I have a switch statement in my action script class.I have a function onKeyDown(event: KeyboardEvent) which contain a switch statement.which control the different keys.
But now I want to handle the same functionality which TAB key is doing using two keys CTRL and SPACE key.
I want add a case more in my switch statement first I pressed CTRL and then SPACE key then a a specific function is called.
Anyone can tell me how two keys used in my switch statement?
private function onKeyDown(event: KeyboardEvent) : void{
if (popUp.displayPopUp){
switch (event.keyCode){
case Keyboard.UP:
case Keyboard.DOWN:
case Keyboard.END:
case Keyboard.HOME:
case Keyboard.PAGE_UP:
case Keyboard.PAGE_DOWN:
inputTxt.selectRange(text.length, text.length)
list.dispatchEvent(event)
break;
case Keyboard.ENTER:
acceptCompletion();
break;
case Keyboard.TAB:
if (requireSelection)
acceptCompletion();
else
popUp.displayPopUp = false
break;
case Keyboard.ESCAPE:
popUp.displayPopUp = false
break;
case Keyboard.CONTROL && Keyboard.SPACE:
if (requireSelection)
acceptCompletion();
else
popUp.displayPopUp = false
break;
}
}
}
This is a pretty common problem.
event.keyCode is only going to give you the keyCode for the most recent key pressed. So you will have to store key presses and key releases. Fortunately, AS3 is a pretty sweet Array implementation that allows this to be done easily.
var _keys:Array;
addEventListener(KeyboardEvent.KEY_DOWN, keyDownEvent);
addEventListener(KeyboardEvent.KEY_UP, keyUpEvent);
function keyDownEvent(e:KeyboardEvent)
{
// turn the key on
_keys[e.keyCode] = true;
// perform logic
keyLogic()
}
function keyUpEvent(e:KeyboardEvent)
{
// turn the key off
_keys[e.keyCode] = false;
}
function keyLogic()
{
// this is where the actual logic is
if(_keys[Keyboard.SPACE] && _keys[Keyboard.CONTROL])
{
if (requireSelection)
acceptCompletion();
else
popUp.displayPopUp = false
}
}
This allows you to have a neat little array that always tells you what keys are down. It also separates your program logic from your input logic. Double win.
In your case you can just check ctrlKey property on KeyboardEvent. But #DingoEatingFuzz's answer will allow check combinations like 'space' + 'letter' and so on.
case Keyboard.SPACE:
if (event.ctrlKey)
{
}
break;
i think this one approch is good........
Related
I have a recursive function which iterates though directory trees listing the file names located in them.
Here is the function:
void WINAPI SearchFile(PSTR Directory)
{
HANDLE hFind;
WIN32_FIND_DATA FindData;
char SearchName[1024],FullPath[1024];
memset(SearchName,0,sizeof(SearchName));
memset(&FindData,0,sizeof(WIN32_FIND_DATA));
sprintf(SearchName,"%s\\*",Directory);
hFind=FindFirstFile(SearchName,&FindData);
if(hFind!=INVALID_HANDLE_VALUE)
{
while(FindNextFile(hFind,&FindData))
{
if(FindData.cFileName[0]=='.')
{
continue;
}
memset(FullPath,0,sizeof(FullPath));
sprintf(FullPath,"%s\\%s",Directory,FindData.cFileName);
if(FindData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
MessageBoxA(NULL, FullPath, "Directory", MB_OK);
SearchFile(FullPath);
}
else
{
MessageBoxA(NULL, FullPath, "File", MB_OK);
}
}
FindClose(hFind);
}
}
There are obviously differences between both functions but I don't understand what's making them act differently. Does anyone know why I am having this problem?
for fast understand error need look for line
goto label;
//SearchFile(FullPath);
at this point hFind containing valid data and FindClose(hFind); need be called for it. but after goto label; executed - your overwrite hFind with hFind = FindFirstFile(SearchName, &FindData); - so you already never close original hFind, never can return to iterate folder after such go to sub-folder. this is key point - need save original hFind before go to sub directory and restore it after. when you do recursive function call - this is done auto - because every sub directory in this case enumerated in self stack frame, which have separate hFind. this is native solution use recursion here.
but possible convert recursion to loop here because we call self always from the single place and as result to this single place. so we can not save return address in stack but do unconditional jump (goto) to known place.
then code have some extra errors, you never check for string buffers overflow, why 1024 as max length is hard-coded when file path can be up to 32768 chars, you not check for reparse point as result can enter to infinite loop, use FindFirstFile instead FindFirstFileEx, etc.
correct code for enumerate sub-folder in loop can be next
void DoEnum(PCWSTR pcszRoot)
{
SIZE_T FileNameLength = wcslen(pcszRoot);
// initial check for . and ..
switch (FileNameLength)
{
case 2:
if (pcszRoot[1] != '.') break;
case 1:
if (pcszRoot[0] == '.') return;
}
static const WCHAR mask[] = L"\\*";
WCHAR FileName[MAXSHORT + 1];
if (_countof(FileName) < FileNameLength + _countof(mask))
{
return;
}
ULONG dwError;
HANDLE hFindFile = 0;
WIN32_FIND_DATA FindData{};
enum { MaxDeep = 0x200 };
//++ stack
HANDLE hFindFileV[MaxDeep];
PWSTR pszV[MaxDeep];
char prefix[MaxDeep+1];
//--stack
ULONG Level = MaxDeep;
memset(prefix, '\t', MaxDeep);
prefix[MaxDeep] = 0;
PWSTR psz = FileName;
goto __enter;
__loop:
hFindFile = FindFirstFileEx(FileName, FindExInfoBasic, &FindData, FindExSearchNameMatch, 0, FIND_FIRST_EX_LARGE_FETCH);
if (hFindFile != INVALID_HANDLE_VALUE)
{
do
{
pcszRoot = FindData.cFileName;
// skip . and ..
switch (FileNameLength = wcslen(pcszRoot))
{
case 2:
if (pcszRoot[1] != '.') break;
case 1:
if (pcszRoot[0] == '.') continue;
}
if (FindData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
if ((SIZE_T)(FileName + _countof(FileName) - psz) < FileNameLength + _countof(mask))
{
continue;
}
__enter:
memcpy(psz, pcszRoot, (1 + FileNameLength) * sizeof(WCHAR));
if (FindData.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)
{
DbgPrint("%sreparse point: <%S>\n", prefix + Level, pcszRoot);
}
else
{
if (Level)
{
DbgPrint("%s<%S>\n", prefix + Level, psz);
hFindFileV[--Level] = hFindFile;
pszV[Level] = psz;
memcpy(psz += FileNameLength, mask, sizeof(mask));
psz++;
goto __loop;
__return:
*--psz = 0;
psz = pszV[Level];
hFindFile = hFindFileV[Level++];
DbgPrint("%s</%S>\n", prefix + Level, psz);
}
}
}
else
{
DbgPrint("%s[%u%u] %S\n", prefix + Level, FindData.nFileSizeLow, FindData.nFileSizeHigh, pcszRoot);
}
if (!hFindFile)
{
// top level exit
return ;
}
} while (FindNextFile(hFindFile, &FindData));
if ((dwError = GetLastError()) == ERROR_NO_MORE_FILES)
{
dwError = NOERROR;
}
FindClose(hFindFile);
}
else
{
dwError = GetLastError();
}
if (dwError)
{
DbgPrint("<%S> err = %u\n", FileName, dwError);
}
goto __return;
}
The reason for the difference is actually the confusion brought to you by goto label.If you are using the recursive version, after the recursive execution is completed, it will return to the recursive place to continue execution.
In your code, you continue to execute while (FindNextFile(hFind, &FindData)), but when you use goto label, it will jump out of the original loop and restart the program from the label, which leads to what you said list a single directory tree before ending.
If you modify the modified code to the following iterative version, you can understand why there is such a problem.
void fun()
{
char* Directory = "D:\\test";
HANDLE hFind;
WIN32_FIND_DATA FindData;
char SearchName[1024], FullPath[1024];
char LastName[1024] = "";
while (1)
{
memset(SearchName, 0, sizeof(SearchName));
memset(&FindData, 0, sizeof(WIN32_FIND_DATA));
sprintf(SearchName, "%s\\*", Directory);
if (strcmp(SearchName, LastName) == 0)
{
return;
}
strcpy(LastName, SearchName);
hFind = FindFirstFile(SearchName, &FindData);
if (hFind != INVALID_HANDLE_VALUE)
{
while (FindNextFile(hFind, &FindData))
{
if (FindData.cFileName[0] == '.')
{
continue;
}
memset(FullPath, 0, sizeof(FullPath));
sprintf(FullPath, "%s\\%s", Directory, FindData.cFileName);
if (FindData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
{
MessageBoxA(NULL, Directory, "Directory", MB_OK);
char cArray[1024];
memset(cArray, 0, sizeof(cArray));
sprintf(cArray, "%s", FullPath);
Directory = cArray;
break;
}
else
{
MessageBoxA(NULL, FullPath, "File", MB_OK);
}
}
FindClose(hFind);
}
}
}
So you cannot achieve the same purpose as recursion by using goto, here you can only use recursion. Of course, I have provided a way to traverse directories non-recursively using queues, which is a more scientific way.
One of the key things that you obtain from recursion is a separate set of local variables for each call to the recursive function. When a function calls itself, and in the recursive call modifies local variables, those local-variable changes do not (directly) affect the local variables of the caller. In your original program, this applies to variables hFind, FindData, SearchName, and FullPath.
If you want similar behavior in a non-recursive version of the function then you need to manually preserve the state of your traversal of one level of the tree when you descend to another level. The goto statement doesn't do any such thing -- it just redirects the control flow of your program. Although there are a few good use cases for goto in C, they are uncommon, and yours is not one of them.
There are several ways to implement manually preserving state, but I would suggest
creating a structure type in which to store those data that characterize the state of your traversal of a particular level. Those appear to be only hFind and FindData -- it looks like the other locals don't need to be preserved. Maybe something like this, then:
struct dir_state {
HANDLE hFind;
WIN32_FIND_DATA FindData;
};
Dynamically allocating an array of structures of that type.
unsigned depth_limit = DEFAULT_DEPTH_LIMIT;
struct dir_state *traversal_states
= malloc(depth_limit * sizeof(*traversal_states));
if (traversal_states == NULL) // ... handle allocation error ...
Tracking the depth of your tree traversal, and for each directory you process, using the array element whose index is the relative depth of that directory.
// For example:
traversal_states[depth].hFind
= FindFirstFile(SearchName, &traversal_states[depth].FindData);
// etc.
Remembering the size of the array, so as to be able to reallocate it larger if the traversal descends too deep for its current size.
// For example:
if (depth >= depth_limit) {
depth_limit = depth_limit * 3 / 2;
struct dir_state *temp
= realloc(traversal_states, depth_limit * sizeof(*traversal_states));
if (temp == NULL) {
// handle error, discontinuing traversal
}
traversal_states = temp;
}
Also, use an ordinary for, while, or do loop instead of a backward-jumping goto. There will be a few details to work out to track when to use FindFirstFile and when FindNextFile (which you would still have with goto), but I'm sure you can sort it out.
Details are left as an exercise.
Unless necessary due to memory or processing constraints or infinite recursion tail conditions that would be complication to introduce there really isn't much need to not use recursion here, since it leads to a readable and elegant solution.
I also want to point out that in "modern" C, any solution using a GOTO is likely not a solution you want since they are so often confusing to use and leads to memory issues (we have loops now to make all of that so much simpler).
Instead of the GOTOs I would suggest implementing a stack of the directories. Wrap the printing logic a while or do-while, and as you are iterating over the files add any directories to the stack. At every new iteration pop and walk the directory at the head of the stack. The loop condition just needs to check if the directory stack is empty, before continuing its block.
According to my understanding, project.getItems({selected: true}) returns wrong results: I'm selecting a curve, it returns the parent Path: Sketch
Try clicking on a curve or a segment. Whole path will be moved. Then try changing the behavior by setting var workaround = false to var workaround = true to observe desired behavior.
How can I get exactly what is really selected?
Current workaround
I'm currently adding those objects into an array on selection and use those items instead of project.getItems({selected: true}).
The thing is that in Paper.js architecture, curves and segments are not items (they are part of a specific item which is the path). So you shouldn't expect project.getItems() to return anything else than items.
Another thing you have to know is that a path is assumed selected if any of its part is selected (curves, segments, points, handles, position, bounds, ...). And a curve is assumed selected if all of its parts are selected (points and handles).
With that in mind, you can create an algorithm to retrieve "what is really selected" based on project.getItems({selected: true}) as its first part. Then, you need to loop through curves and segments to check if they are selected.
Here is a sketch demonstrating a possible solution.
var vector = new Point(10, 10);
// Create path.
var path = new Path({
segments: [
[100, 100],
[200, 100],
[260, 170],
[360, 170],
[420, 250]
],
strokeColor: 'red',
strokeWidth: 10
});
// Translate given thing along global vector.
function translateThing(thing) {
switch (thing.getClassName()) {
case 'Path':
thing.position += vector;
break;
case 'Curve':
thing.segment1.point += vector;
thing.segment2.point += vector;
break;
case 'Segment':
thing.point += vector;
break;
}
}
// On mouse down...
function onMouseDown(event) {
// ...only select what was clicked.
path.selected = false;
hit = paper.project.hitTest(event.point);
if (hit && hit.location) {
hit.location.curve.selected = true;
}
else if (hit && hit.segment) {
hit.segment.selected = true;
}
// We check all items for demo purpose.
// Move all selected things.
// First get selected items in active layer...
project.activeLayer.getItems({ selected: true })
// ...then map them to what is really selected...
.map(getSelectedThing)
// ...then translate them.
.forEach(translateThing);
}
// This method returns what is really selected in a given item.
// Here we assume that only one thing can be selected at the same time.
// Returned thing can be either a Curve, a Segment or an Item.
function getSelectedThing(item) {
// Only check curves and segments if item is a path.
if (item.getClassName() === 'Path') {
// Check curves.
for (var i = 0, l = item.curves.length; i < l; i++) {
if (item.curves[i].selected) {
return item.curves[i];
}
}
// Check segments.
for (var i = 0, l = item.segments.length; i < l; i++) {
if (item.segments[i].selected) {
return item.segments[i];
}
}
}
// return item by default.
return item;
}
That said, depending on your real use case, your current workaround could be more appropriate than this approach.
I am creating an application, where "Left Arrow + Down Arrow" press has different behavior ( It is not same as first left arrow and then left arrow ), currently in keyPressEvent event I am getting them one by one in two separate calls.
Is there any way by which I can get multiple keypress in one keyboard event?
Thanks for this. I am posting code for the Python (PyQt) equivalent so that someone else might find it useful.
def keyPressEvent(self, event):
self.firstrelease = True
astr = "pressed: " + str(event.key())
self.keylist.append(astr)
def keyReleaseEvent(self, event):
if self.firstrelease == True:
self.processmultikeys(self.keylist)
self.firstrelease = False
del self.keylist[-1]
def processmultikeys(self,keyspressed):
print keyspressed
I solved the problem by below code.
QSet<Qt::Key> keysPressed;
void Widget::keyPressEvent(QKeyEvent * event) {
m_bFirstRelease = true;
keysPressed+= event->key();
}
void Widget::keyReleaseEvent(QKeyEvent *) {
if(m_bFirstRelease) {
processMultiKeys(keysPressed);
}
m_bFirstRelease = false;
keysPressed-= event->key();
}
Nothing is "at the same time" and I believe in Qt you can't have that type of behaviour (except for modifier keys like shift, alt, etc).
Approach the problem in a different way. When you receive one of the keys, check to see if you received the other in a short while back, say 20ms before.
in Flex I have something like that:
var dg:DataGrid = new DataGrid();
if (something) dg = dg1 else if (something_2) dg = dg2;
dg.dataProvider.getItemAt(3).id;
and dg is ALWAYS pointing at DataGrid (even if dg1 has name DataGrid_test and dg2 = DataGrid_test2) and finally action is made on my first DataGrid (DataGrid_test).
Why?
How can I pass dg1 or dg2 to dg?
Here is pasted almost full code of this part of application. I edited it to make that more clear.
var dg:DataGrid = null;
if ( currentState == "state1" ) { //if this condition is true then app. go into if and
dg = dataGrid_first; // make dg = DataGrid (1)
test.text = "inco"; // shows "inco" in "test" label
} else if ( currentState == "state2" ) { // if this is true then app. go..
dg = dataGrid_second; //here and set dg as DataGrid (exactly!) (2)
test.text = "outgo"; // and change test label into blank text (earlier text disapears)
}
search(dg);
It is modified with advice of '#splash'
Still not working.
EDIT:
I made this sceond edit to answer for all You who are helping me with that :) I think that it will be the best way. In codeblock above I added comments. (please read now comments and after that come back here :) )
Now I will explain exactly what happens.
I debug it many times and here are results:
dg is pointing at DataGrid (as component in flex, not as my dataGrid_first), I needed to extend DataGrid so now it is ColorColumn component (I don't know if I called it properly), not DataGrid. And dg is pointing at ColorColumn not at dataGrid_first or dataGrid_second. I even tried today the same thing what suggest #splash:
if ( currentState == "state1" ) {
test.text = "inco";
search(dataGrid_first);
} else if ( currentState == "state2" ) {
test.text = "outgo";
search(dataGrid_second);
}
and search still points at ColorColumn :/ My problem is really easy- I just want to pass to search different dataGrid on each state. If You have other ideas how I can do that in right way then I will pleased to hear about it. :)
But still I don't understand why it doesn't work. My search function uses algorhitm Boyer-Moor for searching through dataGrid.dataProvider for some text. If it find something then it is pushed into new array and after passing whole dataProvider I colorize rows with searched word.
If dg is never pointing to dg1 and dg2 then your (something) expressions may be evaluate to false. Check the value of your if-conditions - this should be easy to debug.
This should work:
var dg:DataGrid = null;
if (something)
dg = dg1;
else if (something_2)
dg = dg2;
if (dg)
{
// do something with dg
}
[Update]
I still can't see why your code isn't working, but you could simplify it like this:
if ( currentState == "state1" ) {
test.text = "inco";
search(dataGrid_first);
} else if ( currentState == "state2" ) {
test.text = "outgo";
search(dataGrid_second);
}
I'd propose to write this - since I guess either dg1 or dg2 should be assigned:
if (something) {
dg = dg1;
} else {
dg = dg2;
}
There may be cases, where if () {} else () {} neither executes the first or the second conditional block.
Finally a small hint, which structurally eliminates unwanted assignments in if conditions: Always write the literal left of the comparison operation: if ( "state1" == currentState ). If you accidentally typed = instead of ==, the flex compiler emits an error. The other notation silently assigns a value.
Additionally: Did you single-stepped through your code and watched the variables dg1, dg2 and dg? If not, set a breakpoint a few line before the if-statement and run the code step by step from there on. What do you see?
Here's a another tip: Use assertions to check for inconistencies:
package my.company.utilities {
public function assert(expression:Boolean):void {
// probably conditionally compile this statement
if (!expression) {
throw new Error("Assertion failed!");
}
} // assert
}
Use it e.g. at the beginning of a method like this:
public function doTransaction( fromAccount:int, toAccount:int ) {
assert( 0 < fromAccount );
assert( 0 < toAccount );
}
A typically good use of assert is to check variables regarding their range. As of the above example, fromAccount and toAccount should always be positive. Due to a bug, bad values might get passed to doTransaction(). In this case, the assertion fires an error.
It seems that it is impossible to capture the keyboard event normally used for copy when running a Flex application in the browser or as an AIR app, presumably because the browser or OS is intercepting it first.
Is there a way to tell the browser or OS to let the event through?
For example, on an AdvancedDataGrid I have set the keyUp event to handleCaseListKeyUp(event), which calls the following function:
private function handleCaseListKeyUp(event:KeyboardEvent):void
{
var char:String = String.fromCharCode(event.charCode).toUpperCase();
if (event.ctrlKey && char == "C")
{
trace("Ctrl-C");
copyCasesToClipboard();
return;
}
if (!event.ctrlKey && char == "C")
{
trace("C");
copyCasesToClipboard();
return;
}
// Didn't match event to capture, just drop out.
trace("charCode: " + event.charCode);
trace("char: " + char);
trace("keyCode: " + event.keyCode);
trace("ctrlKey: " + event.ctrlKey);
trace("altKey: " + event.altKey);
trace("shiftKey: " + event.shiftKey);
}
When run, I can never get the release of the "C" key while also pressing the command key (which shows up as KeyboardEvent.ctrlKey). I get the following trace results:
charCode: 0
char:
keyCode: 17
ctrlKey: false
altKey: false
shiftKey: false
As you can see, the only event I can capture is the release of the command key, the release of the "C" key while holding the command key isn't even sent.
Has anyone successfully implemented standard copy and paste keyboard handling?
Am I destined to just use the "C" key on it's own (as shown in the code example) or make a copy button available?
Or do I need to create the listener manually at a higher level and pass the event down into my modular application's guts?
I did a test where I listened for key up events on the stage and noticed that (on my Mac) I could capture control-c, control-v, etc. just fine, but anything involving command (the key) wasn't captured until I released the command key, and then ctrlKey was false (even though the docs says that ctrlKey should be true for the command key on the Mac), and the charCode was 0. Pretty useless, in short.
Another incredibly annoying thing that I just realized is that ctrl-c can't be captured by event.ctrlKey && event.keyCode = Keyboard.C (or ...event.charCode == 67), instead you have to test for charCode or keyCode being 3. It kind of makes sense for charCode since ctrl-c is 3 in the ASCII table, but it doesn't make sense for keyCode, which is supposed to represent the key on the keyboard, not the typed character. The same goes for all other key combos (because every ctrl combo has an ASCII equivalent).
Edit Found a bug in the Flex bug system about this: https://bugs.adobe.com/jira/browse/FP-375
I've found one workaround to this one based on the capture sequence. When you press Cmd+A, for example, the sequence is:
type: KEY_DOWN, keyCode 15
type: KEY_UP, keyCode 15
type: KEY_DOWN, keyCode 65
So everytime you get keyCode 15 down and then up and the next capture is down you can assume that the user pressed the key combination. My implementation end up like this:
protected var lastKeys:Array;
this.stage.addEventListener(KeyboardEvent.KEY_DOWN, keyHandler, false, 0, true);
this.stage.addEventListener(KeyboardEvent.KEY_UP, keyHandler, false, 0, true);
private function getCmdKey(ev:KeyboardEvent):Boolean {
this.lastKeys.push(ev);
this.lastKeys = this.lastKeys.splice(Math.max(0, this.lastKeys.length-3), 3);
if (this.lastKeys.length < 3) return false;
if (ev.keyCode != 15 && ev.type == KeyboardEvent.KEY_UP) {
var firstKey:KeyboardEvent = this.lastKeys[0] as KeyboardEvent;
var secondKey:KeyboardEvent = this.lastKeys[1] as KeyboardEvent;
if (firstKey.keyCode == 15 && firstKey.type == KeyboardEvent.KEY_DOWN &&
secondKey.keyCode == 15 && secondKey.type == KeyboardEvent.KEY_UP) {
return true;
}
}
return false;
}
private function keyHandler(ev:KeyboardEvent):void {
var cmdKey:Boolean = this.getCmdKey(ev.clone() as KeyboardEvent);
var ctrlKey:Boolean = ev.ctrlKey || cmdKey;
if (ctrlKey) {
if (ev.keyCode == 65) {
// ctrl + "a"-- select all!
}
}
}
For me, the following works:
private var _ctrlHoldFlag:Boolean = false;
// Do something if CTRL was held down and C was pressed
// Otherwise release the ctrl flag if it was pressed
public function onKey_Up(event:KeyboardEvent):void {
var keycode_c:uint = 67;
if (_ctrlHoldFlag && event.keyCode == keycode_c)
{
//do whatever you need on CTRL-C
}
if (event.ctrlKey)
{
_ctrlHoldFlag = false;
}
}
// Track ctrl key down press
public function onKey_Down(event:KeyboardEvent):void
{
if (event.ctrlKey)
{
_ctrlHoldFlag = true;
}
}