Apps app error

[ionut hanu]

hi! I try to make an easy app which display sum of 2 number but when i run the app in the virtual manager i receive this error ( first image) why?

 

[Deleted User]

Hi. I moved your thread over to the Application Development forum, which is the place to ask questions about app development.
Please read the following thread, which contains some useful information for beginners, and explains the information needed when asking a question.

https://androidforums.com/threads/please-read-me-before-posting.987318/

Please don't use screenshots for code. Instead paste the code text using [code][/code] tags.
Thanks!

 

[Deleted User]

Your layout issues are probably due to all the components being placed at the same location on the screen. Can you post your layout XML?

 

[ionut hanu]

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.slimjr.proiectf.MainActivity"
    tools:layout_editor_absoluteY="81dp"
    tools:layout_editor_absoluteX="0dp">

    <EditText
        android:id="@+id/txt1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="X"
        android:inputType="number"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        tools:layout_editor_absoluteY="46dp" />

    <EditText
        android:id="@+id/txt2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:ems="10"
        android:hint="Y"
        android:inputType="number"
        tools:layout_editor_absoluteX="85dp"
        tools:layout_editor_absoluteY="108dp" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:eek:nClick="onButtonClick"
        android:text="Suma"
        tools:layout_editor_absoluteX="148dp"
        tools:layout_editor_absoluteY="218dp" />

    <TextView
        android:id="@+id/res"
        android:layout_width="75dp"
        android:layout_height="42dp"
        android:text="rezultat"
        tools:layout_editor_absoluteX="154dp"
        tools:layout_editor_absoluteY="168dp" />

</android.support.constraint.ConstraintLayout>

 

[Deleted User]

You don't need to use the ConstraintLayout. A simple LinearLayout, with vertical orientation would do the job.
I don't know why some app dev starter tutorials use ConstraintLayout. It's way too complicated for a basic app layout, and just causes confusion for beginners.

https://developer.android.com/guide/topics/ui/layout/linear.html

I would save yourself a lot of hassle, and use a LinearLayout.

 

[ionut hanu]

i made it . i used relative layout in xml. this is my first app
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"

 

[Deleted User]

Fantastic. Well done.