I'm trying to link my FAB to a FAB Behavior class so the swipe action hides the FAB, The app will crash on startup, I believe the problem is with the layout_behavior element of the FAB, when I remove that line from the XML the app works fines. The log is listed below.
Here a couple of the Tutorials I've tried.
https://guides.codepath.com/android/floating-action-buttons https://code.luasoftware.com/tutorials/android/android-hide-floatingactionbutton-on-scroll-down/ https://www.dev2qa.com/android-hide-floating-action-button-while-recyclerview-scroll-example/
dependencies {
...
implementation 'com.google.android.material:material:1.2.1'
}
There is currently nothing in the Mainactivty.
activity_main.xml
<androidx.coordinatorlayout.widget.CoordinatorLayout 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">
<com.google.android.material.floatingactionbutton.FloatingActionButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|right"
android:layout_margin="16dp"
// I believe the probelm is here
app:layout_behavior="com.example.deletefab2.MyFab"/>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
FAB Behavior class
package com.example.deletefab2
class MyFab : FloatingActionButton.Behavior() {
// this secion i
override fun nestedScroll( ...) {
Log.i("FAB behavior", "its working")
}
}
My understanding is the FAB should link to the Behavior class through layout_behavior, seems kind of odd to me that you should call this from an Activity.
Log
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.deletefab2, PID: 18065
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.deletefab2/com.example.deletefab2.MainActivity}: android.view.InflateException: Binary XML file line #9 in com.example.deletefab2:layout/activity_main: Could not inflate Behavior subclass com.example.deletefab2.MyFab
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3270)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: android.view.InflateException: Binary XML file line #9 in com.example.deletefab2:layout/activity_main: Could not inflate Behavior subclass com.example.deletefab2.MyFab
Caused by: java.lang.RuntimeException: Could not inflate Behavior subclass com.example.deletefab2.MyFab
at androidx.coordinatorlayout.widget.CoordinatorLayout.parseBehavior(CoordinatorLayout.java:649)
at androidx.coordinatorlayout.widget.CoordinatorLayout$LayoutParams.<init>(CoordinatorLayout.java:2896)
at androidx.coordinatorlayout.widget.CoordinatorLayout.generateLayoutParams(CoordinatorLayout.java:1740)
at androidx.coordinatorlayout.widget.CoordinatorLayout.generateLayoutParams(CoordinatorLayout.java:112)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1125)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
at com.example.deletefab2.MainActivity.onCreate(MainActivity.kt:9)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Caused by: java.lang.NoSuchMethodException: com.example.deletefab2.MyFab.<init> [class android.content.Context, interface android.util.AttributeSet]
at java.lang.Class.getConstructor0(Class.java:2332)
at java.lang.Class.getConstructor(Class.java:1728)
at androidx.coordinatorlayout.widget.CoordinatorLayout.parseBehavior(CoordinatorLayout.java:643)
at androidx.coordinatorlayout.widget.CoordinatorLayout$LayoutParams.<init>(CoordinatorLayout.java:2896)
at androidx.coordinatorlayout.widget.CoordinatorLayout.generateLayoutParams(CoordinatorLayout.java:1740)
at androidx.coordinatorlayout.widget.CoordinatorLayout.generateLayoutParams(CoordinatorLayout.java:112)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:1125)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:1084)
at android.view.LayoutInflater.inflate(LayoutInflater.java:682)
at android.view.LayoutInflater.inflate(LayoutInflater.java:534)
at android.view.LayoutInflater.inflate(LayoutInflater.java:481)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:696)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:170)
at com.example.deletefab2.MainActivity.onCreate(MainActivity.kt:9)
at android.app.Activity.performCreate(Activity.java:7802)
at android.app.Activity.performCreate(Activity.java:7791)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1299)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3245)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3409)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:83)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2016)
at android.os.Handler.dispatchMessage(Handler.java:107)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7356)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:930)
Because the behavior class is defined in the XMXL, you must implement a constructor with context and AttributeSet to call the class linked with layout_behavior.
class MyFABBehaviorclass (context: Context, attrs: AttributeSet): FloatingActionButton.Behavior() {
...
}