Develop Reference

Sort views in layout according to number of views

I am struggling at one thing. Let's say I have linear layout with set height and width is match_parent. I will have a set number of views 1 to 6 and I don't know at runtime how much I will receive from server. The problem is, how can I sort them in a layout so they scale their width accordingly to number of views present ? If there are more than 3 views I need to put them in two lines.
I was thinking about using layout weight, but can't think about solution that can put them to two lines. Any ideas ?

You have to dynamically add views to linear layout.
First create container layout in xml.
<LinearLayout
android:id="#+id/containerLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
/>
Then check,
if(list.size()<=3)
{
Then assign weight to container. i.e weight=list.size
for(int i=0;i<size;i++)
{
TextView textview = new TextView(this);
textview.setText(brandName);
textview.setWeight(1f);
container.addView(textview);
}
}
else
{
int totalRows= (list.size/3)+(list.size%3);
int count=0;
for(int i=0;i<totalRows;i++)
{
LinearLayout newLL = new LinearLayout(mContext);
newLL.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT));
newLL.setOrientation(LinearLayout.HORIZONTAL);
for(int j=count;j<count+3;j++)
{
count++;
TextView textview = new TextView(this);
textview.setText(brandName);
newLL.addView(textview);
}
container.addView(newLL);
}
}
You have to do something like this.This is not actual code.

You should use listview in your rooted LinearLayout and design single list item in an other xml layout , create a custom adapter for your single list item and set the adapter to your list view . this answer will help you how to create custome adapter

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.

How to dynamically wrap root layout in a ScrollView

I want to add a scroll view to all the layouts that I have. But dynamically. Because the app will run in different screen sizes, and when I will get a screen size smaller than a specific size, then I want to show the layout in a scroll view.
So I made this method, it will be called on the check that the screen is small. I will pass my activity and I want to change the root layout to scroll view or just add a ScrollView as the root layout. So if the root layout is a LinearLayout, then I want to put that layout in the ScrollView. And I have not named all the layouts, meaning that I didn't give an ID to the layout, so I cannot use findViewById.
public static void SetActivityRoot(Activity c) {
View v = c.getWindow().getDecorView();
// View v = v.getRootView();
ScrollView sv = new ScrollView(c);
LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
sv.setLayoutParams(lp);
((ViewGroup)v.getParent()).removeView(v);
sv.addView((View) v);
((ViewGroup)v.getParent()).addView(sv);
}
It's giving me an error saying that "you cannot remove view from null" etc. Or that "you cannot add view to layout as it already has parent view". How can I make this work?

Finally solved my problem.
public static void SetActivityRoot(Activity c) {
View v = ((ViewGroup)c.findViewById(android.R.id.content)).getChildAt(0);
ScrollView sv = new ScrollView(c);
LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,
LayoutParams.MATCH_PARENT);
sv.setLayoutParams(lp);
((ViewGroup) v.getParent()).removeAllViews();
sv.addView((View) v);
c.addContentView(sv, lp);
}

Android programmatic relative layout: BELOW rule not working?

I want to create a layout (see class RosterPlayerView below) that comprises an image with text below it and then instantiate that view multiple times in a relative layout. I used relative layout instead of linear as the layout will become more complex.
When I first ran the code below (but without the setId calls) the text appeared above the image. Thanks to this stack overflow article I discovered that relative layout needs unique widget ids to work. But when I added the setId() calls the text view is not displayed at all.
What am I doing wrong?
public class RosterPlayerView extends RelativeLayout {
ImageView imageView;
TextView textView;
static int layoutId = 100;
public RosterPlayerView(Context context, int playerId, Drawable photo) {
super(context);
imageView = new ImageView(context);
textView = new TextView(context);
addView(imageView, new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
imageView.setId(layoutId++);
RelativeLayout.LayoutParams timeLayoutParams = new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
timeLayoutParams.addRule(RelativeLayout.BELOW, imageView.getId());
addView(textView, timeLayoutParams);
imageView.setImageDrawable(photo);
textView.setId(layoutId++);
textView.setText("0:00");
}
}

a LinearLayout would be an awful lot simpler for what you are trying to do. So would inflating an XML layout, for that matter.

Try to set the Id of you imageView before adding it to the layout.
You can also create a LinearLayout with the imageView and textView inside before adding it to the RelativeLayout

Successive ImageViews in a loop

I am working on an app where I have to set up a number of drawables. The number depends on the user input.
I therefore need to use a loop there I set up as many successive images as the user have chosen in one or several rows.
I can not find out how. I know how to put the images in an array and use
(ImageView) findViewById(R.id.img)
to set them up. But I want to create this successive ImageViews in the loop.

try to make a combinatino of LinearLayout and LayoutInflater (to inflate custom views)
LinearLayout layout = (LinearLayout) findViewById(R.id.linear);
for (int i = 0; i < userChoice; i++)
{
LayoutInflater li = LayoutInflater.from(yourContext);
View customView = li.inflate(R.layout.image_holder, this);
// (In case you need to use the image) ImageView yourImage = (ImageView)customView.findViewById(R.id.image_view);
layout.addView(customView);
}
where:
userChoice is the number the user has choose
layout is linear layout inside your main.xml (or the root element itself)
image_holder is an xml with ImageView inside it