Create a custom View by inflating a layout

Question

I am trying to create a custom View that would replace a certain layout that I use at multiple places  but I am struggling to do so   Basically  I want to replace this    lt RelativeLayout  android id    id dolphinLine   android layout width  fill parent   android layout height  wrap content      android layout centerInParent  true   android background   drawable background box light blue   android padding  10dip   android layout margin  10dip  gt     lt TextView    android id    id dolphinTitle     android layout width  200dip     android layout height  100dip     android layout alignParentLeft  true     android layout marginLeft  10dip     android text   string my title     android textSize  30dip     android textStyle  bold     android textColor   2E4C71     android gravity  center   gt     lt Button    android id    id dolphinMinusButton     android layout width  100dip     android layout height  100dip     android layout toRightOf    id dolphinTitle     android layout marginLeft  30dip     android text   string minus button     android textSize  70dip     android textStyle  bold     android gravity  center     android layout marginTop  1dip     android background   drawable button blue square selector     android textColor   FFFFFF     android onClick  onClick   gt     lt TextView    android id    id dolphinValue     android layout width  100dip     android layout height  100dip     android layout marginLeft  15dip     android background   android drawable editbox background     android layout toRightOf    id dolphinMinusButton     android text  0     android textColor   2E4C71     android textSize  50dip     android gravity  center     android textStyle  bold     android inputType  none   gt     lt Button    android id    id dolphinPlusButton     android layout width  100dip     android layout height  100dip     android layout toRightOf    id dolphinValue     android layout marginLeft  15dip     android text   string plus button     android textSize  70dip     android textStyle  bold     android gravity  center     android layout marginTop  1dip     android background   drawable button blue square selector     android textColor   FFFFFF     android onClick  onClick   gt   lt  RelativeLayout gt    By this    lt view class  com example MyQuantityBox      android id    id dolphinBox      android layout width  fill parent      android layout height  wrap content      android myCustomAttribute   string my title   gt    So  I do not want a custom layout  I want a custom View  it should not be possible for this view to have child    The only thing that could change from one instance of a MyQuantityBox to another is the title  I would very much like to be able to specify this in the XML  as I do on the last XML line   How can I do this  Should I put the RelativeLayout in a XML file in  res layout and inflate it in my MyBoxQuantity class  If yes how do I do so   Thanks

User · Answer

Use the LayoutInflater as I shown below       public View myView             View v     Creating an instance for View Object         LayoutInflater inflater    LayoutInflater  getContext   getSystemService Context LAYOUT INFLATER SERVICE           v   inflater inflate R layout myview  null            TextView text1   v findViewById R id dolphinTitle           Button btn1   v findViewById R id dolphinMinusButton           TextView text2   v findViewById R id dolphinValue           Button btn2   v findViewById R id dolphinPlusButton            return v

User · Answer

In practice  I have found that you need to be a bit careful  especially if you are using a bit of xml repeatedly  Suppose  for example  that you have a table that you wish to create a table row for each entry in a list  You ve set up some xml   In my table row xml    lt  xml version  1 0  encoding  utf-8   gt   lt TableRow xmlns android  http   schemas android com apk res android     android orientation  vertical    android layout width  match parent    android layout height  match parent  android id    id myTableRow  gt       lt ImageButton android src   android drawable ic menu delete  android layout width  wrap content  android layout height  wrap content  android id    id rowButton   gt       lt TextView android layout height  wrap content  android layout width  wrap content  android textAppearance   android attr textAppearanceMedium  android text  TextView  android id    id rowText  gt  lt  TextView gt   lt  TableRow gt    Then you want to create it once per row with some code  It assume that you have defined a parent TableLayout myTable to attach the Rows to   for  int i 0  i lt numRows  i                    1  Make the row and attach it to myTable  For some reason this doesn t seem        to return the TableRow as you might expect from the xml  so you need to        receive the View it returns and then find the TableRow and other items  as        per step 2              LayoutInflater inflater    LayoutInflater getBaseContext   getSystemService Context LAYOUT INFLATER SERVICE       View v    inflater inflate R layout my table row  myTable  true           2  Get all the things that we need to refer to to alter in any way      TableRow    tr           TableRow     v findViewById R id profileTableRow       ImageButton rowButton    ImageButton  v findViewById R id rowButton       TextView    rowText      TextView     v findViewById R id rowText           3  Configure them out as you need to     rowText setText  Text for this row        rowButton setId i      So that when it is clicked we know which one has been clicked      rowButton setOnClickListener this      See note below                               To ensure that when finding views by id on the next time round this        loop  or later  gie lots of spurious  unique  ids              rowText setId 1000 i       tr setId 3000 i       For a clear simple example on handling rowButton setOnClickListener this   see Onclicklistener for a programatically created button

User · Answer

Here is a simple demo to create customview  compoundview  by inflating from xml  attrs xml   lt resources gt        lt declare-styleable name  CustomView  gt           lt attr format  string  name  text   gt           lt attr format  reference  name  image   gt       lt  declare-styleable gt   lt  resources gt    CustomView kt  class CustomView  JvmOverloads constructor context  Context  attrs  AttributeSet    null  defStyleAttr  Int   0            ConstraintLayout context  attrs  defStyleAttr         init           init attrs             private fun init attrs  AttributeSet             View inflate context  R layout custom layout  this           val ta   context obtainStyledAttributes attrs  R styleable CustomView          try               val text   ta getString R styleable CustomView text              val drawableId   ta getResourceId R styleable CustomView image  0              if  drawableId    0                    val drawable   AppCompatResources getDrawable context  drawableId                  image thumb setImageDrawable drawable                            text title text   text           finally               ta recycle                       custom layout xml   We should use merge here instead of ConstraintLayout because   If we use ConstraintLayout here  layout hierarchy will be ConstraintLayout- ConstraintLayout -  ImageView   TextView    we have 1 redundant ConstraintLayout    not very good for performance    lt  xml version  1 0  encoding  utf-8   gt   lt merge xmlns android  http   schemas android com apk res android      xmlns app  http   schemas android com apk res-auto      xmlns tools  http   schemas android com tools      tools parentTag  android support constraint ConstraintLayout  gt        lt ImageView         android id    id image thumb          android layout width  wrap content          android layout height  wrap content          tools ignore  ContentDescription          tools src   mipmap ic launcher    gt        lt TextView         android id    id text title          android layout width  wrap content          android layout height  wrap content          app layout constraintEnd toEndOf   id image thumb          app layout constraintStart toStartOf   id image thumb          app layout constraintTop toBottomOf   id image thumb          tools text  Text    gt    lt  merge gt    Using activity main xml   lt  xml version  1 0  encoding  utf-8   gt   lt LinearLayout xmlns android  http   schemas android com apk res android      xmlns app  http   schemas android com apk res-auto      android layout width  match parent      android layout height  match parent      android orientation  vertical  gt        lt your package CustomView         android layout width  wrap content          android layout height  wrap content          android background   f00          app image   drawable ic android          app text  Android    gt        lt your package CustomView         android layout width  wrap content          android layout height  wrap content          android background   0f0          app image   drawable ic adb          app text  ADB    gt    lt  LinearLayout gt    Result    Github demo

User · Answer

Yes you can do this   RelativeLayout  LinearLayout  etc are Views so a custom layout is a custom view   Just something to consider because if you wanted to create a custom layout you could   What you want to do is create a Compound Control   You ll create a subclass of RelativeLayout  add all our your components in code  TextView  etc   and in your constructor you can read the attributes passed in from the XML   You can then pass that attribute to your title TextView   http   developer android com guide topics ui custom-components html

User · Answer

A bit old  but I thought sharing how I d do it  based on chubbsondubs  answer  I use FrameLayout  see Documentation   since it is used to contain a single view  and inflate into it the view from the xml   Code following   public class MyView extends FrameLayout       public MyView Context context  AttributeSet attrs  int defStyle            super context  attrs  defStyle           initView               public MyView Context context  AttributeSet attrs            super context  attrs           initView               public MyView Context context            super context           initView               private void initView             inflate getContext    R layout my view layout  this

[android] Create a custom View by inflating a layout?

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