Question

我有ListView。当我单击listview行的按钮时，将在main.xml中创建一个按钮，我在自定义listView适配器中拥有该按钮的onclicklistener。我在sqlite中保存了该按钮的单击，并且通过该sqlite我正在更新gridview适配器。

所以我的问题是，当我点击按钮时，GridView没有自我更新，当我关闭应用程序并再次打开它时会更新。

我尝试使用notifydatasetchanged()，但没有工作..

这是自定义列表视图适配器中的代码

holder.checkbox.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
             String text = holder.tvName.getText().toString();
             String image = holder.tvimageurl.getText().toString();
             DatabaseHandler db = new DatabaseHandler(activity);
             db.addContact(new Contact(text, image));  
             db.close();

并在主Activity

中

    GridView listView = (GridView) findViewById(R.id.gridview1);
    imgAdapter = new ImageAdapter(this);
    listView.setAdapter(imgAdapter);
    imgAdapter.notifyDataSetChanged();

ImageAdapter代码。

public class ImageAdapter extends BaseAdapter {

    Activity activity;
    List<Contact> item;
    LayoutInflater inflater;
    ImageAdapter imgAdapter;
    private DisplayImageOptions options;
    private DisplayImageOptions options2;
    ImageLoader imageLoader;
    private Contact objBean;
    String getUrl,getId;
    ObjectOutputStream oos;
    FileOutputStream fos;



    public ImageAdapter(Activity act) {
        this.activity=act;

        inflater = act.getLayoutInflater();


        DatabaseHandler db = new DatabaseHandler(activity);
        item = db.getAllContacts();
        db.close();
}

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

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

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

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        final LinearLayout imageView;
        if (convertView == null) {
            imageView = (LinearLayout)        inflater.inflate(R.layout.item_grid_image, parent, false);
        } else {
            imageView = (LinearLayout) convertView;
        }

Answer 1

您可以强制Adapter在onClick方法中自行更新，例如

public void onClick(View v) {
    String text = holder.tvName.getText().toString();
    String image = holder.tvimageurl.getText().toString();
    DatabaseHandler db = new DatabaseHandler(activity);
    db.addContact(new Contact(text, image));
    db.close();
    notifyDataSetChanged(); // This will do the trick
 }

修改

当您在重新启动时获取数据意味着它肯定会保存在数据库中时，这表明当您使Adapter无效时，它不会重新加载数据库。像ImageAdapter中的自定义方法一样尝试这样的事情：

public void onClick(View v) { String text = holder.tvName.getText().toString(); String image = holder.tvimageurl.getText().toString(); DatabaseHandler db = new DatabaseHandler(activity); db.addContact(new Contact(text, image)); db.close(); reloadData(); // will refresh the data notifyDataSetChanged(); // will update the contents } private void reloadData() { DatabaseHandler db = new DatabaseHandler(activity); item = db.getAllContacts(); db.close(); }

Answer 2

在调用notifyDataSetChanged之前，您需要先向ImageAdapter添加数据。或者重新创建它并再次设置为GridView

UPD：好的，然后将加载代码放入ImageAdapter中的单独方法，并在添加新数据后调用刷新

public ImageAdapter(Activity act) {
        this.activity=act;

        inflater = act.getLayoutInflater();
        refresh();
}

void refresh()
{
        DatabaseHandler db = new DatabaseHandler(activity);
        item = db.getAllContacts();
        db.close();
        notifyDatasetChanged();
}

但是，当您点击按钮时，最好手动将新联系人添加到ImageAdapter

public void onClick(View v) {
    String text = holder.tvName.getText().toString();
    String image = holder.tvimageurl.getText().toString();
    DatabaseHandler db = new DatabaseHandler(activity);
    Contact contact = new Contact(text, image)
    db.addContact(contact);  
    db.close();
    imgAdapter.addItem(contact)
    imgAdapter.notifyDatasetChanged();
}

如何刷新我的gridView？

2 个答案: