History for simple calculator - Android
<p>im new in android and i created a simple calculator. Now i want it to show me history of operations in textView. I dont know how to do that, can someone help me with it?  I know it's very simple programing but i just started lerning java and im working in android studio. Thanks.
Edit: i found 1 error so i edited main and im adding layout code.</p>

<pre><code>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.GridLayout;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;


public class MainActivity extends AppCompatActivity {

    Button b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, bplus, bminus, bmulti, bdiv, beq, bc;

    EditText edit1;
    TextView hist;

    int nr1, nr2;

    boolean plus, minus, multi, div;
    //List&lt;String&gt; history= new ArrayList&lt;&gt;();



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


        b0 = (Button) findViewById(R.id.b0);
        b1 = (Button) findViewById(R.id.b1);
        b2 = (Button) findViewById(R.id.b2);
        b3 = (Button) findViewById(R.id.b3);
        b4 = (Button) findViewById(R.id.b4);
        b5 = (Button) findViewById(R.id.b5);
        b6 = (Button) findViewById(R.id.b6);
        b7 = (Button) findViewById(R.id.b7);
        b8 = (Button) findViewById(R.id.b8);
        b9 = (Button) findViewById(R.id.b9);

        bplus = (Button) findViewById(R.id.bplus);
        bminus = (Button) findViewById(R.id.bminus);
        bmulti = (Button) findViewById(R.id.bmulti);
        bdiv = (Button) findViewById(R.id.bdiv);
        bc = (Button) findViewById(R.id.bc);
        beq = (Button) findViewById(R.id.beq);

        edit1 = (EditText) findViewById(R.id.edit1);
        hist = (TextView) findViewById(R.id.hist);
        //history.get(index);



        b0.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "0");
            }


        });

        b1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "1");
            }

        });

        b2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "2");
            }

        });

        b3.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "3");
            }

        });

        b4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "4");
            }

        });

        b4.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "4");
            }

        });

        b5.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "5");
            }

        });

        b6.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "6");
            }

        });

        b7.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "7");
            }

        });
        b8.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "8");
            }

        });

        b9.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText(edit1.getText() + "9");
            }

        });

        bplus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                if (edit1 == null){
                    edit1.setText("");
                }else {
                    nr1 = Integer.parseInt(edit1.getText() + "");
                    plus= true;
                    edit1.setText(null);
                }
            }
        });

        bminus.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nr1 = Integer.parseInt(edit1.getText() + "");
                minus = true ;
                edit1.setText(null);
            }
        });

        bmulti.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nr1 = Integer.parseInt(edit1.getText() + "");
                multi = true ;
                edit1.setText(null);
            }
        });

        bdiv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nr1 = Integer.parseInt(edit1.getText()+"");
                div = true ;
                edit1.setText(null);
            }
        });

        bc.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                edit1.setText("");
            }
        });


        beq.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                nr2 = Integer.parseInt(edit1.getText() + "");

                double res = '0';

                if (plus == true){
                    edit1.setText(nr1 + nr2+"");
                    plus=false;
                }


                if (minus == true){
                    edit1.setText(nr1 - nr2+"");
                    minus=false;
                }

                if (multi == true){
                    edit1.setText(nr1 * nr2+"");
                    multi=false;
                }

                if (div == true){
                    edit1.setText(nr1 / nr2+"");
                    div=false;
                }


            }


        });

}

}
</code></pre>

<hr>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:weightSum="1"&gt;


    &lt;TextView
        android:layout_width="match_parent"
        android:id="@+id/hist"
        android:layout_height="100dp" /&gt;

    &lt;EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/edit1" /&gt;

    &lt;GridLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="1.10"
        android:id="@+id/GridLayout"&gt;

        &lt;Button
            android:text="5"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b5"
            android:layout_row="1"
            android:layout_column="1"/&gt;

        &lt;Button
            android:text="6"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b6"
            android:layout_row="1"
            android:layout_column="2"/&gt;

        &lt;Button
            android:text="-"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bminus" /&gt;

        &lt;Button
            android:text="7"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b7"
            android:layout_row="2"
            android:layout_column="0"/&gt;

        &lt;Button
            android:text="8"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b8"
            android:layout_row="2"
            android:layout_column="1" /&gt;

        &lt;Button
            android:text="9"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b9"
            android:layout_row="2"
            android:layout_column="2" /&gt;

        &lt;Button
            android:text="*"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bmulti"
            android:layout_row="2"
            android:layout_column="3" /&gt;

        &lt;Button
            android:text="+"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bplus"
            android:layout_row="0"
            android:layout_column="3" /&gt;

        &lt;Button
            android:text="3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b3"
            android:layout_row="0"
            android:layout_column="2" /&gt;

        &lt;Button
            android:text="4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b4"
            android:layout_row="1"
            android:layout_column="0" /&gt;

        &lt;Button
            android:text="0"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b0"
            android:layout_row="3"
            android:layout_column="1" /&gt;

        &lt;Button
            android:text="2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b2"
            android:layout_row="0"
            android:layout_column="1" /&gt;

        &lt;Button
            android:text="1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/b1"
            android:layout_row="0"
            android:layout_column="0" /&gt;

        &lt;Button
            android:text="/"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bdiv"
            android:layout_row="3"
            android:layout_column="3" /&gt;

        &lt;Button
            android:text="="
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/beq"
            android:layout_row="3"
            android:layout_column="2" /&gt;

        &lt;Button
            android:text="C"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/bc"
            android:layout_row="3"
            android:layout_column="0" /&gt;

    &lt;/GridLayout&gt;

&lt;/LinearLayout&gt;
</code></pre>