Custom View to existing View

Question

First off, I am very new to Android. There might be silly mistakes, please correct the one(s) you see.

The problem I am having is to add a view to the existing view. There is a button that you can press that should decrease a value. It works if I keep them in separate fragments, however I want one fragment to handle all of it. The problem occurs in Playfield , in it's onCreateView method.

addView(pc.getView(getActivity())); // this I know is the error, but absolutely no clue of how to solve it. This is what I want to accomplish. I want to directly add that view into the current view.

I tried adding another widget and give it the properties of this view, however that failed.

fragment_playfield.xml

<?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" >

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:layout_marginBottom="30dp"
        android:text="@string/fire_button" />

</RelativeLayout>

Playfield

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class Playfield extends Fragment
{
    private View view;

    private PowerComponent pc = new PowerComponent();;

    private final static int BUTTON_FIRE = R.id.button1;
    private Button buttonFire;  

    @Override
    public void onCreate (Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public View onCreateView (LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {        

        view = inflater.inflate(R.layout.fragment_playfield, container, false);

        addView(pc.getView(getActivity())); // this I know is the error, but absolutely no clue of how to solve it.

        buttonFire = (Button) view.findViewById(BUTTON_FIRE);
        buttonFire.setOnClickListener(new OnClickListener() {           
            @Override
            public void onClick(View v) {
                fire ();
            }
        });

        return view;
    }

    private void fire () {
        if (pc.firePower()) {
            System.exit(0);
        }
    }
}

PowerComponent

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.view.View;

public class PowerComponent
{
    private PowerComponentView view;

    private static final int POWER_MAX          = 100;
    private static int power                    = POWER_MAX;

    public View getView (Activity activity) {
        view = new PowerComponentView(activity);
        return view;
    }

    public boolean firePower () {
        if (power < 5) {
            return false;
        }

        power -= 5;
        view.invalidate();
        return true;
    }


    private class PowerComponentView extends View
    {   
        /**
         * Power GUI
         */
        private final Paint paint               = new Paint();
        private final int GUI_BAR_X             = 100;
        private final int GUI_BAR_Y             = 10;
        private final int GUI_BAR_HEIGHT        = 30;
        private final int GUI_BAR_WIDTH_MAX     = 200;      

        private final Rect powerFrame = new Rect (GUI_BAR_X-1, GUI_BAR_Y-1, GUI_BAR_X + GUI_BAR_WIDTH_MAX+1, GUI_BAR_HEIGHT+1);
        private final Rect powerBar = new Rect (GUI_BAR_X, GUI_BAR_Y, GUI_BAR_X + GUI_BAR_WIDTH_MAX, GUI_BAR_HEIGHT);

        /**
         * 
         * @param context
         */
        public PowerComponentView (Context context) {
            super (context);
        }

        @Override
        public void onDraw (Canvas canvas) {
            super.onDraw(canvas);

            // Frame
            paint.setColor (Color.BLACK);
            canvas.drawRect (powerFrame, paint);

            // Bar
            paint.setColor (Color.rgb (255, 255, 0));
            powerBar.right = GUI_BAR_X + (int)(((double)power/(double)POWER_MAX) * (double)GUI_BAR_WIDTH_MAX);
            canvas.drawRect (powerBar, paint);
        }
    }
}

The problem is that I am unable to add the View returned from my PowerComponent.getView() to my current View.

Answer 1

Fragment class doesn't have addView() method. addView is a method from ViewGroup class. Use:

container.addView()