Ak123 SUre. To show a toast in smali, it uses something like
invoke-virtual {v0}, Landroid/widget/Toast;->show()V. (of course the register can be different.) So look in smali for Landroid/widget/Toast;->show(), and remove the line invoking it. This will always work unless you are dealing with an obfuscated APK, in which case you need to either: deobfuscate it, or make a Java class that blocks all toasts from showing and invoke it in every single activity onCreate onResume and maybe onPuase (I might be missing something).
