I have recently started to use Firebase in Android.
Now when i am trying to retrieve the data from Firebase Realtime Database the retrieving process is getting executed after some period of time and till then the code below the this process gets executed first.
So I am not able to store the values in the variable and empty variable gets passed on to the next activity.
public class deffi_key extends AppCompatActivity {
EditText a_key,b_key,p_k1,p_k2;
AlertDialog.Builder builder;
long aliceid;
FirebaseAuth mAuth;
DatabaseReference reference;
String key_val="",alice_val="",bob_val="";
long bobid,keyid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_deffi_key);
p_k1 = findViewById(R.id.gkey_p);
p_k2 = findViewById(R.id.gkey_g);
a_key = findViewById(R.id.p_k1);
b_key = findViewById(R.id.p_k2);
mAuth = FirebaseAuth.getInstance();
reference = FirebaseDatabase.getInstance().getReference("Diffi hell man").child(mAuth.getCurrentUser().getUid());
reference.child("Alice").addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
if (dataSnapshot.exists())
{
aliceid = dataSnapshot.getChildrenCount();
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
if (mAuth.getCurrentUser()==null)
{
startActivity(new Intent(getApplicationContext(),login.class));
finish();
}
builder = new AlertDialog.Builder(this);
}
public void alice(String alice_data)
{
alice_val += alice_data;
}
public void bob(String bob_data)
{
bob_val += bob_data;
}
public void key(String key_data)
{
key_val += key_data;
}
public int alice_initialize()
{
long r = aliceid;
for (long i=1;i<=r;i++)
{
reference = FirebaseDatabase.getInstance().getReference("Diffi hell man").child(mAuth.getCurrentUser().getUid()).child("Alice").child(String.valueOf(i));
reference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
try {
String alice_pt = dataSnapshot.child("alice_pt").getValue().toString();
String alice_send = dataSnapshot.child("alice_sent").getValue().toString();
String alice_receive = dataSnapshot.child("alice_receive").getValue().toString();
String time = dataSnapshot.child("time").getValue().toString();
String date = dataSnapshot.child("date").getValue().toString();
String alice_data = alice_pt+ "," +alice_send+ "," +alice_receive+ "," +date+ "," +time+"@";
alice(alice_data);
}
catch (Exception e)
{
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
return 1;
}
public int bob_initialize() {
long r = bobid;
for (long i = 1; i <= r; i++) {
reference = FirebaseDatabase.getInstance().getReference("Diffi hell man").child(mAuth.getCurrentUser().getUid()).child("bob").child(String.valueOf(i));
reference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
try {
String bob_pt = dataSnapshot.child("bob_pt").getValue().toString();
String bob_send = dataSnapshot.child("bob_sent").getValue().toString();
String bob_receive = dataSnapshot.child("bob_receive").getValue().toString();
String time = dataSnapshot.child("time").getValue().toString();
String date = dataSnapshot.child("date").getValue().toString();
String bob_data = bob_pt + "," + bob_send + "," + bob_receive + "," + date + "," + time + "@";
bob(bob_data);
} catch (Exception e) {
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
return 1;
}
public int key_initialize() {
long r = keyid;
for (long i = 1; i <= r; i++) {
reference = FirebaseDatabase.getInstance().getReference("Diffi hell man").child(mAuth.getCurrentUser().getUid()).child("Key").child(String.valueOf(i));
reference.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
try {
String key_pt = dataSnapshot.child("key_pt").getValue().toString();
String key_send = dataSnapshot.child("key_sent").getValue().toString();
String key_receive = dataSnapshot.child("key_receive").getValue().toString();
String time = dataSnapshot.child("time").getValue().toString();
String date = dataSnapshot.child("date").getValue().toString();
String key_data = key_pt + "," + key_send + "," + key_receive + "," + date + "," + time + "@";
key(key_data);
} catch (Exception e) {
}
}
@Override
public void onCancelled(@NonNull DatabaseError databaseError) {
}
});
}
return 1;
}
public long key_gen(long p,long g,long key_a,long key_b)
{
long x,y;
x = (int)Math.pow(g,key_a) % p;
y = (int)Math.pow(g,key_b) % p;
key_a = (int)Math.pow(y,key_a) % p;
key_b = (int)Math.pow(x,key_b) % p;
System.out.println(key_a+" "+key_b);
return key_a;
}
public void clear(View view) {
p_k1.setText(null);
p_k2.setText(null);
a_key.setText(null);
b_key.setText(null);
}
public void submit(View view) {
String key_a1 =a_key.getText().toString(), key_b1 = b_key.getText().toString(), p1 = p_k1.getText().toString(), g1 = p_k2.getText().toString();
if (key_a1.equals(""))
a_key.setError("Field is empty!");
if (key_b1.equals(""))
b_key.setError("Field is empty!");
if (p1.equals(""))
p_k1.setError("Field is empty!");
if (g1.equals(""))
p_k2.setError("Field is empty!");
else{
long key_a = Long.parseLong(key_a1), key_b = Long.parseLong(key_b1), p = Long.parseLong(p1), g = Long.parseLong(g1);
Intent intent = new Intent(this, diffie_display.class);
long secret_key = key_gen(p,g,key_a,key_b);
intent.putExtra("secret_key",secret_key);
intent.putExtra("p",p);
intent.putExtra("g",g);
intent.putExtra("alice",key_a);
intent.putExtra("bob",key_b);
startActivity(intent);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.removedb,menu);
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
switch (id)
{
case R.id.logout:
builder.setMessage("Are you sure that you want to logout ?").setCancelable(false).setPositiveButton("Yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
mAuth.signOut();
startActivity(new Intent(getApplicationContext(),login.class));
}
}).setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.cancel();
}
});
AlertDialog alertDialog = builder.create();
alertDialog.setTitle("logout.");
alertDialog.show();
break;
case R.id.viewhis:
alice_initialize();
bob_initialize();
key_initialize();
Intent intent = new Intent(this, diffie_history.class);
intent.putExtra("alice",aliceid);
intent.putExtra("a_txt",alice_val);
intent.putExtra("b_txt",bob_val);
intent.putExtra("k_txt",key_val);
System.out.println("sdsdd09"+alice_val);
startActivity(intent);
break;
case R.id.clrhistory:
builder.setMessage("Do you want Clear Your History ?").setCancelable(false).setPositiveButton("yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
reference.removeValue();
aliceid=0;
Toast.makeText(getApplicationContext(),"Your history has been Deleted!!.", Toast.LENGTH_SHORT).show();
}
}).setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
dialogInterface.cancel();
}
});
AlertDialog alert = builder.create();
alert.setTitle("Clear History");
alert.show();
break;
}
return super.onOptionsItemSelected(item);
}
}
