TEXTVIEW substantiation location

Question

I am trying to make an android code that provide a different work for each button.

so when the user press on Button1 a Textview field provides " you pressed on Button1"

my question is about the correct place that I can instantiate the Textview ONLY ONCE as the only working place is inside the Button1 Function.

Java Code for a single button:

 public void Button1(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);
        textView.setText("You clicked the button 1");

    }

total java code

 public class MainActivity extends AppCompatActivity {
    @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();
            }
        });


    }

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

    public void Button1(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);
        textView.setText("You clicked the button 1");

    }
    public void Button2(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);

        textView.setText("You clicked the button 2");
    }
    public void Button3(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);

        textView.setText("You clicked the button 3");
    }
    public void Button4(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);

        textView.setText("You clicked the button 4");

    }
    public void Button5(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);

        textView.setText("You clicked the button 5");
    }
    public void Button6(View view) {
        final TextView textView=(TextView)findViewById(R.id.textView2);

        textView.setText("You clicked the button 6");
    }
}

Total XML Code

<?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:id="@+id/RelativeLayoutID"
    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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.example.sherifsaleh.xmllayout.MainActivity"
    tools:showIn="@layout/activity_main"
    >

    <Button
        android:id="@+id/button3"
        android:onClick="Button3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="3"
        android:layout_above="@+id/button6"
        android:layout_alignLeft="@+id/button6"
        android:layout_alignStart="@+id/button6" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="Button6"
        android:text="6"
        android:id="@+id/button6"
        android:layout_below="@+id/button2"
        android:layout_alignLeft="@+id/button9"
        android:layout_alignStart="@+id/button9" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="9"
        android:id="@+id/button9"
        android:onClick="Button9"
        android:layout_alignTop="@+id/button8"
        android:layout_toRightOf="@+id/button8"
        android:layout_toEndOf="@+id/button8" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="8"
        android:id="@+id/button8"
        android:layout_below="@+id/button5"
        android:layout_toRightOf="@+id/button4"
        android:layout_toEndOf="@+id/button4"
        android:onClick="Button8"/>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="2"
        android:onClick="Button2"
        android:id="@+id/button2"
        android:layout_above="@+id/button5"
        android:layout_toRightOf="@+id/button1"
        android:layout_toEndOf="@+id/button1" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="Button5"
        android:text="5"
        android:id="@+id/button5"
        android:layout_below="@+id/button1"
        android:layout_toRightOf="@+id/button1"
        android:layout_toEndOf="@+id/button1" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="1"
        android:onClick="Button1"
        android:layout_above="@+id/button4"
        android:layout_alignLeft="@+id/button4"
        android:layout_alignStart="@+id/button4" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="4"
        android:id="@+id/button4"
        android:layout_above="@+id/button7"
        android:layout_alignLeft="@+id/button7"
        android:layout_alignStart="@+id/button7" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="7"
        android:id="@+id/button7"
        android:layout_alignParentBottom="true"
        android:layout_alignLeft="@+id/textView2"
        android:layout_alignStart="@+id/textView2"
        android:layout_marginBottom="90dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textIsSelectable="true"
        android:text="New Text"
        android:id="@+id/textView2"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="80dp"
        android:textSize="50dp"/>
</RelativeLayout>

Answer 1

Try like this.

public class MainActivity extends AppCompatActivity {

private TextView textView;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = (TextView)findViewById(R.id.textView2);
    ....
}

And your Button click method as

 public void Button1(View view) {
    textView.setText("You clicked the button 1");
}

Answer 2

1)First try to initialize your references in onCreate which loads once.So references to your views will initialize only once eg-

 @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btnOne = (Button) findViewById(R.id.btnOne);
        btnTwo = (Button) findViewById(R.id.btnTwo);
        textView = (TextView) findViewById(R.id.textView);

        btnOne.setOnClickListener(this);
        btnTwo.setOnClickListener(this);
}

2)Instead of calling seperate methods for each button apply click listeners on buttons as above mentioned

and implement  View.OnClickListener and then

3)Override method

@Override
    public void onClick(View v) {
        Button b = (Button)v;
        String buttonText = b.getText().toString();
        textView.setText("You clicked on  " + buttonText);

    }

So the code in onClick is repeating in your case instead of writing each time seperately write it once and get text or you can set Tag of button and get it(in case when you want to set another value to textview instead of button text) and set to textview as i did in onClick. It will reduce your efforts and increase your code reusability and redability too..!!!!!