Forgot password in Firebase for Android

Reset Android FireBase Password

Java File

    public class ResetPasswordActivity extends AppCompatActivity {

    private EditText inputEmail;

    private Button btnReset, btnBack;

    private FirebaseAuth auth;

    private ProgressBar progressBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_reset_password);

        inputEmail = (EditText) findViewById(R.id.email);

        btnReset = (Button) findViewById(R.id.btn_reset_password);

        btnBack = (Button) findViewById(R.id.btn_back);

        progressBar = (ProgressBar) findViewById(R.id.progressBar);

        auth = FirebaseAuth.getInstance();

        btnBack.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                finish();
            }
        });

        btnReset.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                String email = inputEmail.getText().toString().trim();

                if (TextUtils.isEmpty(email)) {
                    Toast.makeText(getApplication(), "Enter your registered email id", Toast.LENGTH_SHORT).show();
                    return;
                }

                progressBar.setVisibility(View.VISIBLE);

                auth.sendPasswordResetEmail(email)

                        .addOnCompleteListener(new OnCompleteListener<Void>() {
                            @Override
                            public void onComplete(@NonNull Task<Void> task) {
                                if (task.isSuccessful()) {
                                    Toast.makeText(ResetPasswordActivity.this, "We have sent you instructions to reset your password!", Toast.LENGTH_SHORT).show();
                                } else {
                                    Toast.makeText(ResetPasswordActivity.this, "Failed to send reset email!", Toast.LENGTH_SHORT).show();
                                }

                                progressBar.setVisibility(View.GONE);
                            }
                        });
            }
        });
    }

}

XML FILE

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_gravity="center"

    android:fitsSystemWindows="true"
    tools:context=".LoginActivity">

    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="30dp"
        android:gravity="center"
        android:orientation="vertical"
        android:padding="@dimen/activity_horizontal_margin">




        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center_horizontal"
            android:padding="10dp"
            android:text="@string/lbl_forgot_password"
            android:textColor="@android:color/white"
            android:textSize="20dp" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginBottom="10dp"
            android:gravity="center_horizontal"
            android:padding="@dimen/activity_horizontal_margin"
            android:text="@string/forgot_password_msg"
            android:textColor="@android:color/white"
            android:textSize="14dp" />

        <android.support.design.widget.TextInputLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">

            <EditText
                android:id="@+id/email"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:layout_marginBottom="10dp"
                android:layout_marginTop="20dp"
                android:hint="@string/hint_email"
                android:inputType="textEmailAddress"
                android:textColor="@android:color/white"
                android:textColorHint="@android:color/white" />
        </android.support.design.widget.TextInputLayout>

        <!-- Login Button -->

        <Button
            android:id="@+id/btn_reset_password"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_marginTop="20dip"
            android:background="@color/colorAccent"
            android:text="@string/btn_reset_password"
            android:textColor="@android:color/black" />

        <Button
            android:id="@+id/btn_back"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="10dp"
            android:background="@null"
            android:text="@string/btn_back"
            android:textColor="@color/colorAccent" />

    </LinearLayout>

    <ProgressBar
        android:id="@+id/progressBar"
        android:layout_width="30dp"
        android:layout_height="30dp"
        android:layout_gravity="center|bottom"
        android:layout_marginBottom="20dp"
        android:visibility="gone" />
</android.support.design.widget.CoordinatorLayout>

It sounds like you're looking to send a password reset email. See this example from the Firebase documentation:

FirebaseAuth.getInstance().sendPasswordResetEmail("[email protected]")
    .addOnCompleteListener(new OnCompleteListener<Void>() {
        @Override
        public void onComplete(@NonNull Task<Void> task) {
            if (task.isSuccessful()) {
                Log.d(TAG, "Email sent.");
            }
        }
    });