问是否可以将活动转换为浮动窗口？

EN

public class FloatingWindow extends Service{
WindowManager wm;
LinearLayout ll;

@Override
public IBinder onBind(Intent intent) {
    // TODO Auto-generated method stub
    return null;
}

@Override
public void onCreate() {
    // TODO Auto-generated method stub
    super.onCreate();

    wm = (WindowManager) getSystemService(WINDOW_SERVICE);

    ll = new LinearLayout(this);
    ll.setBackgroundColor(Color.RED);
    LinearLayout.LayoutParams layoutParameteres = new LinearLayout.LayoutParams(
            LinearLayout.LayoutParams.MATCH_PARENT, 400);
    ll.setBackgroundColor(Color.argb(66,255,0,0));
    ll.setLayoutParams(layoutParameteres);

    final WindowManager.LayoutParams parameters = new WindowManager.LayoutParams(
            500, 200, WindowManager.LayoutParams.TYPE_PHONE,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,
            PixelFormat.TRANSLUCENT);
    parameters.gravity = Gravity.CENTER | Gravity.CENTER;
    parameters.x = 0;
    parameters.y = 0;

    Button stop = new Button(this);
    stop.setText("Stop");
    ViewGroup.LayoutParams btnParameters = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.WRAP_CONTENT);
    stop.setLayoutParams(btnParameters);

    ll.addView(stop);
    wm.addView(ll, parameters);

    ll.setOnTouchListener(new View.OnTouchListener() {
        WindowManager.LayoutParams updatedParameters = parameters;
        double x;
        double y;
        double pressedX;
        double pressedY;

        @Override
        public boolean onTouch(View v, MotionEvent event) {

            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:

                    x = updatedParameters.x;
                    y = updatedParameters.y;

                    pressedX = event.getRawX();
                    pressedY = event.getRawY();

                    break;

                case MotionEvent.ACTION_MOVE:
                    updatedParameters.x = (int) (x + (event.getRawX() - pressedX));
                    updatedParameters.y = (int) (y + (event.getRawY() - pressedY));

                    wm.updateViewLayout(ll, updatedParameters);

                default:
                    break;
            }

            return false;
        }
    });

    stop.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            wm.removeView(ll);
            stopSelf();
            System.exit(0);
        }
    });
}

@Override
public void onDestroy() {
    super.onDestroy();
    stopSelf();
}

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


<android.support.design.widget.AppBarLayout
    android:id="@+id/actionBar"
    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="@color/black">

        <TextView
            android:textColor="@color/white"
            android:textSize="20dp"
            android:text="Customise"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />


    </android.support.v7.widget.Toolbar>
</android.support.design.widget.AppBarLayout>

<ScrollView
    android:layout_below="@+id/actionBar"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@color/black"
    app:layout_behavior="@string/appbar_scrolling_view_behavior">

    <LinearLayout
        android:layout_below="@+id/actionBar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <RelativeLayout
            android:id="@+id/color"
            android:paddingVertical="10dp"
            android:paddingHorizontal="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
        <TextView
            android:textSize="25dp"
            android:layout_centerVertical="true"
            android:textColor="@color/white"
            android:text="Color"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content" />
    </RelativeLayout>

        <RelativeLayout
            android:id="@+id/font"
            android:paddingVertical="10dp"
            android:paddingHorizontal="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <TextView
                android:textSize="25dp"
                android:layout_centerVertical="true"
                android:textColor="@color/white"
                android:text="Font"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
        </RelativeLayout>

        <RelativeLayout
            android:id="@+id/size"
            android:paddingVertical="10dp"
            android:paddingHorizontal="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <TextView
                android:textSize="25dp"
                android:layout_centerVertical="true"
                android:textColor="@color/white"
                android:text="Size"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
        </RelativeLayout>
</LinearLayout>
</ScrollView>
</RelativeLayout>