Creating a back button with noActionBar

Question

I'm a couple days into learning Android development and I'll admit my code is not pretty, as I have a few weeks of Java under my belt on top of this. I'm trying to create a back button on my 2nd main activity page to get back to the 1st main activity, but the only solutions I've come across are while using the toolbar. How would you go about adding this function while using noActionBar?

Main Activity xml

<?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"
android:background="@drawable/clearwater"
android:scaleType="centerCrop"
tools:context="com.example.goodvibes.helloworld.MainActivity">



<Button
    android:id="@+id/button"
    style="@style/Widget.AppCompat.Button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="146dp"
    android:background="@drawable/btn"
    android:fontFamily="cursive"
    android:text="DIVE"
    android:textSize="24sp"
    android:textStyle="bold" />




</RelativeLayout>

Main Activity 2 xml

<?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"
android:scaleType="centerCrop"
tools:context="com.example.goodvibes.helloworld.MainActivity">

<Button
    android:id="@+id/Button2"
    style="@style/Widget.AppCompat.Button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="76dp"
    android:background="@drawable/timebutton"
    android:fontFamily="serif-monospace"
    android:text="Time Interval Between Dives"
    android:textSize="20sp"
    android:textStyle="bold" />

<ImageButton
    android:id="@+id/imageButton"
    style="@android:style/Widget.ImageButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_alignParentStart="true"
    android:layout_alignParentTop="true"
    android:layout_marginLeft="17dp"
    android:layout_marginStart="17dp"
    android:layout_marginTop="11dp"
    android:adjustViewBounds="false"
    android:background="@android:color/background_light"
    android:cropToPadding="false"
    android:tint="@android:color/background_dark"
    app:srcCompat="?android:attr/actionModeCloseDrawable" />


</RelativeLayout>

Main Activity Java

package com.example.goodvibes.helloworld;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

public Button but1;

    public void init(){
        but1= (Button)findViewById(R.id.button);
        but1.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {

                Intent toy = new 
 Intent(MainActivity.this,activity_main_2.class);

                startActivity(toy);

            }
        });
}


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

}

Main Activity 2 Java

package com.example.goodvibes.helloworld;

import android.content.Intent;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.widget.ImageButton;
import android.widget.ViewAnimator;

public class activity_main_2 extends AppCompatActivity {




@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main_2);




}
}

Manifest

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.goodvibes.helloworld">

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    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=".activity_main_2"></activity>
</application>

</manifest>

I had a lot of great people giving me answers I had to research. In the end here is what solved my problem: I inserted "android:onClick="ImageButton" under my button code in the xml fine THEN under the corresponding java file for my second activity I inserted:

public void ImageButton(View v)
{
    // some code
    finish();
}

Answer 1

Add this to your layout file:

<android.support.v7.widget.Toolbar
    android:id="@+id/toolbar_acashmemoreport"
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    app:theme="@style/ToolbarColoredBackArrow" />

In your activity:

Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar_acashmemoreport);
setSupportActionBar(toolbar);


if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
    Window window = getWindow();
    window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);
    window.setStatusBarColor(getResources().getColor(R.color.colorPrimaryDark));
}

// Show menu icon
final ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setDisplayShowTitleEnabled(true);
toolbar.setTitleTextColor(getResources().getColor(R.color.colorWhite));