When I use percentage value the application crashed-CodePudding

I want to set my button width with percentage value. I searched and read that I should using ConstrainLayout, But when I using app:layout_constraintWidth_percent instead of layout_width for my width of button the application crashed.

The code

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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=".MainActivity">

    <ScrollView
        android:id="@ id/sv_intro_main_id"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@ id/BottomNavigation_main_id"
        android:layout_centerHorizontal="true"
        android:background="#E6E6E6"
        android:padding="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        tools:layout_editor_absoluteX="-16dp">

        <androidx.cardview.widget.CardView
            android:id="@ id/cv_buyButtons_main_id"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            app:cardCornerRadius="10sp">

            <androidx.constraintlayout.widget.ConstraintLayout
                android:id="@ id/CL_buyButtons_main_id"
                android:layout_width="match_parent"
                android:layout_height="150sp"
                tools:layout_editor_absoluteX="20dp"
                tools:layout_editor_absoluteY="20dp">

                <Button
                    android:id="@ id/button_fly_main_id"
                    style="@style/Widget.AppCompat.Button.Borderless.Colored"
                    android:layout_height="50sp"
                    android:fontFamily="@font/samim_bold"
                    android:text="@string/fly"
                    android:textAlignment="textStart"
                    android:textColor="#191919"
                    android:textSize="16sp"
                    app:icon="@drawable/ic_plane_svgrepo_com"
                    app:iconGravity="end"
                    app:iconSize="40sp"
                    app:iconTint="#000000"
                    app:layout_constraintEnd_toEndOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintStart_toEndOf="@id/button_train_main_id"
                    app:layout_constraintWidth_percent="0.5"/>

                <Button
                    android:id="@ id/button_train_main_id"
                    style="@style/Widget.AppCompat.Button.Borderless.Colored"
                    android:layout_height="50sp"
                    android:fontFamily="@font/samim_bold"
                    android:text="@string/train"
                    android:textAlignment="textStart"
                    android:textColor="#191919"
                    android:textSize="16sp"
                    app:icon="@drawable/ic_train_svgrepo_com"
                    app:iconGravity="end"
                    app:iconSize="40sp"
                    app:iconTint="#000000"
                    app:layout_constraintEnd_toStartOf="@ id/button_fly_main_id"
                    app:layout_constraintStart_toStartOf="parent"
                    app:layout_constraintTop_toTopOf="parent"
                    app:layout_constraintWidth_percent="0.5"/>

            </androidx.constraintlayout.widget.ConstraintLayout>
        </androidx.cardview.widget.CardView>
    </ScrollView>

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@ id/BottomNavigation_main_id"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:layout_alignParentBottom="true"
        android:background="#FFFFFF"
        app:layout_constraintBottom_toBottomOf="@ id/sv_intro_main_id"

        tools:layout_editor_absoluteX="1dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

Error log

2022-03-22 21:42:41.793 6096-6096/com.masjedsafa.ali_baba_appearance E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.masjedsafa.ali_baba_appearance, PID: 6096
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.masjedsafa.ali_baba_appearance/com.masjedsafa.ali_baba_appearance.MainActivity}: android.view.InflateException: Binary XML file line #33 in com.masjedsafa.ali_baba_appearance:layout/activity_main: Binary XML file line #33: You must supply a layout_width attribute.
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3635)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7839)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
     Caused by: android.view.InflateException: Binary XML file line #33 in com.masjedsafa.ali_baba_appearance:layout/activity_main: Binary XML file line #33: You must supply a layout_width attribute.
     Caused by: java.lang.UnsupportedOperationException: Binary XML file line #33: You must supply a layout_width attribute.
        at android.content.res.TypedArray.getLayoutDimension(TypedArray.java:831)
        at android.view.ViewGroup$LayoutParams.setBaseAttributes(ViewGroup.java:8230)
        at android.view.ViewGroup$MarginLayoutParams.<init>(ViewGroup.java:8428)
        at androidx.constraintlayout.widget.ConstraintLayout$LayoutParams.<init>(ConstraintLayout.java:2910)
        at androidx.constraintlayout.widget.ConstraintLayout.generateLayoutParams(ConstraintLayout.java:1934)
        at androidx.constraintlayout.widget.ConstraintLayout.generateLayoutParams(ConstraintLayout.java:486)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1129)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1088)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1130)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1088)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1130)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1088)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:1130)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1088)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:686)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:538)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:485)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:706)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:195)
        at com.masjedsafa.ali_baba_appearance.MainActivity.onCreate(MainActivity.java:12)
        at android.app.Activity.performCreate(Activity.java:8051)
        at android.app.Activity.performCreate(Activity.java:8031)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1329)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3608)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3792)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:103)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2210)
        at android.os.Handler.dispatchMessage(Handler.java:106)
2022-03-22 21:42:41.793 6096-6096/com.masjedsafa.ali_baba_appearance E/AndroidRuntime:     at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7839)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)

I try ConstraintLayout and I was expecting it be worked.

CodePudding user response：

Add this attribute to your widget which you want to define width with constraintWidth_percent:

android:layout_width="0dp"

Each element should have both layout_width and layout_height. When you want to make width or height dynamic and dependent on other elements, you should set the element's related property to "0dp".