I'm trying to add an AcroField checkbox to a PDF that's being generated by iText7 pdfHTML. This is not working by default, I saw someone suggest using a custom tag worker but as much as I tried I couldn't get it to work. Does anyone have any idea how to implement this? Or an example?
I've created a very simple example to show you how one can create a custom tag worker and add an acrofield to a document while html to pdf processing.
Look at the next snippet:
class CustomTagWorkerFactory extends DefaultTagWorkerFactory {
#Override
public ITagWorker getCustomTagWorker(IElementNode tag, ProcessorContext context) {
if (tag.name().equals("input")) {
if (AttributeConstants.CHECKBOX.equals(tag.getAttribute(AttributeConstants.TYPE))) {
return new AcroInputTagWorker(tag, context);
}
}
return null;
}
Here I've introduced a custom tag worker factory which will create default tagworkers for all tags except for the one I've specified (<input type="checkbox">).
Now let's add an acrofield to the document on <input type="checkbox"> processing:
class AcroInputTagWorker extends InputTagWorker {
public AcroInputTagWorker(IElementNode element, ProcessorContext context) {
super(element, context);
PdfAcroForm.getAcroForm(context.getPdfDocument(), true)
.addField(PdfFormField.createCheckBox(context.getPdfDocument(), new Rectangle(100, 700, 30, 30), "checkbox", "Off"));
}
That's basically it. The resultant pdf for a very simple html file (basically, just one line: <input type="checkbox">) looks as this:
Now let's briefly discuss what can be improved:
1) you may want to check whether CHECKED attribute is set and consider it while setting the acrofield's value (in the example above I've just set it as "Off")
2) you need to create different acrofield's name values (I've just used "checkbox")
3) you may want to render the acrofield not at a certain position, predefined before html to pdf processing. You may want to let iText define its position dynamically depending on where the input tag is placed.
In that case the solution would be more difficult. You will need to create your own CheckBox element (probably extended from aParagraph) and a renderer for it (probably extended from a ParagraphRender). Then you will need to override its layout method (perhaps just call super.layout() to get the coordinates of the paragraph and only then add the acrofield to the document). That's not easy, but it's certainly worth a try! And if you're not successful, you can always ask another SO question :)
I am currently trying to implement file exports in background so that the user can do some actions while the file is downloading.
I used the apache isis CommandExexuteIn:Background action attribute. However, I got an error
"Not an (encodable) value", this is an error thrown by the ScalarValueRenderer class.
This is how my method looks like:
#Action(semantics = SemanticsOf.SAFE,
command = CommandReification.ENABLED)
commandExecuteIn = CommandExecuteIn.BACKGROUND)
public Blob exportViewAsPdf() {
final Contact contact = this;
final String filename = this.businessName + " Contact Details";
final Map<String, Object> parameters = new HashMap<>();
parameters.put("contact", contact);
final String template = templateLoader.buildFromTemplate(Contact.class, "ContactViewTemplate", parameters);
return pdfExporter.exportAsPdf(filename, template);
}
I think the error has something to do with the command not actually invoking the action but returns the persisted background command.
This implementation actually worked on the method where there is no return type. Did I miss something? Or is there a way to implement background command and get the expected results?
interesting use case, but it's not one I anticipated when that part of the framework was implemented, so I'm not surprised it doesn't work. Obviously the error message you are getting here is pretty obscure, so I've raised a
JIRA ticket to see if we could at least improve that.
I'm interested to know in what user experience you think the framework should provide here?
In the Estatio application that we work on (that has driven out many of the features added to the framework over the last few years) we have a somewhat similar requirement to obtain PDFs from a reporting server (which takes 5 to 10 seconds) and then download them. This is for all the tenants in a shopping centre, so there could be 5 to 50 of these to generate in a single go. The design we went with was to move the rendering into a background command (similar to the templateLoader.buildFromTemplate(...) and pdfExporter.exportAsPdf(...) method calls in your code fragment, and to capture the output as a Document, via the document module. We then use the pdfbox addon to stitch all the document PDFs together as a single downloadable PDF for printing.
Hopefully that gives you some ideas of a different way to support your use case
Thx
Dan
I am very new to coding in Java/Android Studio. I have everything setup that I have been able to figure out thus far. I have a button, and I need to put code inside of the button click event that will fetch information from a website, convert it to a string and display it. I figured I would have to use the html source code in order to do this, so I have installed Jsoup html parser. All of the help with Jsoup I have found only leads me up to getting the HTML into a "Document". And I am not sure if that is the best way to accomplish what I need. Can anyone tell me what code to use to fetch the html code from the website, and then do a search through the html looking for a specific match, and convert that match to a string. Or can anyone tell me if there is a better way to do this. I only need to grab one piece of information and display it.
Here is the piece of html code that contains the value I want:
writeBidRow('Wheat',-60,false,false,false,0.5,'01/15/2015','02/26/2015','All',' ',' ',60,'even','c=2246&l=3519&d=G15',quotes['KEH15'], 0-0);
I need to grab and display whatever value represents the quotes['KEH15'], in that html code.
Thank you in advance for your help.
Keith
Grabbing raw HTML is an extremely tedious way to access information from the web, bad practice, and difficult to maintain in the case that wherever you are fetching the info from changes their HTML.
I don't know your specific situation and what the data is that you are fetching, but if there is another way for you to fetch that data via an API, use that instead.
Since you say you are pretty new to Android and Java, let me explain something I wish had been explained to me very early on (although I am mostly self taught).
The way people access information across the Internet is traditionally through HTML and JavaScript (which is interpreted by your browser like Chrome or Firefox to look pretty), which are transferred over the internet using the protocol called HTTP. This is a great way for humans to communicate with computers that are far away, and the average person probably doesn't realize that there is more to the internet than this--your browser and the websites you can go to.
Although there are multiple methods, for the purpose of what I think you're looking for, applications communicate over the internet a slightly different way:
When an android application asks a server for some information, rather than returning HTML and JavaScript which is intended for human consumption, the server will (traditionally) return what's called JSON (or sometimes XML, which is very similar). JSON is a very simple way to get information about an object, and put it into a form that is readable easily by both humans (developers) and computers, and can be transmitted over the internet easily. For example, let's say you ask a server for some kind of "Video" object for an app that plays video, it may give you something like this:
{
"name": "Gangnam Style",
"metadata": {
"url": "https://www.youtube.com/watch?v=9bZkp7q19f0",
"views": 2000000000,
"ageRestricted": false,
"likes": 43434
"dislikes":124
},
"comments": [
{
"username": "John",
"comment": "10/10 would watch again"
},
{
"username": "Jane",
"number": "12/10 with rice"
}
]
}
That is very readable by us humans, but also by computers! We know the name is "Gangnam Style", the link of the video, etc.
A super helpful way to interact with JSON in Java and Android is Google's GSON library, which lets you cast a Java object as JSON or parse a JSON object to a Java object.
To get this information in the first place, you have to make a network call to an API, Application Programming Interface. Just a fancy term for communication between a server and a client. One very cool, free, and easy to understand API that I will use for this example is the OMDB API, which just spits back information about movies from IMDB. So how do you talk to the API? Well luckily they've got some nice documentation, which says that to get information on a movie we need to use some parameters in the url, like perhaps
http://www.omdbapi.com/?t=Interstellar
They want a title with the parameter "t". We could put a year, or return type, but this should be good to understand the basics. If you go to that URL in your browser, it spits back lots of information about Interstellar in JSON form. That stuff we were talking about! So how would you get this information from your Android application?
Well, you could use Android's built in HttpUrlConnection classes and research for a few hours on why your calls aren't working. But doesn't essentially every app now use networking? Why reinvent the wheel when virtually every valuable app out there has probably done this work before? Perhaps we can find some code online to do this work for us.
Or even better, a library! In particular, an open source library developed by Square, retrofit. There are multiple libraries like it (go ahead and research that out, it's best to find the best fit for your project), but the idea is they do all the hard work for you like low level network programming. Following their guides, you can reduce a lot of code work into just a few lines. So for our OMDB API example, we can set up our network calls like this:
//OMDB API
public ApiClient{
//an instance of this client object
private static OmdbApiInterface sOmdbApiInterface;
//if the omdbApiInterface object has been instantiated, return it, but if not, build it then return it.
public static OmdbApiInterface getOmdbApiClient() {
if (sOmdbApiInterface == null) {
RestAdapter restAdapter = new RestAdapter.Builder()
.setEndpoint("http://www.omdbapi.com")
.build();
sOmdbApiInterface = restAdapter.create(OmdbApiInterface.class);
}
return sOmdbApiInterface;
}
public interface OmdbApiInterface {
#GET("/")
void getInfo(#Query("t") String title, Callback<JsonObject> callback);
}
}
After you have researched and understand what's going on up there using their documentation, we can now use this class that we have set up anywhere in your application to call the API:
//you could get a user input string and pass it in as movieName
ApiClient.getOmdbApiClient().getInfo(movieName, new Callback<List<MovieInfo>>() {
//the nice thing here is that RetroFit deals with the JSON for you, so you can just get information right here from the JSON object
#Override
public void success(JsonObject movies, Response response) {
Log.i("TAG","Movie name is " + movies.getString("Title");
}
#Override
public void failure(RetrofitError error) {
Log.e("TAG", error.getMessage());
}
});
Now you've made an API call to get info from across the web! Congratulations! Now do what you want with the data. In this case we used Omdb but you can use anything that has this method of communication. For your purposes, I don't know exactly what data you are trying to get, but if it's possible, try to find a public API or something where you can get it using a method similar to this.
Let me know if you've got any questions.
Cheers!
As #caleb-allen said, if an API is available to you, it's better to use that.
However, I'm assuming that the web page is all you have to work with.
There are many libraries that can be used on Android to get the content of a URL.
Choices range from using the bare-bones HTTPUrlConnection to slightly higher-level HTTPClient to using robust libraries like Retrofit. I personally recommend Retrofit. Whatever you do, make sure that your HTTP access is asynchronous, and not done on the UI thread. Retrofit will handle this for you by default.
For parsing the results, I've had good results in the past using the open-source HTMLCleaner library - see http://htmlcleaner.sourceforge.net
Similar to JSoup, it takes a possibly-badly-formed HTML document and creates a valid XML document from it.
Once you have a valid XML document, you can use HTMLCleaner's implementation of the XML DOM to parse the document to find what you need.
Here, for example, is a method that I use to parse the names of 'projects' from a <table> element on a web page where projects are links within the table:
private List<Project> parseProjects(String html) throws Exception {
List<Project> parsedProjects = new ArrayList<Project>();
HtmlCleaner pageParser = new HtmlCleaner();
TagNode node = pageParser.clean(html);
String xpath = "//table[#class='listtable']".toString();
Object[] tables = node.evaluateXPath(xpath);
TagNode tableNode;
if(tables.length > 1) {
tableNode = (TagNode) tables[0];
} else {
throw new Exception("projects table not found in html");
}
TagNode[] projectLinks = tableNode.getElementsByName("a", true);
for(int i = 0; i < projectLinks.length; i++) {
TagNode link = projectLinks[i];
String projectName = link.getText().toString();
String href = link.getAttributeByName("href");
String projectIdString = href.split("=")[1];
int projectId = Integer.parseInt(projectIdString);
Project project = new Project(projectId, projectName);
parsedProjects.add(project);
}
return parsedProjects;
}
If you have permission to edit the webpage to add hyper link to specified line of that page you can use this way
First add code for head of line that you want to go there in your page
head your text if wanna
Then in your apk app on control click code enter
This.mwebview.loadurl("https:#######.com.html#target")
in left side of # enter your address of webpage and then #target in this example that your id is target.
Excuse me if my english lang. isn't good
I've written a program to aid the user in configuring 'mechs for a game. I'm dealing with loading the user's saved data. This data can (and some times does) become partially corrupt (either due to bugs on my side or due to changes in the game data/rules from upstream).
I need to be able to handle this corruption and load as much as possible. To be more specific, the contents of the save file are syntactically correct but semantically corrupt. I can safely parse the file and drop whatever entries that are not semantically OK.
Currently my data parser will just show a modal dialog with an appropriate warning message. However displaying the warning is not the job of the parser and I'm looking for a way of passing this information to the caller.
Some code to show approximately what is going on (in reality there is a bit more going on than this, but this highlights the problem):
class Parser{
public void parse(XMLNode aNode){
...
if(corrupted) {
JOptionPane.showMessageDialog(null, "Corrupted data found",
"error!", JOptionPane.WARNING_MESSAGE);
// Keep calm and carry on
}
}
}
class UserData{
static UserData loadFromFile(File aFile){
UserData data = new UserData();
Parser parser = new Parser();
XMLDoc doc = fromXml(aFile);
for(XMLNode entry : doc.allEntries()){
data.append(parser.parse(entry));
}
return data;
}
}
The thing here is that bar an IOException or a syntax error in the XML, loadFromFile will always succeed in loading something and this is the wanted behavior. Somehow I just need to pass the information of what (if anything) went wrong to the caller. I could return a Pair<UserData,String> but this doesn't look very pretty. Throwing an exception will not work in this case obviously.
Does any one have any ideas on how to solve this?
Depending on what you are trying to represent, you can use a class, like SQLWarning from the java.sql package. When you have a java.sql.Statement and call executeQuery you get a java.sql.ResultSet and you can then call getWarnings on the result set directly, or even on the statement itself.
You can use an enum, like RefUpdate.Result, from the JGit project. When you have a org.eclipse.jgit.api.Git you can create a FetchCommand, which will provide you with a FetchResult, which will provide you with a collection of TrackingRefUpdates, which will each contain a RefUpdate.Result enum, which can be one of:
FAST_FORWARD
FORCED
IO_FAILURE
LOCK_FAILURE
NEW
NO_CHANGE
NOT_ATTEMPTED
REJECTED
REJECTED_CURRENT_BRANCH
RENAMED
In your case, you could even use a boolean flag:
class UserData {
public boolean isCorrupt();
}
But since you mentioned there is a bit more than that going on in reality, it really depends on your model of "corrupt". However, you will probably have more options if you have a UserDataReader that you can instantiate, instead of a static utility method.
I need a JFileChooser which acts like notepad.exe or mspaint.exe in save mode. As you may know when you type wildcard (* or ?) characters in the File name field the file view will show only those files which are matching for the users input. This is OK, but my problem is with the Files of type combobox:
In JFileChooser: the Files of type combo box is updated as well when the user enters a wildcard in the File name field.
See the screenshot here!
But if you try this with notepad.exe you will realize that the File name field remains as it was before, so the search pattern is not updated.
See the notepad's screenshot here!
So my question is: Does anybody know a solution how to achieve that the Files of type combo box should NOT be updated by the entered filter?
I need a cross-platform solution, so it should work both on XP and Linux.
Thanks in advance!
Sorry for the links, but I am not allowed to attach it directly!
The glob pattern recognition feature is implemented in the FileChooserUI delegate for each Look & Feel. For example, MetalFileChooserUI contains a nested ApproveSelectionAction, inherited from BasicFileChooserUI, that invokes setFileFilter(). This adds the new pattern, via a PropertyChangeEvent, to the listening MetalFileChooserUI.FilterComboBoxModel. You may be able to intercept the added filter somewhere along the chain.
You may also be able to leverage the file pattern matching capability introduced in Java 7 and discussed here.
Finally I've found a solution:
Using a custom file chooser UI derived from BasicFileChooserUI will solve my issue in the following way: I've overriden the getApproveSelectionAction() method with my custom action:
protected class CustomApproveSelectionAction extends BasicFileChooserUI.ApproveSelectionAction {
#Override
public void actionPerformed(ActionEvent e) {
String filename = getFileName();
// using a custom pattern to accept valid charachters only:
Matcher matcher = pattern.matcher(filename);
if (matcher.matches()) {
// this is the good case, just let the super implementation do what have to do.
super.actionPerformed(e);
} else {
// this is the bad case, we must warn the user and don't let the super implementation take effect.
// display an error message similar like notepad does it.
}
}
}
If the filename is ok, then I allow what super implementation does, otherwise I will display a message.