This code is working in a Firemonkey Windows app, but doesn't work in Android app, i get Goodbye instead of Welcome, what is wrong?
Edit8 Text : 162496 //Computer unique code
Edit9 Text : 1564224593 //serial #
procedure TForm2.Button5Click(Sender: TObject);
var
f2,f1:textfile;
i,j:byte;
s1,s2,s3,c:string;
F: TextFile;
begin
j:=0;
s2 := Edit8.Text;
for i:=1 to Length(s2) do
if (s2[i]>='0') and (s2[i]<='9') then
s3:=s3+s2[i];
for i:=1 to Length(s3)-1 do
if (edit9.Text[i*2-1]<>s3[i]) or (abs(strtoint(s3[i+1])-strtoint(s3[i]))<> strtoint(edit9.Text[i*2])) then
inc(j);
if j=0 then
ShowMessage('Welcome')
else
ShowMessage('Goodbye');
end;
Delphi mobile compilers use zero-based strings.
You have three choices:
As #Günter_the_Beautiful points out, your best choice is to rewrite your code to use string helpers (which are always 0-based)
Rewrite your code to use 0-based indexing: for I := 0 to ...
If you need a quick fix, turn it off locally for your code snippet using the {$ZEROBASEDSTRINGS OFF} directive (and revert it back with {$ZEROBASEDSTRINGS ON} again).
For options 2. and 3., if you need your code to be cross-platform, consider using appropriate platform conditional defines. This is what makes option 1. compelling: no need to clutter your code with conditional defines.
I am using these two helper routines:
FUNCTION GetChar(CONST S : STRING ; OneBasedIndex : LongWord) : CHAR;
BEGIN
{$IF CompilerVersion>=24 }
Result:=S[SUCC(OneBasedIndex-LOW(S))]
{$ELSE }
Result:=S[OneBasedIndex]
{$IFEND }
END;
PROCEDURE SetChar(VAR S : STRING ; OneBasedIndex : LongWord ; NewChar : CHAR);
BEGIN
{$IF CompilerVersion>=24 }
S[SUCC(OneBasedIndex-LOW(S))]:=NewChar
{$ELSE }
S[OneBasedIndex]:=NewChar
{$IFEND }
END;
This way, you can continue working with strings as 1-based (which is the logical choice :-)) as long as you always access the strings as characters using these two functions.
Related
AS. since closing related questions - more examples added below.
The below simple code (which finds a top-level Ie window and enumerates its children) works Ok with a '32-bit Windows' target platform. There's no problem with earlier versions of Delphi as well:
procedure TForm1.Button1Click(Sender: TObject);
function EnumChildren(hwnd: HWND; lParam: LPARAM): BOOL; stdcall;
const
Server = 'Internet Explorer_Server';
var
ClassName: array[0..24] of Char;
begin
Assert(IsWindow(hwnd)); // <- Assertion fails with 64-bit
GetClassName(hwnd, ClassName, Length(ClassName));
Result := ClassName <> Server;
if not Result then
PUINT_PTR(lParam)^ := hwnd;
end;
var
Wnd, WndChild: HWND;
begin
Wnd := FindWindow('IEFrame', nil); // top level IE
if Wnd <> 0 then begin
WndChild := 0;
EnumChildWindows(Wnd, #EnumChildren, UINT_PTR(#WndChild));
if WndChild <> 0 then
..
end;
I've inserted an Assert to indicate where it fails with a '64-bit Windows' target platform. There's no problem with the code if I un-nest the callback.
I'm not sure if the erroneous values passed with the parameters are just garbage or are due to some mis-placed memory addresses (calling convention?). Is nesting callbacks infact something that I should never do in the first place? Or is this just a defect that I have to live with?
edit:
In response to David's answer, the same code having EnumChildWindows declared with a typed callback. Works fine with 32-bit:
(edit: The below does not really test what David says since I still used the '#' operator. It works fine with the operator, but if I remove it, it indeed does not compile unless I un-nest the callback)
type
TFNEnumChild = function(hwnd: HWND; lParam: LPARAM): Bool; stdcall;
function TypedEnumChildWindows(hWndParent: HWND; lpEnumFunc: TFNEnumChild;
lParam: LPARAM): BOOL; stdcall; external user32 name 'EnumChildWindows';
procedure TForm1.Button1Click(Sender: TObject);
function EnumChildren(hwnd: HWND; lParam: LPARAM): BOOL; stdcall;
const
Server = 'Internet Explorer_Server';
var
ClassName: array[0..24] of Char;
begin
Assert(IsWindow(hwnd)); // <- Assertion fails with 64-bit
GetClassName(hwnd, ClassName, Length(ClassName));
Result := ClassName <> Server;
if not Result then
PUINT_PTR(lParam)^ := hwnd;
end;
var
Wnd, WndChild: HWND;
begin
Wnd := FindWindow('IEFrame', nil); // top level IE
if Wnd <> 0 then begin
WndChild := 0;
TypedEnumChildWindows(Wnd, #EnumChildren, UINT_PTR(#WndChild));
if WndChild <> 0 then
..
end;
Actually this limitation is not specific to a Windows API callbacks, but the same problem happens when taking address of that function into a variable of procedural type and passing it, for example, as a custom comparator to TList.Sort.
http://docwiki.embarcadero.com/RADStudio/Rio/en/Procedural_Types
procedure TForm2.btn1Click(Sender: TObject);
var s : TStringList;
function compare(s : TStringList; i1, i2 : integer) : integer;
begin
result := CompareText(s[i1], s[i2]);
end;
begin
s := TStringList.Create;
try
s.add('s1');
s.add('s2');
s.add('s3');
s.CustomSort(#compare);
finally
s.free;
end;
end;
It works as expected when compiled as 32-bit, but fails with Access Violation when compiled for Win64. For 64-bit version in function compare, s = nil and i2 = some random value;
It also works as expected even for Win64 target, if one extracts compare function outside of btn1Click function.
This trick was never officially supported by the language and you have been getting away with it to date due to the implementation specifics of the 32 bit compiler. The documentation is clear:
Nested procedures and functions (routines declared within other routines) cannot be used as procedural values.
If I recall correctly, an extra, hidden, parameter is passed to nested functions with the pointer to the enclosing stack frame. This is omitted in 32 bit code if no reference is made to the enclosing environment. In 64 bit code the extra parameter is always passed.
Of course a big part of the problem is that the Windows unit uses untyped procedure types for its callback parameters. If typed procedures were used the compiler could reject your code. In fact I view this as justification for the belief that the trick you used was never legal. With typed callbacks a nested procedure can never be used, even in the 32 bit compiler.
Anyway, the bottom line is that you cannot pass a nested function as parameter to another function in the 64 bit compiler.
how to convert string to PwideChar in Android Platform using Delphi ? in windows apps its done using..
var
PW: PWideChar;
begin
PW := pwidechar(widestring(String));
PW := pwidechar(widestring(Reply));
A := ExistWordInString(PW,String,[soWholeWord,soDown]); //A : Boolean
....
end;
the problems is Undeclared identifier: 'WideString' , how to work around this ?
Delphi 10 Berlin , Firemonkey, Android
UPDATE
well, according to http://docwiki.embarcadero.com/RADStudio/Tokyo/en/Migrating_Delphi_Code_to_Mobile_from_Desktop ,, we cant use widestring, i cant think of another way to use string this function :
function ExistWordInString(aString:PWideChar;aSearchString:string;aSearchOptions: TStringSearchOptions): Boolean;
var
Size : Integer;
Begin
Size:=StrLen(aString);
Result := SearchBuf(aString, Size, 0, 0, aSearchString, aSearchOptions)<>nil;
Your code is not strictly correct in Windows. Yes you can convert string (an alias for UnicodeString) to the COM WideString, but this is a waste of time and resources. The correct code is:
var
P: PWideChar;
S: string;
....
P := PWideChar(S);
In fact, since you are using a Unicode version of Delphi, it is probably idiomatic to use PChar (an alias for PWideChar), to fit alongside string.
So I would write:
var
P: PChar;
S: string;
....
P := PChar(S);
Now, this code, as well as being the correct way to do this on Windows, works equally on all platforms.
In my app, developed with XE7 for Android/iOS, I have a form for scanning barcodes. Upon a found barcode, my app validates whether it is an acceptable barcode or not. Following tutorials here: http://www.fmxexpress.com/qr-code-scanner-source-code-for-delphi-xe5-firemonkey-on-android-and-ios/
Currently I am testing on Android and I am able to integrate scanning and reading of barcodes, but the 'onBarCode' event does not fire when returned from the shared Activity of finding the barcode. Same code worked well with previous versions of Rad Studio ( XE4, XE5, XE6) but now in XE7 it does not.
Here are some snippets of code:
...
begin
Scanner := TAndroidBarcodeScanner.Create(true);
Scanner.OnBarCode := BarcodeHandler;
Scanner.Scan;
end;
procedure TmScannerForm.BarcodeHandler(Sender: TAndroidBarcodeScanner;
BarCode: String);
begin
text1.Text := Barcode;
memo1.PasteFromClipboard;
AddBarcode(BarCode, true);
end;
AddBarCode is the even I used to validate and add barcode to a list, but I didnt include it, because that code isn't the problem - it's not even triggering. The Text1.text:=Barcode and memo1.paseFromClipboard were in their for validating the even wasn't firing too. I can confirm the barcodes are being read because if I tap and manually paste, the barcode shows.
Why is this not working on XE7 as it did in previous versions of Rad Studio?
Andrea Magni has a more elegant solution than the timer on his blog based on event handling.
I would comment to send the link but I don't have enough reputation.
The link to his blog is :
http://blog.delphiedintorni.it/2014/10/leggere-e-produrre-barcode-con-delphi.html
Maybe this can help you. The blog is in Italian though but the sources are provided and are explaining by themselves.
There is a source code fragment on http://john.whitham.me.uk/xe5/ which looks useable (based on Zxing):
intent := tjintent.Create;
intent.setAction(stringtojstring('com.google.zxing.client.android.SCAN'));
sharedactivity.startActivityForResult(intent,0);
The code in the linked article also shows how to receive the Intent result. (I don't work with Delphi on Android so I am not sure if that part uses a best practice - TTKRBarCodeScanner uses a workaround with a Timer and the Clipboard).
I would try this as an alternative to see if works.
This code works to me!
Set timer enabled to true when you run your scan code
procedure Tform.Timer1Timer(Sender: TObject);
begin
if (ClipService.GetClipboard.ToString <> '') then
begin
timer1.Enabled:=false;
zSearch.Text := ClipService.GetClipboard.ToString;
//Do what you need
end;
end;
This code to me works fine!
in andorid.BarcodeScanner
function TAndroidBarcodeScanner.HandleAppEvent(AAppEvent: TApplicationEvent;
AContext: TObject): Boolean;
var
aeBecameActive : TApplicationEvent;
begin
aeBecameActive := TApplicationEvent.BecameActive;
if FMonitorClipboard and (AAppEvent = aeBecameActive) then
begin
GetBarcodeValue;
end;
end;
I am a newbie to Delphi XE5 and currently developing Android platform applications on my Windows desktop using Delphi XE5.
I have two forms(Form1 and Form2) and tried to show Form2 in modal way on Form1 according to the way showed in Marco's RAD Blog(http://blog.marcocantu.com/blog/xe5_anonymous_showmodal_android.html).
But result was not as expected.
procedure TForm1.Button1Click(Sender: TObject);
var
frm2: TForm2;
begin
frm2 := TForm2.Create(nil);
ShowMessage('before frm2.ShowModal...');
frm2.ShowModal (
procedure(ModalResult: TModalResult)
begin
if ModalResult = mrOK then
if frm2.ListBox1.ItemIndex >= 0 then
edit1.Text := frm2.ListBox1.Items [frm2.ListBox1.ItemIndex];
frm2.DisposeOf;
end
);
ShowMessage('after frm2.ShowModal...');
end;
I wrote above code and run the application on an Android device.
I clicked the Button1, then I got the messagebox "before frm2.ShowModal... ", next "after frm2.ShowModal...", and then Form2 was showed.
I expect that the order should be 1)"before frm2.ShowModal... " message, 2) Form2 being showed, and 3) "after frm2.ShowModal..." message.
What's wrong with me?
The call to the anonymous ShowModal is not blocking, which means that any code after the ShowModal will be executed first.
One note here. Calling frm2.DisposeOf is wrong.
You must use this pattern:
declare
procedure TFrm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
Action := TCloseAction.caFree;
end;
See http://www.malcolmgroves.com/blog/?p=1585.
The documentation has been corrected in XE7, Using FireMonkey Modal Dialog Boxes, but this pattern can be used in all Delphi versions.
Conclusion: if you want to execute code after the modal dialog is closed, put that code inside the anonymous method.
How can I get a phone's contact list in a FireMonkey mobile application?
here you go .. It's not finished as it reads all numbers for one person and if there are two numbers you will have two times this person listed inside list .. but from here I think you can work and adjust it to your needs :))
function GetContact: TStringList;
var
cursorContacts, cursorContactsPhone: JCursor;
hasPhoneNumber: Integer;
id: Int64;
displayName, phoneNumber, contactID: string;
begin
Result := TStringList.Create;
cursorContacts := SharedActivity.getContentResolver.query(TJContactsContract_Contacts.JavaClass.CONTENT_URI, nil, nil, nil, nil);
if (cursorContacts.getCount > 0) then
begin
while (cursorContacts.moveToNext) do
begin
id := cursorContacts.getLong(cursorContacts.getColumnIndex(StringToJString('_ID')));
displayName := JStringToString(cursorContacts.getString(cursorContacts.getColumnIndex(StringToJString('DISPLAY_NAME'))));
hasPhoneNumber := cursorContacts.getInt(cursorContacts.getColumnIndex(StringToJString('HAS_PHONE_NUMBER')));
if (hasPhoneNumber > 0) then
begin
cursorContactsPhone := SharedActivity.getContentResolver.query(TJCommonDataKinds_Phone.JavaClass.CONTENT_URI, nil,StringToJString('CONTACT_ID = ' + IntToStr(id)),nil, nil);
while (cursorContactsPhone.moveToNext) do
begin
phoneNumber := JStringToString(cursorContactsPhone.getString(cursorContactsPhone.getColumnIndex(StringToJString('DATA1'))));
contactID := JStringToString(cursorContactsPhone.getString(cursorContactsPhone.getColumnIndex(StringToJString('CONTACT_ID'))));
Result.Add(displayName + ': ' + phoneNumber);
end;
cursorContactsPhone.close;
end;
end;
end;
cursorContacts.close;
end;
Best Regards,
Kruno
Here's my code (inspired and originally created by #mali kruno, I only changed it to my needs!) to search through all contacts based on TEdit OnChange event:
I use this function in my commonfunctions.pas unit:
function GetContact (Name: string; Number: string; const tip: integer) : TStringList;
var
cursorContactsPhone: JCursor;
Typo1, Typo2: string;
FindBy: JString;
ToFind: TJavaObjectArray<JString>;
CurRec: integer;
begin
Result:=TStringList.Create;
CurRec:=0;
ToFind:= TJavaObjectArray<JString>.Create(2);
if Name <> '' then
begin
ToFind.Items[0] := StringToJString('data1');
ToFind.Items[1] := StringToJString('display_name');
FindBy := StringToJString('display_name LIKE "%' + Name + '%"');
Typo1:='data1';
Typo2:='display_name';
end
else if Number <> '' then
begin
ToFind.Items[0] := StringToJString('display_name');
ToFind.Items[1] := StringToJString('data1');
FindBy := StringToJString('data1 LIKE "%' + Number + '%"');
Typo1:='display_name';
Typo2:='data1';
end;
cursorContactsPhone := SharedActivity.getContentResolver.query(TJCommonDataKinds_Phone.JavaClass.CONTENT_URI, ToFind, FindBy, nil, nil);
while (cursorContactsPhone.moveToNext) do
begin
Result.Add
(JStringToString(cursorContactsPhone.getString(cursorContactsPhone.getColumnIndex(StringToJString(Typo2)))) + ' - ' +
JStringToString(cursorContactsPhone.getString(cursorContactsPhone.getColumnIndex(StringToJString(Typo1)))));
CurRec:=CurRec+1;
end;
cursorContactsPhone.close;
end;
I call it from ContactSearch.Change event (it's TEdit component) like this:
procedure TMainF.ContactsSearch.Change(Sender: TObject);
var ResultNo: integer; SearchContacts: string; Results: TStringList;
begin // begin main procedure
if ContactsSearch.Text.Length > 1 then
begin //begin search and memo update
SearchContacts:=ContactsSearch.Text;
Results:=GetContact(SearchContacts, '', 0);
ResultNo:=0;
Memo1.Lines.Clear;
for ResultNo := 0 to Results.Count-1
do
begin
Memo1.Lines.Add(Results.Strings[ResultNo]);
end;
Results.Free;
end;
end;
Note, that the Result is a TStringList created in a function and freed in a procedure after Memo update.
Note also, that I only search if TEdit length is 2 or more, since otherwise entering just "a" in a tedit would show all contacts that have a letter "a" in their name, and therefore it would freeze a little every time you search, use backspace etc...
The workaround would be to load the phonebook in a TStringList on application start, and then search through the stringlist only, but that would make few other troubles:
a) phonebook update wouldn't be detected, or you'd have to implement "Update" button, which would make no sense to do the workaround at all..
b) app start would take longer
c) haven't tried that and not sure how much would it actually speed-up the search, since the Memo.Lines.Add takes more time than the query itself, so...
As for the duplicates, you can see that here are not handled, because currently I don't have a need to do so, but you can easily handle this using "sort" in a Memo, or, even better if you don't want to lose the entries that would otherwise appear as a duplicate, manage them inside a TStringList itself, so that you merge numbers in the same line, or create sub-stringlists for each name (of course, only if a name appears more than once, if you don't want to end up having twice as much stringlists as you'd actually need).
Hope this helps.
You do it in much the same way as a programmer would who uses the native programming APIs, given that Delphi does not provide a unified/wrapped solution to this problem.
You need to research how the Android SDK surfaces the contact list and how the iOS SDK surfaces its contact list, then make use of the native APIs to access it.
It will differ wildly between the 2 platforms, but it would be feaible to write some OS-independent interface to it once you've established the implementation on the 2 different OSs and seen what is on offer and what is accessible across the two implementations. This is what FMX does in other instances of similar features implemented on the two platforms.
If the required APIs haven't already been imported into Delphi's RTL, which is quite possible, then you'd also need to write the imports for those APIs you need in order to be able to call them in the first place.
Executive summary:
Roll up your sleeves
Get stuck in
Code it up yourself
Bask in the pleasure of having got some cool API stuff working