Question

我需要在点击按钮时重新加载适配器。但是我该怎么做呢？我的代码如下。

public class CustomGridAdapter extends BaseAdapter {

private Context context;
//private final String[] gridValues;
ArrayList<Bitmap> arrayList;
ImageButton i1;

//Constructor to initialize values
public CustomGridAdapter(Context context, ArrayList<Bitmap> ob) {
    arrayList = ob;
    this.context = context;
    // this.gridValues     = gridValues;
}

@Override
public int getCount() {
    return arrayList.size();
}

@Override
public Object getItem(int position) {

    return null;
}

@Override
public long getItemId(int position) {

    return 0;
}

public View getView( int position,  View convertView,  ViewGroup parent) {
    final int pos = position;
    // LayoutInflator to call external grid_item.xml file

    LayoutInflater inflater = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);

    View gridView;

    if (convertView == null) {

        gridView = new View(context);

        // get layout from grid_item.xml ( Defined Below )

        gridView = inflater.inflate(R.layout.grid_item, null);
        ImageView imageView = (ImageView) gridView
                .findViewById(R.id.grid_item_image);

        imageView.setImageBitmap(arrayList.get(position));
        ImageButton imageButton = (ImageButton) gridView
                .findViewById(R.id.imageButton);
        imageButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

                Log.d("myLogs", "Yes, onclick "+pos);
                arrayList.remove(pos);
                 !!!THERE I NEED TO RELOAD IT
            }
        });
    } else {

        gridView = (View) convertView;
    }

    return gridView;
}

}

Answer 1

首先，您必须设置事件并在活动中使用它...您必须修改适配器并向其添加OnClickListener attr：

private Context context;
private OnClickListener listener;
ArrayList<Bitmap> arrayList;
ImageButton i1;

//Constructor to initialize values
public CustomGridAdapter(Context context, ArrayList<Bitmap> ob, OnClickListener listener) {
    arrayList = ob;
    this.context = context;
    this.listener = listener;
}

然后设置setOnClickListener，您必须执行以下操作：

imageView.setImageBitmap(arrayList.get(position));
ImageButton imageButton = (ImageButton) gridView
            .findViewById(R.id.imageButton);
imageButton.setOnClickListener(listener);

然后，在java中，您需要让您的活动实现OnClickListener，然后覆盖onClickListener方法，您可以使用以下方法重新加载列表：

@Override
public void onClick(View v) {   
        adapter = new CustomGridAdapter(MyActivity.this, myArrayListWithMyData, MyActivity.this);

        listView.setAdapter(adapter);

        listView.invalidate();
}

要设置适配器，您可以传递上下文（例如this）作为OnClickListener的参数：

adapter = new CustomGridAdapter(this, myArrayListWithMyData, this);

希望它有所帮助！

Answer 2

我相信你可以使用NotifyDataSetChanged（）;那应该重新加载数据。

Answer 3

您的代码的问题在于您的列表正在重用旧视图，并且在重用视图时，不会为当前视图重新注册侦听器，因为只有在创建新视图（未重用）时才注册侦听器。使用以下代码：

...    
if (convertView == null) {
                gridView = new View(context);
                // get layout from grid_item.xml ( Defined Below )
                gridView = inflater.inflate(R.layout.grid_item, null);
            } else {
                gridView = (View) convertView;
            }
            ImageView imageView = (ImageView) gridView.findViewById(R.id.grid_item_image);
            imageView.setImageBitmap(arrayList.get(position));
            ImageButton imageButton = (ImageButton) gridView.findViewById(R.id.imageButton);
            imageButton.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Log.d("myLogs", "Yes, onclick " + pos);
                    arrayList.remove(pos);
                    notifyDataSetChanged();
                }
            });
    ...

有关使用和优化ListView的详细信息，请参阅this Blog。

如何从getView方法重新加载Base Adapter

3 个答案: