How to add checkboxes dynamically in android

Just change your listener to(perfectly working,I have tried):

b.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View v) {
        for(int i = 0; i < 20; i++) {
            CheckBox cb = new CheckBox(getApplicationContext());
            cb.setText("I'm dynamic!");
            ll.addView(cb);
        }
    }
});

Note the two changes:

1. View.OnClickListener to OnClickListener
2. new CheckBox(this) to new CheckBox(getApplicationContext())

 CheckBox ch = new CheckBox(this);

change (this) to new CheckBox(your activity name.this); because if you pass this it will not take the Context of your activity because you code this line inside the click listener.

It's a few years on from this question but the requirement has not changed... here is how I made it work on API 22. The slight variation is I have a floating action button (fab) on a main layout and a content layout which is where I dynamically create the LinearLayout.

Note: b.setOnClickListener(new View.OnClickListener() and

CheckBox ch = new CheckBox(v.getContext());

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"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

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

    <include layout="@layout/content_main" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        app:srcCompat="@android:drawable/ic_dialog_email" />

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

content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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/layout_id"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity"
    tools:showIn="@layout/activity_main"
    tools:layout_editor_absoluteY="81dp"
    tools:layout_editor_absoluteX="0dp">

</android.support.constraint.ConstraintLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

        final ViewGroup layout = (ViewGroup) findViewById(R.id.layout_id);

        ScrollView sv = new ScrollView(this);
        final LinearLayout ll = new LinearLayout(this);
        ll.setOrientation(LinearLayout.VERTICAL);
        sv.addView(ll);

        TextView tv = new TextView(this);
        tv.setText("Dynamic layouts! Plain Text");
        ll.addView(tv);

        EditText et = new EditText(this);
        et.setText("This is edit text");
        ll.addView(et);

        Button b = new Button(this);
        b.setText("This is a dynamically added button");
        ll.addView(b);


        b.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub

                for(int i = 0; i < 20; i++) {
                    CheckBox ch = new CheckBox(v.getContext());
                    ch.setText("I'm dynamic! "+i);

                    ll.addView(ch);
                }
            }
        });


        //this.setContentView(sv);  // this causes the fab to fail
        layout.addView(sv);

        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();

            }
        });
    }