Java – Code does not work, buttons do not respond

I created a registered activity that sends data to the database, and the button must open another activity, which is MainActivity. The code works fine, but there is a problem. When the button is clicked, it responds and sends information to the database, but the activity does not change.

How do I change the code to open another activity?

Registration request .java

public class RegisterRequest extends StringRequest {

private static final String REGISTER_REQUEST_URL = "http://loginacti.comli.com/Register.php";
private Map<String, String> params;

public RegisterRequest(String Expect, String Prize, String Name, String Email, Response.Listener<String> listener) {
        super(Method.POST, REGISTER_REQUEST_URL, listener, null);
    params = new HashMap<>();
    params.put("Expect", Expect);
    params.put("Prize", Prize);
    params.put("Name", Name);
    params.put("Email", Email);

}

@Override
public Map<String, String> getParams() {
    return params;
}

Register the Activity .java

public class RegisterActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_register);

final EditText etUknown = (EditText) findViewById(R.id.etUknown);
    final EditText etPrize = (EditText) findViewById(R.id.etPrize);
    final EditText etName = (EditText) findViewById(R.id.etName);
    final EditText etEmail = (EditText) findViewById(R.id.etEmail);
    final Button bRegister = (Button) findViewById(R.id.bRegister);

bRegister.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            final String Expect = etUknown.getText().toString();
            final String Prize = etPrize.getText().toString();
            final String Name = etName.getText().toString();
            final String Email = etEmail.getText().toString();

Response.Listener<String> responseListener = new Response.Listener<String>(){

@Override
                public void onResponse(String response) {
                    try {
                        JSONObject jsonResponse = new JSONObject(response);
                        boolean success = jsonResponse.getBoolean("success");
                        if (success){
                            Intent intent = new Intent(RegisterActivity.this, MainActivity.class);
                            RegisterActivity.this.startActivity(intent);
                        }else{
                            AlertDialog.Builder builder = new AlertDialog.Builder(RegisterActivity.this);
                            builder.setMessage("Register Failed")
                                    .setNegativeButton("Retry", null)
                                    .create()
                                    .show();

}

} catch (JSONException e) {
                        e.printStackTrace();
                    }
                }
            };

RegisterRequest registerRequest = new RegisterRequest(Expect, Prize, Name, Email, responseListener);
            RequestQueue queue = Volley.newRequestQueue(RegisterActivity.this);
            queue.add(registerRequest);
        }
    });
}

The main activity .java

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

final TextView registerLink = (TextView) findViewById(R.id.eRegister);

registerLink.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent registerIntent = new Intent(MainActivity.this, RegisterActivity.class);
            MainActivity.this.startActivity(registerIntent);
        }
    });
}

list

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name=". MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=". RegisterActivity"></activity>
</application>

activity_register.xml

    <EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/etUknown"
    android:layout_alignParentTop="true"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_marginTop="60dp"
    android:layout_alignParentRight="true"
    android:layout_alignParentEnd="true"
    android:hint="Numbers" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/etPrize"
    android:hint="Secret CD"
    android:layout_below="@+id/etUknown"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignRight="@+id/etUknown"
    android:layout_alignEnd="@+id/etUknown" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="textPersonName"
    android:ems="10"
    android:id="@+id/etName"
    android:hint="Full Name"
    android:layout_below="@+id/etPrize"
    android:layout_alignRight="@+id/etPrize"
    android:layout_alignEnd="@+id/etPrize"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true" />

<EditText
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:inputType="textEmailAddress"
    android:ems="10"
    android:id="@+id/etEmail"
    android:hint="New Email"
    android:layout_below="@+id/etName"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignRight="@+id/etName"
    android:layout_alignEnd="@+id/etName" />

<Button
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Register"
    android:id="@+id/bRegister"
    android:layout_marginTop="46dp"
    android:layout_below="@+id/etEmail"
    android:layout_centerHorizontal="true" />

In onclick, you cannot use .finish() that would normally exit the current activity. However, you can create a method exitActivity() and then call it from your onclick. So, after you write to the database, at the end of your onClick, create a try block with the following code:

try {
     exitActivity();
}
catch (Exception e){
      e.printStackTrace();
}

Then create an exitActivity() in your RegisterActivity as follows:

private void exitActivity(){
    this.finish();
}

You want to do this because if you go your way, you will create multiple instances of mainactivity as you try to register more items. This can cause your app to eventually run out of memory.