You can raise PR for any contribution and optimization. :-)

ToastHandler

Reference from StackOverFlow

An Android library wrapper over ToastCompat for handling Toast BadTokenException happening on Android API level 25 and showing Toast smoothly on All Android versions. (Handling some memory leaks and changed to Kotlin with Custom Lint added)

Please refer this blog for more details and findings.

Usage

Add this to your app build.gradle:

implementation "com.toastfix:toastcompatwrapper:1.2.0"

Use this wherever you are showing Toast:

Java

ToastHandler.showToast(this, "Hello,I am Toast", Toast.LENGTH_SHORT);

Kotlin

ToastHandler.showToast(this, "Hello,I am Toast", Toast.LENGTH_SHORT)

Also, If you forget to use it, Let the Android Lint help you :-)

Latest Feature:

Added a custom lint which disallow the usage of Android's Toast class in favor of ToastHandler.

These are the properties of the custom lint.

message          = "Usage of android Toast is prohibited"
briefDescription = "The android Toast should not be used"
explanation      = "The android Toast should not be used, use ToastHandler instead to avoid BadTokenException on Android API level 25"
category         = Category.CORRECTNESS
priority         = 6
severity         = Severity.WARNING

The custom lint is added in the toasthandler module as lintPublish. So, adding the library dependency into any project will also include this custom lint.

This lint replaces Toast.makeText with ToastHandler.getToastInstance.

- Toast.makeText(this, "Hi, I am Toast", Toast.LENGTH_SHORT).show()
+ ToastHandler.getToastInstance(this, "Hi, I am Toast", Toast.LENGTH_SHORT).show()

Here's a small GIF showing how this will look in the IDE.

Please refer the demo for usage.

Why

From API 25, Android added a new param IBinder windowToken for Toast#handleShow(), and It brought an exception. As Android said on API 26:

// Since the notification manager service cancels the token right
// after it notifies us to cancel the toast there is an inherent
// race and we may attempt to add a window after the token has been
// invalidated. Let us hedge against that.

So they try-catch the mWM.addView(mView, mParams) on API 26. However, API 25 is still at risk. Our applications will continue to produce such an exception, and can not capture it:

Fatal Exception: android.view.WindowManager$BadTokenException: 
Unable to add window -- token android.os.BinderProxy@1c4411f is not valid; is your activity running?
       at android.view.ViewRootImpl.setView(ViewRootImpl.java:679)
       at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:342)
       at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:94)
       at android.widget.Toast$TN.handleShow(Toast.java:459)
       at android.widget.Toast$TN$2.handleMessage(Toast.java:342)
       at android.os.Handler.dispatchMessage(Handler.java:102)
       at android.os.Looper.loop(Looper.java:154)
       at android.app.ActivityThread.main(ActivityThread.java:6236)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:891)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:781)

This exception occurs regardless of whether the Context you passed to Toast is an Activity or ApplicationContext or Service. And you can not try-catch it.

See the detail diff of Android Toast sources:

Have also handled some memory leaks and created ToastHandler as Singleton(lazy-loading) for better performance.

This project is CI configured using Github Actions.