Question

I want to check if the method Camera.Parameters.getHorizontalViewAngle() exists on the device (it’s only available from API 8 and my min SDK API is 7). I tried to use “reflection”, as explained here, but it catches an error saying the number of arguments is wrong:

java.lang.IllegalArgumentException: wrong number of arguments

Anybody could help?

Camera camera;
camera = Camera.open();
Parameters params = camera.getParameters();
Method m = Camera.Parameters.class.getMethod("getHorizontalViewAngle", new Class[] {} );
float hVA = 0;
try {
    m.invoke(params, hVA);
} catch (IllegalArgumentException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (IllegalAccessException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
} catch (InvocationTargetException e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

Answer 1

m.invoke(params, hVA);

should be

m.invoke(params, null);

Camera.Parameters.getHorizontalViewAngle() doesn’t take any arguments and the above line has the argument hVA. If you’re looking for the return variable do hVA = m.invoke(params, null);