How to add all the elements of an array of strings?

Question

I am writing an application on Android Studio. Through the code at the press of a button, additional fields are added to the post.

In the loop, I get values from dynamically added fields. Question: how to put all the fields in a variable to use it in the future?

String[] items = new String[allEds.size()]; //запускаем чтение всех елементов этого списка и запись в массив for (int i = 0; i < allEds.size(); i++) { String strNamePers = (items[i] = ((EditText) allEds.get(i).findViewById(R.id.perona1)).getText().toString()); String strNameVoz = (items[i] = ((EditText) allEds.get(i).findViewById(R.id.peronavoz2)).getText().toString()); String strNameTreb = (items[i] = ((EditText) allEds.get(i).findViewById(R.id.peronatreb3)).getText().toString()); String strNameInt = (items[i] = ((EditText) allEds.get(i).findViewById(R.id.peronasumm4)).getText().toString()); String hr="<hr>"; String br = "<br>"; fnlstr = (br +"название персонажа: " + strNamePers + br+"возраст: "+strNameVoz+br+"требования к типажу: "+strNameTreb+br+"Сумма оплаты"+strNameInt+br+hr); Log.d("mylog", "масив с полей " + fnlstr); }

The problem is that the variable fnlstr stores only the value of the last iteration of the loop. How to make all iterations add up to one line and enter the fnlstr variable?

default locale default locale 13.7k 3 nineteen 36 · Accepted Answer · 2017-03-16T03:18:42

If you need to concatenate (concatenate) all the received strings into one, then this is done through the operator + ( += ):

 fnlstr += (br +"название персонажа: " + strNamePers + br+"возраст: "+strNameVoz+br+"требования к типажу: "+strNameTreb+br+"Сумма оплаты"+strNameInt+br+hr);

If the fnlstr loop fnlstr not initialized, then you need to do it.

 fnlstr = ""; for...

Unfortunately, string concatenation in a loop is similarly inefficient, since each iteration creates a new, longer string. So when you need to add strings together in a loop, you use a StringBuilder .

 StringBuilder fnlstrBuilder = new StringBuilder(); for (int i = 0; i < allEds.size(); i++) { //пропущен не имеющий отношения к делу код fnlstrBuilder.append(br +"название персонажа: " + strNamePers + br+"возраст: "+strNameVoz+br+"требования к типажу: "+strNameTreb+br+"Сумма оплаты"+strNameInt+br+hr); }

After the loop, you can get the string with toString :

 fnlstr = fnlstrBuilder.toString();

The application crashes with the error java.lang.NullPointerException
the first option is fnlstr + = (br + "character name:" + strNamePers + br + "age:" + strNameVoz + br + "type requirements:" + strNameTreb + br + "Payment amount" + strNameInt + br + hr);
@ dimasta68 Please, if that error says that you have not created a StringBuilder .

How to add all the elements of an array of strings?

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