package com.example.soft_1.loginthing;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{
static String premadeUsername = "Gigi";
static String premadePassword = "1234567";
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button btnLogin = (Button) findViewById(R.id.btn_Login);
        btnLogin.setOnClickListener(this);

        Button btnCancel = (Button) findViewById(R.id.btn_Cancel);
        btnCancel.setOnClickListener(this);
    }
    public void onClick(View v) {
        Button btnLogin = (Button) findViewById(R.id.btn_Login);
        Button btnCancel = (Button) findViewById(R.id.btn_Cancel);
        EditText etPassword   = (EditText)findViewById(R.id.etxt_Password);
        EditText etUsername   = (EditText)findViewById(R.id.etxt_Username);
        TextView txtError   = (TextView)findViewById(R.id.txt_error);

        switch (v.getId()) {
            case R.id.btn_Login:
                if(etPassword.getText().toString().length() < 6)
                {
                    txtError.setVisibility(View.VISIBLE);
                    txtError.setText("Password cannot be shorter than 6 letters");
                }
                else
                if(etPassword.getText().toString() == premadePassword && etUsername.getText().toString() == premadeUsername )
                {
                    txtError.setVisibility(View.VISIBLE);
                    txtError.setText("Logged in!");
                }
                else
                {
                    txtError.setVisibility(View.VISIBLE);
                    txtError.setText("Username or Password is incorrect lol");
                }

                break;
            case R.id.btn_Cancel:
                finish();
                break;
        }
    }
}









<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
    tools:context=".MainActivity">

    <TextView
        android:textSize="50dp"
        android:id="@+id/txt_Login"
        android:layout_marginTop="20dp"
        android:layout_centerHorizontal="true"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Login"
        tools:layout_editor_absoluteX="163dp"
        tools:layout_editor_absoluteY="52dp" />

    <TextView
        android:textSize="18dp"
        android:id="@+id/txt_Username"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/etxt_Username"
        android:layout_alignParentStart="true"
        android:layout_marginStart="18dp"
        android:text="Username:"
        tools:layout_editor_absoluteX="59dp"
        tools:layout_editor_absoluteY="169dp" />

    <TextView
        android:textSize="18dp"
        android:id="@+id/txt_Password"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/etxt_Password"
        android:layout_alignStart="@+id/txt_Username"
        android:text="Password:"
        tools:layout_editor_absoluteX="59dp"
        tools:layout_editor_absoluteY="222dp" />

    <EditText
        android:id="@+id/etxt_Username"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentTop="true"
        android:layout_marginEnd="48dp"
        android:layout_marginTop="115dp"
        android:ems="10"
        android:inputType="textPersonName"
        android:hint="Username"
        tools:layout_editor_absoluteX="129dp"
        tools:layout_editor_absoluteY="157dp" />

    <Button
        android:id="@+id/btn_Login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentStart="true"
        android:layout_alignTop="@+id/btn_Cancel"
        android:layout_marginStart="31dp"
        android:text="Login"
        android:textSize="30dp"
        tools:layout_editor_absoluteX="73dp"
        tools:layout_editor_absoluteY="332dp" />

    <Button
        android:id="@+id/btn_Cancel"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        android:layout_marginBottom="83dp"
        android:layout_marginEnd="31dp"
        android:text="Cancel"
        android:textSize="30dp"
        tools:layout_editor_absoluteX="207dp"
        tools:layout_editor_absoluteY="332dp" />

    <EditText
        android:id="@+id/etxt_Password"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignStart="@+id/etxt_Username"
        android:layout_marginTop="211dp"
        android:ems="10"
        android:hint="Password"
        android:inputType="textPassword"
        tools:layout_editor_absoluteX="126dp"
        tools:layout_editor_absoluteY="214dp" />

    <TextView
        android:textSize="30dp"
        android:id="@+id/txt_error"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="187dp"
        android:text="Error"
        android:visibility="invisible"/>
</RelativeLayout>