Notes

///////////
data
/////////
[Volley]
(insert.php)
<?php
$conn=mysqli_connect("localhost","root","","android_db");

$name=$_POST['t1'];
$uname=$_POST['t2'];
$pwd=$_POST['t3'];

$qry="INSERT INTO `tbl_user` (`id`, `name`, `username`, `password`) VALUES (NULL, '$name', '$uname', '$pwd')";
mysqli_query($conn,$qry);

echo "Inserted Successfully";

?>

private void Jsondatainsert() {

StringRequest request=new StringRequest(Request.Method.POST, webView.getUrl(), new Response.Listener<String>() {
@Override
public void onResponse(String response) {

}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {
Map<String,String> stringMap=new HashMap<String,String>();
stringMap.put("name","value");
stringMap.put("namse","valuess");
return stringMap;
}
};
RequestQueue requestQueue= Volley.newRequestQueue(getApplicationContext());
requestQueue.add(request);
}

(Select.php)
<?php
$conn
$result=array();
$result['data']=array();
$qry="select*from table";
$resp=mysqli_query($conn,$qry);
while($row=mysqli_fetch_array($resp))
{
$index['id']=$row['0'];
[''name]=['1'];
array_push($result['$data'],$index);

}
$result["success"]="1"
echo json_encode[$result];
?>

TextView mTextViewResult;
private RequestQueue mQueue;
StringRequest request;
String url = "http://192.168.0.103/PhpProject1/retrive.php";

ListView lstv;
ArrayList<String> list;
lstv = findViewById(R.id.lstv);
registerForContextMenu(lstv);

private void Showdata() {

request = new StringRequest(Request.Method.GET, url, new Response.Listener<String>() {
@Override
public void onResponse(String response) {

try {

JSONObject object = new JSONObject(response);
//Arraylist
list = new ArrayList<String>();
JSONArray jsonArray = object.getJSONArray("data");
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject employee = jsonArray.getJSONObject(i);

String id = employee.getString("id");
String name = employee.getString("name");
String contact = employee.getString("contact");

list.add(id + "," + name + "," + contact);
// mTextViewResult.append(id + ", " + name + ", " + contact + "nn");
}
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getApplicationContext(), android.R.layout.simple_list_item_1, list);
lstv.setAdapter(adapter);

} catch (JSONException e) {
e.printStackTrace();

}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
error.printStackTrace();
}
});
mQueue.add(request);
}

(delete.php)
<?php
$connection = mysqli_connect("localhost","id11477192_arsltech","12345678","id11477192_employee_management_system");
$id = $_POST["id"];
$sql = "DELETE FROM data WHERE id='$id'";
$result = mysqli_query($connection,$sql);
if($result){echo "Data Deleted";}
?>
private void deleteData(final String id) {

StringRequest request = new StringRequest(Request.Method.POST, "https://arsltechmysql.000webhostapp.com/delete.php",
new Response.Listener<String>() {
@Override
public void onResponse(String response) {

if(response.equalsIgnoreCase("Data Deleted")){
Toast.makeText(MainActivity.this, "Data Deleted Successfully", Toast.LENGTH_SHORT).show();
}
else{
Toast.makeText(MainActivity.this, "Data Not Deleted", Toast.LENGTH_SHORT).show();
}


}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(MainActivity.this, error.getMessage(), Toast.LENGTH_SHORT).show();
}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {

Map<String,String> params = new HashMap<String,String>();
params.put("id", id);
return params;
}
};

RequestQueue requestQueue = Volley.newRequestQueue(this);
requestQueue.add(request);


}

(update.php)

<?php

$connection = mysqli_connect("localhost","id11477192_arsltech","12345678","id11477192_employee_management_system");
$id = $_POST["id"];
$name = $_POST["name"];
$email = $_POST["email"];
$contact = $_POST["contact"];
$address = $_POST["address"];

$sql = "UPDATE data SET name = '$name', email = '$email', contact = '$contact', address = '$address' WHERE id = '$id' ";
$result = mysqli_query($connection,$sql);
if($result){echo "Data Updated";}
?>

StringRequest request = new StringRequest(Request.Method.POST, "https://arsltechmysql.000webhostapp.com/update.php",
new Response.Listener<String>() {
@Override
public void onResponse(String response) {

Toast.makeText(Edit_Activity.this, response, Toast.LENGTH_SHORT).show();
startActivity(new Intent(getApplicationContext(),MainActivity.class));
finish();
progressDialog.dismiss();
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {

Toast.makeText(Edit_Activity.this, error.getMessage(), Toast.LENGTH_SHORT).show();
progressDialog.dismiss();

}
}){
@Override
protected Map<String, String> getParams() throws AuthFailureError {

Map<String,String> params = new HashMap<String,String>();

params.put("id",id);
params.put("name",name);
params.put("email",email);
params.put("contact",contact);
params.put("address",address);

return params;
}
};

RequestQueue requestQueue = Volley.newRequestQueue(Edit_Activity.this);
requestQueue.add(request);

}
==================================================================================================================
[TelephonyManager]
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
-----------------------------------------------------------------------
tele =(TextView) findViewById(R.id.tele);

TelephonyManager tm = (TelephonyManager) getSystemService(Context.TELEPHONY_SERVICE);

String IMEINumber = tm.getDeviceId();
String subscriberID = tm.getDeviceId();
String SIMSerialNumber = tm.getSimSerialNumber();
String networkCountryISO = tm.getNetworkCountryIso();
String SIMCountryISO = tm.getSimCountryIso();
String softwareVersion = tm.getDeviceSoftwareVersion();
String voiceMailNumber = tm.getVoiceMailNumber();

String strphoneType="";

int phoneType=tm.getPhoneType();

switch (phoneType)
{
case (TelephonyManager.PHONE_TYPE_CDMA):
strphoneType="CDMA";
break;
case (TelephonyManager.PHONE_TYPE_GSM):
strphoneType="GSM";
break;
case (TelephonyManager.PHONE_TYPE_NONE):
strphoneType="NONE";
break;
}

boolean isRoaming=tm.isNetworkRoaming();

String info="Phone Details:n";
info+="n IMEI Number:"+IMEINumber;
info+="n SubscriberID:"+subscriberID;
info+="n Sim Serial Number:"+SIMSerialNumber;
info+="n Network Country ISO:"+networkCountryISO;
info+="n SIM Country ISO:"+SIMCountryISO;
info+="n Software Version:"+softwareVersion;
info+="n Voice Mail Number:"+voiceMailNumber;
info+="n Phone Network Type:"+strphoneType;
info+="n In Roaming? :"+isRoaming;

tele.setText(info);

[NOtification]
private void ControlInitialization()
{
btnNotification =(Button) findViewById(R.id.btnNotification);
btnNotification.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {

NotificationCompat.Builder builder = new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.drawable.ic_launcher_foreground)
.setContentTitle("Notification Demo")
.setContentText("This is notification demo")
.setAutoCancel(true)
.setPriority(NotificationCompat.PRIORITY_DEFAULT);

Intent objIntent = new Intent(getApplicationContext(),NotificationViewActivity.class);
objIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
objIntent.putExtra("message","Hello...Good Morning Everyone");

PendingIntent pi = PendingIntent.getActivity(getApplicationContext(),0,objIntent,
PendingIntent.FLAG_UPDATE_CURRENT);
builder.setContentIntent(pi);

NotificationManager nm = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
nm.notify(0,builder.build());
}
});
}
[Downloadmanager]
btnDown=findViewById(R.id.btnDownload);


if(ActivityCompat.checkSelfPermission(ActivityDownloadFile.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED
|| ActivityCompat.checkSelfPermission(ActivityDownloadFile.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){

// this will request for permission when user has not granted permission for the app
ActivityCompat.requestPermissions(ActivityDownloadFile.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
}

else{
DownloadManager downloadmanager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
Uri uri = Uri.parse("http://utu.ac.in/bmiit/download/2021-22/Sem7/060010715_LP.pdf");
DownloadManager.Request request = new DownloadManager.Request(uri);
request.setTitle("My File");
request.setDescription("Downloading");
request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED);
request.setDestinationUri(Uri.parse("file://Download/myfile.mp3"));
downloadmanager.enqueue(request);
}

[Contactprovider]
<uses-permission android:name="android.permission.READ_CONTACTS"/>
ListView list;
ArrayList list1;

list=findViewById(R.id.qwe1);
list1=new ArrayList();

//run time permission
if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS)!= PackageManager.PERMISSION_GRANTED)
{
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_CONTACTS},0);
}
else
{
Cursor phone=getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null);
while(phone.moveToNext())
{
String name=phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
String no=phone.getString(phone.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

//To store number and name we declare arraylist

list1.add(name+"n"+no);

}

//Use ARRAYadapter

ArrayAdapter adapter=new ArrayAdapter(MainActivity.this, android.R.layout.simple_list_item_1,list1);
list.setAdapter(adapter);
}

[Database sqlite]
(DBhelper.class)
public class DBhelper extends SQLiteOpenHelper {
public DBhelper(@Nullable Context context) {
super(context, "Userdata.db", null, 1);
}

@Override
public void onCreate(SQLiteDatabase DB) {
DB.execSQL("create Table Userdetails(txtEdit TEXT primary key, txtEmail TEXT)");
}

@Override
public void onUpgrade(SQLiteDatabase DB, int i, int i1) {
DB.execSQL("drop Table if exists Userdetails");
}

public Boolean insertuserdata(String txtEdit, String txtEmail)
{
SQLiteDatabase DB = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("txtEdit", txtEdit);
contentValues.put("txtEmail", txtEmail);
long result=DB.insert("Userdetails", null, contentValues);
if(result==-1){
return false;
}else{
return true;
}
}


public Boolean updateuserdata(String txtEdit, String txtEmail) {
SQLiteDatabase DB = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put("txtEmail", txtEmail);
Cursor cursor = DB.rawQuery("Select * from Userdetails where txtEdit = ?", new String[]{txtEdit});
if (cursor.getCount() > 0) {
long result = DB.update("Userdetails", contentValues, "txtEdit=?", new String[]{txtEdit});
if (result == -1) {
return false;
} else {
return true;
}
} else {
return false;
}}


public Boolean deletedata (String txtEdit)
{
SQLiteDatabase DB = this.getWritableDatabase();
Cursor cursor = DB.rawQuery("Select * from Userdetails where txtEdit = ?", new String[]{txtEdit});
if (cursor.getCount() > 0) {
long result = DB.delete("Userdetails", "txtEdit=?", new String[]{txtEdit});
if (result == -1) {
return false;
} else {
return true;
}
} else {
return false;
}

}

public Cursor getdata ()
{
SQLiteDatabase DB = this.getWritableDatabase();
Cursor cursor = DB.rawQuery("Select * from Userdetails", null);
return cursor;

}
}
(mainactivity)
Button insert,update,select,delete;
DBhelper db;

db=new DBhelper(this);
insert.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String nameTXT=txtEdit.getText().toString();
String emailTXT=txtEmail.getText().toString();

Boolean aBoolean=db.insertuserdata(nameTXT,emailTXT);
if(aBoolean=true)
{
Toast.makeText(getApplicationContext(), "insert Success", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(getApplicationContext(), "problem", Toast.LENGTH_SHORT).show();
}
}
});
update.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String nameTXT=txtEdit.getText().toString();
String emailTXT=txtEmail.getText().toString();

Boolean updateaBoolean=db.updateuserdata(nameTXT,emailTXT);
if(updateaBoolean=true)
{
Toast.makeText(getApplicationContext(), "Updated Success", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(getApplicationContext(), "Updated problem", Toast.LENGTH_SHORT).show();
}
}
});
delete.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
String nameTXT=txtEdit.getText().toString();


Boolean checkdeletedata=db.deletedata(nameTXT);
if(checkdeletedata=true)
{
Toast.makeText(getApplicationContext(), "Deleted Success", Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(getApplicationContext(), "Deleted problem", Toast.LENGTH_SHORT).show();
}
}
});
select.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Cursor res=db.getdata();
if(res.getCount()==0)
{
Toast.makeText(getApplicationContext(), "NOentry exists", Toast.LENGTH_SHORT).show();
return;
}
StringBuffer buffer=new StringBuffer();

while (res.moveToNext())
{
buffer.append(res.getString(0)+"n");
buffer.append(res.getString(1)+"n");
}
AlertDialog.Builder builder=new AlertDialog.Builder(MainActivity.this);
builder.setCancelable(true);
builder.setMessage(buffer.toString());
builder.show();
}
});
//////////////////////////////////
[spineer]
(Dropdown menu)
<Spinner
android:id="@+id/dropdown"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:spinnerMode="dropdown" />

String[] items;
String dropdownvaluess;
items=new String[]{"First","Second","Last"};

ArrayAdapter<String> adapter=new ArrayAdapter<>(this, android.R.layout.simple_spinner_dropdown_item,items);
dropdown.setAdapter(adapter);

dropdown.setOnItemSelectedListener(this);

dropdownvaluess=adapterView.getItemAtPosition(i).toString();

switch (i)
{
case 0:
Toast.makeText(getApplicationContext(), "First Item selected", Toast.LENGTH_SHORT).show();
break;
case 1:
Toast.makeText(getApplicationContext(), "Second Item selected", Toast.LENGTH_SHORT).show();
break;
case 2:
Toast.makeText(getApplicationContext(), "Last Item selected", Toast.LENGTH_SHORT).show();
break;
}

---------
[radio Button]
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">

<RadioGroup
android:id="@+id/radiogrp"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<RadioButton
android:id="@+id/radiobtn1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:checked="true"
android:text="Male" />
<RadioButton
android:id="@+id/radiobtn2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Female" />
</RadioGroup>
</LinearLayout>

if(radiogrp!=null)
{
radiogrp.setOnCheckedChangeListener(this);
}

@Override
public void onCheckedChanged(RadioGroup radioGroup, int i) {
text="You selected:";
text +=(R.id.radiobtn1==i) ?"Male":"Female";
Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show();

}

------------
[WebView]
webView.setWebViewClient(new MYBrowser());
webView.getSettings().setJavaScriptEnabled(true);
webView.getSettings().setLoadsImagesAutomatically(true);
webView.loadUrl(txtEdit.getText().toString());

private static class MYBrowser extends WebViewClient {

@Override
public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
return super.shouldOverrideUrlLoading(view, request);
}
}
----------
[Serachview]
String[] demos;
demos=getResources().getStringArray(R.array.data);
adapter1=new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,demos);

views.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
@Override
public boolean onQueryTextSubmit(String s) {
return false;
}

@Override
public boolean onQueryTextChange(String s) {
adapter1.getFilter().filter(s);
return false;
}
});
------------
[Context menu]
<TextView
android:layout_marginTop="500dp"
android:id="@+id/menus"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Menu Context" />

registerForContextMenu(menus);
@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
super.onCreateContextMenu(menu, v, menuInfo);
menu.setHeaderTitle("Chose one");
menu.add(0,v.getId(),0,"Yellow");
menu.add(0,v.getId(),0,"Blue");
}

@Override
public boolean onContextItemSelected(@NonNull MenuItem item) {
if(item.getTitle()=="Yellow")
{
layout.setBackgroundColor(Color.YELLOW);
}
else if(item.getTitle()=="Blue")
{
layout.setBackgroundColor(Color.BLUE);
}
return true;

}
-----------
[internal storage]
private void internalstorage() {
String Filename="MyFile.txt";

try {
FileOutputStream stream=openFileOutput(Filename,MODE_APPEND);
OutputStreamWriter writer=new OutputStreamWriter(stream);
writer.write(txtEdit.getText().toString());
writer.flush();
writer.close();
Toast.makeText(getApplicationContext(), "Success File input", Toast.LENGTH_SHORT).show();
}
catch (FileNotFoundException e)
{

}
catch (Exception e){

}
}
private void ReadDataformStorage() {
String line,FileContact="";

try {
FileInputStream stream=openFileInput("MyFile.txt");
BufferedReader reader=new BufferedReader(new InputStreamReader(stream));
while((line=reader.readLine())!=null)
{
FileContact+=line;
txtEmail.setText(FileContact);
Toast.makeText(getApplicationContext(), "retrive data", Toast.LENGTH_SHORT).show();
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

}
------------------
[Gallery]
<Gallery
android:id="@+id/languagesGallery"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="100dp"
android:animationDuration="2000"
android:padding="10dp"
android:spacing="5dp"
android:unselectedAlpha="50" />

<ImageView
android:id="@+id/imageView"
android:layout_width="fill_parent"
android:layout_height="200dp"
android:scaleType="fitXY" />
public class CustomizedGalleryAdapter extends BaseAdapter {
private Context context;
private int[] images;

public CustomizedGalleryAdapter(Context c, int[] images) {
context = c;
this.images = images;
}

public int getCount() {
return images.length;
}

public Object getItem(int position) {
return position;
}

public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {

ImageView imageView = new ImageView(context);

imageView.setImageResource(images[position]);

imageView.setLayoutParams(new Gallery.LayoutParams(200, 200));
return imageView;
}
}

Gallery simpleGallery;
CustomizedGalleryAdapter customGalleryAdapter;
ImageView selectedImageView;

//to store image
int[] images = {R.drawable.img1,
R.drawable.img2, R.drawable.img3, R.drawable.img4, R.drawable.img5};


@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);

simpleGallery = findViewById(R.id.languagesGallery);
selectedImageView = findViewById(R.id.imageView);

//make new java file and extended baseadapter
customGalleryAdapter = new CustomizedGalleryAdapter(getApplicationContext(),images);
simpleGallery.setAdapter(customGalleryAdapter);

//to create setonclicklistener
simpleGallery.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
selectedImageView.setImageResource(images[position]);
}
});
------------
[permission]
if(ActivityCompat.checkSelfPermission(getApplicationContext(),Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, 1);
}
---------
[shape]
setContentView(new shape1(this));

public class shape1 extends View {
public shape1(Context context) {
super(context);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int x = canvas.getWidth()/2;
int y = canvas.getHeight()/2;
Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setColor(Color.WHITE);
canvas.drawColor(Color.GRAY);
Paint blackEar = new Paint(Paint.ANTI_ALIAS_FLAG);
Paint blackLine = new Paint(Paint.FAKE_BOLD_TEXT_FLAG);
blackLine.setStrokeWidth(10);
blackLine.setColor(Color.BLACK);

canvas.drawCircle(x,y,450,p);
canvas.drawCircle(x-350,y-350,150,blackEar);
canvas.drawCircle(x+350,y-350,150,blackEar);
canvas.drawLine(x,y,x-50,y+150,blackLine);
canvas.drawLine(x,y,x+50,y+150,blackLine);
canvas.drawLine(x-50,y+150,x+50,y+150,blackLine);

canvas.drawRect(x-175,y-150,x-150,y-100,blackLine);
canvas.drawRect(x+175,y-150,x+150,y-100,blackLine);
canvas.drawArc(new RectF(x-250,y+100,x+250,y+350),0,180,false,blackLine);

}
}
--------
[Validation]
if (email.getText().toString().isEmpty()) {
emailError.setError(getResources().getString(R.string.email_error));
isEmailValid = false;
}
else if (!Patterns.EMAIL_ADDRESS.matcher(email.getText().toString()).matches()) {
emailError.setError(getResources().getString(R.string.error_invalid_email));
isEmailValid = false;
}

else if(!Pattern.matches("^[6-9]\d{9}$",phone.getText().toString()))
{
phoneError.setError(getResources().getString(R.string.phone_error));
isPhoneValid = false;

}
--------------------------
[SharedPrefrences]
EditText txtEmail,txtPassword;
Button btnLogin;
SharedPreferences sharedPreferences;

String Email=txtEmail.getText().toString();
String Password=txtPassword.getText().toString();

sharedPreferences=getSharedPreferences("MyPreferences",MODE_PRIVATE);
btnLogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(Email.equalsIgnoreCase("[email protected]") && (Password.equalsIgnoreCase("12345"))) {
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putString("email", Email);
editor.commit();
Intent intent = new Intent(getApplicationContext(), MainActivity8.class);
startActivity(intent);
}
else
{
Toast.makeText(MainActivity7.this, "Wrong Input", Toast.LENGTH_SHORT).show();
}

}
});
btnLogout = findViewById(R.id.btnLogout);

sh = getSharedPreferences("MyPreferences", MODE_PRIVATE);
if (sh.contains("email")) {
text1.setText(sh.getString("email",""));
}
btnLogout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SharedPreferences.Editor editor = sh.edit();

editor.putString("email", "");
editor.commit();
finish();

}
});
---------------------------------------------
=============================================
https://buildcoding.com/android-tutorial-for-crud-operations-with-retrofit/