My ArrayList contains has two records:
Item 1
Item 2
Here is the loop I am using to get these records
String global = null;
for(int i=0; i<arrayList.size(); i++) {
String name = arrayList.get(i).getName().toString();
}
global = global+name+", ";
Log.d("items:", global);
Output:
D/items:: nullItem 2,
Whereas I was expecting
Item 1, Item 2
Initialize String global to empty string instead of null. Concatenation should not be done between null and a string object.
String global ="";
global = global +"item"; // global is now item;
If you initalize global to null
String global = null;
global = global + "item"; // treated as "null" + "item"
Modify global variable inside the loop, you are trying to access name variable outside its scope, so name variable is overwritten for each iteration in loop even if you declare name outside the loop.
for(int i=0; i<arrayList.size(); i++) {
String name = arrayList.get(i).getName().toString();
global = global+name+", ";
}
StringBuilder global = new StringBuilder();
for(int i=0; i<arrayList.size(); i++) {
global.append(arrayList.get(i).getName().toString());
}
Log.d("items:", global.toString());
global.append(", " +arrayList.get(i).getName().toString());String global = "";
for(int i=0; i<arrayList.size(); i++) {
global+ = arrayList.get(i).getName().toString();
}
Log.d("items:", global);
You could use a for each loop to avoid having to manage a loop index:
StringBuilder global = new StringBuilder();
for (Yourclass object : arrayList) {
global.append(object.getName().toString());
}
Log.d("Items: ", global);
global = global + ", " +arrayList.get(i).getName().toString();inside a loop