解决方案：

修改MainActivity.dart文件

package com.example.credit_card

import android.os.Bundle

import io.flutter.app.FlutterActivity

import io.flutter.plugins.GeneratedPluginRegistrant

class MainActivity: FlutterActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {

        super.onCreate(savedInstanceState)

        GeneratedPluginRegistrant.registerWith(this)

    }

}

同时修改android/app/src/main/AndroidManifest.xml

在activity标签内添加

<!-- This keeps the window background of the activity showing

                until Flutter renders its first frame. It can be removed if

                there is no splash screen (such as the default splash screen

                defined in @style/LaunchTheme). -->

            <meta-data

                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"

                android:value="true" />