I have my own dictionary application WordYard and in that whenever we type in AutoCompleteTextView i am showing the words list in dropdown.
In addTextChangedListener of autoCompleteTextView i am querying for written text in sqlite database. Since database is very huge of 1.5 lac words it takes time to make the arraylist of particular text.
Suppose I wrote 'A' then this string will searched in database and written inside arraylist of limit 15 data starting from 'A'. On scrolling the dropdown list i am adding next 15 words in getView of adapter.
Scrolling is fine but whenever i type in autocompleteTextview to read 15 words from database also it take time if we write faster. Please tell me if there is any other method i can do it to make my app better.
Everytime you type anything within AutoCompleteTextView a query to your relative huge database is sent thus causing the (justified) delay.
The addTextChangedListener (TextWatcher watcher); method needs a TextWatcher object to operate. What your are going to to is create a TextWatcher and override it's afterTextChanged (Editable s) method in order to perform queries to your database less often.You will also need a custom Filter for that.
autoCompleteTextView.addTextChangedListener(new TextWatcher() {
public void onTextChanged(CharSequence s, int start, int before, int count) {
yourAdapter.getFilter().filter(s);
}
then you will create a class that extends [Filter][1] and override the methods suitable to your needs.
For example optimize your implementation to send queries only after 4 characters are typed or some time has passed.
Related
So, after going through some docs regarding TextWatcher, I'm still not too sure why it's actually needed. Any help with real example (no code) will be great. Thanks.
TextWatcher is needed to know if a field text has been changed.
Presume you have a mobile number, and you need to check the length of it. As a standard mobile number should contain 10 digits. You have an error field at the side which will go away once the edittext length will be greater than 10. How will you know that now the length is greater than 10?
To overcome this we have textwatcher method which watch over the edittext field. Generally we will check length of edittext in AfterTextChanged callback and it will work in realtime. After that you can make your logics behind what to do after the length is greater than 10.
This is just an example. There are certain many more ways in which you can use textwatcher.
TextWatcher :
TextWatcher is used to keep watch on the EditText content while user inputs the data. It allows you to keep track on each character when entered on EditText. A Text Watcher is really helpful for scenarios like login/register screen validation.
The TextWatcher have Three method is below :
Method 1 : afterTextChanged(Editable s)
=> This method is called to notify you that, somewhere within s, the text has been changed.
Method 2 : beforeTextChanged(CharSequence s, int start, int count, int after)
=> This method is called to notify you that, within s, the count characters beginning at start are about to be replaced by new text with length after.
Method 3 : onTextChanged(CharSequence s, int start, int before, int count)
=> This method is called to notify you that, within s, the count characters beginning at start have just replaced old text that had length before.
I am making a search application in android, my searching purpose is that when i type word in edittext then when the textchange, it will jump to select the position of the word that begin with that letter in listview.
This is my code. it work well but the speed of text when i type or delete in edittext seems slow, not smoothly.
What can i do to make it faster?
I have over 20,000 entries from database.
txtword.addTextChangedListener(new TextWatcher() {
#Override
public void onTextChanged(CharSequence s, int start, int before, int count){
// TODO Auto-generated method stub
for(int i =0;i<list.size();i++)
{
if(list.get(i).toLowerCase().startsWith(s.toString()))
{
pos = i;
break;
}
}
lv.setSelection(pos);
}
You can use the patricia trie data structure to perform the search:
Here are the typical steps:
Populate your Strings into the patricia trie.
Perform look-up for strings starting with the entered characterd in onTextChanged().It will return you a sub-trie. For next character entered, search in that sub-trie.
When a text is removed from the editText, go back one level in the trie.
Here is the reference:
https://code.google.com/p/patricia-trie/
And, here is a sample example:
https://code.google.com/p/patricia-trie/wiki/Examples
you can user search filter in baseAdapter and arrayadapter for Listview.
use this
1)https://stackoverflow.com/a/2726348/942224
2)https://stackoverflow.com/a/14359161/942224
to get detail information.
You may consider that iterating an ArrayList with over 20000 may take a lot of resource. I think you have to reevaluate the problem and how you can solve it.
Why don't you try to research via SQL request ? You can use the "LIKE" operator.
SQLite Android Doc
Like operator example
I am using onTextChanged(CharSequence s, int start, int before, int count) of Text watcher which is attached to MultiAutoCompleteTextView in my activity.
When I type some text for eg. 'nik' in MultiAutoCompleteTextView , then drop down list opens with some suggested sentences, when one item is selected from the drop down eg. (nikhil kaushik;) and then I do back press too delete a character, every thing gets deleted expect initial search value 'Nik'.
How to prevent this, I don't want every thing to get deleted, only last character should be deleted from 'nikhil kaushik;'.
Request you to please help me on this.
Set empty string "" in the text view at the end of your onTextChanged method or Override afterTextChanged method of text watcher and set text view with empty string.
My app is using api 7. I don't know where to start with this challenge.
I have SQLite DB with some numbers stored between 1-99. Now I would like to make number picker for this range which would also remove numbers that are already in DB.
Create a list off the numbers 0-99, then do a query on your database. For every row in the results from the database, check if the list contains is (something like list.contains(number). If it is there, remove it (list.remove(item)) then proceed to the next row
You'll probably have to make your own widget. This will be somewhat involved, and since you are an Android beginner you might better spend your time coming up with a different input method.
In case you do decide to write your own widget, I would recommend extending LinearLayout, then inside of the constructor, doing something like this psuedocode:
setOrientation(VERTICAL);
addView ImageButton arrowUpButton;
addView EditText numberEditText;
addView ImageButton arrowDownButton;
arrowUpButton.setOnClickListener {
int num = myListOfInts.get(currentIndex++);
numberEditText.setText(num);
}
//vice versa for arrowDownButton
you'd also have to create a setter for the myListOfInts.
Good luck!
I've added a TextWatcher to an EditText and am listening for changes in the text via the onTextChanged(CharSequence s, int start, int before, int count) method. When I paste text that has say 10 characters, into this EditText, onTextChanged() gets called 10 times, once for each character in the text I pasted, from left to right. I want onTextChanged() to be called only once after all 10 characters have been pasted into the EditText. I'm sure this should be possible, because otherwise what's the point in having the "count" param if it's always going to be 1?
count won't always be 1: for instance, if you select and delete a block of text or if you choose an autocomplete option.
In any case, the details of whether pasting happens in one chunk or one character at a time is an implementation detail, and if you rely on either behavior it's likely your app will break in the future.
Try using afterTextChanged it will only get one call