Unable to add a view programmatically

Question

    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_marginHorizontal="@dimen/para"
        android:layout_weight="0.5"
        android:background="@color/gray_medium_dark"
        app:layout_constraintTop_toTopOf="parent">

        <LinearLayout
            android:id="@+id/messages_parent"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="vertical">


            <LinearLayout style="@style/hor_layout">

                <TextView
                    style="@style/message_text"
                    android:background="@color/gray_blue_medium"
                    android:text="@string/dummy_short" />

                <Space style="@style/message_space" />

            </LinearLayout>
        </LinearLayout>
    </ScrollView>

Above is my xml and I want to add a LinearLayout packed with a TextView and Space to the LinearLayout with the id messages_parent. I want it to happen when a button is pressed.

private fun sendMessage(message: String) {
    var newMessage: LinearLayout = LinearLayout(context)
    newMessage.style(R.style.hor_layout)

    //    <style name="hor_layout">
    //        <item name="android:layout_width">match_parent</item>
    //        <item name="android:layout_height">wrap_content</item>
    //        <item name="android:orientation">horizontal</item>
    //   </style>



    var newMessageTxt: TextView = TextView(context)
    newMessageTxt.style(R.style.message_text)
    newMessageTxt.text = message


    //    <style name="message_text" parent="myText">
    //        <item name="android:layout_width">0dp</item>
    //        <item name="android:layout_height">wrap_content</item>
    //        <item name="android:layout_weight">0.85</item>
    //        <item name="android:layout_margin">@dimen/sec</item>
    //        <item name="android:padding">@dimen/sec</item>
    //        <item name="android:background">@color/gray_blue_medium</item>
    //    </style>


    // message_text's parent
    //    <style name="myText">
    //        <item name="android:textColor">@color/gray_light</item>
    //        <item name="fontFamily">monospace</item>
    //        <item name="android:lineSpacingExtra">4sp</item>
    //        <item name="android:letterSpacing">0.1</item>
    //        <item name="android:textSize">@dimen/para</item>
    //  I've checked all my dimens are correct.
    //    </style>





    // setting height by the lines below won't help either
    // newMessageTxt.layoutParams.height = 500
    // newMessageTxt.height = 500


    println("orientation: ${newMessage.orientation.toString()}\n" +
            "text size: ${newMessageTxt.textSize}\n" +
            "text: ${newMessageTxt.text}\n" +
            "height: ${newMessageTxt.height}\n" +
            "width: ${newMessageTxt.width}")


    // log-
    // 2021-03-27 11:32:48.428 31468-31468/com.example.firechat3 I/System.out: orientation: 0
    // 2021-03-27 11:32:48.428 31468-31468/com.example.firechat3 I/System.out: text size: 32.0
    // 2021-03-27 11:32:48.428 31468-31468/com.example.firechat3 I/System.out: text: Why am I invisible??
    // 2021-03-27 11:32:48.428 31468-31468/com.example.firechat3 I/System.out: height: 0
    // 2021-03-27 11:32:48.428 31468-31468/com.example.firechat3 I/System.out: width: 0


    var newMessageSpace: Space = Space(context)
    newMessageSpace.style(R.style.message_space)

    //    <style name="message_space">
    //        <item name="android:layout_width">0dp</item>
    //        <item name="android:layout_height">match_parent</item>
    //        <item name="android:layout_weight">0.15</item>
    //    </style>



    // adding the TextView and Space to the new LinearLayout
    newMessage.addView(newMessageTxt)
    newMessage.addView(newMessageSpace)


    // adding the new LinearLayout to the parent
    requireView().findViewById<LinearLayout>(R.id.messages_parent).addView(newMessage)
}

But the height and width of the newly added views remain 0 no matter how I try to do it and the orientation too whether I set it horizontal or vertical. I am using a package Paris by airbnb to set the style as told in this story on medium and I am using Paris because the solutions from this thread didn't helped me. The first message is added before runtime in the xml by hand and I want the other messages to look like that.

score 0 · Answer 1 · answered Jul 30 '21 at 06:59

Create an xml file in layout folder named item.xml

<?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="horizontal">
    <TextView
         style="@style/message_text"
         android:background="@color/gray_blue_medium"
         android:text="@string/dummy_short" />
    <Space style="@style/message_space" />
</LinearLayout>

your main xml will look like this

<ScrollView
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_marginHorizontal="@dimen/para"
    android:layout_weight="0.5"
    android:background="@color/gray_medium_dark"
    app:layout_constraintTop_toTopOf="parent">
    <LinearLayout
        android:id="@+id/messages_parent"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"/>
</ScrollView>

In onCreate() get reference to your linear layout

LinearLayout newMessage;
View view=null;

@Override
onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    newMessage = findViewById(R.id.messages_parent);
    ------
    ------
    ------

    //Then on the click event (where you want to add item in your main container) Infalte item.xml as follows (this code is in java)

    view = LayoutInflater.from(YourActivity.this).inflate(R.layout.item,newMessage,false);
    TextVIew msgText = view.findViewById(R.id.message_text);
    msgText.setText("some new message");
    newMessage.addView(view);
                   
}

Unable to add a view programmatically

1 Answers1