Question

我在第一个活动中使用带有毕加索的字符串数组URL在gridview中显示随机图像，当我在gridview中单击任何图像时，我想在下一个活动中显示确切的随机图像。我正在使用put extra并像int r = random.nextInt(array.length);那样发送该位置，我正在r中使用r到gridview中，把extra作为位置。但是当我在imageview中设置r时，它显示的是另一幅不精确的随机图像。

这是我的代码

public class MainActivity extends Activity {

   static Random random;
    private GridView photoGrid;
    private int mPhotoSize, mPhotoSpacing;
static int p;
    // Some items to add to the GRID


static final String[] icons= {
                "https://abhiandroid.com/ui/wp-content/uploads/2015/12/horizontalSpacing-in-Gridview.jpg",
                "http://www.whatsappstatusmessages.com/wp-content/uploads/2017/01/whatsapp-dp-images-in-english.jpg",
                "http://www.sarkarinaukrisearch.in/wp-content/uploads/2019/02/whatsapp-dp-status-in-english-1-77.jpg",
                "https://www.trueshayari.in/wp-content/uploads/2018/07/Love-Status-DP-for-Couple.jpg",
                "https://4.bp.blogspot.com/-2iawNx83Kpw/XL21pPj0aPI/AAAAAAAAKiE/VRR7pupbWDUj0TNNAKdGH8Baaz_c9IcSgCLcBGAs/s1600/ss.jpg",
                "https://www.trueshayari.in/wp-content/uploads/2018/07/Love-Status-DP-for-Couple.jpg",
                "https://3.bp.blogspot.com/-8us6YRiZEh0/XL21c6ibbXI/AAAAAAAAKh4/eNyjErq7q04YCeWxDPWojYfOoAC8BCodwCLcBGAs/s1600/s.jpg"

        };


GridView gridView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    gridView = findViewById(R.id.albumGrid);

    CustomAdopter customAdopter=new CustomAdopter();

gridView.setAdapter(customAdopter);
    gridView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent intent = new Intent(MainActivity.this, SwipeView.class);
            intent.putExtra("id", p);
            startActivity(intent);
        }
    });


}

private static class CustomAdopter extends BaseAdapter {

     static int p;

    @Override
    public int getCount() {
        return icons.length;
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {


        View view = getLayoutInflater().inflate(R.layout.phototem, null);
        ImageView imageView = view.findViewById(R.id.cover);
        random = new Random(); // or create a static random field...
        p=  random.nextInt(icons.length);


        Picasso.get().load(icons[p]).placeholder(R.mipmap.ic_launcher).error(R.mipmap.ic_launcher).into(imageView);

        return view;
    }

}

在此活动中显示图像

public class SwipeView extends Activity
{
    int positions;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_swipe_view);

    // get intent data
    Intent i = getIntent();

    // Selected image id
     positions = i.getExtras().getInt("id");

    ViewPager viewPager = (ViewPager) findViewById(R.id.view_pager);
    ImagePagerAdapter adapter = new ImagePagerAdapter();
    viewPager.setAdapter(adapter);
    viewPager.setCurrentItem(technoapps4.goodnightshayariworld.MainActivity.p);
}

private class ImagePagerAdapter extends PagerAdapter
{

     String[] icons =MainActivity.icons ;
     @Override
    public int getCount()
    {
        return icons.length;
    }

    @Override
    public boolean isViewFromObject(View view, Object object)
    {
        return view == ((ImageView) object);
    }

    @Override
    public Object instantiateItem(ViewGroup container, int position)
    {
        Context context = SwipeView.this;
        ImageView imageView = new ImageView(context);


        Picasso.get().load(icons[position]).into(imageView);

         container.addView(imageView, 0);
        return imageView;
    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object)
    {
container.removeView((ImageView) object);
    }
}

}

Answer 1

为此，您应该创建一个Interface并通过该接口传递随机位置。并且变量p不是单击的项目位置。 p的值在gridView填充项的同时不断变化。 编辑： 像这样创建一个Interface：

public interface ItemClickListener {
    void onItemClick(int position);
}

现在使用公共设置器初始化ItemClickListener类中的CustomAdopter实例。

public void setItemClickListener(ItemClickListener clickListener) {
    onItemClickListener = clickListener;
}

最后，在getview方法内添加以下代码，以将适配器位置传递给侦听器。

view.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        onItemClickListener.onItemClick(p);
    }
});

现在，使用该界面来获取正确的位置，而不是GridView的{{1}}。像这样-

OnItemClickListener()

Answer 2

我将为您提供此问题的替代方法，即使用带有gridLayoutManager的recyclerview并创建实现RecyclerView.Adapter的自定义布局。...我想所有这些似乎都使您感到困惑，所以我很快创建一个单元测试来模拟您的代码想要实现的目标，然后是结果。

public class ExampleUnitTest {
    private static String data = null;

    @Test
    public void setParentData(){
        data = "I set You";

        Subclass subclass = new Subclass();
        subclass.getParentData();
    }

    private static class Subclass{
        void getParentData(){
            assertEquals("I set You", data);
        }
    }
}
//Tests passed

由于您将自定义适配器作为MainActivity的子类，所以我将花一分钟的时间对此进行解释，然后我相信该子类应该可以访问其父类的某些值。我在说的是：static int p;，所以您无需像在子类（CustomAdopter类）中创建的那样创建其中的两个。因此，下面是对您的代码的修改，我认为它应该在测试通过后才能起作用，否则，请让我知道，以便我再次查看。这并不是真正的答案，但这是我共享代码并详细解释一些事情的唯一方法。

public class MainActivity extends Activity {

   static Random random;
    private GridView photoGrid;
    private int mPhotoSize, mPhotoSpacing;
   static int p;
    // Some items to add to the GRID


static final String[] icons= {
                "https://abhiandroid.com/ui/wp-content/uploads/2015/12/horizontalSpacing-in-Gridview.jpg",
                "http://www.whatsappstatusmessages.com/wp-content/uploads/2017/01/whatsapp-dp-images-in-english.jpg",
                "http://www.sarkarinaukrisearch.in/wp-content/uploads/2019/02/whatsapp-dp-status-in-english-1-77.jpg",
                "https://www.trueshayari.in/wp-content/uploads/2018/07/Love-Status-DP-for-Couple.jpg",
                "https://4.bp.blogspot.com/-2iawNx83Kpw/XL21pPj0aPI/AAAAAAAAKiE/VRR7pupbWDUj0TNNAKdGH8Baaz_c9IcSgCLcBGAs/s1600/ss.jpg",
                "https://www.trueshayari.in/wp-content/uploads/2018/07/Love-Status-DP-for-Couple.jpg",
                "https://3.bp.blogspot.com/-8us6YRiZEh0/XL21c6ibbXI/AAAAAAAAKh4/eNyjErq7q04YCeWxDPWojYfOoAC8BCodwCLcBGAs/s1600/s.jpg"

        };


GridView gridView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    gridView = findViewById(R.id.albumGrid);

    random = new Random(); // or create a static random field...
    p=  random.nextInt(icons.length);

    CustomAdopter customAdopter=new CustomAdopter();

gridView.setAdapter(customAdopter);
    gridView.setOnItemClickListener(new OnItemClickListener() {

        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            Intent intent = new Intent(MainActivity.this, SwipeView.class);
            intent.putExtra("id", p);
            startActivity(intent);
        }
    });


}

private static class CustomAdopter extends BaseAdapter {

    @Override
    public int getCount() {
        return icons.length;
    }

    @Override
    public Object getItem(int position) {
        return null;
    }

    @Override
    public long getItemId(int position) {
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {


        View view = getLayoutInflater().inflate(R.layout.phototem, null);
        ImageView imageView = view.findViewById(R.id.cover);

Picasso.get().load(icons[p]).placeholder(R.mipmap.ic_launcher).error(R.mipmap.ic_launcher).into(imageView);

        return view;
    }

}

如何发送随机位置到下一个活动

2 个答案: