<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@android:color/black"
    >
    
  <info.hellovass.snowingview.widgets.SnowingView
      android:id="@+id/snowing_view"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:visibility="gone"
      app:src="@drawable/ic_snowflake"
      />

  <Switch
      android:id="@+id/sw_snowing"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:layout_gravity="center"
      android:text="winter is coming..."
      android:textColor="@android:color/white"
      android:textSize="16sp"
      />
      
</FrameLayout>

public class SampleActivity extends AppCompatActivity {

  private SnowingView mSnowingView;

  private Switch mSwitch;

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

    mSwitch = (Switch) findViewById(R.id.sw_snowing);
    mSnowingView = (SnowingView) findViewById(R.id.snowing_view);

    mSwitch.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
      @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {

        if (isChecked) {
          mSnowingView.startFall();  // 开始下雪
        } else {
          mSnowingView.stopFall(); // 停止下雪
        }
      }
    });
  }
}