Add button using code dynamically in android

How to Add button using code dynamically in android

Main.xml

<LinearLayout
        android:id="@+id/LinearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >

</LinearLayout>

Main.java

LinearLayout myLayout = (LinearLayout) findViewById(R.id.LinearLayout1);
LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT);
myLayout.setOrientation(LinearLayout.VERTICAL);
  
Button button = new Button(this);
button.setText("B1");
myLayout.addView(button, params);

How to check Wifi State (On or off) - Android

Add this line to AndroidManifest.xml

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>

Main.java

ConnectivityManager connectivityManager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);

boolean isWifiConnected = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_WIFI).isConnectedOrConnecting();

if (isWifiConnected) // true if wifi connected
editText.setText("Wifi is connected");
else
editText.setText("Wifi is NOT connected");

ListView - Get data from xml - Android

Main.xml

<ListView
        android:id="@+id/listView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

Main.java

ListView listView = (ListView) findViewById(R.id.listView1);
listView.setAdapter(new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.countries)));