我如何收集数组中的所有项目

Question

I have an array which is :

ArrayList<Integer> array = new ArrayList<Integer>();
String a1 = edittext.getText().toString();
int integer = Integer.parseInt(a1);
array.add(integer);

like that. There are about 15 items but I don't know exactly how much they are. I want to collect all items on this array. How can I do that ? While or something else?

I hope you will able to understand my problem. I don't know English very well.

Answer 1

I want to collect all items on this array. How can i do that ? while or something else?

Iterate through every element in the Array using a for-each :

for(Integer i : array){
  //Do whatever you want to do
}

That loop is either called a for-each or advanced for-loop . It will iterate through every Object in your array and returns that object (In your case, Integer i )

OR

Use a regular for-loop. You probably used it before so it will be easier for you -

for(int i = 0; i < array.size(); i++) {
 Integer item = array.get(i);
}

---

To implicitly tackle your code, I will be assuming:

1. You're receiving user input
2. You wish to parse user input to an Integer (Meaning you only want numbers)
3. You want to repeat this loop X number of times.

If there's something I'm missing please correct me.

    ArrayList<Integer> array = new ArrayList<Integer>();
    Integer tempInteger;
    try{
        tempInteger = Integer.parseInt(edittext.getText().toString());
    }catch(NumberFormatException e){
        e.printStackTrace();
    }
    array.add(tempInteger);

    /*
     * Once you have your array filled with 'elements' (In your case
     * with Integer values) you can use the following loop called a 
     * 'for-each' loop to loop through ALL the elements in your list.
     */
    for(Integer i : array){
        System.out.println("array["+array.get(i)+"]" + " = " + i);
    }

OR

Using a regular for-loop :

    for(int i = 0; i < array.size() - 1; i++){
        Integer myInteger = array.get(i);
        System.out.println("array["+i+"]" + " = " + myInteger);
    }

Answer 2

Hope I understand the question correct. To get each item in array you may do the following:

for(int i = 0; i < array.size(); i++)
{
     Integer item = array.get(i);
     //do whatever you want with item
}

Here is how to find a sum of all items in array:

Integer sum = 0;
for(int i = 0; i < array.size(); i++)
{
     sum += array.get(i);
}
//sum is now contains sum of all items