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Java Question Need to understand some Java Code
- Thread starter XverhelstX
- Start date
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Actually, I don't think it calls onPreviewFrame.
When I do this code:
I get this in B4A log:
I will clean up library first and upload it.
Thank you very much for looking into it Agraham!
XverhelstX
When I do this code:
B4X:
public synchronized byte[] getPicture(int Width, int Height) throws InterruptedException {
FrameWidth = Width;
FrameHeight = Height;
try {
Log.i("B4A", "Try Mode.");
// while (!isPreviewOn) wait();
Log.i("B4A", "IsPreviewOn is True");
isDecoding = true;
Log.i("B4A", "Decoding is true.");
c.setOneShotPreviewCallback(this);
Log.i("B4A", "Callback Done.");
wait(5000);
Log.i("B4A", "Outside isDecoding.");
} catch (Exception e) {
Log.i("B4A", "An error occured.");
return null;
}
return mCurrentFrame;
}I get this in B4A log:
I will clean up library first and upload it.
Thank you very much for looking into it Agraham!
XverhelstX
Library and Zip file is attached.
getPicture is called in Sub mnuFocusMode_Click
XverhelstX
getPicture is called in Sub mnuFocusMode_Click
XverhelstX
Ow sorry, missed that.
XverhelstX
XverhelstX
I may have found the problem. It is a sort of deadlock. From the documentation for Camera.PreviewCallback onPreviewFrame.
The callback can't run because the thread it wants to run on is blocked in getPicture. The application you took that code from presumably calls getPicture from a different thread than the one that opened the camera. Your best bet is probably to let getPicture return and raise an event at the end of onPreviewFrame. As it runs on the main thread it looks like you can use raiseEvent rather than raiseEventFromDifferentThread.
The callback can't run because the thread it wants to run on is blocked in getPicture. The application you took that code from presumably calls getPicture from a different thread than the one that opened the camera. Your best bet is probably to let getPicture return and raise an event at the end of onPreviewFrame. As it runs on the main thread it looks like you can use raiseEvent rather than raiseEventFromDifferentThread.
Yes, Main.java calls currentJPEG = cameraFrame.getPicture(); from CameraView.java.
Is there any documentation on ba.raiseEvent(null, eventName + "_ready", true);? As I don't know what all these things mean: "readyCount.addAndGet(1) == 2" etc.
And how I should retrieve the data with camera_ready2.
I really appreciate your effort in this.
XverhelstX
No but
public Object raiseEvent(Object sender, String event, Object[] params)
The first parameter is the object returned by Sender in the event Sub. The second is the lowercase name of the Sub to invoke, the third is an array of Objects corresponding to the parameters the event Sub requires, if any. The return Object is the return value of the Sub
So I'd do something like
raiseEvent(this, eventName + "_somename", Object[] = { mCurrentFrame });
for the event Sub
Sub camera_somename(picture as Byte())
I don't know what that means either. Where is it from?
Last edited:
Oh, Ok.
So I don't have to raise the event in Basic4Android?
It's in Eclipse itself(?)
This is from readyCount.addAndGet(1) == 2" etc
and raiseEvent(this, eventName + "_somename", Object[] = { mCurrentFrame });
doesn't seem to work but
raiseEvent(this, eventName + "_somename", mCurrentFrame );
does.
Any other thing I should do/ know?
So I now have something like this:
XverhelstX
So I don't have to raise the event in Basic4Android?
It's in Eclipse itself(?)
B4X:
@SuppressWarnings("static-access")
public void Initialize(final BA ba, ViewGroup Panel, String EventName) {
this.ba = ba;
readyCount.set(0);
this.eventName = EventName.toLowerCase(BA.cul);
sv = new SurfaceView(ba.context);
anywheresoftware.b4a.BALayout.LayoutParams lp = new anywheresoftware.b4a.BALayout.LayoutParams(
0, 0, Panel.getLayoutParams().width,
Panel.getLayoutParams().height);
Panel.addView(sv, lp);
if (c != null) {
readyCount.set(1);
}
sv.getHolder().setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
sv.getHolder().setFixedSize(Panel.getLayoutParams().width,
Panel.getLayoutParams().height);
sv.getHolder().addCallback(new SurfaceHolder.Callback() {
@Override
public void surfaceChanged(SurfaceHolder holder, int format,
int width, int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
if (readyCount.addAndGet(1) == 2) {
ba.raiseEvent(null, eventName + "_ready", true);
}
}This is from readyCount.addAndGet(1) == 2" etc
and raiseEvent(this, eventName + "_somename", Object[] = { mCurrentFrame });
doesn't seem to work but
raiseEvent(this, eventName + "_somename", mCurrentFrame );
does.
Any other thing I should do/ know?
So I now have something like this:
B4X:
public void getPicture(int Width, int Height){
FrameWidth = Width;
FrameHeight = Height;
try {
Log.i("B4A", "Try Mode.");
Log.i("B4A", "IsPreviewOn is True");
isDecoding = true;
Log.i("B4A", "Decoding is true.");
c.setOneShotPreviewCallback(this);
Log.i("B4A", "Callback Done.");
Log.i("B4A", "Outside isDecoding.");
} catch (Exception e) {
Log.i("B4A", "An error occured.");
return;
}
return;
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Log.i("B4A", "In onPreviewFrame");
int width = FrameWidth;
int height = FrameHeight;
int[] temp = new int[width * height];
OutputStream out = new ByteArrayOutputStream();
Bitmap bm = null;
Log.i("B4A", "Initialize raw2jpg");
raw2jpg(temp, data, width, height);
bm = Bitmap.createBitmap(temp, width, height, Bitmap.Config.RGB_565);
bm.compress(CompressFormat.JPEG, 100, out);
mCurrentFrame = ((ByteArrayOutputStream) out).toByteArray();
isDecoding = false;
Log.i("B4A", "isDecoding false");
ba.raiseEvent(null, eventName + "_previewtaken", mCurrentFrame);
}XverhelstX
Sorry but I don't understand what your problem is with "This is from readyCount.addAndGet(1) == 2" etc" but it has nothing to do with events.
If that's working its because your event Sub takes no parameters so mCurrentFrame is being ignored. Parameters have to be passed in an Object array as I stated.
Don't worry at the readycount, I thought it had to do something with it.
I showed it because you asked where I saw that.
I have this error:
"Syntax error on tokens, EnumHeader expected instead"
here:
ba.raiseEvent(this, eventName + "_previewtaken", Object[] = { mCurrentFrame });
Also in B4A, My sub is:
Sub Camera1_PreviewTaken (Picture As Byte(), Byte As String)
but I cannot seem to execute it.
byte is not a valid identifier.
Occurred on line: 81
Sub Camera1_PreviewTaken (Picture As Byte(), Byte As String)
Note that I added this:
I showed it because you asked where I saw that.
I have this error:
"Syntax error on tokens, EnumHeader expected instead"
here:
ba.raiseEvent(this, eventName + "_previewtaken", Object[] = { mCurrentFrame });
Also in B4A, My sub is:
Sub Camera1_PreviewTaken (Picture As Byte(), Byte As String)
but I cannot seem to execute it.
byte is not a valid identifier.
Occurred on line: 81
Sub Camera1_PreviewTaken (Picture As Byte(), Byte As String)
Note that I added this:
B4X:
@Events(values = { "Ready (Success As Boolean)",
"PictureTaken (Data() As Byte)","PreviewTaken (Picture as Byte())" })Ok, thank you very much Agraham.
probably this:
This is probably correct, Although, Everything seems to work except Camera1_PreviewTaken (Data() As Byte) is not called.
B4A
B4X:
ba.raiseEvent(null, eventName + "_previewtaken", new Object[] { mCurrentFrame });This is probably correct, Although, Everything seems to work except Camera1_PreviewTaken (Data() As Byte) is not called.
B4X:
@Events(values = { "Ready (Success As Boolean)","PictureTaken (Data() As Byte)","PreviewTaken (Data() As Byte)" })
public void getPicture(int Width, int Height){
FrameWidth = Width;
FrameHeight = Height;
try {
Log.i("B4A", "Try Mode.");
Log.i("B4A", "IsPreviewOn is True");
isDecoding = true;
Log.i("B4A", "Decoding is true.");
c.setOneShotPreviewCallback(this);
Log.i("B4A", "Callback Done.");
Log.i("B4A", "Outside isDecoding.");
} catch (Exception e) {
Log.i("B4A", "An error occured.");
return;
}
return;
}
@Override
public void onPreviewFrame(byte[] data, Camera camera) {
Log.i("B4A", "In onPreviewFrame");
int width = FrameWidth;
int height = FrameHeight;
int[] temp = new int[width * height];
OutputStream out = new ByteArrayOutputStream();
Bitmap bm = null;
Log.i("B4A", "Initialize raw2jpg");
raw2jpg(temp, data, width, height);
bm = Bitmap.createBitmap(temp, width, height, Bitmap.Config.RGB_565);
bm.compress(CompressFormat.JPEG, 100, out);
mCurrentFrame = ((ByteArrayOutputStream) out).toByteArray();
isDecoding = false;
Log.i("B4A", "isDecoding false");
ba.raiseEvent(null, eventName + "_previewtaken", data);
}B4A
B4X:
Sub mnuFocusMode_Click
Msgbox("Getting Picture.","")
camera1.getPicture(480,320)
's = b.HexFromBytes(camera1.getPicture(480,320))
Msgbox("s","")
End Sub
Sub Camera1_PreviewTaken (Data() As Byte)
Msgbox("on Preview Taken","")
s = b.HexFromBytes(Data)
Msgbox(s,"")
End Sub
Last edited:
Hey,
Is it the .jar and .xml?
Could you upload the java file to?
As I don't see what I have to enter exactly:
As I want something like this:
XverhelstX
XverhelstX
Is it the .jar and .xml?
Could you upload the java file to?
As I don't see what I have to enter exactly:
As I want something like this:
B4X:
Sub Camera1_PreviewTaken (Success As Boolean, Data() as Byte, PictureFrame as Byte)
' As I want something to play with the success and Data bytes too.
End SubXverhelstX
XverhelstX
Isn't it another file?
At the events tag shouldn't be some more things added there?
@Events(values = { "Ready (Success As Boolean)",
"PictureTaken (Data() As Byte)" })
and how can I add more things like Succes boolean, data in that array?
XverhelstX
At the events tag shouldn't be some more things added there?
@Events(values = { "Ready (Success As Boolean)",
"PictureTaken (Data() As Byte)" })
and how can I add more things like Succes boolean, data in that array?
XverhelstX
Why should there be another file? That Java file as it stands will compile to a library and raise an event. The rest is up to you.
The @Events attribute is only needed for IDE Intellisense support, I assumed you could do that.
To add parameters to the event just include them in the parameter Object array.
Sigh! I really don't know why I bother at times 
The @Events attribute is only needed for IDE Intellisense support, I assumed you could do that.
To add parameters to the event just include them in the parameter Object array.
B4X:
ba.raiseEvent(this, eventName + "_previewtaken", new Object[] { success, mCurrentFrame, pictureFrame } );
}Why should there be another file? That Java file as it stands will compile to a library and raise an event. The rest is up to you.
The @Events attribute is only needed for IDE Intellisense support, I assumed you could do that.
To add parameters to the event just include them in the parameter Object array.
Sigh! I really don't know why I bother at timesB4X:ba.raiseEvent(this, eventName + "_previewtaken", new Object[] { success, mCurrentFrame, pictureFrame } ); }
Ok, I didn't know that that was for the IDE Intellisense support.
So I copied your java file, pasted it on my library, compiled it into .jar and .xml, putted it in my library folder, refreshed the tab: did the following code:
B4X:
Sub mnuFocusMode_Click
Msgbox("Getting Picture.","")
camera1.getPicture(480,320)
's = b.HexFromBytes(camera1.getPicture(480,320))
Msgbox("s","")
End Sub
Sub Camera1_PreviewTaken(mCurrentFrame() As Byte)
Msgbox("on Preview Taken","")
s = b.HexFromBytes(mCurrentFrame)
Msgbox(s,"")
End Subgetting Picture and S appear
but Camera1_PreviewTaken is not called...
XverhelstX
Last edited:
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