在尝试检查parse.com column
或Key
特定行在列(名为File
)中是否具有值(数据),这不是我以前在iOS上迅速执行的操作
guard let photo = object["File"] as? PFFile else { do soothing else }
// here am firstly assigning a PFFile name Photo the value of an parseObject's column ( if object haves file than assign else ( do nothing) )
photo.getDataInBackgroundWithBlock{
(imageData:NSData?, error:NSError?)-> Void in
// now am querying for data
if (error == nil){
if object["File"] != nil {
cell.cellAttachment.alpha = 1
}}
else if error != nil{
print("error") //do nothing
}
}
}
//as you can see - if parse object say (list) have value inside a key (File) than do something else do nothing
所以我的问题是我如何才能使用java为android创建一种方法,像这样检查键是否包含值,而不是在数组中添加
true
,否则在数组中添加false
任何指导都会对我有帮助
最佳答案
//get all images
ParseQuery<ParseObject> query = ParseQuery.getQuery("Images");
query.whereWithinKilometers("location", parseGeoPoint, 100);
query.orderByDescending("createdAt");
query.findInBackground(new FindCallback<ParseObject>() {
@Override
public void done(List<ParseObject> objects, ParseException e) {
if (objects.size() > 0) {
if (e == null) {
if (!objects.isEmpty()) {
setupAdapter((ArrayList) (objects));
}
} else if (e.getCode() == ParseException.REQUEST_LIMIT_EXCEEDED) {
makeSnack("Error! Reloading images.");
displayImages(); // How many times you do this is your business...
} else {
e.printStackTrace();
Log.v("error", e.getMessage());
}
} else {
//TODO:// if not images, reregister loclistener
makeSnack("No images located near you.");
}
}
});