android - 在 Image View android 上绘图

Question

每次从另一个 Activity 接收到像素值(要绘制的圆的中心)时，任何人都可以帮助我如何在 ImageView 上绘制一个特定半径的圆>?

Answer 1

扩展ImageView并覆盖 onDraw(Canvas c)方法 - 添加 c.drawCirle(x,y,radius,Paint)

或者对于绘制圆，您也可以使用纯 Canvas。

我试过这种方法，还是不行

public class MyActivity extends Activity {
private MyImageView myImageView;
 float x, y;
 float [] loc;
float radius = 50;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_show_location);
    myImageView = (MyImageView) findViewById(R.id.mapimageView);
    myImageView.setImageResource(R.drawable.mymap);

    //Receiving location information(x/y pixels array) from myLocation Activity         
        Intent i = getIntent();     
        loc = i.getFloatArrayExtra("Location");

}
public class MyImageView extends ImageView
{

    public MyImageView(Context context) {
        super(context);         
    }
    // Constructor for inflating via XML
   public MyImageView(Context context, AttributeSet attrs) {
   super(context, attrs);         
    }


            @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Paint p = new Paint();
        x= loc[0];
        y=loc[1];
        p.setColor(Color.RED);
        p.setStrokeWidth(2);        
        canvas.drawCircle(x, y, radius, p);
    }       
}

并在 xml 中更改 <ImageView至 your.package.name.MyImageView

//EDIT 我只是凭内存写的，所以可能会有错别字