当我从Firebase检索数据形式时，检索过程将在一段时间后执行

时间：2020-04-15 19:38:22

标签： android database firebase firebase-realtime-database

我最近开始在Android中使用Firebase。

现在，当我尝试从Firebase实时数据库中检索数据时，检索过程将在一段时间后执行，直到此过程下面的代码首先执行。

因此，我无法将值存储在变量中，并且空变量将传递给下一个活动。

Image of my database 

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);
}

}

0 个答案:

没有答案
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