Develop Reference

what is the characters behind the characters down the line?

I am converting between "\n" to ":" in file .txt. And here, this is my paragraph before convert:
You can see that, between string "Hoa" and string "Đàm", it have one character " " and two character "\n". And this is my convert function:
private String convertData(){
String different = "~`!##$%^&*()-_=+*/\\\"'|]}{[:;?/.><,\n ";
StringBuilder data = new StringBuilder(tvData.getText().toString().trim());
for (int j = 0; j < data.length(); j++){
if(different.contains("" + data.charAt(j))) data.setCharAt(j, ':');
}
String convertData = data.toString().trim();
return convertData;
}
And this is result:
You can see behind character "\n" have a character, and it is not in string different.
Can anyone tell me what to do?

1 - Proceed like you're currently doing, but the \n (and the other escaped sequences).
So, use
String different = "~`!##$%^&*()-_=+*/'|]}{[:;?/.><, ";
2 - After the loop, use string.replace() to replace only the substring "\n" and the other sequences, i.e.: "\\" and "\"".
You could use a loop to replace the sequences, but you must replace 2 characters instead of one.
Basically, in the first loop you replace all the single characters.
Then, you replace the character sequences.

Notepad only supports Windows line endings (\r\n), so that must be what your file contains. Convert the file to Unix line endings (\n) using literally any program that is not Notepad, or add \r to your search pattern.

Android TextView : "Do not concatenate text displayed with setText"

I am setting text using setText() by following way.
prodNameView.setText("" + name);
prodOriginalPriceView.setText("" + String.format(getString(R.string.string_product_rate_with_ruppe_sign), "" + new BigDecimal(price).setScale(2, RoundingMode.UP)));
In that First one is simple use and Second one is setting text with formatting text.
Android Studio is so much interesting, I used Menu Analyze -> Code Cleanup and i got suggestion on above two lines like.
Do not concatenate text displayed with setText. Use resource string
with placeholders. less... (Ctrl+F1)
When calling TextView#setText:
Never call Number#toString() to format numbers; it will not handle fraction separators and locale-specific digits properly. Consider
using String#format with proper format specifications (%d or %f)
instead.
Do not pass a string literal (e.g. "Hello") to display text. Hardcoded text can not be properly translated to other languages.
Consider using Android resource strings instead.
Do not build messages by concatenating text chunks. Such messages can not be properly translated.
What I can do for this? Anyone can help explain what the thing is and what should I do?

Resource has the get overloaded version of getString which takes a varargs of type Object: getString(int, java.lang.Object...). If you setup correctly your string in strings.xml, with the correct place holders, you can use this version to retrieve the formatted version of your final String. E.g.
<string name="welcome_messages">Hello, %1$s! You have %2$d new messages.</string>
using getString(R.string.welcome_message, "Test", 0);
android will return a String with
"Hello Test! you have 0 new messages"
About setText("" + name);
Your first Example, prodNameView.setText("" + name); doesn't make any sense to me. The TextView is able to handle null values. If name is null, no text will be drawn.

Don't get confused with %1$s and %2$d in the accepted answer.Here is a few extra information.
The format specifiers can be of the following syntax:
%[argument_index$]format_specifier
The optional argument_index is specified as a number ending with a “$” after the “%” and selects the specified argument in the argument list. The first argument is referenced by "1$", the second by "2$", etc.
The required format specifier is a character indicating how the argument should be formatted. The set of valid conversions for a given argument depends on the argument's data type.
Example
We will create the following formatted string where the gray parts are inserted programmatically.
Hello Test! you have 0 new messages
Your string resource:
< string name="welcome_messages">Hello, %1$s! You have %2$d new
messages< /string >
Do the string substitution as given below:
getString(R.string.welcome_message, "Test", 0);
Note:
%1$s will be substituted by the string "Test"
%2$d will be substituted by the string "0"

I ran into the same lint error message and solved it this way.
Initially my code was:
private void displayQuantity(int quantity) {
TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
quantityTextView.setText("" + quantity);
}
I got the following error
Do not concatenate text displayed with setText. Use resource string with placeholders.
So, I added this to strings.xml
<string name="blank">%d</string>
Which is my initial "" + a placeholder for my number(quantity).
Note: My quantity variable was previously defined and is what I wanted to append to the string. My code as a result was
private void displayQuantity(int quantity) {
TextView quantityTextView = (TextView) findViewById(R.id.quantity_text_view);
quantityTextView.setText(getString(R.string.blank, quantity));
}
After this, my error went away. The behavior in the app did not change and my quantity continued to display as I wanted it to now without a lint error.

Do not concatenate text inside your setText() method, Concatenate what ever you want in a String and put that String value inside your setText() method.
ex: correct way
int min = 120;
int sec = 200;
int hrs = 2;
String minutes = String.format("%02d", mins);
String seconds = String.format("%02d", secs);
String newTime = hrs+":"+minutes+":"+seconds;
text.setText(minutes);
Do not concatenate inside setText() like
text.setText(hrs+":"+String.format("%02d", mins)+":"+String.format("%02d", secs));

You should check this thread and use a placeholder like his one (not tested)
<string name="string_product_rate_with_ruppe_sign">Price : %1$d</string>
String text = String.format(getString(R.string.string_product_rate_with_ruppe_sign),new BigDecimal(price).setScale(2, RoundingMode.UP));
prodOriginalPriceView.setText(text);

Don't Mad, It's too Simple.
String firstname = firstname.getText().toString();
String result = "hi "+ firstname +" Welcome Here";
mytextview.setText(result);

the problem is because you are appending "" at the beginning of every string.
lint will scan arguments being passed to setText and will generate warnings, in your case following warning is relevant:
Do not build messages by
concatenating text chunks. Such messages can not be properly
translated.
as you are concatenating every string with "".
remove this concatenation as the arguments you are passing are already text. Also, you can use .toString() if at all required anywhere else instead of concatenating your string with ""

I fixed it by using String.format
befor :
textViewAddress.setText("Address"+address+"\n"+"nCountry"+"\n"+"City"+"city"+"\n"+"State"+"state")
after :
textViewAddress.setText(
String.format("Address:%s\nCountry:%s\nCity:%s\nState:%s", address, country, city, state));

You can use this , it works for me
title.setText(MessageFormat.format("{0} {1}", itemList.get(position).getOppName(), itemList.get(position).getBatchNum()));

If you don't need to support i18n, you can disable this lint check in Android Studio
File -> Settings -> Editor -> Inspections -> Android -> Lint -> TextView Internationalization(uncheck this)

prodNameView.setText("" + name); //this produce lint error
val nameStr="" + name;//workaround for quick warning fix require rebuild
prodNameView.setText(nameStr);

I know I am super late for answering this but I think you can store the data in a varible first then you can provide the variable name. eg:-
// Java syntax
String a = ("" + name);
String b = "" + String.format(getString(R.string.string_product_rate_with_ruppe_sign);
String c = "" + new BigDecimal(price).setScale(2, RoundingMode.UP));
prodNameView.setText(a);
prodOriginalPriceView.setText(b, c);

if it is textView you can use like that : myTextView.text = ("Hello World")
in editText you can use myTextView.setText("Hello World")

how to get text with using substring

I try to get only this part "9916-4203" in "Region Code:9916-4203 " in android. How can I do this?
I tried below code, I used substring method but it doesn't work:
firstNumber = Integer.parseInt(message.substring(11, 19));

If you know that string contains "Region Code:" couldn't you do a replace?
message = message.replace("Region Code:", "");

Assumed that you have only one phone number in your String, the following will remove any non-digit characters and parse the resulting number:
public static int getNumber(String num){
String tmp = "";
for(int i=0;i<num.length();i++){
if(Character.isDigit(num.charAt(i)))
tmp += num.charAt(i);
}
return Integer.parseInt(tmp);
}
Output in your case: 99164203
And as already mentioned, you won't be able to parse any String to Integer in case there are any non-digit characters

Im going to guess that what you want to extract is the full region code text minus the title. So maybe using regex would be a good simple fit for you?
String myString = "Region Code:9916-4203";
String match = "";
String pattern = "\:(.*)";
Pattern regEx = Pattern.compile(pattern);
Matcher m = regEx.matcher(myString);
// Find instance of pattern matches
Matcher m = regEx.matcher(myString);
if (m.find()) {
match = m.group(0);
}
Variable match will contain "9916-4203"
This should work for you.
Java code sourced from http://android-elements.blogspot.in/2011/04/regular-expressions-in-android.html

In Java the substring() method works with the first parameter being inclusive and the second parameter being exclusive. Meaning "Hello".substring(0, 2); will result in the string He.
In addition to excluding the parsing of something that isn't a number like #Opiatefuchs mentioned, your substring method should instead be message.substring(12, 21).

How to roud off a String value "5571.329849243164" in android

I'm getting below error while converting String array to Long array.
java.lang.NumberFormatException: Invalid long: "5571.329849243164". How to round off this value like 5571.

Use this
String.format("%.2f", d)

//try this way, hope this will help you...
String value = "5571.329849243164";
Toast.makeText(MyActivity.this,""+Math.round(Double.parseDouble(value)),Toast.LENGTH_SHORT).show();

round(Double value)`
see here
String string = "5571.329849243164";
Double value1 = Double.parseDouble(string);
tv.setText(Math.round(value1) + "/");

I understand you want to convert a String representing a floating point value to an Integer with rounding, not truncation. Perfectly reasonable.
Two choices.
Convert the string to a Double first (Double.valueOf()), then convert to Integer (intValue()) using a rounding algorithm. Usually it's enough to just add 0.5 to the Double.
Round the String using string operations, then convert to Integer. Split the string at the first ".", convert it to Integer (getInteger()). If the digit after the "." is in the range 5-9 then add one.
I'm sure you can write the code.

Remove garbage character from String

In my Android Application when I am reading the particular data from NFC chip it's giving garbage values as show follows which is printed on Log
����������������
I used following line to remove garbage value
str.replaceAll("[^\\p{ASCII}]", "")
but it is not working.
Please provide me solution.

That is because � is not an ASCII character. It is a unicode character with (int) � returning 65533.
And your code str.replaceAll("[^\\p{ASCII}]", "") works perfectly fine.
scala> val str ="����������������"
str: String = ����������������
scala> str.replaceAll("[^\\p{ASCII}]", "")
res8: String = ""
You need to show more code and explain what exactly you are trying to do.

Better to retrieve the data in the form of UTF-8 format then it helps. try it out.
or convert the string to UTF-8 format
i.e, String _data=new String(str.getBytes(),"UTF-8");
it returns the data in UTF-8 format

One solution using this method .replaceAll("[^\\x00-\\x7F]", "")
String str = "jorgesys���������������� was here!";
str = str.replaceAll("[^\\x00-\\x7F]", ""));
so the result of str is:
jorgesys was here!