How to Programmatically Add Views to Views

Question

Let s say I have a LinearLayout  and I want to add a View to it  in my program from the Java code  What method is used for this  I m not asking how it s done in XML  which I do know  but rather  how can I do something along the lines of this sample code    One View  add Another View    Like one can do in Swing

User · Answer

The idea of programmatically setting constraints can be tiresome. This solution below will work for any layout whether constraint, linear, etc. Best way would be to set a placeholder i.e. a FrameLayout with proper constraints (or proper placing in other layout such as linear) at position where you would expect the programmatically created view to have.

All you need to do is inflate the view programmatically and it as a child to the FrameLayout by using addChild() method. Then during runtime your view would be inflated and placed in right position. Per Android recommendation, you should add only one childView to FrameLayout [link].

Here is what your code would look like, supposing you wish to create TextView programmatically at a particular position:

Step 1:

In your layout which would contain the view to be inflated, place a FrameLayout at the correct position and give it an id, say, "container".

Step 2 Create a layout with root element as the view you want to inflate during runtime, call the layout file as "textview.xml" :

<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent" android:layout_height="match_parent">

</TextView>

BTW, set the layout-params of your frameLayout to wrap_content always else the frame layout will become as big as the parent i.e. the activity i.e the phone screen.

android:layout_width="wrap_content"
android:layout_height="wrap_content"

If not set, because a child view of the frame, by default, goes to left-top of the frame layout, hence your view will simply fly to left top of the screen.

Step 3

In your onCreate method, do this :

FrameLayout frameLayout = findViewById(R.id.container);
                TextView textView = (TextView) View.inflate(this, R.layout.textview, null);
                frameLayout.addView(textView);

(Note that setting last parameter of findViewById to null and adding view by calling addView() on container view (frameLayout) is same as simply attaching the inflated view by passing true in 3rd parameter of findViewById(). For more, see this.)

User · Answer

LinearLayout is a subclass of ViewGroup  which has a method called addView  The addView method should be what you are after

User · Answer

Calling addView is the correct answer  but you need to do a little more than that to get it to work   If you create a View via a constructor  e g   Button myButton   new Button      you ll need to call setLayoutParams on the newly constructed view  passing in an instance of the parent view s LayoutParams inner class  before you add your newly constructed child to the parent view   For example  you might have the following code in your onCreate   function assuming your LinearLayout has id R id main   LinearLayout myLayout   findViewById R id main    Button myButton   new Button this   myButton setLayoutParams new LinearLayout LayoutParams                                       LinearLayout LayoutParams MATCH PARENT                                       LinearLayout LayoutParams MATCH PARENT     myLayout addView myButton     Making sure to set the LayoutParams is important  Every view needs at least a layout width and a layout height parameter  Also getting the right inner class is important  I struggled with getting Views added to a TableRow to display properly until I figured out that I wasn t passing an instance of TableRow LayoutParams to the child view s setLayoutParams

User · Answer

You guys should also make sure that when you override onLayout you HAVE to call super onLayout with all of the properties  or the view will not be inflated

User · Answer

This is late but this may help someone       For adding the view programmatically try like  LinearLayout rlmain   new LinearLayout this         LinearLayout LayoutParams llp   new LinearLayout LayoutParams LinearLayout LayoutParams FILL PARENT LinearLayout LayoutParams FILL PARENT             LinearLayout   ll1   new LinearLayout  this    ImageView iv   new ImageView this   iv setImageResource R drawable logo                 LinearLayout  LayoutParams lp   new LinearLayout LayoutParams LinearLayout LayoutParams MATCH PARENT  LinearLayout LayoutParams MATCH PARENT    iv setLayoutParams lp   ll1 addView iv   rlmain addView ll1                 setContentView rlmain  llp     This will create your entire view programmatcally  You can add any number of view as same  Hope this may help

User · Answer

for anyone yet interested   the best way I found is to use the inflate static method of View   View inflatedView   View inflate context  yourViewXML  yourLinearLayout     where yourViewXML is something like R layout myView  please notice that you need a ViewGroup in order to add a view  which is any layout you can think of    so as an example lets say you have a fragment which it view already been inflated and you know that the root view is a layout  and you want to add a view to it       View view   getView       returns base view of the fragment     if  view    null          return      if    view instanceof ViewGroup           return       ViewGroup viewGroup    ViewGroup  view      View popup   View inflate viewGroup getContext    R layout someView  viewGroup

User · Answer

One more way to add view from Activity  ViewGroup rootLayout   findViewById android R id content   rootLayout addView view

[android] How to Programmatically Add Views to Views

Examples related to android