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Which of the two code is better on memory basis?

I am learning android development from a course by Udacity.While I was going through the Lesson 2,there came a situation where we had to create multiple Textviews,set the text from previously created ArrayList of strings and add those Textviews to Linear layout.
Common code:
ArrayList<String> words = new ArrayList<String>();
words.add("one");
words.add("two");
words.add("three");
words.add("four");
words.add("five");
words.add("six");
words.add("seven");
words.add("eight");
words.add("nine");
words.add("ten");
LinearLayout rootView =(LinearLayout) findViewById(R.id.rootView);
Now what they did:
for(int i=0;i<10;i++){
TextView wordView=new TextView(this);
wordView.setText(words.get(i));
rootView.addView(wordView);
}
What I did:
ArrayList<TextView> wordView = new ArrayList<TextView>();
for(int i=0;i<10;i++)
{
wordView.add(new TextView(this));
wordView.get(i).setText(words.get(i));
rootView.addView(wordView.get(i));
}
Now,my question is weather my way to approach the task has more memory overheads than their way?
I feel my code is better because I have reference to each TextView even after the loop.

No difference. In both cases TextView instances could not be garbage collected, so memory foot print is equal.
because I have reference to each TextView even after the loop.
If you don't really need these references then it's just senseless. It's not memory related advantage.

Your code looks good. But I don't see a point on having 10 the same TextViews. I would consider using a listView or recyclerView if you are using it as a list and thinking about optimising your code.
But still your code is fine.

It doesn't matter performance wise.. Just like you said:
I feel my code is better because I have reference to each TextView even after the loop.
If you need that, do it..

Exploring the view tree in Android

It's maybe a bit abstract but I'd like to know if some of you have a decent solution to that problem:
I have a complicated layout and I need to find ALL the instances of a certain type of view.
I have few solutions but I find none of them perfect and I'd like to know if there is another way or a way to improve them.
MY FIRST OPTION
We can iterate in the view tree with getChildCount() and getChildAt() and then check with instanceof like in lots of SO answers.
for (int i = 0; i<parentContainer.getChildCount(); i++){
View child = getChildAt(i);
if (child instanceof BlaBla){
// Do something wonderful
}
}
It is highly inefficient because I have these instances in many places and in particular in nested places so I need to make this method recursive.
MY SECOND OPTION
It would be to work with dynamic tags or ids and use findViewById or findViewWithTag. But the issue is that it makes something more to configure and as always it makes the software more complicated.
So my question is: how can I do a complete search in the view tree in
order to find all instances of a component without doing the search
myself (because it would be probably be very inefficient)? Is that
somehow possible?

So, I'm not sure second option is possible as in this case you'll need to create this views in runtime and assign some generated ID with some bit mask to recognize them later. If to create your views from layout you will end up with traversing tree view and assigning these special IDs which is pretty much accends to 1st option.
In my project I also have to dynamically apply colors to some views and I do it without recursion. Pattern is following:
ArrayList<View> views = new ArrayList<>();
views.add(getWindow().getDecorView());
do {
View v = views.remove(0);
if (v instanceof ViewGroup) {
ViewGroup group = (ViewGroup) v;
for (int i = 0; i < group.getChildCount(); i++) {
views.add(group.getChildAt(i));
}
}
if (v instanceof MyCustomView) {
//do whatever you need here
}
} while(!views.isEmpty());
So you get rid of using recursion and replace it with own stack and iteration through it. This solution quite efficient especially if you can skip things like ListView, RecyclerView.

Does Android API have something like Flash's duplicate movieclip?

I used to do alot of Flash Actionscript and now I am getting into Android. Is there something in the Android API that is similar to duplicateMovieClip() in Actionscript? I'm sure there is probably a way to write such a method, but I am wondering if there are any existing shortcuts.
For example, say I have an ImageView, TextView, or other kind of View Object on screen and I want to have a button to click which will make a duplicate of some object on screen.

If you don't mind my asking, why do you need something like duplicateMovieClip()?
To answer the question, Android doesn't have a notion of the AS2 duplicateMovieClip(). Much like in AS3 (which also didn't have duplicateMovieClip()) you'll have to implement your own cloning method. Java does have an unimplemented '.clone()' method as part of every Java object, so if there's a particular View you would like to clone you might be able to implement your cloning there by
Overriding the clone method.
I think what you'd probably end up doing instead is doing something more akin to instantiating from the Library by making small view layouts in xml and inflating them using the Inflater tools.
View result = null;
// where pContext is a context object, either supplied by the application
// or just by the current Activity (if available)
LayoutInflater inflater = (LayoutInflater) pContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// where id is the layout id such as R.layout.myclonableview.
// where pRoot is the parent container for the new result.
// where pAttachToRoot is whether to immediately inflate the new view into the root.
result = inflater.inflate(id, pRoot, pAttachToRoot);
// Now "clone" your old view by copying relevant fields from the old one to the
// one stored in result

Faster and shorter way of finding views

Is there a quicker or shorter way to initialize all view in my layout than this:
row2[0] = (RelativeLayout) findViewById(R.id.ll22);
row2A[0] = (RelativeLayout) findViewById(R.id.ll22alt);
row2B[0] = (RelativeLayout) findViewById(R.id.ll22blank);
mOffsiteDataBackup[0] = (TextView) findViewById(R.id.ll22_backup);
mRam[0] = (TextView) findViewById(R.id.ll22_ram);
mCpu[0] = (TextView) findViewById(R.id.ll22_cpu);
mHdd[0] = (TextView) findViewById(R.id.ll22_hdd);
mOs[0] = (TextView) findViewById(R.id.ll22_system);
mStatusIcon[0] = (ImageView) findViewById(R.id.ll22_image);
.
.
.
It is really annoying to write lot of lines only to find views. Until I find all of them and initialize some listeners, my onCreate has more than 400 lines, which is something I certainly don't want.
Thanks for your tips !

Any way you do it it's going to be around the same amount of typing, in some cases even more. 50> an extreme amount of views in an activity...
The only way I can think of making this smaller is splitting them up into Fragments and use the updated framework... 70 elements shouldn't be in one ui.. a ui is meant to be simple and easy to use. Not with lots of elements to it that distracts the user from the main task they want it for.

If few UI elements are functional unity(like your progresBar and textView), you can create custom view with these elements. That makes code is much more clear, especially if you use more instances of this view in one activity.

Bunch of questions about View ids

i would like to ask a lot of questions about how this whole id system works in android. I looked up the View documentation, but the description was too shallow for my taste.
Is there a pattern, how the IDE (Eclipse/Netbeans) generates the ids
when i use android:id="#+id/..."? Or is it completely random?
If i set ids programmatically, then will it be found by the Context
classes findViewById() function?
If the answer for the previous question is yes, then if i want to
create a large amount of Views, but i want them to have distinct ids
for later identification, then wich one is better to use? (To answer
this question, it would be really useful to know the answer for the
first two)
For example generating random ids in the largest possible range:
Random random = new Random();
for(int i=0; i<100; i++)
{
View view = new View(someContext);
view.setId(random.nextInt(Integer.MAX_VALUE));
}
Or setting the ids in some sort of order, for example:
final int addToId = 5670;
for(int i=0; i<100; i++)
{
View view = new View(someContext);
view.setId(i+addToId);
}
Also i would like to know, what happens, when you use a
LayoutInflater for example to populate a ListView using a
pre-defined xml layout for every item in the list. Then you get your
sub-views in the getView() function by the findViewById(). So i
assume, that all the identical Views across your listitems have the
same id. If so, then is it a good practice to use the tag
attribute to distinguish the items in an inflated layout?
Any clear explanation for these question would be highly appreciated!

#+id/.... creates an id value that lives within the applications namespace. Contrast this with #android:id/.... which lives in the android namespace.
When you set the id in code and add the view element to the layout it will then become available to access through the code. You won't be able to reference it from the xml
Not sure you want to be using random to generate your ids? think sequential would be better but even then what is the point of a random id? How do you know which view you are referring to?
Definitely use the tag option and look to use the ViewHolder pattern for smoother list scrolling. You could add the id to the view holder class if you need access to it but it would be available anyway through the data set being used to populate the list. A quick search will give you plenty of examples for this.