Error when creating Toast

问题

My code is

Context c = getApplicationContext();

CharSequence c1 = "Invalid Data Entered";

Toast t= Toast.makeText(c, c1, Toast.LENGTH_SHORT);

t.show();

it showing NULL POINTER EXCEPTION AT Toast.makeText() line

Any help..? thanks..

回答1:

It was actually because i was calling it from a different class and not an activity.. that was the reason.. IV can't create Toast in an Activity which is not running..

回答2:

you just have to use your view instead of getApplicationContext() for example if it is rowView just call :

Toast.makeText(rowView.getContext, " " ,Toast.LENGTH_SHORT).show();

回答3:

Maybe I am being blind, but the only thing I can see that could be null is your

getApplicationContext();

Check if that's null, and have it log it if it is, so you know the cause.

Can you show the code surrounding it please?

回答4:

try this and check.

Context c = getBaseContext(); 
CharSequence c1 = "Invalid Data Entered";

Toast t= Toast.makeText(c, c1, Toast.LENGTH_SHORT);

t.show();

or Toast t= Toast.makeText(activity, c1, Toast.LENGTH_SHORT);

you can also use activity instead of context..

回答5:

Try to use this:

Toast t= Toast.makeText(YourActivity.this, c1, Toast.LENGTH_SHORT);// YourActivity is the class name

for showing toast.

回答6:

The issue may be in line Context c = getApplicationContext();

if context is null then you will get NULLPOINTER EXCEPTION in Toast t= Toast.makeText(c, c1, Toast.LENGTH_SHORT);

You can use the following if your class extends Activity

Toast t= Toast.makeText(Classname.class, c1, Toast.LENGTH_SHORT);

Toast t= Toast.makeText(this, c1, Toast.LENGTH_SHORT);

If your class doesnot extend Activity better pass the context value to this class from the calling environment. after that use that context to create Toast

Thanks Deepak

回答7:

Context c=getApplicationContext();
Toast t=Toast.makeText(c, "invalid data enterd", Toast.LENGTH_SHORT);
t.show();

I tried this and it is working...

回答8:

Write this..

Toast t = Toast.makeText(this, "Invalid Data Entered", Toast.LENGTH_SHORT);
t.show();

回答9:

First of all check if you are calling toast.show() method inside an activity . Because toast is meant to show on user screen and you can not show it outside like service or non activity class . If you are trying to show toast some where in activity your code should work.

来源：https://stackoverflow.com/questions/6196960/error-when-creating-toast

标签

android

toast