An Android library to hook and fix Toast BadTokenException

Usage

implementation 'me.drakeet.support:toastcompat:1.1.0'

ToastCompat.makeText(context, "hello world!", Toast.LENGTH_SHORT).show();

Or with BadTokenListener#onBadTokenCaught(@NonNull Toast toast):

ToastCompat.makeText(this, "hello", Toast.LENGTH_SHORT)
    .setBadTokenListener(toast -> {
        ...
    }).show();

Goodbye, BadTokenException.

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:

How

So I created this library, and replace the base Context to a SafeToastContext, it will hook the WindowManagerWrapper.addView(view, params) method and fix the exception.

License

Copyright 2017 drakeet.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.