I'm having more and more trouble while trying to make an easy excercise.
i'm trying to delete all eventual starting charater " " in a string.
Example:space-space-space50(i cannot figure it because this forum remove extra space)
result:50
Here's the code ...
char c=textToShow.getText().toString().charAt(1);
int i=1;
while (c == ' '){
textToShow.setText(textToShow.getText().toString().substring(i));
//New char
i++;
c=textToShow.getText().toString().charAt(i);
}
You have the right idea, but your implementaion is off.
First
char c=textToShow.getText().toString().charAt(1);
should start at 0, that is how the indexes are made.
The int is properly initialized but is not even really needed. This is because you work with only the beginning of the String.
However your loop is where things go awry.
Your substring code is proper, but now, you don't need to increment i, since you're modifying the String by shortening it. Also,
c=textToShow.getText().toString().charAt(i);
Should be c=textToShow.getText().toString().charAt(0); You are still checking the beginning of the String.
A more efficient implementation using the loop could be:
char c=textToShow.getText().toString().charAt(0);
String temp = textToShow.setText(textToShow.getText().toString();
while (c == ' ' && temp.length > 0)//also check to see if you're accessing an empty string.
{
temp = temp.substring (1);
c = temp.charAt (0);
}
textToShow.setText (temp);
Of course, this is for an excersice, if you wanted to do it the right way, you'd use temp.trim();
Related
I have written a calculator type app. My mates found that entering single decimal points only into the editText's makes the app crash. Decimal numbers and integers work fine, but I get a number format exception when .'s are entered.
I want to check if a single . has been placed in an editText, in order for me to display a toast telling the user to stop trying to crash the app.
My issue is that a . doesn't have a numerical value...
You can wrap it in a try/catch which should be done anyway when parsing text. So something like
try
{
int someInt = Integer.parseInt(et.getText().toString());
// other code
}
catch (NumberFormatException e)
{
// notify user with Toast, alert, etc...
}
This way it will protect against any number format exception and will make the code more reusable later on.
You can treat .1 as 0.1 by the following.
String text = et.getText().toString();
int len = text.length();
// Do noting if edit text just contains a "." without numbers
if(len==0 || (len==1 && text.charAt(0).equals(".")))
return;
if(text.charAt(0).equals(".") && text.length() > 1) {
text = "0" + text;
}
// Do your parsing and calculations
I have a string like this:
_id:2 thread_id:189 address:0292 m_size:null person:0 date:1372494272447 date_sent:0 protocol:0 read:1 status:-1 type:1 reply_path_present:0 subject:null body:Ok. Reply message. service_center:051108 locked:0 sim_id:0 error_code:0 seen:1 _id:1 thread_id:189 address:292 m_size:null person:0 date:1372493695831 date_sent:0 protocol:null read:1 status:-1 type:2 reply_path_present:null subject:null body:Test message service_center:null locked:0 sim_id:0 error_code:0 seen:0
I want to retrieve only parts of this string, for example the address:0292 and the body:xyz from the entire string. I want all instances of these two from a very large String (above is just a sample). Let's assume its more than 20000 characters.
How can I achieve this?
Looks like every address is followed by m_size, so use the string.split() function, to split over the keyword address then select the string.substring() (from each string in the resulting array) until reaching the keyword m_size. And repeat the entire thing for the keywords body and service_center. I can't think of any other way.
You are right, it doesn't seem pretty. But it works :)
String[] splitString = string.split(" ");
for (int i = 0; i < splitString.length; i++) {
if (splitString[i].startsWith("body") || splitString[i].startsWith("address"))
Log.i(TAG, "Found: " + splitString[i]);
// Do whatever you need to do
}
I need the user to enter text in an EditText according to this specfic pattern:
123.456-7890-123.456
The user can input any number of integers, so they could as well enter 123.456-7
I do not want the user to enter . or - just the numbers, like an input mask.
Also the numeric keyboard should only show.
I've searched StackOverflow extensively and have seen examples that use InputFilter, ChangedListener, TextWatcher but have not found anything simlar to what I'm trying to do. I've tried in various implementations of what I've found, but I'm inexperienced in using these so I may have overlooked something.
Any suggestions would be welcome.
You're going to have to use a TextWatcher and a regular expression pattern matcher to accomplish what you're trying to do.
This answer should be helpful: Android AutoCompleteTextView with Regular Expression?
You can create your own class that implements InputFilter. Then you would apply it as follows:
MyInputFilter filter = new MyInputFilter(...);
editText.setFilters(new InputFilter[]{filter});
Refer to the docs for how InputFilter is intended to work, then refer to the source code for some of the InputFilters used in Android for some ideas how to implement them.
After many failed attempts to implement InputFilter or Regular Expressions I opted for something a little more straight forward:
public void onTextChanged(CharSequence s, int start, int before, int count) {
String a = "";
String str = id.getText().toString();
String replaced = str.replaceAll(Pattern.quote("."),"");
replaced = replaced.replaceAll(Pattern.quote("-"),"");
char[] id_char = replaced.toCharArray();
int id_len = replaced.length();
for(int i = 0; i < id_len; i++) {
if(i == 2 || i == 12) {
a += id_char[i] + ".";
}
else if (i == 5 || i == 9) {
a += id_char[i] + "-";
}
else a += id_char[i];
}
id.removeTextChangedListener(this);
id.setText(a);
if(before > 0) id.setSelection(start);
else id.setSelection(a.length());
id.addTextChangedListener(this);
}
I don't know if this is the best approach but it does work. One problem I still haven't solved is how to handle cursor placement after the user deletes or inserts a number. If the user inserts the cursor somewhere in the EditText and enters a new number the cursor jumps to the end of the EditText. I would like the cursor to stay where it is at. Another problem if the user inserts the cursor within the EditText number and backspaces to delete a number, then the first key entry doesn't work and on the second key the number is entered. I can only guess this has to do with focus?
Use this: https://github.com/alobov/SimpleMaskWatcher.
Just set your mask for this watcher (###.###-####-###.###). It will add special symbols automatically and wont check your input string for being complete.
But showing the numeric keyboard you must handle by your own using android:inputType="number" tag for your EditText.
For my app I have created a QR Code, then took that bitmap and added text to the bitmap, however I need the text not to extend longer then the bitmap is. So what I want to do is create an Array of the text by taking 25 characters then find the last index of (" ") in that 25 character section. at that space I want to be able to replace that space that was located with \n to start a new line.
So the plan is if I have a String that looks like "Hello this is my name and I am longer than 25 charters and I have lots of spaces so that this example will work well."
I want it to out up this
Hello this is my name and
I am longer than 25
charters and I have lots
of spaces so that this
example will work well.
To make this I counted 25 characters then went back to the most resent space, at that point I hit enter, I want my app to do this for me.
I am not very good at English so if something doesn't make sense tell me and I will try to explain it. Thanks
I haven't tested this but you can try it and tweak as necessary
String fullText = "your text here";
String withBreaks = "";
while( fullText.length() > 25 ){
String line = fullText.substring(0,24);
int breakPoint = line.lastIndexOf( " ");
withBreaks += fullText.substring(0,breakPoint ) + "\n";
fullText = fullText.substring( breakPoint );
withBreaks += fullText;
char [] way (more C like):
public static String reduceLength(String s, int len){
char [] c = s.toCharArray();
int i=len, j=0, k;
while(true){
for(k=j; k<=i; k++){
if (k >= s.length()) return new String(c);
if (c[k] == ' ') j=k;
}
c[j] = '\n';
i= j+ len;
}
}
This isn't safe, just something i threw together.
All,
I have a database that will store an HTML tagged text to retain formatting information from an EditText. I create this string using HTML.toHtml(EditText.getText). I notice this method wraps whatever Spanned Text is put in it with <p> and </p>. The issue with that is when I got to use the method HTML.fromHtml(HTMLFormattedString) and then use the setText method of either a TextView or EditText there are two extra lines at the end of my actual text, which makes sense because that is how the paragraph tag works with HTML.
My question is is there anyway to make the textView or EditText shrink to not display the extra blank lines? What is the simplest way to do this? I have experimented with just removing the last <p> and </p>, but that only works if the user did not enter 3 or more new lines with the return key.
I ended up searching for white space at the end of the spanned text that was created and removed it. This took care of extra spaces due to the <p> </p> and was less time consuming than overriding the mentioned class to achieve the same results.
public SpannableStringBuilder trimTrailingWhitespace(
SpannableStringBuilder spannableString) {
if (spannableString == null)
return new SpannableStringBuilder("");
int i = spannableString.length();
// loop back to the first non-whitespace character
while (--i >= 0 && Character.isWhitespace(spannableString.charAt(i))) {
}
return new SpannableStringBuilder(spannableString.subSequence(0, i + 1));
}
Well this is just a round about approach. I had the same issue. And you are provided with two options,
1)As you said that paragraph tag works the way what you have suspected. What it does , it appends two "\n" values to the end of each <\p> tag. So you can convert the html to string and remove the last two characters which are usually two "\n"s
or
2) You have get into the Html Class itself. That is, you have to override the HTML class and look for handleP(SpannableStringBuilder text) and change its core logic a little bit.
private static void handleP(SpannableStringBuilder text) {
int len = text.length();
if (len >= 1 && text.charAt(len - 1) == '\n') {
if (len >= 2 && text.charAt(len - 2) == '\n') {
return;
}
text.append("\n");
return;
}
if (len != 0) {
text.append("\n\n");
}
}
As you can see here, it appends two "\n" in len!=0 which is were you have to do the change.