How to create a dynamic array button in Android?

Question

I have a button. I want to write the function "onClick" for the button. Each time that I click on it I want a new button to be created on screen. And also that new button to be added into an array list of buttons.

I searched but I couldn't find any answer. All of the answers talk about creating buttons with drop and drag, not with dynamic creation of them.

Thanks

<?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:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Click to add"
        android:id="@+id/B1"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:onClick="clicktoaddcode"
        />
</RelativeLayout>

package com.example.yas.dynamicbutton;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {

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

    public void clicktoaddcode(View V){
        Toast.makeText(MainActivity.this, "Created", Toast.LENGTH_SHORT).show();
    }
}

Answer 1

The most simple method to create an unlimited size array is using String Builder. This allows you to add many elements in runtime. It has 3 major components.

1. Declaration and Initialization.
2. Value addition/ Append
3. Print out/ Usage

Use the bellow code anywhere in Android Studio.

//Basic Decleration
        StringBuilder myString = new StringBuilder();
        
//Adding data
       myString.append("Hello text <br>");
        myString.append("some more data <br>");
        myString.append("more data to store <br>");
        
//Displaying in already created text view
        deviceDetails.setText(Html.fromHtml(callLogs+""));

Note: I'm treating this as HTML string and " " tags will create the next line in text view. So, all added data will be displayed in a new line.

Answer 2

You must using ArrayList.

List<Button> btnList = new ArrayList<>();

// Call Your ClickListener
btnList.add(new Button(YourContext));
YourParent.addView(btnList.get(btnList.size() - 1 ));

Edited

MainActivity.java

public class MainActivity extends AppCompatActivity {

    LinearLayout container;

    List<Button> btnList = new ArrayList<>();

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

        container = (LinearLayout)findViewById(R.id.container);


    }

    public void addBtn(View v){
        btnList.add(new Button(this));
        container.addView(btnList.get(btnList.size() - 1 ));
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    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:fitsSystemWindows="true"
    tools:context=".MainActivity">

    <LinearLayout
        android:id="@+id/container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:clickable="true"
        android:onClick="addBtn">

    </LinearLayout>

</android.support.design.widget.CoordinatorLayout>

Answer 3

Have this for your XML -

<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center">

        <Button
            android:id="@+id/myButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Add one more" />

        <LinearLayout
            android:orientation="vertical"
            android:id="@+id/myLinearLayout"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:gravity="center">

        </LinearLayout>

    </LinearLayout>
</ScrollView>

And this in Java-

final LinearLayout linearLayout = (LinearLayout)findViewById(R.id.myLinearLayout);
    Button button = (Button)findViewById(R.id.myButton);
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Button button = new Button(MainActivity.this);
            button.setText("A new Button");
            linearLayout.addView(button);
        }
    });