I want to know is there any method or any link or tutorial to perform redo undo operation in Android edittext. If any one knows than please let me know.
Quick note on the Antti-Brax/Divers(Kidinov) solution. It works great, except if you try to use it with a TextView post-API 23, you'll run into problems, because guess-what, Google actually added a hidden UndoManager (android.content.UndoManager) and didn't document it or make it obvious it was there. But if you have a hard/bluetooth keyboard in Marshmallow or Nougat and hit ^Z or SHIFT-^Z, you'll get undo/redo.
The problem comes if you're already using Antti-Brax's class with an EditText, and you also hook it to ^Z and shift-^Z, you'll run into problems with anyone using a hard keyboard. Namely the ^Z will trigger BOTH the native and Antti-Brax's undo, leading to two undos simultaneously, which isn't good. And after a few of them, you'll probably get a Spannable out of bounds crash.
A possible solution I found is to subclass the TextView/TextEdit/whatever and intercept the undo/redo calls from the TextView so they don't run as follows:
#Override
public boolean onTextContextMenuItem(int id) {
int ID_UNDO, ID_REDO;
try {
ID_UNDO = android.R.id.undo;
ID_REDO = android.R.id.redo;
} catch (Resources.NotFoundException e) {
ID_UNDO = 16908338; // 0x1020032
ID_REDO = 16908339; // 0x1020033
}
return !((id == ID_UNDO) || (id == ID_REDO)) && super.onTextContextMenuItem(id);
}
Those magic id numbers were found here, and are used only as a backup if the android.R.id.undo values aren't found. (it also might be reasonable to assume that if the values aren't there the feature isn't there, but anyway...)
This is not the best solution because both undo trackers are still there and both are running in the background. But at least you won't trigger both of them simultaneously with ^Z. It's the best I could think to do until this gets officially documented and the getUndoManager() methods of TextView is no longer hidden...
Why they made a feature you can't turn off (or even know if it was there or not) "live" in released Android I can't say.
I just opened an issue on Android's issue tracker if anyone wants to follow this.
There is an implementation of undo/redo for Android EditText in
http://credentiality-android-scripting.googlecode.com/hg/android/ScriptingLayerForAndroid/src/com/googlecode/android_scripting/activity/ScriptEditor.java
The code works but does not handle configuration changes properly. I am working on a fix and will post here when it is complete.
My Google search was :-
android edittext onTextChanged undo
I know this is an old question, but as there is no accepted answer, and this is an issue I've tackled myself from many angles, I'd like to add my solution in case it helps anyone. My answer is probably most relevant to large (1,000words+) volumes of text editing apps that require this feature.
The simplest way to resolve this problem is to make periodic copies of all text on screen, save it to an array and call setText() every time the Undo method is called. This makes for a reliable system, but it isn't ideal for large (i.e. 1,000words+) text editing apps. This is because it:
Is wasteful. It could be that only one word changes in a two thousand word document, so that's one thousand, nine hundred and ninety nine words needlessly committed to memory.
Can lead to performance issues, as some low-tier hardware struggles with rendering large amounts of text. On some of my test devices, this method can lead to freezes of a few seconds whenever Undo is called.
The solution I currently use is comparatively complex, but I've published the results in a library here.
Essentially, this library saves a copy of text as soon as a user begins typing, and then another copy of text once they've stopped typing for a set amount of time (in my case, two seconds). The two text strings are then compared, and the altered section of text returned, the indexes where the alterations occured, and details on whether or not the change was an addition of new text, a deletion, or a replacement of old text with new text.
The net result is that only the necessary text is saved, and when Undo is called, there is only a local delete(), replace() or insert() call, which makes for much faster operations on large text fields.
Here is the undo/redo implementation that was linked to from Gary Phillips' answer extracted into a reusable and universal undo/redo plugin for any widget that descends from a TextView. I added some code for persisting the undo history.
http://code.google.com/p/android/issues/detail?id=6458#c123
Hope this helps.
To preserve EditText Styling with regards to undo:
You can create an ArrayList<EditText> or ArrayList<String> (String containing html text) to store your last 10 (for example) actions. So ArrayList [0] would contain html text from your first action and ArrayList [9] would contain html text from your very last action. Each time the user taps "undo" in your app, you would apply ArrayList [size()-1] to your EditText and then remove ArrayList [size()-1] from your Array.
Related
I really hope this question has not been answered everywhere else already but every search seems to focus on listeners and other uses of a button array but i want to also use it for formatting all buttons at the same time (activate, deactivate etc)
So here is what I have tried;
val buttons = arrayOf(btn1,btn2,btn3,btn4)
This will work, BUT will only change a single button
buttons[0].isEnabled=true; //
Then this is the bit that I am struggling with;
buttons[0..buttons.size].isEnabled=true;
The response is basically that it expects a single number and not a range.
I also tried;
buttons[].isEnabled=true;
The response is that it requires an index
I also tried
buttons.isEnabled=true;
This of course will not resolve properly
My key question really is can I apply formatting/state changes to all using an array or will I always have to do it for each button in turn?
I think it would be possible to create a loop but that isn't the route I wanted to follow here if there is an alternative
Don't think there is a way mate. You gotta loop and regardless of what syntatic sugar a language has in the end its still a for loop.
You could do:
buttons.forEach {
it.isEnabled = true
}
I am building an app that displays a bunch of information that the user can edit, and I am having trouble keeping the UI updating the data displaid so it is consistent with the new edits done at runtime.
I have implemented updateUI methods that basically look like:
void updateUI(){
((TextView) fieldDisplay).setText(fieldCurrentValue);
...
}
I know I can run this method in things like an AsyncTask or similar stuff that makes it execute continuously. But Im concerned about efficency since its not really necesary to update the UI all the time, but only when the user inputs a value wich is not that often.
What would be the best approach to this?
EDIT:
The question is how to make sure the an UI element shows the current value of a field, regardless of how or why that field is updated.
My case specifically is the with this. Im trying to make an RPG character sheet, and I have like a bazillion Skills, wich are affected by another lot of fields, such as Characteristics, Modifiers, Categories...
The application should behave so, whenever any of the many fields affects it changes, it should display the new value.
Now, since keeping track of what field affects what is part of the problem, if could update whenever any field whatsoever changes, but I dont know how to do that.
I will start this by saying that on iOS this algorithm takes, on average, <2 seconds to complete and given a simpler, more specific input that is the same between how I test it on iOS vs. Android it takes 0.09 seconds and 2.5 seconds respectively, and the Android version simply quits on me, no idea if that would be significantly longer. (The test data gives the sorting algorithm a relatively simple task)
More specifically, I have a HashMap (Using an NSMutableDictionary on iOS) that maps a unique key(Its a string of only integers called its course. For example: "12345") used to get specific sections under a course title. The hash map knows what course a specific section falls under because each section has a value "Course". Once they are retrieved these section objects are compared, to see if they can fit into a schedule together based on user input and their "timeBegin", "timeEnd", and "days" values.
For Example: If I asked for schedules with only the Course ABC1234(There are 50 different time slots or "sections" under that course title) and DEF5678(50 sections) it will iterate through the Hashmap to find every section that falls under those two courses. Then it will sort them into schedules of two classes each(one ABC1234 and one DEF5678) If no two courses have a conflict then a total of 2500(50*50) schedules are possible.
These "schedules" (Stored in ArrayLists since the number of user inputs varies from 1-8 and possible number of results varies from 1-100,000. The group of all schedules is a double ArrayList that looks like this ArrayList>. On iOS I use NSMutableArray) are then fed into the intent that is the next Activity. This Activity (Fragment techincally?) will be a pager that allows the user to scroll through the different combinations.
I copied the method of search and sort exactly as it is in iOS(This may not be the right thing to do since the languages and data structures may be fundamentally different) and it works correctly with small output but when it gets too large it can't handle it.
So is multithreading the answer? Should I use something other than a HashMap? Something other than ArrayLists? I only assume multithreading because the errors indicate that too much is being done on the main thread. I've also read that there is a limit to the size of data passed using Intents but I have no idea.
If I was unclear on anything feel free to ask for clarification. Also, I've been doing Android for ~2 weeks so I may completely off track but hopefully not, this is a fully functional and complete app in the iTunes Store already so I don't think I'm that far off. Thanks!
1) I think you should go with AsynTask of Android .The way it handle the View into `UI
threadandBackground threadfor operations (Like Sorting` ) is sufficient enough to help
you to get the Data Processed into Background thread And on Processing you can get the
Content on UI Thread.
Follow This ShorHand Example for This:
Example to Use Asyntask
2) Example(How to Proceed):
a) define your view into onPreExecute()
b) Do your Background Operation into doInBackground()
c) Get the Result into onPostExceute() and call the content for New Activty
Hope this could help...
I think it's better for you to use TreeMap instead of HashMap, which sorts data automatically everytime you mutate it. Therefore you won't have to sort your data before start another activity, you just pass it and that's all.
Also for using it you have to implement Comparable interface in your class which represents value of Map.
You can also read about TreeMap class there:
http://docs.oracle.com/javase/7/docs/api/java/util/TreeMap.html
I have been creating Spinner controls (Combo boxes/Drop downs) in one of my apps, and was surprised to find out how difficult it was to achieve all of the following features:
User facing Strings are externalized, taking advantage of strings.xml internationalisation (I18N) feature of Android.
Spinner selections operate using a System view, which facilitates not having to work with or map Strings to meaningful values (yuck).
User view to System view mapping should be easy, automated and minimal (i.e not hand rolled for every component).
Others have attempted solutions to this, but universally as far as I could see they suffer from one or many of the following problems:
UI code is creeping into their enum class which doesn’t belong there (messy), nearly all existing solutions suffered from this.
Hardcoded User facing Strings in their enum classes. Because these are not externalized you cannot do I18N using the stock Android features.
Authors typically make the Fragment or Activity an OnItemSelectedListener which perpetuates a common problem of inheritance for convenience, where composition is more appropriate.
I have developed my own solution which does this: http://www.androidanalyse.com/android-spinner-externalize-user-strings-mapped-to-system-enum/
My question is, have I missed something? This seems like something that should not have been this hard (which makes me feel like I'm possibly reinventing the wheel).
Below is some example code showing my solution in-use (which is available Apache 2 license from the link above).
String none = getString(R.string.none);
String light = getString(R.string.light);
String medium = getString(R.string.medium);
String strong = getString(R.string.strong);
SpinnerUtil.createNewSpinner(view, R.id.wind, Arrays.asList(none, light, medium, strong), WindLevel.values(),
new SpinnerItemSelectedListener<WindLevel>() {
public void onItemSelected(Spinner item, WindLevel value) {
// Take whatever action you wish to here.
}});
I would just use ArrayAdapter<WindLevel>. Yes, you created a custom typed listener, but the regular event listener gets the position and can call getItem() on the ArrayAdapter<WindLevel> to get a WindLevel properly typed.
IMHO, the vast majority of Spinner widgets will be populated with material read in from a database, the Internet, or some other dynamic data source, rather than populated by some sort of enum with display values coming from static strings that can be internationalized ahead of time.
This is not to say that your code is useless: if you find it useful, then it was worth writing. And I am sure that there are apps out there that contain your targeted pattern (i.e., a Spinner backed by an enum or equivalent where the display values are known in advance and can be internationalized) who might find your solution useful as well. Every developer who writes enough code cooks up these sorts of helper classes and the like that help map an OS or framework model into something that better fits the developer's own mental model. So long as you are not perceiving any performance issues, it's all good.
Also, note that OnItemSelectedListener is an interface; implementing that interface on an existing class is not inheritance.
I believe the reason nobody answered you is :
What problem are you trying to solve ? Spinners existed prior to your well designed attempt.
Why reinvent them in exactly the same way they exist in Android ?
http://developer.android.com/guide/topics/ui/controls/spinner.html
It is a beautiful wheel indeed you designed, but still, it is just a wheel :)
UPDATE :
I think I begin to understand what you did. This is interesting. I'm not sure why you did not go to the pattern implemented by the ListPreference with its entries and entryvalues.
In fact, I'm not sure I understand why the Android team did not go that route either.
In any case, it is worth proposing your idea to the Android framework. It is after all open source.
I am facing the problem of low memory. Low memory:no more background process And here is the scenario.
I am using a list which gets its data from a string array, it has a custom background, Clicking on item, the list gets another string array to display as second or third level. Information for three levels written in database.
After third level, there are two more levels for which data is going to be fetched from web services,
And that causes the low memory error.
How can I get rid of the solution?
Edit : After having some digging I found that the GC is trying to (kill or) restart in case of its already crashed com.android.inputmethod.latin/.latinIMEservice. One notable point is that the application is translated in french and italian, but this screen does not have any text for translation, does this information helps??
Edit 2: After a detailed study of traceview I found that all the text views have custom fonts applied in it. (There is a call of TypeFace.createFromAsset()) that IMO causes the crashes.
And the problem lies in the fact that I have to keep the fonts....
can It be possible to avoid crash and have the fonts?? (Because i think the answer is no: But still waiting for some opinions)
Edit 3 : After removing the custom fonts the performance of application is much better. Hence I can suspect the font is the only culprit here. And that's why I am editing question. The font I use is helvetica.
Can using external fonts cause application to crash or running out of memory? If yes can you describe the cause in more detail??
Thanks
If you are using code similar to:
Typeface font = Typeface.createFromAsset(getContext().getAssets(),
"fonts/Helvetica.ttf");
try making "font" a global variable so it only gets loaded once. Otherwise it can be loaded repeatedly, quickly consuming memory. See this message for a little more detail
Well, question is a bit unclear to have answered:
After each level - do you switch/start to another Activity? If so you shouldn't keep anywhere references to old activity. Otherwise it could trigger OOM problems
I suppose you're fetching data using some kind of Cursor alike object. Cursor's are very memory-consuming objects, so you'd better not only just close Cursor's, but you should also call Cursor.deactivate()