[android]根据文件名动态设置ImageView图片

final ImageView img =findViewById(R.id.imageView1);               
int id = getResId("图片文件名", R.drawable.class);
img.setImageResource(id);

int getResId(String variableName, Class c)
{
        try {
            Field idField = c.getDeclaredField(variableName);
            return idField.getInt(idField);
        } catch (Exception e) {
            e.printStackTrace();
            return -1;
        }
}