EXCEPTION CAUGHT BY WIDGETS LIBRARY in flutter app

Question

When i am trying to run my own flutter app in android studio it gives error like this

This is my app screenshot:

This is my logcat:

Answer 1

The problem is that Colors.black is a single color, but primarySwatch expects a palette of multiple colors. If you look at the documentation for Colors , the different built in palettes are shown. For example, Colors.blue is a blue palette, and can be passed to primarySwatch .

new MaterialApp(theme: new ThemeData(primarySwatch: Colors.blue))

Answer 2

在单引号中查看您的空间，您应该这样写： var first = ['answer':'black','white',...];