Develop Reference

Put EditText in First Activity to TextView on Second Activity

I'm french so sorry for my bad english.
I need to update on my second activity my TextView with a EditText of my first Activity. But I don't how to do.
That is my code on First Activity:
public class MainActivity extends AppCompatActivity {
private TextView mGreetingTextView;
private EditText mLoginEditText,mEmailEditText,mPasswordEditText;
private Button mLoginButton;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mGreetingTextView = findViewById(R.id.main_textview_info);
mLoginEditText = findViewById(R.id.main_edittext_login);
mEmailEditText = findViewById(R.id.main_edittext_email);
mPasswordEditText = findViewById(R.id.main_edittext_password);
mLoginButton = findViewById(R.id.main_button_log);
mLoginButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
validateLogin();
}
String login = mLoginEditText.getText().toString();
});
}
private void validateLogin(){
if (mEmailEditText.getText().toString().equals("admin#admin.com") &&
mPasswordEditText.getText().toString().equals("admin")) {
Toast.makeText(getApplicationContext(), "Login successful",Toast.LENGTH_SHORT).show();
callHome();
} else {
Toast.makeText(getApplicationContext(), "Wrong login",Toast.LENGTH_SHORT).show();
}
}
public void callHome(){
Intent i = new Intent(getApplicationContext(),HomeActivity.class);
i.putExtra("mLoginText", mLoginEditText.getText());
startActivity(i);
}
But I search a same topic who has the same problem and I don't find.
Apologize for my bad level on Android but I'm student on Android. This is my first topic on StackOverFlow ^^

You are calling mLoginEditText.getText() and that returns Editable. You will need to call mLoginEditText.getText().toString() and that will be a String.

You can update your second activity (HomeActivity) like this
public class HomeActivity extends AppCompatActivity {
TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
textView = findViewById(R.id.textView);
// get the text from main activity
Intent intent = getIntent();
String text = intent.getStringExtra("mLoginText");
textView.setText(text);
}}

I found a result :)
MainActivity:
public class MainActivity extends Activity {
public final static String LOGIN_DATA = "mLoginText";
private EditText mLoginEditText,mEmailEditText,mPasswordEditText;
private Button mLoginButton;
private boolean isValid;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mLoginEditText = findViewById(R.id.main_edittext_login);
mEmailEditText = findViewById(R.id.main_edittext_email);
mPasswordEditText = findViewById(R.id.main_edittext_password);
mLoginButton = findViewById(R.id.main_button_log);
mLoginButton.setOnClickListener(v -> {
isValid = validateLogin();
if (isValid){
callHome();
}
});
}
private boolean validateLogin(){
if (mEmailEditText.getText().toString().equals("admin#admin.com") &&
mPasswordEditText.getText().toString().equals("admin")) {
Toast.makeText(getApplicationContext(), "Login successful",Toast.LENGTH_SHORT).show();
return true;
} else {
Toast.makeText(getApplicationContext(), "Wrong login",Toast.LENGTH_SHORT).show();
return false;
}
}
public void callHome(){
Intent i = new Intent(MainActivity.this,HomeActivity.class);
i.putExtra(LOGIN_DATA, mLoginEditText.getText().toString());
startActivity(i);
}
}
HomeActvity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
mHelloText = findViewById(R.id.home_textview_hello);
Intent intent = getIntent();
String login = intent.getStringExtra(MainActivity.LOGIN_DATA);
mHelloText.setText(login);
With that, the login name of the first activity is in the second activity :)

Callbacks in Android

I am new to Android and programming as a whole and I need a little help with callbacks. I understand the gist of callbacks but I am unsure of how to go about implementing.
Context: I am writing a simple notetaking app that allows the user to write text and saving it to the app. The user can then request to read the file with a button. The text is then displayed on a textview in the main activity. There is an option to wipe this file and this is done with a confirmation pop up, which is another activity. This pop up contains 2 buttons, one to cancel and one to wipe. If the file is not empty it will wipe and does nothing if empty. I am not sure if this is the best way to implement it but I want to use the wipe button to callback to the main activity to clear the textview. The way I was thinking of was by using the callback to send a boolean value back. The main activity will check if the boolean is true and clear the textview if it is. I am unsure of how to implement the callback in my popup display to send this boolean value back to the main activity.
Code for main activity
public class MainActivity extends AppCompatActivity implements Popout.ClearTextView {
Button bnRead,bnWrite,bnClear;
TextView tvFileOP;
EditText etInput;
// private static final String INPUT_CONTENT = "inputContent";
public static final String TV_CONTENT = "textViewContent";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bnRead = (Button) findViewById(R.id.bnRead);
bnWrite = (Button) findViewById(R.id.bnWrite);
bnClear = (Button) findViewById(R.id.bnClear);
tvFileOP = (TextView) findViewById(R.id.tvFileOP);
etInput = (EditText) findViewById(R.id.etInput);
tvFileOP.setMovementMethod(new ScrollingMovementMethod());
final String fileName = "test_file";
String data;
bnRead.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
FileInputStream fIn = openFileInput(fileName);
int c;
String temp = "";
while ( (c=fIn.read()) != -1){
temp = temp + Character.toString((char) c);
}
tvFileOP.setText(temp);
Toast.makeText(getBaseContext(),"file successfully read", Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
});
bnWrite.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
String data = etInput.getText().toString();
try {
FileOutputStream fOut = openFileOutput(fileName,MODE_APPEND);
fOut.write(data.getBytes());
fOut.close();
etInput.setText("");
Toast.makeText(getBaseContext(),"file successfully written", Toast.LENGTH_LONG).show();
} catch (Exception e) {
e.printStackTrace();
}
}
});
bnClear.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(MainActivity.this,Popout.class));
}
});
}
#Override
protected void onSaveInstanceState(#NonNull Bundle outState) {
outState.putString(TV_CONTENT,tvFileOP.getText().toString());
super.onSaveInstanceState(outState);
}
#Override
protected void onRestoreInstanceState(#NonNull Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
tvFileOP.setText(savedInstanceState.getString(TV_CONTENT));
}
#Override
public void clearTextView(Boolean clear) {
if (clear){
tvFileOP.setText("");
}
}
}
Code for popup confirmation menu
public class Popout extends AppCompatActivity {
Button bnClosepopup,bnWipe;
TextView tvConfirmation;
String fileName = "test_file";
TextView tvFileOP;
public interface ClearTextView {
public void clearTextView(Boolean clear);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.popupwindow);
bnClosepopup = (Button) findViewById(R.id.bnClosepopup);
bnWipe = (Button) findViewById(R.id.bnWipe);
tvConfirmation = (TextView) findViewById(R.id.tvConfirmation);
//HIDING THE TOOL BAR AT THE TOP OF THE SCREEN
this.getSupportActionBar().hide();
//GETTING THE SIZE OF THE SCREEN
DisplayMetrics displayMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
int height = displayMetrics.heightPixels;
int width = displayMetrics.widthPixels;
getWindow().setLayout((int) (width*0.8) , (int) (0.8*height));
bnClosepopup.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
bnWipe.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
File dir = getFilesDir();
File file = new File(dir, fileName);
boolean deleted = file.delete();
Toast.makeText(getBaseContext(),"file has been deleted",Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_LONG).show();
}
finish();
}
});
}
}
I am very new to android development and any tips on how to improve my code would be greatly appreciated :)

In this case there is no way to pass the interface to the other activity, because this is an activity to activity communication.
You have to use some other method, there is multiple ways to approach, the best way I can think of is to use startActivityForResult() to start the activity and then wait for a response to come back, and then query this response in the MainActivity by overriding the onActivityResult() method:
Example
In the MainActivity:
//on click of this button
bnClear.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,Popout.class);
int requestCode = 12; //it could be whatever you want
startActivityForResult(intent , requestCode);
}
});
//override this method
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
//this is triggered when you finish the Popout Activity
if(requestCode == 12 && resultCode == Activity.RESULT_OK){
// get the boolean data returned from the Popout Activity
boolean deleted = data.getBooleanExtra("deleted_state" , false); //false is default if no value exists
}
}
In the Popout activity:
bnWipe.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
try {
File dir = getFilesDir();
File file = new File(dir, fileName);
boolean deleted = file.delete();
//send the result to onActivtyResult() in MainActivity
Intent result = new Intent();
result.putExtra("deleted_state", deleted );
setResult(Activity.RESULT_OK, result);
Toast.makeText(getBaseContext(),"file has been deleted",Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(getBaseContext(), e.getMessage(), Toast.LENGTH_LONG).show();
}
finish();
}
});
UPDATE:
It will be like this:
// get the boolean data returned from the Popout Activity
boolean deleted = data.getBooleanExtra("deleted_state" , false);
if (deleted){
tvFileOP.setText("");
}
..........

As far as what if Understood your problem correctly: You want to control your 'Wipe' button click event from your activity. Here is the solution which may help you.
1: Make an overridden constructor of your dialog class.
2: Create one abstract method in the dialog class. (say - onWipeButtonClick)
You need to make your dialog class abstract as well.
3: Inside on Click Listener of 'Wipe' button, call onWipeButtonClick abstract method.
4: Create the instance of dialog in the main activity where ever you want. The compiler will give you an error because you haven't implemented the call back method.
do implement your onWipeButtonClick method and do needful for wipe data inside the method.
public abstract class WipeDialog extends Dialog{
private Context context;
public WipeDialog(Context context){
this.context = context;
}
public abstract void onWipeButtonClick(boolean isTextEmpty);
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.<XML_FILE>);
<initialization>
btnWipe.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
onWipeButtonClick(<YOUR_BOOLEAN_CHECK>);
}
});
}
}
And now in Activity:
WipeDialog dialog = new WipeDialog(MainActivity.this) {
#Override
public void onWipeButtonClick(boolean isTextEmpty) {
//Do Need full with respected to your requirement on click of button 'WIPE'
}
};
Hope this will help.
Thanks!

Multiple Instances and Multiple Activities calling the same Activity

I have three Activities. MainActivity,ActivityB and ActivityC. In activity A and B there are two buttons source and destination in both activities. in Activity C there is a list of data. when button is clicked (either Source or destination) from activity A and B. both Activities are calling Activity C
code for Activity A is following
public class MainActivity extends Activity {
TextView source,destination;
Button sendSource,sendDestination,btnTob;
String src,des,activity,checksrc,checkdes;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
source=(TextView)findViewById(R.id.tv_rcvDataA);
destination=(TextView)findViewById(R.id.tv_rcvDataAa);
sendSource=(Button)findViewById(R.id.btn_sendA);
sendDestination=(Button)findViewById(R.id.btn_sendAa);
btnTob=(Button)findViewById(R.id.btn_toB);
sendSource.setText("source");
sendDestination.setText("destination");
src=sendSource.getText().toString();
des=sendDestination.getText().toString();
activity=getClass().getSimpleName();
sendSource.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent send= new Intent(MainActivity.this,ActivityC.class);
send.putExtra("source",src);
send.putExtra("Activity",activity);
startActivity(send);
}
});
sendDestination.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent senda= new Intent(MainActivity.this,ActivityC.class);
senda.putExtra("destination",des);
senda.putExtra("Activity",activity);
startActivity(senda);
}
});
btnTob.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent movetoB= new Intent(MainActivity.this,ActivityB.class);
startActivity(movetoB);
finish();
}
}); }}
and code for Activity B is
public class ActivityB extends Activity {
TextView sourceB,destinationB;
Button sendSourceB,sendDestinationB;
String src,des,activity,checksrc,checkdes;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_b);
sourceB=(TextView)findViewById(R.id.tv_rcvDataB);
destinationB=(TextView)findViewById(R.id.tv_rcvDataBa);
sendSourceB=(Button)findViewById(R.id.btn_sendB);
sendDestinationB=(Button)findViewById(R.id.btn_sendDataBa);
activity=getClass().getSimpleName();
sendDestinationB.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent senda= new Intent(ActivityB.this,ActivityC.class);
senda.putExtra("destination",src);
senda.putExtra("Activity",activity);
startActivity(senda);
}
});
sendSourceB.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent send= new Intent(ActivityB.this,ActivityC.class);
send.putExtra("source",src);
send.putExtra("Activity",activity);
startActivity(send);
}
});}}
now how to check in activityC which activity is calling this activity and which buttonclicklistener is calling the intent

You need to send the value for determine what value and what activity via Intent.putExtra(). Please be remember that you need to set the key as the first parameter for Intent.putExtra(), like
intent.putExtra(THIS_IS_THE_KEY, THIS_IS_YOUR_VALUE);
You need to create something like this:
// This is the key for your putExtra
// you need to create this as global variable.
public static final String FROM_KEY = "FROM";
public static final String ACTIVITY_KEY = "ACTIVITY";
public static final boolean IS_FROM_SOURCE = true;
// This is a sample to send data to Activity C
// where the activity caller is B and from source
Intent senda= new Intent(ActivityB.this,ActivityC.class);
senda.putExtra(FROM_KEY, IS_FROM_SOURCE);
senda.putExtra(ACTIVITY_KEY,"activity_a");
Then in your Activity C, you need to receive the Intent Extra.
You can get the value in Activity onCreate(), something like this:
Bundle extras = getIntent().getExtras();
boolean from = extras.getBoolean(FROM_KEY);
String act = extras.getString(ACTIVITY_KEY);
// do something here if from activity a
if(act.equals("activity_a")) {
if(IS_FROM_SOURCE) {
// do something if from source
} else {
// do something if from destination.
}
} else { // if from activity a
if(IS_FROM_SOURCE) {
// do something if from source
} else {
// do something if from destination.
}
}

In onCreate or anytime after that method is called in Activity-C, you should do the following:
Intent intent = getIntent();
if (intent != null) {
String activity = intent.getStringExtra("Activity");
String src = intent.getStringExtra("source");
// Do something with those values
}

onActivityResult not getting string out of Intent

I need some help with my android app. I have two activities, first starts the second one with startActivityForResult(). When the second one closes it sends the intent as it should, however when i want to access extra from onActivityResult() i get a null instead of what I put in.
I also tried using bundle with
Bundle b = getIntent().getExtras();
b.getString(AddTable.EXTRA_NAME);
but it resulted in RuntimeException and failure delivering result.
Here's my code:
public class RunnerApp extends Activity {
private ListView listView;
private static ArrayList<String> values = new ArrayList<String>();
private ArrayAdapter<String> adapter;
private Intent newTable;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_runner_app);
listView = (ListView) findViewById(R.id.mylist);
adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, android.R.id.text1, values);
listView.setAdapter(adapter);
}
public void addTable(View v){
newTable = new Intent(this, AddTable.class);
startActivityForResult(newTable, 1);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
super.onActivityResult(requestCode, resultCode, data);
if(requestCode == 1 && resultCode == Activity.RESULT_OK && data != null){
data = getIntent();
Log.d("add", "got intent");
String newName = data.getStringExtra(AddTable.EXTRA_NAME);
Log.d("add", "string " + newName); //always prints string null
values.add(newName);
Log.d("add", "added to list");
}
}
#Override
public void onResume(){
super.onResume();
setContentView(R.layout.activity_runner_app);
adapter.notifyDataSetChanged();
}
}
Second activity started by startActivityForResult()
public class AddTable extends Activity {
public final static String EXTRA_NAME = "com.example.runnerapp.NAME";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_table);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_add_table, menu);
return true;
}
public void addThisTable(View v) {
Intent addTable = new Intent(this, RunnerApp.class);
EditText editText = (EditText) findViewById(R.id.addTableField);
String name = editText.getText().toString();
addTable.putExtra(EXTRA_NAME, name);
Log.d("intenyt", name);
setResult(Activity.RESULT_OK, addTable);
this.finish();
}
}

In your first activity your code reads
data = getIntent();
But the actual data you want is in
data.getData()

use this in the onActivityResult function..
data.getStringExtra(EXTRA_NAME)

How to create a login page as always be logged in if once logged in?

I have a login page for my project.Here my requirement is,that login page always want to be logged-in,if once i log in.I have got some ideas through Google,ie., it recommended me to use shared-preference concept,right now i am following this concept and i have tried some code.
In my project the problem is after giving the proper username and password,it does not switch to another screen,at the same i am getting nothing on my log-cat too.How to achieve this concept?
Suggestions please..
please find my sources for reference
class SaveSharedPreferece
public class SaveSharedPreference
{
static final String PREF_USER_NAME= "username";
static SharedPreferences getSharedPreferences(Context ctx) {
return PreferenceManager.getDefaultSharedPreferences(ctx);
}
public static void setUserName(Context ctx, boolean userName)
{
Editor editor = getSharedPreferences(ctx).edit();
editor.putBoolean(PREF_USER_NAME, userName);
editor.commit();
}
public static String getUserName(Context ctx)
{
return getSharedPreferences(ctx).getString(PREF_USER_NAME, "");
}}
MainActivity.java
public class MainActivity extends Activity
{
Button btn;
EditText edt1,edt2;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
public void loginpage()
{
edt1 = (EditText)findViewById(R.id.editText_username);
edt2 = (EditText)findViewById(R.id.editText_password);
btn = (Button)findViewById(R.id.button_login);
btn.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
if(edt1.getText().toString().length()!=0 && edt1.getText().toString().length()!=0)
{
Intent intvar = new Intent(v.getContext(), ResultActivity.class);
startActivity(intvar);
}
else
{
Toast.makeText(getApplicationContext(), "oops! empty..", Toast.LENGTH_SHORT).show();
}
}
});
if(SaveSharedPreference.getUserName(MainActivity.this).length() == 0)
{
// call Login Activity
loginpage();
}
else
{
// Call Next Activity
}
if (getIntent().getBooleanExtra("EXIT", false))
{
finish();
}
}
}
ResultActivity.java
public class ResultActivity extends Activity
{
Button btn_exit;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main1);
btn_exit = (Button)findViewById(R.id.button_exit);
btn_exit.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
Intent intent = new Intent(ResultActivity.this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.putExtra("EXIT", true);
startActivity(intent);
}
});
}}
thanks for your precious time!..

You are saving boolean to SharedPreferences and getting String. How that is possible.
Better to save and get either boolean or String.
Change your setUserName() code in SaveSharedPreference class as below and it works
public static void setUserName(Context ctx, String userName)
{
Editor editor = getSharedPreferences(ctx).edit();
editor.putString(PREF_USER_NAME, userName);
editor.commit();
}

First add another field in SharedPrefernce file as password. Do same whatever you have done foe username(make it string instead of boolean in setter method) like setter and getter methods.
Create one method which will fetch values from sharedPrefernce like this :
private void validateUser(){
String username = SaveSharedPreference.getUserName(MainActivity.this);
String password = SaveSharedPreference.getPassword(MainActivity.this);
if (check_for_any_condition){
Intent intvar = new Intent(v.getContext(), ResultActivity.class);
startActivity(intvar);
}
}
Call this method in your oncreate method.
Hope it will help you.