Software Engineer Snippet

20201011   https://pub.dev/packages/admob_flutter   Firebase build.gradle classpath 'com.google.gms:google-services:4.3.4' app>src>build.gradle apply plugin : 'com.google.gms.google-services' implementation platform( 'com.google.firebase:firebase-bom:25.12.0' ) implementation  'com.google.firebase:firebase-analytics'                                                                                                                                                         Admob-Android app>src>main>AndroidManifest.xml <application android :name ="io.flutter.app.FlutterApplication" android :label ="keys" android :icon ="@mipmap/ic_launcher" > <meta-data android :name ="com.google.android.gms.ads.APPLICATION_ID" android :value ="ca-app-pub-6080925650058329~5412407969" /> ☝<meta-data android:name..../> must under the <application> and out of &l

20201011   Flexible( child: Text()),

  Firebase build.gradle classpath 'com.google.gms:google-services:4.3.4' app>src>build.gradle apply plugin : 'com.google.gms.google-services' implementation platform( 'com.google.firebase:firebase-bom:25.12.0' ) implementation  'com.google.firebase:firebase-analytics'                                                                                                                                                         Admob-Android app>src>main>AndroidManifest.xml <application android :name ="io.flutter.app.FlutterApplication" android :label ="keys" android :icon ="@mipmap/ic_launcher" > <meta-data android :name ="com.google.android.gms.ads.APPLICATION_ID" android :value ="ca-app-pub-6080925650058329~5412407969" /> ☝<meta-data android:name..../> must under the <application> and out of </activity> Admob-iOS <key>GADApplicatio

   20201011   iOS < key > NSFaceIDUsageDescription </ key > < string > Why is my app authenticating using face id? </ string >                                                                                                                                                                       Android Android -Trouble Error: PlatformException(no_fragment_activity, local_auth plugin requires activity to be a FragmentActivity., null) Trouble shotting: app>src>main>kotlin>[bundle id]> MainActivity.kt   package co.et.keys import androidx.annotation.NonNull ; import io.flutter.embedding.android.FlutterFragmentActivity import io.flutter.embedding.engine.FlutterEngine import io.flutter.plugins.GeneratedPluginRegistrant class MainActivity: FlutterFragmentActivity() { override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) { GeneratedPluginRegistrant.registerWith(flutterEngine) ; } } app>src>res> AndroidMaifest.xm

package co.et.keys import androidx.annotation.NonNull ; import io.flutter.embedding.android.FlutterFragmentActivity import io.flutter.embedding.engine.FlutterEngine import io.flutter.plugins.GeneratedPluginRegistrant class MainActivity: FlutterFragmentActivity() { override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) { GeneratedPluginRegistrant.registerWith(flutterEngine) ; } } <uses-permission android :name ="android.permission.USE_BIOMETRIC" /> refer 1 refer2  

20201004 import 'dart:convert' ; import 'dart:io' ; void main () { String data = '' ; for (int i = 0 ; i < 100 ; i++) { data = data + 'i love flutter \r\n ' ; } List origin = utf8.encode(data) ; List compress = GZIP.encode(origin) ; List decompress = GZIP.decode(compress) ; String decode = utf8.decode(decompress) ; assert (data == decode) ; print( 'origin size : ${origin. length } bytes' ) ; print( 'GZIP size: ${compress. length } bytes' ) ; print( 'decompress size: ${decompress. length } bytes' ) ; int encodeCompress(zipType) { List compress = zipType.encode(origin) ; int size = compress. length ; return size ; } print( '---- GZIP vs ZLIB -----' ) ; print( 'GZIP size : ${encodeCompress(GZIP)} ' ) ; print( 'ZLIB size : ${encodeCompress(ZLIB)} ' ) ; } Performing hot restart... Syncing files to device iPhone 11 Pro... Restarted application in 87ms. flutter

20201004 import 'dart:io' ; import 'package:flutter/material.dart' ; import 'package:path_provider/path_provider.dart' ; void main () async { WidgetsFlutterBinding. ensureInitialized () ; await getApplicationDocumentsDirectory().then((Directory dir) { File file = File ( ' ${dir. path } /text.txt' ) ; file.writeAsString( '123' ) ; void read() async { String contents = await file.readAsString() ; print(contents) ; } read() ; }) ; }   [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: FileSystemException: Cannot open file, path = '//test.txt' (OS Error: Read-only file system, errno = 30) FileSystemException: Cannot open file OS Error: Is a directory reading-writing-files