Develop Reference

Removing Views dynamically

I search a lot for this, but I can't solve it. I have LinearLayout with two textviews and a button (to add others LinearLayout) like this:
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="match_parent">
<EditText android:id="#+id/ingredientsField"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="#dimen/boxes_margin"
android:hint="#string/ingredients"
android:inputType="text"
xmlns:android="http://schemas.android.com/apk/res/android" />
<EditText
android:id="#+id/quantityField"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="#dimen/boxes_margin"
android:hint="#string/quantity"
android:inputType="number"
/>
<com.google.android.material.button.MaterialButton
android:id="#+id/add_ingredient_btn"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/add"
android:layout_margin="#dimen/boxes_margin"
app:icon="#drawable/ic_add_ingr_btn"
/>
</LinearLayout>
The layout added is like this:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="50dp">
<EditText android:id="#+id/ingredientsField"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="#dimen/boxes_margin"
android:hint="#string/ingredients"
android:inputType="text"
xmlns:android="http://schemas.android.com/apk/res/android" />
<EditText android:id="#+id/quantityField"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="#dimen/boxes_margin"
android:hint="#string/quantity"
android:inputType="number"
xmlns:android="http://schemas.android.com/apk/res/android" />
<ImageButton
android:id="#+id/remove_ingredient_btn"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_margin="#dimen/boxes_margin"
android:src="#drawable/ic_remove_ing_qnt"/>
</LinearLayout>
In the Activity, I created a method to add new Layouts (and it works), and inside of it a method to delete the corresponding Layout with the Delete Button. Delete Button works only one time and only if it's in the first layout added. Here's the code:
add_ingredient.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View rowView = inflater.inflate(R.layout.ingredient_quantity_layout, null);
// Add the new row before the add field button.
parentIngredientLayout.addView(rowView);
ImageButton removeChildIngredient = findViewById(R.id.remove_ingredient_btn);
removeChildIngredient.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
parentIngredientLayout.removeView((View) v.getParent());
}
});
}
});

You have to set the OnClickListenerevent on the ImageButton from the last inserted layout.
To do that, just change this line
ImageButton removeChildIngredient = findViewById(R.id.remove_ingredient_btn);
to
ImageButton removeChildIngredient = rowView.findViewById(R.id.remove_ingredient_btn);
rowView.findViewById search the ImageButton on the last inserted layout and not the whole layout which contains other layouts.

In this line :
parentIngredientLayout.removeView((View)
v.getParent());
You are trying to remove the parent of the removeChildIngredient ImageButton, which is probably parentIngredientLayout, which i think is not what you want,
You could try this :
parentIngredientLayout.
removeView(rowView);
But in your implementation, you could encounter issues when you will add multiples ingredients, because you are setting a new onClickListener to each new ingredient, and The ImageButton will only delete the last one you have added(the last onClickListener set),
Instead, you could use a List/RecyclerView or search for another implementation, eg. put the ImageButton inside the Inflated Layout so you'll have one Remove Button in each Layout you add,
Then you should replace the findViewById of your ImageButton by rowView.findViewById
And this line should stay unchanged
parentIngredientLayout.removeView((View) v.getParent());

Creating dynamic linearlayout with textviews on it

I am pretty new in Android.
I have some problems to create a dynamic LinearLayout programmatically.
I actually have some information in ArrayLists that I need to display. The problem is that I don't know how many items are in the ArrayList, so I need to create the same layout (LinearLayoutChild) for every item in the ArrayList.
For example, I have created this (in this case, let's say the ArrayLists have 2 items each)
ArrayList<String> alistA = new ArrayList<String>();
ArrayList<String> alistB = new ArrayList<String>();
ArrayList<String> alistC = new ArrayList<String>();
ArrayList<String> alistD = new ArrayList<String>();
ArrayList<String> alistE = new ArrayList<String>();
alistA.add(0, "TextA1");
alistA.add(1, "TextA2");
alistB.add(0, "TextB1");
alistB.add(1, "TextB2");
alistC.add(0, "TextC1");
alistC.add(1, "TextC2");
alistD.add(0, "TextD1");
alistD.add(1, "TextD2");
alistE.add(0, "TextE1");
alistE.add(1, "TextE2");
int NumberArray = 2;
for(int i = 0; i<NumberArray;i++){
// How can i do this?
}
I want to display it like :
alistA[0] -> Tv1
alistB[0] -> Tv2
and so on...
alistA[[1]] -> Tv1 (newly created)
alistB[[1]] -> Tv2 (newly created)
...
My XML file :
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.murat.testlol.MainActivity"
android:id="#+id/LinearLayout1"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Et1"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Btn1"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="12"
android:orientation="horizontal"
android:id="#+id/LinearLayoutChild">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="4"
android:orientation="vertical"
android:id="#+id/Ll1">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Tv1"
android:gravity="center"
android:text="TextView1"
/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView2"
android:id="#+id/Tv2"
android:gravity="center"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="4"
android:orientation="vertical"
android:id="#+id/Ll2">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Tv3"
android:gravity="center"
android:text="TextView3"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:id="#+id/Tv4"
android:text="TextView4"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="4"
android:orientation="vertical"
android:id="#+id/Ll3">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Tv5"
android:gravity="center"
android:text="TextView5"/>
</LinearLayout>
</LinearLayout>
The EditText and button need to stay at the same place.
Thank you.

Sounds like a good use case for Android's ListView. From Google's documentation:
ListView is a view group that displays a list of scrollable items. The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database query and converts each item result into a view that's placed into the list.
To go this route, update main.xml to include a ListView element -- and move the LinearLayoutChild into its own XML file.
main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context="com.example.murat.testlol.MainActivity"
android:id="#+id/LinearLayout1"
android:orientation="vertical">
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Et1"/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Btn1"/>
<ListView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/list"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>
generic_linear_layout_child.xml:
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="4"
android:orientation="vertical"
android:id="#+id/linear_layout_child">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/Tv1"
android:gravity="center"
android:text="TextView1"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="TextView2"
android:id="#+id/Tv2"
android:gravity="center"/>
</LinearLayout>
Then, create an adapter to bind the data in your array to the appropriate UI elements. Here's a SO post on how to create a custom adapter: Custom Adapter for List View

You need to create the linearlayouts and textviews dynamically, using routines like this:
public TextView makeTextView (String text)
{
TextView tv = new TextView (context)
tv.setText (text) ;
// customise the layout of the text here, eg...
tv.setTextColor(Color.RED) ;
return tv;
}
public LinearLayout makeHorizLayout ()
{
LinearLayout ll = new LinearLayout (context);
ll.setOrientation(LinearLayout.HORIZONTAL);
ll.setLayoutParams(new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
return ll;
}
After you have loaded the schema, you find the view that you want to insert the linearLayouts into like this:
View mainView = findViewById (R.id.LinearLayout1);
You then add a linearlayout to a view like this:
LinearLayout ll = makeHorizlayout ();
mainView.add(ll);
Then you add textviews to the LinearLayout like this:
TextView tv = makeTextView ("whatever text");
ll.addView (tv);

Do the following. Get your data and fill a linearLayout container during runtime after you have retrieved / created your data. Here is an example for creating the views.
private LinearLayout container;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
container = new LinearLayout(this);
container.setOrientation(LinearLayout.VERTICAL)
// + other layout stuff / better inflate this from xml
// Get data and call createLayout with the data
}
createLayout(List<List<String>> lists) {
for (List<String> list : lists) {
LinearLayout linearLayout = new LinearLayout(this);
linearLayout.setOrientation(LinearLayout.HORIZONTAL);
// + other layout stuff / better inflate this from xml
for (String string : list) {
TextView textView = new AppCompatTextView(this);
textView.setText(string);
linearLayout.addView(textView);
}
container.addView(linearLayout);
}
}

Layout weight not working as intended

I have a slight problem getting my layout_weight to work. I am creating a custom bottomBar. But i cant make it to stretch as i want it to.
Bottom Bar View
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/bottom_bar_root"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/bottom_bar_container"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:weightSum="4"
android:orientation="horizontal"/>
</RelativeLayout>
This is the big container i am adding my buttons (items) to.
Bottom Bar Item
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="1">
<android.support.v7.widget.AppCompatImageView
android:id="#+id/bottom_bar_item_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="#android:drawable/arrow_up_float"/>
<TextView
android:id="#+id/bottom_bar_item_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TEXT"/>
</LinearLayout>
This is my items that i add dynamically to the view. But somehow the view is not stretched properly.
But when i hardcode it in. It works. So could it be that layout weight does not work dynamically?
How i add the views (items)
private void updateItems(final List<BottomBarTab> bottomBarTabs) {
if (bottomBarTabs.size() < TABS_COUNT) {
throw new RuntimeException("Not enough buttons for bottomBar");
}
for (int i = 0; i < TABS_COUNT; i++) {
bottomBarTabs.get(i).setOnClickListener(this);
bottomBarTabs.get(i).prepareLayout();
container.addView(bottomBarTabs.get(i));
}
}
Screenshot

LayoutWeight is given to inner components of layout only not on parent Linearlayout.
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="0dp"
android:layout_height="match_parent"
android:weightSum="2">
<android.support.v7.widget.AppCompatImageView
android:id="#+id/bottom_bar_item_icon"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:src="#android:drawable/arrow_up_float"/>
<TextView
android:id="#+id/bottom_bar_item_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="TEXT"/>
</LinearLayout>

public void prepareLayout() {
View view = inflate(getContext(), R.layout.bottom_bar_item,this);
LinearLayout.LayoutParams params =
new LayoutParams(0,LayoutParams.MATCH_PARENT,LAYOUT_WEIGHT);
view.setLayoutParams(params);
if(backgroundColor != null) {
view.setBackgroundColor(backgroundColor);
}
TextView titleText = (TextView) view.findViewById(R.id.bottom_bar_item_text);
titleText.setText(title);
AppCompatImageView imageView = (AppCompatImageView) view.findViewById(R.id.bottom_bar_item_icon);
imageView.setImageResource(iconResId);
}
I changed in my prepareLayout function and put new layoutParams. Because somehow after inflation. The view ignores the weight that was set to it. So i had to force it by code. Maybe this is a android bug?

Android: setting text in each new view within a for loop

So I have an XML layout1 which is just a LinearLayout with three text views. I also have another XML layout2 with ScrollView and a LinearLayout inside it. I'm using this for loop to create several of the layout2 inside the LinearLayout of the ScrollView. It's working fine but I want to be able to set the text of each of the TextViews within the for loop. I'm not sure how to access these TextViews as I can only set one id within the XML file, will that not cause problems if I tried to access their id inside the for loop?
private void setUpResults() {
for (int i = 1; i < totalQuestions; i++) {
parent.addView(LayoutInflater.from(getBaseContext()).inflate(
R.layout.result_block, null));
}
}
Here is the result_block xml file (layout1) :
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<LinearLayout
android:id="#+id/layoutSelectedAnswer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/border"
android:orientation="horizontal"
android:paddingBottom="#dimen/option_padding_bottom"
android:paddingTop="#dimen/option_padding_top" >
<TextView
android:id="#+id/tvOptionALabel2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="4dp"
android:text="#string/option_a"
android:textColor="#color/white"
android:textSize="#dimen/option_text_size" />
<TextView
android:id="#+id/tvSelectedAnswer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="4dp"
android:text="#string/option"
android:textColor="#color/white"
android:textSize="#dimen/option_text_size" />
</LinearLayout>
<LinearLayout
android:id="#+id/layoutCorrectAnswer"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/border"
android:orientation="horizontal"
android:paddingBottom="#dimen/option_padding_bottom"
android:paddingTop="#dimen/option_padding_top" >
<TextView
android:id="#+id/tvOptionBLabel2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="4dp"
android:text="#string/option_b"
android:textColor="#color/white"
android:textSize="#dimen/option_text_size" />
<TextView
android:id="#+id/tvCorrectAnswer"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="4dp"
android:text="#string/option"
android:textColor="#color/white"
android:textSize="#dimen/option_text_size" />
</LinearLayout>
</LinearLayout>
Let's say I wanted to set the TextView with the id as tvCorrectAnswer to a different String value in each loop, how should I access it?

Sure, you can do it like this:
private void setUpResults () {
LayoutInflater i = LayoutInflater.from(getBaseContext());
for (int i = 1 /* should be zero? */; i < totalQuestions; i++) {
View view = i.inflate(R.layout.result_block, parent, false);
TextView correctAnswer = (TextView) view.findViewById(R.id.tvSelectedAnswer);
correctAnswer.setText("My Answer Text");
parent.addView(view);
}
}
The key is, inflate using the parent as the container, but don't attach it (the false parameter). Then you'll get a reference to the inflated view, which you can then directly reference to do your findViewById() calls (which will limit the search to that particular ViewGroup). Then add it to the parent and continue to the next item.

Once you have added all your views in your ViewGroup you can use ViewGroup.getChildAt(int) to get a one of the views you have inserted. Once you get one of the views you can access any of its inner views. Something like this.
for(int i = 0; i < parentView.getChildCount();++i) {
View v = parentView.getChildAt(i);
Textview tv = (TextView) v.findViewById(R.id.tvOptionALabel2);
//And so on...
}

Add different TextViews to ScrollView

I Have activity that get some data from the internet, and shows it to the screen.
I'm using scroll view cause it's long text, I also want different text style for a different data,so I use few textViews with a different style and to show it on the Activity screen,
my problem is that scroll view can handle only one view, so how can I use scrolling to show different style of Text view, I tried to add LinearLayout to the scrollView and add all the textViews dynamically in code to this LinearLayout ,but I'm getting exception - scroll view can host only one direct child.
The code below:
/** this is the function, which called from the onClick method.
wanted data object contains 2 strings title message and the message itself.
When debug the code i can see that there's two String values in each loop.
but i cant add the linearLayout to my scrollView - exception ScrollView can host only one direct child */
private void showResult(ArrayList<WantedData> result) {
// TODO Auto-generated method stub
TextView title;
TextView data;
scrollLayout = (LinearLayout) findViewById(R.id.LlScrollView);
for (WantedData curr : result) {
if (curr.getTitle() == null) {
break;
}
title = new TextView(this);
title.setText(curr.getTitle());
scrollLayout.addView(title, LayoutParams.FILL_PARENT,
LayoutParams.WRAP_CONTENT);
data = new TextView(this);
data.setText(curr.getData());
scrollLayout.addView(data, LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
}
scroll.addView(scrollLayout, LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT);
//at the onCreate method - scroll = (ScrollView) findViewById(R.id.SvShowTextFromServer);
}
the xml file:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<include
android:id="#+id/layout_reffernce"
layout="#layout/explore" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter City" />
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >
<EditText
android:id="#+id/EtCity"
android:layout_width="210dp"
android:layout_height="wrap_content"
android:layout_weight="0.14"
android:orientation="vertical" >
<requestFocus />
</EditText>
<Button
android:id="#+id/bSearchCity"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Search" />
</LinearLayout>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter State" />
<EditText
android:id="#+id/EtState"
android:layout_width="253dp"
android:layout_height="wrap_content"
android:orientation="vertical" />
</LinearLayout>
<ScrollView
android:id="#+id/SvShowTextFromServer"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
<LinearLayout
android:id="#+id/LlScrollView"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#drawable/backround"
android:orientation="vertical" >
</LinearLayout>
</ScrollView>
</LinearLayout>

The problem is double creating of container in ScrollView. You should not create it in activity, but take already defined from xml:
LinearLayout scrollContainer = (LinearLayout)findViewById(R.id.LlScrollView);
for (...) {
//create here some text
scrollLayout.addView(text);
}

If you have defined a LinearLayout in XML you don't have to create a new LinearLayout in your code but you have to retrieve the existing one in this way
LinearLayout linearLayout = (LinearLayout) findViewById(R.id.LlScrollView);
Otherwise you have to remove the LinearLayout in your XML and add all by code.