Looping in onCreate method

Question

So I'm creating a program which will randomly spawn circles on the screen every 5 seconds. I had it working by just displaying 1 circle but when I tried to loop in the onCreate method to draw multiple circles, I got compiler errors and I have no idea what to do now, been stuck for 30 minutes. Here is my code and the main error. Any help will be appreciated.

public class RandomCircles extends ActionBarActivity {

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

        Timer timer = new Timer();
        timer.scheduleAtFixedRate(new TimerTask() {
            public void run() {
                setContentView(new MyView(R.layout.activity_random_circles);
            }
        }, 0, 5 * 1000L);//5 seconds
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_random_circles, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

class MyView extends View {
    public MyView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    @Override
    protected void onDraw(Canvas canvas)
    {
        super.onDraw(canvas);
        //800, 1162
        Random rand = new Random();

        double x = rand.nextInt(getWidth());

        if(getWidth() - x < 100)
            x -= 100;
        else if(getWidth() - x > getWidth() - 100)
            x += 100;

       double y = rand.nextInt(getHeight());

        if(getHeight() - y < 100)
            y -= 100;
        else if(getHeight() - x > getHeight() - 100)
            y += 100;

        int radius;
        radius = 100;
        Paint paint = new Paint();
        paint.setStyle(Paint.Style.FILL);
        paint.setColor(Color.WHITE);
        canvas.drawPaint(paint);
        // Use Color.parseColor to define HTML colors
        paint.setColor(Color.parseColor("#CD5C5C"));
        canvas.drawCircle(x, y, radius, paint);
    }
}

enter image description here

score 1 · Answer 1 · answered Jun 15 '15 at 03:09

1

Your MyView constructor seeks a Context as parameter, but you are passing R.layout.activity_random_circles which is basically a auto-generated int value mapped to your layout xml file in res/layout. Try passing RandomCircles.this instead that refers to your Activity context

answered Jun 15 '15 at 03:09

Mithun

2,075
3
19
26

Thanks, this works. However, it's only displaying 1 circle and not repeating them now. This is kinda off-topic but any ideas on that? – Sygnerical Jun 15 '15 at 03:33
How about you have a dummy layout file, set an id to your root layout(say, `android:id="@+id/root_layout"` and in `onCreate` you `setContentView` to this layout. Next, while running your timer, you can get context of this root view `LinearLayout layout = (LinearLayout) findViewById(R.id.root_layout);` and add to it your `layout.addView(new MyView(...))` – Mithun Jun 15 '15 at 03:59

score 1 · Answer 2 · answered Jun 15 '15 at 03:14

The MyView constructor needs a Context parameter but you are passing it a layout id. Your MyView constructor should probably look like this

public class MyView extends View {

public MyView(Context context) {
    super(context);

    View view = inflate(context, R.layout.activity_random_circles, null);
    view.setFocusable(true);
    addView(view);
}
..
}

And then inside your onCreate() method, do this

public void run() {
    setContentView(new MyView(this));
}

Phuc Tran · Answer 3 · 2015-06-15T03:20:56.353

1

new MyView(Context context)

MyView constructor needs a "context". You are passing a layout id (it's integer value). It should be

new MyView(this)

edited Jun 15 '15 at 03:20

answered Jun 15 '15 at 03:15

Phuc Tran

7,555
1
39
27

Looping in onCreate method

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