I am new to react-native and I seek your help please. What I am planning to do is to get the app icon associated with an app that the user has installed on his device.
I did take a look at this code and realized that I have no way of passing it back to my JS.
Here is what I am doing currently.
private List<String> getNonSystemApps() {
List<PackageInfo> packages = this.reactContext
.getPackageManager()
.getInstalledPackages(0);
List<String> ret = new ArrayList<>();
for (final PackageInfo p: packages) {
if ((p.applicationInfo.flags & ApplicationInfo.FLAG_SYSTEM) == 0) {
JSONObject jsonObject = new JSONObject();
try {
jsonObject.put("name", p.packageName);
jsonObject.put("firstInstallTime", p.firstInstallTime);
jsonObject.put("installLocation", p.installLocation);
jsonObject.put("applicationInfo", p.applicationInfo);
jsonObject.put("permissions", getPermissionsByPackageName(p.packageName));
Drawable icon = reactContext.getPackageManager().getApplicationIcon(p.packageName);
ret.add(jsonObject.toString());
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return ret;
}
Can you please help me out with this ?
Thanks
Edit
I managed to get it working, based on Aaron's suggestion, I created another private function just to work with the images. This function will generate the base 64 version of an app's icon.
private String getBitmapOfAnAppAsBase64(String packageName) {
if(packageName.isEmpty() ) return new String("");
String base64Encoded = "";
Bitmap bitmap;
try {
Drawable appIcon = this.reactContext.getPackageManager().getApplicationIcon(packageName);
if(appIcon instanceof BitmapDrawable) {
bitmap= ((BitmapDrawable)appIcon).getBitmap();
} else {
bitmap = Bitmap.createBitmap(appIcon.getIntrinsicWidth(), appIcon.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
}
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 90, byteArrayOutputStream);
byte[] byteArray = byteArrayOutputStream .toByteArray();
base64Encoded = Base64.encodeToString(byteArray, Base64.DEFAULT);
} catch(Exception e) {
Log.d(TAG,"An error was encounted while getting the package information. The error follows : " + e.toString());
}
return base64Encoded;
}
I then use this generated string in my original function, with the following modifications.
Old Non working code
Drawable icon = reactContext.getPackageManager().getApplicationIcon(p.packageName);
New working code
jsonObject.put("icon", getBitmapOfAnAppAsBase64(p.packageName));
and then in React-Native - its a piece of pie, since it supports base64 already.
"icon" : 'data:image/png;base64,'+installAppObj.icon
Huge thanks to Aaron , for guiding me in the correct direction.
If you haven't already, read through the entire Android Native Modules page. It's not that long and addresses several issues you're likely to run into.
Only these types can be sent to your JS code (via a #ReactMethod):
Boolean -> Bool
Integer -> Number
Double -> Number
Float -> Number
String -> String
Callback -> function
ReadableMap -> Object
ReadableArray -> Array
So you effectively have two options:
Encode the Drawable to one of these types, then decode it on the JavaScript side, or
Write the file to disk, and send the path over
I'm not sure what type of Drawable the icon is or if there are guarantees. But any of them should be convertible in some way. For example if it's a Bitmap you can do a Bitmap to Base64 String conversion.
Related
I was already finished with the creation of a native module for the latest OpenCV for Android.
However, I am trying to access the haarcascade_frontalface_alt2.xml file using the file directory format below but it cannot be loaded.
Has anyone tried to create a react native module for OpenCV and was able to create face recognition using Java in React Native?
I am expecting to create a function in react native using OpenCV java that will have 2 base64 inputs and then do face matching then face recognition.
#ReactMethod
public void faceRecognition(String referenceBase64, String capturedBase64, Callback errorCallback, Callback successCallback) {
try {
//######## REGION FOR IMAGE CONVERTION ########
BitmapFactory.Options options = new BitmapFactory.Options();
options.inDither = true;
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
//reference base64 image convertion
byte[] decodedString_reference = Base64.decode(referenceBase64, Base64.DEFAULT);
Bitmap image_reference = BitmapFactory.decodeByteArray(decodedString_reference, 0, decodedString_reference.length);
//captured base64 image convertion
byte[] decodedString_captured = Base64.decode(capturedBase64, Base64.DEFAULT);
Bitmap image_captured = BitmapFactory.decodeByteArray(decodedString_captured, 0, decodedString_captured.length);
//######## REGION FOR FACE DETECTION ########
String response = "";
String filenameFaceCascade = "D://React-Native//FaceRecognition_v2//android//app//src//main//java/com//reactlibrary//haarcascade_frontalface_alt2.xml";
CascadeClassifier classifier = new CascadeClassifier();
if (!classifier.load(filenameFaceCascade))
{
response = "Error"; //this is being returned for the success callback. The plan is that it should return a response of "Test_only"
}
else
{
response = "Test_only";
}
successCallback.invoke(response);
} catch (Exception e) {
errorCallback.invoke(e.getMessage());
}
}
I am new to Xamarin.Android. I am using Visual Studio 2017 for developing an Android application.
I need to capture an image through camera which I have done the following way:
protected override void OnActivityResult(int requestCode, [GeneratedEnum] Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
if (resultCode == Result.Ok)
{
Bitmap bitmap = (Bitmap)data.Extras.Get("data");
Photo.SetScaleType(ImageView.ScaleType.FitCenter);
Photo.SetImageBitmap(bitmap);
}
Snap.Click += (sender, e) =>
{
Intent intent = new Intent(MediaStore.ActionImageCapture);
StartActivityForResult(intent, 0);
};
Now the problem is I want to save/insert this photo(bitmap) to a Sql Server table in a column type Image so that I may display this photo in a Windows Form Application and further use it in crystal reports.
Connecting to a SQL Server directly from the App is a terrible practice and should be managed by a Web Service instead, because it is very easy to decode the binary of APK or IPA files. Then, a user can just destroy your SQL database. That's why you don't find any tutorials on how to do it.
That being said, when you begin the image capture, your code will look something like this StartActivityForResult(intent, save_request_code);
And then you have to override the OnActivityResult function that gets called once the picture has been taken (or chosen from the gallery). If the action was successful, we create a byte array and pass that into SQL
private const int save_request_code = 7; // You can use any integer
// "protected override void OnActivityResult(int requestCode, int resultCode, Intent data)" depending on your Android support library version
protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
base.OnActivityResult(requestCode, resultCode, data);
switch (requestCode)
{
case save_request_code:
switch ((Result)resultCode) // (Result) conversion not needed if it is already a Result object above
{
case Result.Canceled:
break;
case Result.FirstUser:
break;
case Result.Ok:
{
try
{
Bitmap bitmap = MediaStore.Images.Media.GetBitmap(this.ContentResolver, data.Data);
using (MemoryStream stream = new MemoryStream())
{
bitmap.Compress(Bitmap.CompressFormat.Jpeg,100, stream);
byte[] array=stream.ToArray();
SqlConnection CN = new SqlConnection(txtConnectionString.Text);
string qry = "insert into ImagesStore(OriginalPath,ImageData) values(#OriginalPath, #ImageData)";
SqlCommand SqlCom = new SqlCommand(qry, CN);
SqlCom.Parameters.Add(new SqlParameter("#OriginalPath", (object)txtImagePath.Text));
SqlCom.Parameters.Add(new SqlParameter("#ImageData", (object)imageData));
CN.Open();
SqlCom.ExecuteNonQuery();
CN.Close();
}
}
catch (Exception ex)
{
System.Console.WriteLine (ex.Message)
}
}
default:
throw new ArgumentOutOfRangeException("resultCode");
}
break;
}
}
It also seems like you did not give you app the permission to read the phone data, so you do that by adding this to your manifest file:
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
Again, please don't put this code into production without using a Web Service.
I'm trying to attach a PDF File to a Print Dialog, but I haven't find out the way to do it.
I'm using a WPF app, and I have some code related with printing and looks like this:
private void Imprimir()
{
try
{
FixedDocument document = null;
PageContent pageContent = null;
FixedPage fixedPage = null;
PrintDialog printDlg = new PrintDialog();
if (printDlg.ShowDialog() != true)
return;
document.DocumentPaginator.PageSize = new System.Windows.Size(1400, 1450);
fixedPage.Width = document.DocumentPaginator.PageSize.Width;
fixedPage.Height = document.DocumentPaginator.PageSize.Height;
fixedPage.Margin = new Thickness(96, 96, 0, 0);
fixedPage.Children.Add(this);
((System.Windows.Markup.IAddChild)pageContent).AddChild(fixedPage);
document.Pages.Add(pageContent);
printDlg.PrintDocument(document.DocumentPaginator, "Impresion Cierre");
fixedPage.Children.Clear();
}
catch (Exception ex)
{
System.Windows.MessageBox.Show(ex.Message);
}
}
But, by this way I'm just printing a UI Element added to Fixed Page.
I've looked for other codes, but I find nothing.
So, I don´t know if is possible to add a PDF File stored locally to the Print Dialog ?
Thanks for the help...
Well you cannot do this using PrintDialog. There are several options, depending on your goals:
var printQueue = LocalPrintServer.GetDefaultPrintQueue();
using (var input = File.OpenRead("path_to_your.pdf")) {
using (var job = printQueue.AddJob()) {
using (var output = job.JobStream) {
input.CopyTo(output);
}
}
}
Will silently send print job for your file to local print queue. Print job is configurable.
Alternatively you can use adobe reader to handle that for you (or another pdf reader installed on user's machine) but starting process with path to your pdf as FileName and Verb="print".
One more option is to use third party tools (like ghostscript) which can help you with that.
hi im working on a project that uses invoke and threads.. it is a simple remote desktop program with chat.. i got a sample here on the internet in c# winform, but i would like to convert it to wpf.. i have no problem in sending message to another client using the wpf program but it cannot receive ( or cannot read) the sent messages from the others.. i think it has something to do with the thread and the invoke method, i read that wpf does invoke differently and i did try the dispatcher.invoke, but it still doesnt do the trick
pls hellp
here's the code
wait = new Thread(new ThreadStart(waitForData));
wait.Start();
that snippet above is executed when a successful connection is made in tcpclient
private void waitForData()
{
try
{
NetworkStream read = tcpclnt.GetStream();
while (read.CanRead)
{
byte[] buffer = new byte[64];
read.Read(buffer, 0, buffer.Length);
s = new ASCIIEncoding().GetString(buffer);
System.Console.WriteLine("Recieved data:" + new ASCIIEncoding().GetString(buffer));
rcvMsg = new ASCIIEncoding().GetString(buffer) + "\n";
hasNewData = true;
bool f = false;
f = rcvMsg.Contains("##");
bool comand = false;
comand = rcvMsg.Contains("*+*-");
/*File receive*/
if (f)
{
string d = "##";
rcvMsg = rcvMsg.TrimStart(d.ToCharArray());
int lastLt = rcvMsg.LastIndexOf("|");
rcvMsg = rcvMsg.Substring(0, lastLt);
NetworkStream ns = tcpclnt.GetStream();
if (ns.CanWrite)
{
string dataS = "^^Y";
byte[] bf = new ASCIIEncoding().GetBytes(dataS);
ns.Write(bf, 0, bf.Length);
ns.Flush();
}
try
{
new Recieve_File().recieve_file(rcvMsg);
}
catch (Exception ec)
{
System.Console.WriteLine(ec.Message);
}
}
/*Command-shutdown/restart/logoff*/
else if (comand)
{
string com = "*+*-";
rcvMsg = rcvMsg.TrimStart(com.ToCharArray());
execute_command(rcvMsg);
}
else
{
this.Invoke(new setOutput(setOut));
Thread.Sleep(1000);
}
}
}
catch (Exception ex)
{
wait.Abort();
output.Text += "Error..... " + ex.StackTrace;
}
}
the snippet above is a code that listens if there is a message or command.. the line
this.invoke(new setoutput(setout)) is a code for appending text in the rtb
hope someone could help me thanks
You've posted a lot of code, but I'm assuming it's only the call to Control.Invoke which is causing the problem. In WPF, use Dispatcher.Invoke (or Dispatcher.BeginInvoke) instead, via the Dispatcher property on the relevant UI element.
I'd also strongly encourage you to:
Refactor your code into smaller methods
Stop catching just Exception except at the top level of any large operation (it should just be a fall-back; usually you catch specific exceptions)
Start following .NET naming conventions
Add a using directive for System so you can just write Console.WriteLine instead of System.Console.WriteLine everywhere
Use Encoding.ASCII instead of creating a new ASCIIEncoding each time you need one
Use a StreamReader to read character data from a stream, instead of reading it as binary data first and then encoding it
For either Stream or TextReader, don't ignore the return value from Read - it tells you how many bytes or characters have been read
I have a WebBrowser control on a form, but for the most part it remains hidden from the user. It is there to handle a series of login and other tasks. I have to use this control because there is a ton of Javascript that handles the login. (i.e., I can't just switch to a WebClient object.)
After hopping around a bit, we end up wanting to download a PDF file. But instead of downloading, the file is displayed within the webBrowser control, which the user can not see.
How can I download the PDF instead of having it load in the browser control?
Add a SaveFileDialog control to your form, then add the following code on your WebBrowser's Navigating event:
private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
{
if (e.Url.Segments[e.Url.Segments.Length - 1].EndsWith(".pdf"))
{
e.Cancel = true;
string filepath = null;
saveFileDialog1.FileName = e.Url.Segments[e.Url.Segments.Length - 1];
if (saveFileDialog1.ShowDialog() == DialogResult.OK)
{
filepath = saveFileDialog1.FileName;
WebClient client = new WebClient();
client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);
client.DownloadFileAsync(e.Url, filepath);
}
}
}
//Callback function
void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
MessageBox.Show("File downloaded");
}
Source: http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral/thread/d338a2c8-96df-4cb0-b8be-c5fbdd7c9202
The solution I ended up using:
I did everything else as-needed to get the URL where it needed to go. Knowing that all of the login information, required settings, viewstates, etc. were stored in the cookies, I was finally able to grab the file using a hybrid of the web control to navigate then the WebClient object to actually snag the file bytes.
public byte[] GetPDF(string keyValue)
{
DoLogin();
// Ask the source to generate the PDF. The PDF doesn't
// exist on the server until you have visited this page
// at least ONCE. The PDF exists for five minutes after
// the visit, so you have to snag it pretty quick.
LoadUrl(string.Format(
"https://www.theMagicSource.com/getimage.do?&key={0}&imageoutputformat=PDF",
keyValue));
// Now that we're logged in (not shown here), and
// (hopefully) at the right location, snag the cookies.
// We can use them to download the PDF directly.
string cookies = GetCookies();
byte[] fileBytes = null;
try
{
// We are fully logged in, and by now, the PDF should
// be generated. GO GET IT!
WebClient wc = new WebClient();
wc.Headers.Add("Cookie: " + cookies);
string tmpFile = Path.GetTempFileName();
wc.DownloadFile(string.Format(
"https://www.theMagicSource.com/document?id={0}_final.PDF",
keyValue), tmpFile);
fileBytes = File.ReadAllBytes(tmpFile);
File.Delete(tmpFile);
}
catch (Exception ex)
{
// If we can't get the PDF here, then just ignore the error and return null.
throw new WebScrapePDFException(
"Could not find the specified file.", ex);
}
return fileBytes;
}
private void LoadUrl(string url)
{
InternalBrowser.Navigate(url);
// Let the browser control do what it needs to do to start
// processing the page.
Thread.Sleep(100);
// If EITHER we can't continue OR
// the web browser has not been idle for 10 consecutive seconds yet,
// then wait some more.
// ...
// ... Some stuff here to make sure the page is fully loaded and ready.
// ... Removed to reduce complexity, but you get the idea.
// ...
}
private string GetCookies()
{
if (InternalBrowser.InvokeRequired)
{
return (string)InternalBrowser.Invoke(new Func<string>(() => GetCookies()));
}
else
{
return InternalBrowser.Document.Cookie;
}
}
bool documentCompleted = false;
string getInnerText(string url)
{
documentCompleted = false;
web.Navigate(url);
while (!documentCompleted)
Application.DoEvents();
return web.Document.Body.InnerText;
}
private void web_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
{
documentCompleted = true;
}