Develop Reference

How to set position of view while using addView

I'm adding multiple Views by code into Layout. I need each new View to be above previous one(top of the parent layout).
EDIT: To be more accurate I'll describe what the app module should does. User start with clean screen and one button at the bottom of the screen. The button adds a View at the top of the screen. Next clicks should add next views above previous ones to make the newest View be on the top of a container. The app saves state and on restart user see views in the same order.

Call the following method from Button's onClick Event.
private final int LAYOUT_TOP_INDEX = 0;
private void addViewOnTop(View view){
if(layout != null && view !=null)
layout.addView(view, LAYOUT_TOP_INDEX);
}
where 'layout' is your Layout (e.g., LinearLayout) to which the View is to be added.

Would really need more information from you to give a more accurate answer, but if you're saying what i think you are then you can just add these views to a LinearLayout with orientation set to vertical.
And assuming you're iterating through a list to dynamically add views, instead of incrementing from 0, increment down from the size of the list.
for(int i = size; i >= 0; i--){
linearLayout.add(new TextView(Context));
}

View positions inside ViewGroups are defined by the LayoutParams
How does this happen? Views pass their LayoutParams to their parent ViewGroups
//100% programatic approach with simple LayoutParams
LinearLayout myLinearLayout = new LinearLayout(this);
//if the **parent** of the new linear layout is a FrameLayout
FrameLayout.LayoutParams layoutParams =
new FrameLayout.LayoutParams(
FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT);
//or if you have the XML file you don't have to worry about this
//myLinearLayout = (LinearLayout)findViewById(R.id.my_simple_linear_layout);
//you could have a LinkedList<TextView>
LinkedList<TextView> textViewList = new LinkedList<>();
//assuming the order is the correct order to be displayed
Iterator<TextView> descendingIterator = textViewList.descendingIterator();
while(descendingIterator.hasNext())
{
//just add each TextView programatically to the ViewGroup
TextView tView = descendingIterator.next();
myLinearLayout.addView(tView);
}
Just like we defined LayoutParams for the LinearLayout we could also define LayoutParams for the TextView
IMPORTANT: when setting LayoutParams you need to be sure they fit the VIEWGROUP, that is the parent of the View being added
private TextView textViewFactory(String myText) {
TextView tView = new TextView(getBaseContext());
//controling the position relatively to the PARENT
//because you are adding the textview to a LINEAR LAYOUT
LinearLayout.LayoutParams paramsExample =
new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,
LinearLayout.LayoutParams.WRAP_CONTENT, 1.0f);
tView.setLayoutParams(paramsExample);
//configuring the insides of the textview
//you can also do all kinds of stuff programatically
tView.setGravity(Gravity.CENTER_HORIZONTAL);
tView.setPadding(10, 10, 10, 10);
tView.setTypeface(Typeface.DEFAULT_BOLD);// (null, Typeface.BOLD_ITALIC);
tView.setTypeface(Typeface.SANS_SERIF);
tView.setTypeface(null, Typeface.ITALIC);
tView.setTypeface(Typeface.defaultFromStyle(R.style.AppTheme));
tView.setId(R.id.aux_info);
tView.setText(myText);
//.........all kinds of stuff really
return tView;
}

If you mean adding a view programmatically so that the new one is added above the previous one, instead of below it, then I suggest this:
Maintain an ArrayList with the items you want to turn into views
Put them into a ListView
When you want to add a new view that must appear at the top of the list, insert it as the first element of your ArrayList and recreate the ListView from it.

Confusion with findViewById()

I am trying to programmatically add LinearLayouts inside an existing RelativeLayout. Each LinearLayout will contain some buttons and I want to be able to toggle the visibility of each set of buttons by setting the visibility of the container LinearLayout.
// We iterate over a list and call the following to create the new
// layout assigning an index from a int counter
LinearLayout LL = new LinearLayout(MainActivity.this);
LL.setOrientation(LinearLayout.VERTICAL);
LL.setId(nextId);
LinearLayout.LayoutParams LLParams = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.MATCH_PARENT, LinearLayout.LayoutParams.MATCH_PARENT);
LL.setWeightSum(6f);
LL.setLayoutParams(LLParams);
LinearLayout mll=((LinearLayout) findViewById(R.id.menuLayout));
mll.addView(LL);
My problem comes when I try to retrieve these layouts later, for instance to be able to toggle their visibility on/off. I thought I would be able to use
LinearLayout ll = (LinearLayout) findViewById(layoutIndex);
But findViewById() gives me an error when I try to supply an int, it wants a resource ID. Is there an easy way I can convert the ints that I have assigned as the Ids for these layouts to R.id.XXX ids?
Thanks,
Andy

findViewById(id) looks up elements that were included as part of the XML defining a layout.
You will probably have better luck with getChildAt(index), which returns the View at the passed index.

Yes! Find all LinearLayout in a container without using ID.
LinearLayout mll= (LinearLayout) findViewById(R.id.menuLayout);//container
for(int i=0; i<mll.getChildCount(); ++i) {
View nextChild = mll.getChildAt(i);
if (nextChild instanceof LinearLayout ) {
//TODO add your code here nextChild is a LL that you wanna find
}
}

Adding views dynamically in a for loop results in haphazard positioning - Android

I am adding views dynamically to a relative layout (let's say container) in a for loop. There is some thing strange I am noticing. When adding rows one below the other in a relative layout in a for loop, I see that the first time a few of the views are overlapping. But when I lock and unlock the screen, I can see that the views are placed correctly.
Should I be aware of something when adding views dynamically to a relative layout?
Edit
I have found a solution as to how to get rid of this (please check my answer). But I would be more than glad to accept an answer that analyses this problem and tells me why this happens.
I have simplified to code and the comments should give a good idea as to what I am doing.
int prev_id=ID_OF_THE_ELEMENT_ABOVE;
/*Empty RelativeView with width and height as MATCH_PARENT and WRAP_CONTENT respectively*/
RelativeLayout container=(RelativeLayout) findViewById(R.id.container);
while(ThereIsData){
/*GET THE DATA HERE THAT HAS TO BE ASSIGNED TO EACH TEXTVIEW*/
...
/* ADD TEXTVIEW #1 below prev_id/
...
...
/*ADD TEXTVIEW #2 (WITH BASELINE OF TEXTVIEW#
...
...
/*TEXTVIEW #3 (BELOW TEXTVIEW#1)*/
...
...
/*TEXTVIEW #4 (BELOW TEXTVIEW#2)*/
...
...
/*ASSIGN THE ID OF TEXTVIEW#3 TO prev_id SO THAT
IN THE NEXT ITERATION TEXTVIEW#1 CAN USE prev_id
*/
prev_id=ID(TEXTVIEW#2);
/*ADD TEXTVIEWS CREATED IN THIS ITERATION*/
container.addView(TEXTVIEW#1);
container.addView(TEXTVIEW#2);
container.addView(TEXTVIEW#3);
container.addView(TEXTVIEW#4);
}

It is due to the fact that you are having a RelativeLayout with height as WRAP_CONTENT, and adding a view doesn't refresh the whole container at that time.. so as you answered you can add a line to measure the dimensions explicitly or invalidate the view to recreate it completely.
In any case LinearLayout would be better to opt-for as it will automatically arrange the children in horizontal or vertical manner and you can even add the new view in any place other than last position and it will automatically be updated..

I used to struggle against common issues a year ago, when I was working on a library for dynamically creating layouts from XML files (as Android does not support this). So when you dynamically add views to a RelativeLayout you have to take in mind a few things:
Create the container View (in this case the RelativeLayout)
Create all views without assigning any layout parameters.
Add all child views to the container.
Iterate over the container's children and populate each child's layout parameters. This is needed because when the relational constraints are applied an Excpetion is thrown if the relative View is missing (was not previously added to the container).
This is an example code taken from the project I used to work on. Take in mind that it is just a single part so it contains references to classes that are not defined in the Android API. I am sure it will give you the basic idea of dynamically creating RelativeLayot:
private void setChildren(RelativeLayout layout, T widget,
InflaterContext inflaterContext, Context context,
Factory<Widget, View> factory) {
List<Widget> children = widget.getChildren();
if (Utils.isEmpty(children))) {
return;
}
// 1. create all children
for (Widget child : children) {
View view = factory.create(inflaterContext, context, child);
layout.addView(view);
}
// 2. Set layout parameters. This is done all children are created
// because there are relations between children.
for (Widget child : children) {
try {
View view = ViewIdManager.getInstance().findViewByName(layout, child.getId());
if (view != null) {
populateLayoutParmas(child, view);
}
} catch (IndexNotFoundException e) {
Log.e(LOG_TAG, "Cannot find a related view for " + child.getId(), e);
}
}
}

I have not yet found the answer to why this is happening. But I have found a solution. After adding each row in the loop, call container.measure(RelativeLayout.LayoutParams.WRAP_CONTENT,RelativeLayout.LayoutParams.WRAP_CONTENT);
This seems to solve the problem. But I really think that container.addView() should also be calling measure().
/*ADD TEXTVIEWS CREATED IN THIS ITERATION*/
container.addView(TEXTVIEW#1);
container.addView(TEXTVIEW#2);
container.addView(TEXTVIEW#3);
container.addView(TEXTVIEW#4);
//---------------------------------------------------------------------
container.measure(RelativeLayout.LayoutParams.WRAP_CONTENT,RelativeLayout.LayoutParams.WRAP_CONTENT);

//Declare globally
LinearLayout[] layout;
ImageView[] imageView1;
ImageView[] imageView2;
ImageView[] imageView3;
// Initialize your layout. It would be RelativeLayout too. Just reference to it.
LinearLayout ll = (LinearLayout) findViewById(R.id.mylinear);
// set listview row size as your demand
layout = new LinearLayout[200];
imageView1 = new ImageView[200];
imageView2 = new ImageView[200];
imageView3 = new ImageView[200];
for (int i = 0; i < 200; i++) {
layout[i] = new LinearLayout(this);
layout[i].setBackgroundResource(R.drawable.book_shelf);
// layout[i].setLayoutParams(new
// LinearLayout.LayoutParams(android.widget.LinearLayout.LayoutParams.FILL_PARENT,
// 120));
layout[i].setLayoutParams(new LinearLayout.LayoutParams(
android.widget.LinearLayout.LayoutParams.FILL_PARENT, 220));
imageView1[i] = new ImageView(this);
imageView2[i] = new ImageView(this);
imageView3[i] = new ImageView(this);
imageView1[i].setLayoutParams(new LinearLayout.LayoutParams(0, 200,
0.33f));
imageView1[i].setPadding(0, 20, 0, 0);
imageView1[i].setImageResource(R.drawable.bibid_one_bankim);
imageView2[i].setLayoutParams(new LinearLayout.LayoutParams(0, 200,
0.33f));
imageView2[i].setPadding(0, 20, 0, 0);
imageView2[i].setImageResource(R.drawable.bibid_two_bankim);
imageView3[i].setLayoutParams(new LinearLayout.LayoutParams(0, 200,
0.33f));
imageView3[i].setImageResource(R.drawable.dena_pawna);
imageView3[i].setPadding(0, 20, 0, 0);
layout[i].setId(i);
layout[i].setClickable(true);
final int j = i;
layout[i].addView(imageView1[i]);
layout[i].addView(imageView2[i]);
layout[i].addView(imageView3[i]);
ll.addView(layout[i]);
}
}

Try adding your views in vertical Linear Layout.
Following link might help you
http://www.myandroidsolutions.com/2012/06/19/android-layoutinflater-turorial/
Inflate your layout in for loop.

tablelayout getchildat scroll to that child

I actually trying something quite straightforward, however android and java are making my life not easy. The idea is to scroll to a specified child in the table layout.
I am using a Layoutinflater to add the entries to the table layout like the following :
TableLayout tl = (TableLayout)findViewById(R.id.myTableLayout3);
LayoutInflater inflater = (LayoutInflater)getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View itemView = inflater.inflate(R.layout.element_news, null);
TextView firstname = (TextView) itemView.findViewById(R.id.tvname);
firstname.setText(FN + " " + iLN);
TextView date = (TextView) itemView.findViewById(R.id.tvdate);
date.setText(newPD);
TextView post = (TextView) itemView.findViewById(R.id.tvpost);
post.setText(c.getString(iP));
post.setFocusable(true);
tl.addView(itemView, new TableLayout.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.WRAP_CONTENT));
I tried to use the getChildAt() for the tablelayout and I do get the child, however when I use the child it returns for everything "0".
Example Code:
LinearLayout row = (LinearLayout) tl.getChildAt(1);
TextView tv = (TextView) row.getChildAt(1);
tv.requestFocus();
Log.w("news", Integer.toString(tv.getHeight()));
For the TextView Height it returns "0" eventhough it contains multiple lines and the requestfocus() does not work either.
So how can I scroll to the child in the table layout?
Thanks in advance for any help.

That code sample doesn't work because you probably use it in the onCreate method and at that time the UI isn't drawn yet so the views don't have any dimensions. If this is the case you could simply post a Runnable on one of your views to delay a bit the dimensions gathering until after the onCreate method like this:
// post the Runnable
tl.post(new Runnable() {
#Override
public void run() {
LinearLayout row = (LinearLayout) tl.getChildAt(1);
// get the top position relative to the parent
int top = tr.getTop();
// scroll to that top position the wrapping ScrollView
sv.scrollTo(0, top);
}
});
There is something strange about your code(from my point of view), if the code above doesn't work you should post more details about your layout files and use scenario.

what is the position constant for addview

I am trying to dynamically add textviews to a linearLayout, say the textview is boo and the linearlayout is foo.
TextView boo = new TextView(this)
LinearLayout foo = findViewByID(R.id.examplelayout)
I am trying to add the textview right below the existing textview in the layout. when I add it
foo.addView(boo, int position new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.WRAP_CONTENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
how do I specify the position parameter to achieve it, because the default one is to add it above. I have been searching the docs but couldn't find any explanation for the position parameter. all I got is this:
public void addView (View child, int index, ViewGroup.LayoutParams params)
Since: API Level 1
Adds a child view with the specified layout parameters.
Parameters
child the child view to add
index the position at which to add the child
params the layout parameters to set on the child
any headsup would be appreciated.

You can use method foo.getChildCount()