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Send data from one activity to another

I want sent the content of the variable indicatorpositionstart of main2Activity to mainActivity. I used the solution "extra", but does not work.
What's the problem?
public class Main2Activity extends AppCompatActivity {
private Button imageValidate;
int indicatorPositionStart = 1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
imageValidate = findViewById(R.id.buttonValidate);
imageValidate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent intent2 = new Intent(Main2Activity.this, MainActivity.class);
intent2.putExtra("indicatorPositionStartt", indicatorPositionStart );
startActivity(intent2);
}
});
}
public class MainActivity extends AppCompatActivity{
int id = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.textView3);
if (id != 0) {
int id = getIntent().getExtras().getInt("indicatorPositionStartt", 0);
String indicatorPositionStart = String.valueOf(id);
textView.setText(indicatorPositionStart);
}
}
}
Thank you in advance.

The problem is that you are checking the value before you get them from the extras, see this lines on the second activity:
// you are using it here, before getting the value
if (id != 0) {
int id = getIntent().getExtras().getInt("indicatorPositionStartt", 0);
String indicatorPositionStart = String.valueOf(id);
textView.setText(indicatorPositionStart);
}
}
Another problem on the MainActivity is that you are not filling in the id field.
I fixed it, just replace this one with your second activity:
public class MainActivity extends AppCompatActivity{
int id = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.textView3);
// get the value first
id = getIntent().getExtras().getInt("indicatorPositionStartt", 0);
// then use it
if (id != 0) {
String indicatorPositionStart = String.valueOf(id);
textView.setText(indicatorPositionStart);
}
}
}

In your MainActivity, remove this check if (id !=0 ) because activity started you set the value of id =0 so if (id !=0 ) this if is never true.
For Sending Data:
Intent intent = new Intent(this, SecondActivity.class);
intent.putExtra("arg", YourData);
startActivity(intent);
For Receiving Data:
String data = getIntent().getExtras().getString("arg");
Update
remove if( id != 0) and use if(getIntent().hasExtra("indicatorPositionStartt"))
like this:
if (getIntent().hasExtra("indicatorPositionStartt")) {
int id = getIntent().getExtras().getInt("indicatorPositionStartt", 0);
String indicatorPositionStart = String.valueOf(id);
textView.setText(indicatorPositionStart);
}

app crashes while transferring data android

This is my code:
public class MainActivity extends AppCompatActivity {
ListView listView ;
ArrayList<String> StoreContacts, id;
Bundle bundle;
ArrayAdapter<String> arrayAdapter ;
Cursor cursor;
Intent intent;
String name, phonenumber ;
public static final int RequestPermissionCode = 1 ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView)findViewById(R.id.listview1);
StoreContacts = new ArrayList<String>();
id = new ArrayList<String>();
EnableRuntimePermission();
GetContactsIntoArrayList();
arrayAdapter = new ArrayAdapter<String>(
MainActivity.this,
R.layout.contact_items_listview,
R.id.textView, StoreContacts
);
listView.setAdapter(arrayAdapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
bundle =new Bundle();
/*SharedPreferences.Editor editor=getSharedPreferences("Suyash",MODE_PRIVATE).edit();
editor.putString("ID",id.get(i));
editor.apply();*/
intent = new Intent(MainActivity.this, SingleContact.class);
bundle.putString("ID",id.get(i));
intent.putExtra("ID",id.get(i));
startActivity(intent);
}
});
}
public void GetContactsIntoArrayList(){
cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null, null, null);
while (cursor.moveToNext()) {
id.add(cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone._ID)));;
name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
phonenumber = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
StoreContacts.add(name + " " + ":" + " " + phonenumber);
}
cursor.close();
}
public void EnableRuntimePermission(){
if (ActivityCompat.shouldShowRequestPermissionRationale(
MainActivity.this,
Manifest.permission.READ_CONTACTS))
{
Toast.makeText(MainActivity.this,"CONTACTS permission allows us to Access CONTACTS app", Toast.LENGTH_LONG).show();
} else {
ActivityCompat.requestPermissions(MainActivity.this,new String[]{
Manifest.permission.READ_CONTACTS}, RequestPermissionCode);
}
}
#Override
public void onRequestPermissionsResult(int RC, String per[], int[] PResult) {
switch (RC) {
case RequestPermissionCode:
if (PResult.length > 0 && PResult[0] == PackageManager.PERMISSION_GRANTED) {
Toast.makeText(MainActivity.this,"Permission Granted, Now your application can access CONTACTS.", Toast.LENGTH_LONG).show();
} else {
Toast.makeText(MainActivity.this,"Permission Canceled, Now your application cannot access CONTACTS.", Toast.LENGTH_LONG).show();
}
break;
}
}
}
on receiving end:
public class SingleContact extends AppCompatActivity {
Bundle bundle=getIntent().getExtras();
//SharedPreferences preferences=getSharedPreferences("Suyash",MODE_PRIVATE);
0String string = bundle.getString("ID",null);
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_single_contact);
button= (Button) findViewById(R.id.button);
//string= bundle.getString("ID");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(SingleContact.this, string, Toast.LENGTH_SHORT).show();
}
});
}
}
the crashes when I click the item.
i have tried sharedpreference too, it does the same thing. im using android studio 2.3.3.
anyone suggest what i should do.
please help

You can not get the bundle before onCreate(). Write your code something like below and it will resolve your error.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_single_contact);
// Your bundle code.
Bundle bundle=getIntent().getExtras();
String string = bundle.getString("ID",null);
}

Probably wrong initialization of bundle data in SingleContact Activity, you should initialise inside of onCreate method
public class SingleContact extends AppCompatActivity {
Bundle bundle;
String string;
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_single_contact);
bundle = getIntent().getExtras()
button= (Button) findViewById(R.id.button);
string= bundle.getString("ID");
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(SingleContact.this, string, Toast.LENGTH_SHORT).show();
}
});
}
}

savedInstanceState causing a crash while screen rotation

public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE="com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN="com.example.ferhat.geoquiz.answer_shown";
private static final String CHEATER="com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mIsCheater;
public static Intent newIntent(Context packageContext, boolean answerIsTrue){
Intent i=new Intent(packageContext,CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE,answerIsTrue);
return i;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
mIsCheater=true;
setAnswerShownResult();
}
});
if(savedInstanceState!=null){
mIsCheater=savedInstanceState.getBoolean(CHEATER,false);
}
}
private void setAnswerShownResult(){
Intent data=new Intent();
data.putExtra(EXTRA_ANSWER_SHOWN,mIsCheater);
setResult(RESULT_OK,data);
}
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER,mIsCheater);
}
}
I try to solve challenge in Anroid Programming, Big Nerds Ranch Guide (Chap.5)
Challenge asks me to keep Cheat data while rotation of screen and transaction between questions.Main Activity holds questions and CheatActivity has answers from Main activity. And i created BooleanArray to hold cheat data for questions.
Problem is ,i cheated for first question and then when i am in the CheatActivity(CheatPage) of other questions ,program crashes if i rotate the screen.
Error caused by this line savedInstanceState.putBoolean(CHEATER,mIsCheater);
i think i need to clear data from previous Cheat Data(BooleanArray already holding it) but i dont know how to do it.

public class CheatActivity extends AppCompatActivity {
private static final String EXTRA_ANSWER_IS_TRUE = "com.example.ferhat.geoquiz.answer_is_true";
public static final String EXTRA_ANSWER_SHOWN = "com.example.ferhat.geoquiz.answer_shown";
public static final String EXTRA_CHEATED = "com.example.ferhat.geoquiz.cheated";
private static final String CHEATER = "com.example.ferhat.geoquiz.cheated";
private Boolean mAnswerIsTrue;
private TextView mAnswerTextView;
private Button mShowAnswer;
private Boolean mAnswerEverShown;
private Boolean twoStep=false;
//Yeni intent methodu yarattık Cevabı alıyor ve bu activity i başlatıyor
public static Intent newIntent(Context packageContext, boolean answerIsTrue, boolean checked) {
Intent i = new Intent(packageContext, CheatActivity.class);
i.putExtra(EXTRA_ANSWER_IS_TRUE, answerIsTrue);
i.putExtra(EXTRA_CHEATED, checked);
return i;
}
private void setAnswerShownResult(Boolean isAnswerShown) {
Intent data = new Intent();
**if(mAnswerEverShown) {
isAnswerShown=mAnswerEverShown;
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}else {
data.putExtra(EXTRA_ANSWER_SHOWN, isAnswerShown);
setResult(RESULT_OK, data);
}
twoStep=isAnswerShown;**
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_cheat);
mAnswerIsTrue = getIntent().getBooleanExtra(EXTRA_ANSWER_IS_TRUE, false);
mAnswerTextView = (TextView) findViewById(R.id.answerTextView);
**mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);**
mShowAnswer = (Button) findViewById(R.id.showAnswerButton);
mShowAnswer.setOnClickListener(new View.OnClickListener() {
//Cevabı gösteriyor ve Kopya çekildi bilgisi veriliyor
#Override
public void onClick(View v) {
if (mAnswerIsTrue) {
mAnswerTextView.setText(R.string.true_button);
} else {
mAnswerTextView.setText(R.string.false_button);
}
twoStep=true;
setAnswerShownResult(twoStep);
}
});
**if (savedInstanceState != null) {
setAnswerShownResult(savedInstanceState.getBoolean(CHEATER, false));
}
}
#Override
public void onSaveInstanceState (Bundle savedInstanceState){
super.onSaveInstanceState(savedInstanceState);
savedInstanceState.putBoolean(CHEATER, twoStep);
}
}**
i found solution like for every situation.
first think i did; i get info from main activity
mAnswerEverShown = getIntent().getBooleanExtra(EXTRA_CHEATED, false);
And Then i changed setAnswerShownResult for two situation.If it is not cheated ever program sends current data(cheated or not).
i marked where i changed with *.

You need to putBoolean before callback the super method.
#Override
public void onSaveInstanceState(Bundle savedInstanceState){
savedInstanceState.putBoolean(CHEATER,mIsCheater);
super.onSaveInstanceState(savedInstanceState);
}
if not the CHEATER won't be saved and you can't call it when resume activity

Issues in SharedPreference

I have one button in mainactivity when i click on button formactivty opened then after saved the data and i killed the app it display from main activity, it doesn't show welcome activity by using shared preference. any one can solve this one
Main Activity
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void open(View v) {
Intent i = new Intent(MainActivity.this,Form.class);
startActivity(i);
}
}
FormActivty
public class Form extends Activity {
SharedPreferences sp;
public static String Filename= "LoginFile";
public static String key = "status";
EditText namee,emaill;
String Name,Email;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sp = getSharedPreferences(Filename,MODE_PRIVATE);
boolean res = sp.getBoolean(key,false);
if (res) {
setContentView(R.layout.welcom);
} else {
setContentView(R.layout.form);
}
}
public void save(View v) {
namee = (EditText)findViewById(R.id.name);
emaill = (EditText)findViewById(R.id.email);
Name = namee.getText().toString();
Email = emaill.getText().toString();
SharedPreferences.Editor ed = sp.edit();
ed.putBoolean(key,true);
ed.putString("k1",Name);
ed.putString("k2",Email);
ed.commit();
Intent i = new Intent(this,Welcome.class);
startActivity(i);
}
}
Welcome Activity
public class Welcome extends Activity {
SharedPreferences sp;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.welcom);
sp = getSharedPreferences(Form.Filename,MODE_PRIVATE);
TextView tv= (TextView)findViewById(R.id.text);
TextView tv1= (TextView)findViewById(R.id.text1);
String username,email;
Intent i = getIntent();
Bundle b = new Bundle();
b= i.getExtras();
username = sp.getString("k1","");
email = sp.getString("k2","");
tv.setText(username);
tv1.setText(email);
}
public void logout(View v) {
SharedPreferences.Editor ed = sp.edit();
ed.putBoolean(Form.key,false);
ed.commit();
Intent i = new Intent(this,MainActivity.class);
startActivity(i);
}
}

On your MainActivity, under onCreate(), there should be a code that checks if your SharedPreference is empty. If it's empty, it should go to Form.class or it should not do anything since you have a button there in MainActivity. If not, then go to Welcome.class. You're almost there, just do some minor tweaks on your code and you'll get it.
public class MainActivity extends AppCompatActivity {
SharedPreferences sp;
public static String Filename= "LoginFile";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sp = getSharedPreferences(Filename,MODE_PRIVATE);
String name = sp.getString("k1", "");
if(!name.isEmpty()){
Intent intent = new Intent(MainActivity.this, Welcome.class);
startActivity(intent);
}
}
public void open(View v) {
Intent i = new Intent(MainActivity.this,Form.class);
startActivity(i);
}
}
If you'll notice on this code, every time the app is killed and you start it again, it'll check if sharedpreference is empty. If not, it will go directly to Welcome.class.

Multiple startActivityForResult()

I need to call this function twice in my application pointing to two different activities. I have a unique request code for each call, however my app seems to crash everytime it launches the second activity.
Here is my code (only relevant parts):
MainActivity:
//Request Info vars
static final int GET_DETAILS = 1;
static final int EDIT_DETAILS = 2;
#Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
public void onMapClick(LatLng latLng) {
lat = latLng.latitude;
lon = latLng.longitude;
startActivityForResult(new Intent(MapsActivity.this,NewMarkerActivity.class), GET_DETAILS);
}
});
mMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
#Override
public void onInfoWindowClick(Marker marker) {
current_marker = marker;
startActivityForResult(new Intent(MapsActivity.this,EditMarkerActivity.class), EDIT_DETAILS);
}
});
}
#Override
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
if (requestCode == GET_DETAILS) {
if (resultCode == RESULT_OK) {
String marker_title=data.getStringExtra("title");
String marker_snippet = data.getStringExtra("snippet");
addMarker(lat, lon, marker_title, marker_snippet);
mMap.animateCamera(CameraUpdateFactory.newLatLng(new LatLng(lat, lon)));
}
} if (requestCode == EDIT_DETAILS) {
if (resultCode == RESULT_OK) {
String marker_title=data.getStringExtra("title");
String marker_snippet = data.getStringExtra("snippet");
current_marker.setTitle(marker_title);
current_marker.setSnippet(marker_snippet);
}
}
}
EditMarkerActivity:
public class EditMarkerActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.edit_marker_activity);
Button save_btn = (Button)findViewById(R.id.btn_save);
save_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
EditText editName = (EditText)findViewById(R.id.editName);
String marker_title = editName.getText().toString();
EditText editSnippet = (EditText)findViewById(R.id.editSnippet);
String marker_snippet = editSnippet.getText().toString();
Intent _result = new Intent();
_result.putExtra("title", marker_title);
_result.putExtra("snippet", marker_snippet);
setResult(Activity.RESULT_OK, _result);
finish();
}
});
}
}
NewMarkerActivity:
public class NewMarkerActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.new_marker_activity);
Button save_btn = (Button)findViewById(R.id.btn_save);
save_btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
EditText editName = (EditText)findViewById(R.id.editName);
String marker_title = editName.getText().toString();
EditText editSnippet = (EditText)findViewById(R.id.editSnippet);
String marker_snippet = editSnippet.getText().toString();
Intent _result = new Intent();
_result.putExtra("title", marker_title);
_result.putExtra("snippet", marker_snippet);
setResult(Activity.RESULT_OK, _result);
finish();
}
});
}
}
Any obvious issues? Help or insight to this problem will be greatly appreciated :)
Here is my output from Logcat:
android.content.ActivityNotFoundException: Unable to find explicit activity class {com.geekybrackets.virtualtourguide/com.geekybrackets.virtualtourguide.EditMarkerActivity}; have you declared this activity in your AndroidManifest.xml?

Turns out the issue was that I hadn't defined the activity in the manifest file.
Dear old me, now i know to check my errors !
Thanks again guys, case closed.