We Keep Coding

How to add String list view ArrayAdapter<String>

am scan Qr code/Barcode, so I want to scan different qr code/barcode and arrange them is String listview.
Example I want to setText() like this ,scanNumber1,scanNumber2,....,..., so far i have managed to scan that Qr Code/Barcode but when i scan the next number it remove the first one, so I want ti arrange those number.
here is my code
public void scanCode(View view){
IntentIntegrator intentIntegrator = new IntentIntegrator(this);
intentIntegrator.initiateScan();
}
#Override
protected void onActivityResult(int requestCode, int resultCode, #Nullable Intent data) {
IntentResult intentResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
String scanNumber=intentResult.getContents();
if (intentResult != null) {
if(intentResult.getContents() == null) {
Toast toast = Toast.makeText(getApplicationContext(), "Scan The QR code/Barcode", Toast.LENGTH_LONG);
toast.show();
}
//validate ur scan numbers
else if (intentResult.getContents().length() == 10) {
textView1.setText(intentResult.getContents());
}
else if(intentResult.getContents().length() == 12){
textView2.setText(intentResult.getContents());
}
else {
Toast toast = Toast.makeText(getApplicationContext(), "That Number is Out Of Our Range", Toast.LENGTH_LONG);
toast.show();
}
}
super.onActivityResult(requestCode, resultCode, data);
}
and this is output
so I want on that Slave to appear like ,scanNumber1,scanNumber2,....,...,

you can use a global JointoString function object to achieve the desired behaviour i.e. "barcode1","barcode2"....
ArrayList<String> results = new ArrayList<String>()
when you receive the result try
results.add(<value>)
while displaying to text view use
textView.setText(results.joinToString(","))

Error When Trying To Pick A contact and Show its Number in a TextBox in Android

First of all sorry for my Bad English
i'm new To Android development.
I'm trying to develop this App in which user can click on a button and the Contacts will show up and then can pick one and only one one of the Contacts and show its number in a textbox.
But i face this Error every time :
"Couldn't read row 0, col -1 from CursorWindow. Make sure the Cursor
is initialized correctly before accessing data from it"
and The Funny thing is when i use HAS_PHONE_NUMBER it returns 1 which means the Contact has Phone Number.
and when i use DISPLAY_NAME it returns contact name without any problem.
but when i use NUMBER that Error shows Up!
can anyone help me?
BTW i use Fragment if it helps..?
and this is my code :
#Override
public void onClick(View v) {
if (v.getId() == R.id.btnContact) {
Intent intent = new Intent(Intent.ACTION_PICK, ContactsContract.Contacts.CONTENT_URI);
startActivityForResult(intent, PICK_CONTACT); }
}
private Uri uriContact;
private String contactID; // contacts unique ID
#Override
public void onActivityResult(int reqCode, int resultCode, Intent data) {
super.onActivityResult(reqCode, resultCode, data);
switch (reqCode) {
case (PICK_CONTACT):
if (resultCode == Activity.RESULT_OK) {
Uri contactData = data.getData();
Cursor phone = getActivity().getContentResolver().query(contactData, null, null, null, null);
phone.moveToFirst();
if (phone.moveToFirst()) {
String num = phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
// Todo something when contact number selected
placeholderNumber.setText("" + num);
}
}
break;
}
}

How can I iterate through an Arraylist in android studio

I am making an android studio app and I want it to make a TextView disappear when I say a certain phrase. The code saves everything I say into an array list. I want to see if it includes the phrase.
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode){
case 100:
if (resultCode == RESULT_OK && data != null){
ArrayList<String> result = data.getStringArrayListExtra(RecognizerIntent.EXTRA_RESULTS);
boolean yes = Arrays.asList(result.get(0)).contains(InputActivity.Item1);
if(yes == true){
result1.setVisibility(View.GONE);
}
}
break;
}
}

Use
for(String s:result){
if(s.equals(InputActivity.Item1)){
//hide text view
}
}

Nullpointerexception - while Passing data via intents

I am having an issue where I can not sort out the NullPointerException (NPE) that I am getting.
Here is my MainActivity code
public void onActivityResult(int requestCode, int resultCode, Intent data) {
IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
String bccode = result.getContents();
if(result != null) {
if(result.getContents() == null) {
Toast.makeText(this, "Cancelled", Toast.LENGTH_LONG).show();
} else {
Intent sendBarCode= new Intent(MainActivity.this, showdata.class);
sendBarCode.putExtra("barccode", bccode);
startActivity(sendBarCode);
startActivity(new Intent(MainActivity.this, showdata.class));
}
} else {
super.onActivityResult(requestCode, resultCode, data);
}
}
And my class that receives it showdata.class:
public String barcode = getIntent().getStringExtra("barccode");
The exact error:
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.content.Intent.getStringExtra(java.lang.String)' on a null object reference
This particular NPE has me a bit perplexed as I have followed all the instructions I can find online.

So, you're calling startActivity twice, once with the data and once with a new Intent which will not have any data..

Protect from NPE
final Intent intent = getIntent();
if (intent != null) {
...
}
else {
Log.d(TAG, "No intent");
}

TRY This out in the showdata class.
public String barcode = null;
Intent i = getIntent();
barcode =i.getStringExtra("barccode");

App crash when picking a contact from REQUEST_CONTACTPICKER

Following this solution I have run into an issue with the code presented. The app forces a close every time I pick a contact from the list that pops up. Something tells me the culprit has something to do with this which I found in logcat.
Here is my version of the code:
public void onActivityResult(int reqCode, int resultCode, Intent data) {
super.onActivityResult(reqCode, resultCode, data);
switch (reqCode) {
case (1) :
if (resultCode == Activity.RESULT_OK) {
Uri contactData = data.getData();
Cursor cursor = managedQuery(contactData, null, null, null, null);
cursor.moveToFirst();
String name = cursor.getString(cursor.getColumnIndexOrThrow(Contacts.People.NAME));
String number = cursor.getString(cursor.getColumnIndexOrThrow(Contacts.People.NUMBER));
name1.setText(name);
num1.setText(number);
}
break;
}
}
Take a look at the logcat