App crashes everytime crash code provided below

Question

05-03 04:47:23.906 6489-6489/com.example.alondra.positive1 E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.alondra.positive1, PID: 6489 java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.alondra.positive1/com.example.alondra.positive1.LoginActivity}: java.lang.ClassNotFoundException: Didn't find class "com.example.alondra.positive1.LoginActivity" on path: DexPathList[[zip file "/data/app/com.example.alondra.positive1-2/base.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_dependencies_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_0_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_1_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_2_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_3_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_4_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_5_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_6_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_7_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_8_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]] at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2236) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387) at android.app.ActivityThread.access$800(ActivityThread.java:151) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:135) at android.app.ActivityThread.main(ActivityThread.java:5254) at java.lang.reflect.Method.invoke(Native Method) at java.lang.reflect.Method.invoke(Method.java:372) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) Caused by: java.lang.ClassNotFoundException: Didn't find class "com.example.alondra.positive1.LoginActivity" on path: DexPathList[[zip file "/data/app/com.example.alondra.positive1-2/base.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_dependencies_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_0_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_1_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_2_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_3_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_4_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_5_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_6_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_7_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_8_apk.apk", zip file "/data/app/com.example.alondra.positive1-2/split_lib_slice_9_apk.apk"],nativeLibraryDirectories=[/vendor/lib, /system/lib]] at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56) at java.lang.ClassLoader.loadClass(ClassLoader.java:511) at java.lang.ClassLoader.loadClass(ClassLoader.java:469) at android.app.Instrumentation.newActivity(Instrumentation.java:1066) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2226) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)  at android.app.ActivityThread.access$800(ActivityThread.java:151)  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)  at android.os.Handler.dispatchMessage(Handler.java:102)  at android.os.Looper.loop(Looper.java:135)  at android.app.ActivityThread.main(ActivityThread.java:5254)  at java.lang.reflect.Method.invoke(Native Method)  at java.lang.reflect.Method.invoke(Method.java:372)  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)  Suppressed: java.lang.NoClassDefFoundError: com.example.alondra.positive1.LoginActivity at dalvik.system.DexFile.defineClassNative(Native Method) at dalvik.system.DexFile.defineClass(DexFile.java:226) at dalvik.system.DexFile.loadClassBinaryName(DexFile.java:219) at dalvik.system.DexPathList.findClass(DexPathList.java:321) at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:54) ... 14 more Suppressed: java.io.IOException: Failed to open dex file '/data/app/com.example.alondra.posit

Answer 1

Activity Register

XML

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center_horizontal"
    android:layout_marginTop="50dp"
    android:text="Positive + 1"
    android:textSize="30sp"
    android:padding="20dp"
    android:textColor="@color/Black" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:inputType="textEmailAddress"
    android:maxLines="1"
    android:id="@+id/etEmail"
    android:hint="Email"
    android:textColorHint="@color/Black"
    android:layout_marginTop="20dp"
    android:layout_marginBottom="10dp"
    android:layout_marginRight="10dp"
    android:layout_marginLeft="10dp"/>

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/etPass"
    android:inputType="textPassword"
    android:hint="Password"
    android:textColorHint="@color/Black"
    android:maxLines="1"
    android:layout_marginBottom="10dp"
    android:layout_marginRight="10dp"
    android:layout_marginLeft="10dp"/>


<Button
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/btnReg"
    android:text="Register"
    android:layout_marginBottom="10dp"
    android:layout_marginRight="10dp"
    android:layout_marginLeft="10dp"
    android:onClick="register"
    />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:text="Back to Login"
    android:id="@+id/tvLogin"
    android:textColor="@color/Black"
    android:layout_gravity="center_horizontal"
    />

Java

package com.example.alondra.positive1;

import android.content.Intent; 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; import android.widget.Toast; 2

public class RegisterActivity extends AppCompatActivity implements View.OnClickListener { private Button reg; private TextView tvLogin; private EditText etEmail, etPass; private DbHelper db; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_register);

    db = new DbHelper(this);
    reg = (Button)findViewById(R.id.btnReg);
    tvLogin = (TextView)findViewById(R.id.tvLogin);
    etEmail = (EditText)findViewById(R.id.etEmail);
    etPass = (EditText)findViewById(R.id.etPass);
    reg.setOnClickListener(this);
    tvLogin.setOnClickListener(this);


}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.btnReg:
            register();
            break;
        case R.id.tvLogin:
            startActivity(new Intent(RegisterActivity.this,LoginActivity.class));
            finish();
            break;
        default:

    }
}
private void register(){
    String email = etEmail.getText().toString();
    String pass = etPass.getText().toString();
    if (email.isEmpty() && pass.isEmpty()){
        displayToast("Username & Password Fields are empty");
    }else {
        db.addUser(email,pass);
        displayToast("Your account has been created succesfully");
        finish();
    }
}

private void displayToast (String message){
    Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
} }