Unable to load script from assets 'index.android.bundle'.Make sure your bundle is packaged correctly or you're running a packager server

curl -k 'http://localhost:8081/index.android.bundle?platform=android' > android/app/src/main/assets/index.android.bundle      在项目根目录中（即index.js）所在位置，输入前面的指令，得到以下有值的就成功了，