i can't understand the value wrap_content for View's elements (like ProgressBar, Switch, primitive View with background - that for some reason takes all the available place on screen), it isn't trivial such as TextView that wrap_content means "be as tall and wide" as the text inside you". Can anyone help me to understand it?
<androidx.constraintlayout.widget.ConstraintLayout
android:id="@+id/prog_bar_containter"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="@color/black"
android:elevation="20dp"
app:layout_constraintBottom_toBottomOf="@+id/rc"
app:layout_constraintEnd_toEndOf="@+id/rc"
app:layout_constraintStart_toStartOf="@+id/rc"
app:layout_constraintTop_toTopOf="@+id/rc">
<ProgressBar
android:id="@+id/prog_bar"
style="?android:attr/progressBarStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
If you want to find how much is width and height of an component which is used in the layout, you can use this code. Here height and width of a progressbar is set to wrap_content, it means that its width and height have default sizes, and we want to know how much is these default sizes. Result is in px
.
activity_main.xml
<?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"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ProgressBar
android:id="@+id/progressbar"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.kt
import android.os.Bundle
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import kotlinx.android.synthetic.main.activity_main.*
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
progressbar.post(Runnable {
val a= progressbar.getWidth()
val b=progressbar.getHeight()
Log.d("abc", a.toString())
Log.d("abc", b.toString())
})
}
}