我正试图通过AsyncTaskRunner从Parse.com获取一些数据。那么我打算用ListView来展示它们。我的自定义适配器代码附在下面：
public class ParseObjectAdapter extends BaseAdapter {
Context mContext;
LayoutInflater mInflater;
List<ParseObject> parseArray;
DBShoppingHelper mydb2;
public ParseObjectAdapter(Context context, LayoutInflater inflater) {
mContext = context;
mInflater = inflater;
parseArray = new ArrayList<>();
}
@Override
public int getCount() {
try {
return parseArray.size();
}
catch (Exception e){
return 0;
}
}
@Override
public ParseObject getItem(int position) { return parseArray.get(position); }
@Override
public long getItemId(int position) {
return position;
}
public String getObjectId(int position){
return getItem(position).getObjectId();
}
public void sortByExpiry()
{
Comparator<ParseObject> comparator = new Comparator<ParseObject>() {
@Override
public int compare(ParseObject lhs, ParseObject rhs) {
return ((Integer) lhs.getInt("expiresIn")).compareTo(rhs.getInt("expiresIn"));
}
};
Collections.sort(parseArray, comparator);
notifyDataSetChanged();
}
@Override
public View getView(final int position, View convertView, final ViewGroup parent) {
ViewHolder holder;
// Inflate the custom row layout from your XML.
convertView = mInflater.inflate(R.layout.list_item, null);
// create a new "Holder" with subviews
holder = new ViewHolder();
holder.itemNameView = (TextView) convertView.findViewById(R.id.item_name);
holder.itemExpiryView = (TextView) convertView.findViewById(R.id.item_expiry);
// Taking care of the buttons
holder.editButton = (Button) convertView.findViewById(R.id.button_edit);
holder.deleteButton = (Button) convertView.findViewById(R.id.button_delete);
holder.shoppingListButton = (Button) convertView.findViewById(R.id.button_shopping);
// hang onto this holder for future recycling
convertView.setTag(holder);
int expiry = getItem(position).getInt("expiresIn");
if (expiry <= 0) {
holder.itemExpiryView.setTextColor(Color.rgb(255,80,54));
}
// Set listener on the buttons
holder.editButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Toast.makeText(mContext, "Edit Button CLicked", Toast.LENGTH_SHORT).show();
ParseObject p = getItem(position);
Intent goToAddItem = new Intent(mContext,ItemAddPage.class);
goToAddItem.putExtra("catg_passed", p.getString("category"));
goToAddItem.putExtra("update_flag", "YES");
goToAddItem.putExtra("name passed", p.getString("itemName"));
goToAddItem.putExtra("expires_in_passed", p.getString("expiresIn"));
goToAddItem.putExtra("price_passed", p.getString("itemPrice"));
mContext.startActivity(goToAddItem);
}
});
holder.deleteButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ParseObject p = getItem(position);
String android_id = Settings.Secure.getString(mContext.getContentResolver(), Settings.Secure.ANDROID_ID);
ParseQuery itemToBeDeleted = new ParseQuery("Items");
itemToBeDeleted.whereEqualTo("ACL", p.getACL());
itemToBeDeleted.whereEqualTo("objectId", p.getObjectId());
final Date deletionDate = new Date();
itemToBeDeleted.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> Items, com.parse.ParseException e) {
if (e == null) {
Log.d("score", "Retrieved " + Items.size() + " scores");
if (Items.size() == 1) {
ParseObject itemToDelete = Items.get(0);
itemToDelete.put("deleted", true);
itemToDelete.put("deletedOn", deletionDate);
itemToDelete.saveEventually();
}
} else {
Log.d("score", "Error: " + e.getMessage());
}
}
});
parseArray.remove(p);
sortByExpiry();
notifyDataSetChanged();
Toast.makeText(mContext, "Item deleted", Toast.LENGTH_SHORT).show();
}
});
holder.shoppingListButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v)
{
ParseObject p = getItem(position);
String add_to_list = p.getString("itemName");
SimpleDateFormat sdf = new SimpleDateFormat("dd-MMM-yyyy");
String add_date = sdf.format(new Date());
System.out.println(add_date);
mydb2.insertItem(add_to_list, add_date);
Toast.makeText(mContext, "Item added to shopping list", Toast.LENGTH_SHORT).show();
}
});
ParseObject p = getItem(position);
String name2 = p.getString("itemName");
Integer ex = p.getInt("expiresIn");
String days_s ="";
if (ex == 0) {
days_s = "Expires today" ;
}
else if (ex == -1) {
days_s = "Expired yesterday";
}
else if (ex < 0) {
days_s = "Expired " + Math.abs(ex) + " days ago";
}
else if (ex == 1) {
days_s = "Expires tomorrow";
}
else {
days_s = "Expires in " + ex + " days";
}
holder.itemNameView.setText(name2);
holder.itemExpiryView.setText(days_s);
return convertView;
}
public void onClick(View v)
{
Intent viewItem = new Intent(v.getContext(), ItemAddPage.class);
v.getContext().startActivity(viewItem);
}
private static class ViewHolder {
public TextView itemNameView;
public TextView itemExpiryView;
public Button editButton;
public Button deleteButton;
public Button shoppingListButton;
}
public void updateData(List<ParseObject> arrayPassed) {
// update the adapter's data set
parseArray = arrayPassed;
notifyDataSetChanged();
}
}
这是我称之为的方法..
public class WelcomeParse extends Activity {
ListView currentListView;
List<ParseObject> currentList;
ParseObjectAdapter itemAdder;
String catg;
DBShoppingHelper mydb2;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
overridePendingTransition(R.anim.left_in, R.anim.right_out);
setTheme(android.R.style.Theme_Holo_Light_DarkActionBar);
setContentView(R.layout.activity_main);
itemAdder = new ParseObjectAdapter(this, getLayoutInflater());
mydb2 = new DBShoppingHelper(this);
AsyncTaskAllItems runner = new AsyncTaskAllItems();
runner.execute();
// itemAdder.notifyDataSetChanged();
this.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
}
public class AsyncTaskAllItems extends AsyncTask<String, String, String> {
private String resp;
private Integer numItems = 0;
@Override
protected String doInBackground(String... params) {
try {
ParseQuery itemsAll = new ParseQuery("Items");
itemsAll.whereEqualTo("owner", ParseUser.getCurrentUser().getUsername());
// itemsByCategory.whereEqualTo("category", catg);
itemsAll.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> Items, ParseException e) {
if (e == null) {
Log.d("score", "Retrieved " + Items.size() + " scores");
Log.d("owner", ParseUser.getCurrentUser().getUsername());
// HERE SIZE is 0 then 'No Data Found!'
numItems = Items.size();
if (numItems > 0) {
currentList = Items;
}
} else {
Log.d("score", "Error: " + e.getMessage());
}
}
});
resp = "Done";
}
// catch (InterruptedException e) {
// e.printStackTrace();
// resp = e.getMessage();
// }
catch (Exception e) {
e.printStackTrace();
resp = e.getMessage();
}
return resp;
}
@Override
protected void onPostExecute(String result) {
currentListView = (ListView) findViewById(R.id.all_list);
itemAdder.updateData(currentList);
if (numItems > 0) {
itemAdder.sortByExpiry();
}
currentListView.setAdapter(itemAdder);
// onWindowFocusChanged(true);
}
@Override
protected void onPreExecute() {
}
@Override
protected void onProgressUpdate(String... text) {
}
}
}
我没有收到任何错误，日志正确显示了应该检索的项目数。但是视图没有得到相关数据的更新。 任何人请告诉我我错在哪里？你需要的任何其他东西，请告诉我。非常感谢。
答案 0 :(得分：0)
更换后尝试
@Override
protected void onPostExecute(String result) {
currentListView = (ListView) findViewById(R.id.all_list);
itemAdder.updateData(currentList);
if (numItems > 0) {
itemAdder.sortByExpiry();
}
currentListView.setAdapter(itemAdder);
// onWindowFocusChanged(true);
}
用
@Override
protected void onPostExecute(String result) {
currentListView = (ListView) findViewById(R.id.all_list);
currentListView.setAdapter(itemAdder);
itemAdder.updateData(currentList);
if (numItems > 0) {
itemAdder.sortByExpiry();
}
}