getInstance();
setHasOptionsMenu(true);
}
#Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
// TODO Add your menu entries here
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.item_menu, menu);
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()){
case R.id.signOut:
firebaseAuth.getInstance().signOut();
return true;
}
return super.onOptionsItemSelected(item);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_profile, container, false);
}
I want to log out from a fragment. I have three of them with bottom Navigation but the sign out is not happening it should be intent on the LogInActivity.
Please help me out solve this problem.

I won't believe that signout is not working.It might be because android saves activities states.
As you are saying on clicking on signout you want to launch loginActivity.You can do this by removing all activities from back stack.
To do this use it.
case R.id.signOut:
firebaseAuth.getInstance().signOut();
Intent i = new Intent(getActivity(),
NewActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
return true;
OR
for AlertDialog you can create a method alertsignout() outside onCreate() like this :
public void alertsignout()
{
AlertDialog.Builder alertDialog2 = new
AlertDialog.Builder(
getActivity());
// Setting Dialog Title
alertDialog2.setTitle("Confirm SignOut");
// Setting Dialog Message
alertDialog2.setMessage("Are you sure you want to Signout?");
// Setting Positive "Yes" Btn
alertDialog2.setPositiveButton("YES",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Write your code here to execute after dialog
firebaseAuth.getInstance().signOut();
Intent i = new Intent(getActivity(),
NewActivity.class);
i.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK |
Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(i);
}
});
// Setting Negative "NO" Btn
alertDialog2.setNegativeButton("NO",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Write your code here to execute after dialog
Toast.makeText(getApplicationContext(),
"You clicked on NO", Toast.LENGTH_SHORT)
.show();
dialog.cancel();
}
});
// Showing Alert Dialog
alertDialog2.show();
}
And call this method like this :
case R.id.signOut:
alertsignout();
return true;
PS : I havn't tested it so if there are any error.. ask me

You need to change this line of code:
firebaseAuth.getInstance().signOut();
with
FirebaseAuth.getInstance().signOut();

Android Studio: Back Button for previous Activity

I've created an Activity with a Navigation Drawer and replaced the options icon (placed in the top-right corner) with an ImageButton to handle the back click.
The problem is, that I don't know how to do it. I'm a little confused about how to use the back button. What code should I do to go to the previous Activity?
A back button for:
Activity to Another Activity and MainActivity to Fragment activity.
this is my Manifest code:
<activity
android:name="com.teamamazing.with_sidebar.activity.Accomodation"
android:label="Accomodation"
android:parentActivityName="com.teamamazing.with_sidebar.activity.SpecialPage">
<meta-data
android:name="android.support.PARENT_ACTIVITY"
android:value="com.teamamazing.with_sidebar.activity.SpecialPage" />
</activity>
this is my Accommodation activity:
package com.teamamazing.with_sidebar.activity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import com.teamamazing.with_sidebar.R;
public class Accomodation extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_accomodation);
} }
and this is my SpecialPage code: which will be the parent activity.
package com.teamamazing.with_sidebar.activity;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import com.teamamazing.with_sidebar.R;
public class SpecialPage extends AppCompatActivity {
public ImageButton accomodation;
public void init() {
accomodation = (ImageButton) findViewById(R.id.AccomodationButton);
accomodation.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent accomodation = new Intent(SpecialPage.this, Accomodation.class);
startActivity(accomodation);
}
});
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_special_page);
init();
}}
Thank you for the answer.

You can use onBackPressed() or finish() Method.
buttonClickOBJ.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
onBackPressed();
}
});
onBackPressed ()
Called when the activity has detected the user's press of the back
key. The default implementation simply finishes the current activity,
but you can override this to do whatever you want.

You can also use the following method.
#Override
public boolean onOptionsItemSelected(MenuItem item){
switch(item.getItemId()){
case android.R.id.home:
finish();
return true;
}
return super.onOptionsItemSelected(item);
}

Easy way
public void onBackPressed() {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setTitle(R.string.app_name);
builder.setIcon(R.mipmap.ic_launcher);
builder.setMessage("If You Enjoy The App Please Rate us?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Intent play =
new Intent(Intent.ACTION_VIEW, Uri.parse("https://play.google.com/store/apps/details?id=kd.travellingtips"));
startActivity(play);
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
finish();
}
});
AlertDialog alert = builder.create();
alert.show();
}

Firstly, Add the Listener to the button you want to associate with it. Then initiate a back-press option within the method.

Android Studio - Expression Expected

I am creating a weather app and I am getting a message that an Expression was expected.
Here is my Main Activity:
package com.haziqhussain.hazweather;
import android.support.v7.app.AppCompatActivity;
import android.text.InputType;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
public class WeatherActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_weather);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new WeatherFragment())
.commit();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
/*int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);*/
if(item.getItemId() == R.id.change_city){
showInputDialog();
}
return false;
}
private void showInputDialog(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Change city");
final EditText input = new EditText(this);
input.setInputType(InputType.TYPE_CLASS_TEXT);
builder.setView(input);
builder.setPositiveButton("Go", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
changeCity(input.getText().toString());
}
});
builder.show();
}
public void changeCity(String city){
WeatherFragment wf = (----->WeatherFragment<------).getSupportFragmentManager()
.findFragmentById(R.id.container);
wf.changeCity(city);
new CityPreference(this).setCity(city);
}
}
The Error is in the Public Void ChangeCity where weather fragment is being called. This is an error that keeps occuring and I am not sure what is going on.

Use this:
public void changeCity(String city){
WeatherFragment wf = (WeatherFragment) getSupportFragmentManager()
.findFragmentById(R.id.container); // removed '.'
wf.changeCity(city);
(new CityPreference(this)).setCity(city);
}

Android Studio - Cannot resolve method 'add(int, com.*.*.WeatherFragment)'

I am creating a weather app and I am getting an error message.
Here is my Main Activity:
package com.haziqhussain.hazweather;
import android.support.v7.app.ActionBarActivity;
import android.text.InputType;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.EditText;
public class WeatherActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_weather);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction()
.add(R.id.container, new WeatherFragment())
.commit();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
/*int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);*/
if(item.getItemId() == R.id.change_city){
showInputDialog();
}
return false;
}
private void showInputDialog(){
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Change city");
final EditText input = new EditText(this);
input.setInputType(InputType.TYPE_CLASS_TEXT);
builder.setView(input);
builder.setPositiveButton("Go", new DialogInterface.OnClickListener() {
#Override
public void onClick(DialogInterface dialog, int which) {
changeCity(input.getText().toString());
}
});
builder.show();
}
public void changeCity(String city){
WeatherFragment wf = (WeatherFragment).getSupportFragmentManager()
.findFragmentById(R.id.container);
wf.changeCity(city);
new CityPreference(this).setCity(city);
}
}
Please could someone help and the problem is the onCreate section, .add is causing an error and it is not resolving the container.

Most likely, WeatherFragment inherits from android.app.Fragment. In WeatherActivity, you are using the backport of fragments (e.g., getSupportFragmentManager()). That means that WeatherFragment has to extend android.support.v4.app.Fragment.