Toast Crash on Android 7.1
Many Android developers have encountered crashes like this:
android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@e2815e is not valid; is your activity running?
at android.view.ViewRootImpl.setView(ViewRootImpl.java:679)
at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:342)
at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:93)
at android.widget.Toast$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:6119)
at java.lang.reflect.Method.invoke(Native Method)
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The Root Cause
Through analysis on the APM platform, it was found that this issue only occurs on Android 7.1 (API Level 25). Therefore, it's determined to be a system bug in Android 7.1. By examining the source code, we can see:
public class Toast {
final TN mTN;
public void handleShow(IBinder windowToken) {
if (localLOGV) Log.v(TAG, "HANDLE SHOW: " + this + " mView=" + mView
+ " mNextView=" + mNextView);
if (mView != mNextView) {
// remove the old view if necessary
handleHide();
mView = mNextView;
Context context = mView.getContext().getApplicationContext();
String packageName = mView.getContext().getOpPackageName();
if (context == null) {
context = mView.getContext();
}
mWM = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
// We can resolve the Gravity here by using the Locale for getting
// the layout direction
final Configuration config = mView.getContext().getResources().getConfiguration();
final int gravity = Gravity.getAbsoluteGravity(mGravity, config.getLayoutDirection());
mParams.gravity = gravity;
if ((gravity & Gravity.HORIZONTAL_GRAVITY_MASK) == Gravity.FILL_HORIZONTAL) {
mParams.horizontalWeight = 1.0f;
}
if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == Gravity.FILL_VERTICAL) {
mParams.verticalWeight = 1.0f;
}
mParams.x = mX;
mParams.y = mY;
mParams.verticalMargin = mVerticalMargin;
mParams.horizontalMargin = mHorizontalMargin;
mParams.packageName = packageName;
mParams.hideTimeoutMilliseconds = mDuration ==
Toast.LENGTH_LONG ? LONG_DURATION_TIMEOUT : SHORT_DURATION_TIMEOUT;
mParams.token = windowToken;
if (mView.getParent() != null) {
if (localLOGV) Log.v(TAG, "REMOVE! " + mView + " in " + this);
mWM.removeView(mView);
}
if (localLOGV) Log.v(TAG, "ADD! " + mView + " in " + this);
mWM.addView(mView, mParams); // The crash occurs here
trySendAccessibilityEvent();
}
}
private static class TN extends ITransientNotification.Stub {
final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case SHOW: {
IBinder token = (IBinder) msg.obj;
handleShow(token);
break;
}
case HIDE: {
handleHide();
// Don't do this in handleHide() because it is also invoked by handleShow()
mNextView = null;
break;
}
case CANCEL: {
handleHide();
// Don't do this in handleHide() because it is also invoked by handleShow()
mNextView = null;
try {
getService().cancelToast(mPackageName, TN.this);
} catch (RemoteException e) {
}
break;
}
}
}
};
}
}
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How To Solve It?
In the Android O (API Level 26) source code, this issue has been fixed. The fix is a simple try-catch:
public class Toast {
final TN mTN;
public void handleShow(IBinder windowToken) {
if (localLOGV) Log.v(TAG, "HANDLE SHOW: " + this + " mView=" + mView
+ " mNextView=" + mNextView);
// If a cancel/hide is pending - no need to show - at this point
// the window token is already invalid and no need to do any work.
if (mHandler.hasMessages(CANCEL) || mHandler.hasMessages(HIDE)) {
return;
}
if (mView != mNextView) {
// remove the old view if necessary
handleHide();
mView = mNextView;
Context context = mView.getContext().getApplicationContext();
String packageName = mView.getContext().getOpPackageName();
if (context == null) {
context = mView.getContext();
}
mWM = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);
// We can resolve the Gravity here by using the Locale for getting
// the layout direction
final Configuration config = mView.getContext().getResources().getConfiguration();
final int gravity = Gravity.getAbsoluteGravity(mGravity, config.getLayoutDirection());
mParams.gravity = gravity;
if ((gravity & Gravity.HORIZONTAL_GRAVITY_MASK) == Gravity.FILL_HORIZONTAL) {
mParams.horizontalWeight = 1.0f;
}
if ((gravity & Gravity.VERTICAL_GRAVITY_MASK) == Gravity.FILL_VERTICAL) {
mParams.verticalWeight = 1.0f;
}
mParams.x = mX;
mParams.y = mY;
mParams.verticalMargin = mVerticalMargin;
mParams.horizontalMargin = mHorizontalMargin;
mParams.packageName = packageName;
mParams.hideTimeoutMilliseconds = mDuration ==
Toast.LENGTH_LONG ? LONG_DURATION_TIMEOUT : SHORT_DURATION_TIMEOUT;
mParams.token = windowToken;
if (mView.getParent() != null) {
if (localLOGV) Log.v(TAG, "REMOVE! " + mView + " in " + this);
mWM.removeView(mView);
}
if (localLOGV) Log.v(TAG, "ADD! " + mView + " in " + this);
// 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.
try {
mWM.addView(mView, mParams);
trySendAccessibilityEvent();
} catch (WindowManager.BadTokenException e) { // Ignore the exception
/* ignore */
}
}
}
}
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Therefore, Booster also simply catches the exception. However, instead of catching mWM.addView(mView, mParams), it catches the mHandler of the internal class Toast$TN by setting a Handler.Callback:
public class ShadowToast {
/**
* Fix {@code WindowManager$BadTokenException} for Android N
*
* @param toast
* The original toast
*/
public static void show(final Toast toast) {
if (Build.VERSION.SDK_INT == 25) {
workaround(toast).show();
} else {
toast.show();
}
}
private static Toast workaround(final Toast toast) {
final Object tn = getFieldValue(toast, "mTN");
if (null == tn) {
Log.w(TAG, "Field mTN of " + toast + " is null");
return toast;
}
final Object handler = getFieldValue(tn, "mHandler");
if (handler instanceof Handler) {
if (setFieldValue(handler, "mCallback", new CaughtCallback((Handler) handler))) {
return toast;
}
}
final Object show = getFieldValue(tn, "mShow");
if (show instanceof Runnable) {
if (setFieldValue(tn, "mShow", new CaughtRunnable((Runnable) show))) {
return toast;
}
}
Log.w(TAG, "Neither field mHandler nor mShow of " + tn + " is accessible");
return toast;
}
}
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In booster-transform-toastopen in new window, the show() method calls of the Toast class and its subclasses are replaced with ShadowToast.show(Toast).
Getting Started
To fix the Android 7.1 Toast bug, simply include booster-transform-toastopen in new window, as shown below:
buildscript {
ext {
kotlin_version = "1.5.31"
booster_version = "4.16.3"
}
repositories {
mavenCentral()
google()
}
dependencies {
classpath 'com.android.tools.build:gradle:3.5.0'
classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
classpath "com.didiglobal.booster:booster-gradle-plugin:$booster_version"
/* Include this module */
classpath "com.didiglobal.booster:booster-transform-toast:$booster_version"
}
}
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