startActivityForResult()里你可能忽视的r

直接说：
android.support.v4.app.FragmentActivity下调用startActivityForResult(Intent intent, int requestCode)的话，requestCode的取值范围是：0 to 65535。
源码：
@Override public void startActivityForResult(Intent intent, int requestCode) { if (requestCode != -1 && (requestCode&0xffff0000) != 0) { throw new IllegalArgumentException("Can only use lower 16 bits for requestCode"); } super.startActivityForResult(intent, requestCode); }