按下按钮即可关闭其他活动并打开一个新活动：Android Studio

我想在按下Android Studio上的一个按钮来打开另一个活动的同时关闭一个活动，我已经尝试过：

public void MainActivity(View v) {
    Intent intent = new Intent(getApplicationContext(), MainActivity.class);
    startActivity(intent);

    (FirstActivity(MainActivity();)).finish();

}

这段代码是在我的项目中的FirstActivity.java中编写的。但不幸的是，它没有奏效。

还有其他方法可以做吗，或者我做错了吗？

感谢您的帮助！

必要信息：

FirstActivity.java

    package com.ardacebi.libra;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.content.Intent;
import android.net.Uri;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import com.google.android.gms.common.api.GoogleApiClient;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;

public class FirstActivity extends AppCompatActivity {

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



    public void MainActivity(View v) {
        Intent intent = new Intent(getApplicationContext(), MainActivity.class);
        startActivity(intent);



    }



}

MainActivity.java

    package com.ardacebi.libra;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends AppCompatActivity
        implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();


        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

Activity_First.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/activity_first"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.ardacebi.libra.FirstActivity">


    <ImageView
        android:layout_width="200dp"
        android:layout_height="150dp"
        android:src="@drawable/libralogo"
        android:id="@+id/imageView"
        android:layout_above="@+id/textView6"
        android:layout_centerHorizontal="true" />



    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Welcome to Libra"
        android:textSize="25sp"
        android:id="@+id/textView5"
        android:gravity="center"
        android:layout_marginTop="185dp"
        android:layout_alignParentTop="true"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="The file sharing platform"
        android:textSize="15sp"
        android:id="@+id/textView6"
        android:gravity="center"
        android:layout_below="@+id/textView5"
        android:layout_alignParentStart="true" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Libra, let's you to share your files over a private, secured network to your friends easily"
        android:textSize="15sp"
        android:id="@+id/textView4"
        android:gravity="center"
        android:layout_marginTop="20dp"
        android:layout_below="@+id/textView6"
        android:layout_alignParentStart="true" />


    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Start Sharing"
        android:layout_below="@+id/textView4"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="17dp"
        android:id="@+id/button2"
        android:onClick="MainActivity"/>



</RelativeLayout>

注意：我想在FirstActivity上按下“开始共享”按钮时将用户发送到MainActivity。

见截图