问题
My device runs Android 5.1.1 and I found out that if I use
Toast.makeText(this, "This is a toast", Toast.LENGTH_SHORT).show();
I got this:
But if I use getApplicationContext() instead of this,
Toast.makeText(getApplicationContext(), "This is a toast", Toast.LENGTH_SHORT).show();
I got this:
Both are called directly from the activity.
Why is this?
回答1:
It has to do with the Theme the Context has associated with it. Using this is using a context (I'm assuming your Activity or Fragment) that has a different theme than the Application Context.
If you have a reason you need to be using the application context, you can wrap it in whichever theme your activities are using (usually set in your AndroidManifest.xml) and it should show the "round" toast.
Toast.makeText(new ContextThemeWrapper(getApplicationContext(), R.style.AppTheme), "This is a toast", Toast.LENGTH_SHORT).show();
来源：https://stackoverflow.com/questions/33045471/toast-difference-between-this-and-getapplicationcontext