Develop Reference

How to set text by date and increment loop android?

I want to set text by date and incrementing loop, and when the day changes looping start from the beginning.
Example
1. day 1 =
a. nameFile 110920190001
b. nameFile 110920190002, etc.
2. day 2 =
a. nameFile 120920190001
b. nameFile 120920190002, etc.
Code
Date documentsDate = Calendar.getInstance().getTime();
SimpleDateFormat documentDates = new SimpleDateFormat("ddMMyy");
String setTitleDocument = documentDates.format(documentsDate);
for(int i = 1; i <= 1000; i++) {
String countDocument = String.format("%04d", i);
textNameDocument.setText("Document " + setTitleDocument + countDocument);
}

Just put the Date Initialization in the for loop for it to always take the new Instance of the date.
public static void replace(String s) {
for (int i = 1; i <= 1000; i++) {
Date documentsDate = Calendar.getInstance().getTime();
SimpleDateFormat documentDates = new SimpleDateFormat("ddMMyy");
String setTitleDocument = documentDates.format(documentsDate);
String countDocument = String.format("%04d", i);
textNameDocument.setText("Document " + setTitleDocument + countDocument);
}
}

How to change json string of date and format it to only show the day without, year, month, or time

I have a JSONObject and an ArrayList from where i get the data, the data date string i get is yyyy/MM/dd 00:00:00, i only want to show the day of the month 1-31, how would i format that string to only show the day ?
I've tried to use SimpleDateFormat, but without any luck, maybe since I'm doing this inside a for loop ?
public void onResponse(String response) {
try {
//getting the whole json object from the response
JSONObject obj = new JSONObject(response);
ArrayList<ListModel> ListModelArrayList = new ArrayList<>();
JSONArray dataArray = obj.getJSONArray("events");
for (int i = 0; i < dataArray.length(); i++) {
ListModel List = new ListModel();
JSONObject dataobj = dataArray.getJSONObject(i);
List.setId(dataobj.getString("id"));
List.setInit_date(dataobj.getString("init_date"));
List.setEnd_date(dataobj.getString("end_date"));
List.setTitle(dataobj.getString("title"));
List.setDescription(dataobj.getString("description"));
List.setColor_code(dataobj.getString("color_code"));
List.setAll_day(dataobj.getString("all_day"));
ListModelArrayList.add(List);
}
for (int j = 0; j < ListModelArrayList.size(); j++) {
textViewDate.setText(textViewDate.getText() +
ListModelArrayList.get(j).getInit_Date() + "\n");
textViewEvent.setText(textViewEvent.getText() +
ListModelArrayList.get(j).getTitle() + "\n");
}
right now i am getting this format 2019-05-17 00:00:00, i want to display 17 only

You can alter SimpleDateFormat as you suggested and instead of putting the date directly in the for loop here :
textViewDate.setText(textViewDate.getText() +
ListModelArrayList.get(j).getInit_Date() + "\n");
You will do the following inside your loop :
String s = ListModelArrayList.get(j).getInit_Date();
SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.ENGLISH);
Date date = null;
try {
date = fmt.parse(s);
SimpleDateFormat fmtOut = new SimpleDateFormat("dd", Locale.ENGLISH);
textViewDate.setText(textViewDate.getText() +
fmtOut.format(date) + "\n");
} catch (ParseException e) {
textViewDate.setText(textViewDate.getText() + "\n");
e.printStackTrace();
}
Which allows you to format the date according to the pattern you wish in this line :
SimpleDateFormat fmtOut = new SimpleDateFormat("dd", Locale.ENGLISH);
references for patterns
Oracle Documentation
SimpleDateFormat Patterns

How to get hours and minutes from a String variable ?

I have a String timme = "13:10". I was wondering how would I best go about getting the hours and minutes and converting them into integers. i.e. int hours = 13 , int minute = 10. I know a for-loop wouldn't be the most efficient way, is there anything simpler?

Try this way, by split() method,
String timme = "13:10";
String[] time = timme.split ( ":" );
int hour = Integer.parseInt ( time[0].trim() );
int min = Integer.parseInt ( time[1].trim() );

Better use Date and DateFormat:
String time = "13:10";
DateFormat sdf = new SimpleDateFormat("HH:mm"); // or "hh:mm" for 12 hour format
Date date = sdf.parse(time);
date.getHours(); // int
date.getMinutes(); // int

You can try this...
String time = "13:10";
SimpleDateFormat formatter = = new SimpleDateFormat("hh:mm");
Date dTime = formatter.parse(time);
int hour = dTime.getHours();
int minute = dTime.getMinutes();

You could use Calendar object of java instead of Date object,
SimpleDateFormat dateFormatter = new SimpleDateFormat("HH:mm", Locale.ENGLISH);
try {
Calendar c = Calendar.getInstance();
c.setTime(dateFormatter.parse("07:30"));
String hour = String.valueOf(c.get(Calendar.HOUR_OF_DAY));
String mintue = String.valueOf(c.get(Calendar.MINUTE));
System.out.println("Hour: " + hour);
System.out.println("Minute: " + mintue);
} catch (ParseException e) {
e.printStackTrace();
}

JAVA 8
LocalTime localTime = LocalTime.parse("13:10", DateTimeFormatter.ofPattern("HH:mm"));
int hour = localTime.getHour();
int minute = localTime.getMinute();
System.out.println("Hours : "+hour +" Minutes : "+minute);

Convert the string "8:00" into the minutes (integer value)

I'm reading the data from CSV file. One of the fields is the time in the format H:mm, i.e. "8:00". How to convert this string value into the minutes (integer value), i.e. 8:00 = 8*60 = 480 minutes?
String csvFilename = "test.csv";
CSVReader csvReader = new CSVReader(new FileReader(csvFilename));
String[] row = null;
csvReader.readNext(); // to skip the headers
int i = 0;
while((row = csvReader.readNext()) != null) {
int open = Integer.parseInt(row[0]);
}
csvReader.close();

You can use java.text.SimpleDateFormat to convert String to Date. And then java.util.Calendar to extract hours and minutes.
Calendar cal = Calendar.getInstance();
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
Date date = sdf.parse("8:00");
cal.setTime(date);
int mins = cal.get(Calendar.HOUR)*60 + cal.get(Calendar.MINUTE);

Try something like this
String str = "8:10";
int minutes=0;
String[] arr= str.split(":");
if(arr.length==2){
minutes=Integer.parseInt(arr[0])*60+Integer.parseInt(arr[1]);
}
System.out.println(minutes);

Write something like this to convert into int
public int convertToMin(String hrmin) {
String[] tokens = hrmin.split(":");
int minutes = 0;
for (int i = tokens.length; i > 0; i--) {
int value = Integer.parseInt(tokens[i - 1]);
if (i == 1) {
minutes += 60 * value;
}
else {
minutes += value;
}
}
return minutes;
}

Try this
String str = "8:20";
int ans = (Integer.parseInt(str.split(":")[0])* 60)+Integer.parseInt(str.split(":")[1]);
System.out.println("Answer = "+ans);

Not able to add 15 minute to 00:00

I have written a function for adding time in a 24 hour format as given below
for (int i = 0; i < cursor.getCount(); i++) {
String RevisedTime="00:00";
// get hour and minute from time string
StringTokenizer st1 = new StringTokenizer(RevisedTime, ":");
int j = 0;
int[] val = new int[st1.countTokens()];
// iterate through tokens
while (st1.hasMoreTokens()) {
val[j] = Integer.parseInt(st1.nextToken());
j++;
}
// call time add method with current hour, minute and minutesToAdd,
// return added time as a string
String date = addTime(val[0], val[1], 15);
}
public String addTime(int hour, int minute, int minutesToAdd) {
Calendar calendar = new GregorianCalendar(1990, 1, 1, hour, minute);
calendar.add(Calendar.MINUTE, minutesToAdd);
SimpleDateFormat sdf = new SimpleDateFormat("kk:mm");
String date = sdf.format(calendar.getTime());
return date;
}
The problem is that while adding 15 minutes to 00:00 I am getting the output as 12.15....
I need to get it as 00:15......Pleas help me.....

You have to use 0-23 hour format, not 1-24.
Instead of SimpleDateFormat sdf = new SimpleDateFormat("kk:mm");
use SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");

You just have to change a bit and it would work fine.
Replace
SimpleDateFormat sdf = new SimpleDateFormat("kk:mm");
By
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");