小编oom*_*ler的帖子

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.os.Parcelable;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends Activity {

    ImageView iv;
    Bitmap bTemp;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);




        Button cameraClick = (Button) findViewById(R.id.click);
        iv = (ImageView) findViewById(R.id.imageView1);

        final Bitmap data = (Bitmap) getLastNonConfigurationInstance();
        if (data == null) { 

           iv.setImageBitmap(bTemp);
        }


        cameraClick.setOnClickListener(myhandler);

    }


    OnClickListener myhandler = new OnClickListener() {
        public void onClick(View v) {
            Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE); …

template <typename _CountofType, size_t _SizeOfArray>
char( *__countof_helper1( _CountofType(&_Array)[_SizeOfArray]))[_SizeOfArray];

#define _myCountOf(_Array) (sizeof(*__countof_helper1(_Array)) + 0)

我试图理解 _countof 宏，但无法理解它如何能够计算数组的大小。请有人一点一点解释上面的代码