Question

我已按照有关如何使用GridView的文档进行操作，并遇到与此人ImageAdapter cannot be applied to a Fragment Class

相同的问题

我的片段类中的代码如下

public class SecondFragment extends Fragment {

    View myView;
    GridView gridview;

    @Nullable
    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, Bundle savedInstanceState) {
        myView = inflater.inflate(R.layout.second_layout, container, false);
        gridview = (GridView) myView.findViewById(R.id.gridview);
        gridview.setAdapter(new ImageAdapter(getActivity()));
        return myView;
    }
}

但是我在倒数第二行出现错误“Image Adapter无法应用于android.app.activity”

我的ImageAdapter如下

public class ImageAdapter extends BaseAdapter {

    private Context mcontext;

    @Override
    public int getCount() {
        return mthumbids.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) {
        ImageView imageView;
        if (convertView == null) {
            imageView = new ImageView(mcontext);
            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);
        }
        else  {
            imageView = (ImageView)convertView;
        }

        return imageView;
    }

    private Integer[] mthumbids =
            {
              R.drawable.img1, R.drawable.img2,
              R.drawable.img3, R.drawable.img4,
              R.drawable.img5, R.drawable.img6
            };
}

Answer 1

在ImageAdapter类中添加此代码。

{{1}}

Answer 2

您还可以从USER_ID中的父级获取上下文。然后，您不必传递和存储上下文。所以你的getView()看起来像这样：

getView

Answer 3

缺少ImageAdapter的参数上下文的构造函数。只会自动创建空构造函数你应该编写具有特定参数值的构造函数。

public ImageAdapter(Context context){

mContext = context; }

Answer 4

你需要在ImageAdapter类中有一个构造函数，它将上下文作为参数。

您还必须根据适配器位置设置图像的背景。

这是修改后的适配器类。

public class ImageAdapter extends BaseAdapter {

    private Context mcontext;

    public ImageAdapter (Context context) {
        mContext = context;
    }

    @Override
    public int getCount() {
        return mthumbids.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) {
        ImageView imageView;
        if (convertView == null) {
            imageView = new ImageView(mcontext);
            imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
            imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
            imageView.setPadding(8, 8, 8, 8);

            // Add the following to load the image
            imageView.setBackground(ContextCompat.getDrawable(context, mthumbids[position]));
        }
        else  {
            imageView = (ImageView)convertView;
        }

        return imageView;
    }

    private Integer[] mthumbids =
            {
              R.drawable.img1, R.drawable.img2,
              R.drawable.img3, R.drawable.img4,
              R.drawable.img5, R.drawable.img6
            };
}

ImageAdapter不能应用于片段类

4 个答案: