android - 如何在 Android 中创建一个球？

Question

我一直在尝试在 Eclipse 中创建一个球。我试图找出在这篇文章中要做什么，但我似乎不知道在我的 Ball 课上放什么。有什么建议么？

Answer 1

这是一个简单的 java 类，您可以从中创建一个球对象：

public class Ball {

    private int x, y, r;
    private Color c = Color.YELLOW;

    public Ball (int x, int y, int r)
    {
        this.x = x;
        this.y = y;
        this.r = r;
    }

    // draws the ball
    public void draw (Graphics g)
    {
        g.setColor(c);
        g.fillOval(x-r, y-r, 2*r, 2*r);
    }   

}

Answer 2

试试这个，以防你决定改变主意。

public class MainActivity extends Activity {
private int c = Color.YELLOW;
private Canvas g;
@Override
public void onCreate(Bundle savedInstanceState) 
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    draw();
    }

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}


// draws the ball
public void draw ()
{
    Display display = getWindowManager().getDefaultDisplay();

    int width = display.getHeight();
    int height = display.getWidth();

    Bitmap bitmap = Bitmap.createBitmap(width, height, Config.RGB_565);

    g = new Canvas(bitmap);
    g.drawColor(c);
    Paint paint = new Paint();
    paint.setColor(Color.BLACK);
    g.drawCircle(50, 10, 25, paint); //Put your values

    // In order to display this image, we need to create a new ImageView that we can display.
    ImageView imageView = new ImageView(this);

    // Set this ImageView's bitmap to ours
    imageView.setImageBitmap(bitmap);

    // Create a simple layout and add imageview to it.
    RelativeLayout layout = new RelativeLayout(this);
    RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT,
    LayoutParams.WRAP_CONTENT);
    params.addRule(RelativeLayout.CENTER_IN_PARENT);
    layout.addView(imageView, params);
    layout.setBackgroundColor(Color.BLACK);

    // Show layout in activity.
    setContentView(layout);   
}
}

Answer 3

我知道渲染球体的唯一方法是在 openGl 中 .. 在这里查看

对于 2D 渲染，您可能会看到这个 tut .. 它安静简单 ..链接