小编Tra*_*ean的帖子

我正在尝试使用flutter创建IP语音（VOIP）移动应用程序。我还没有看到twilio语音api的flutter插件的实现，因此我使用MethodChannel将我的应用程序与本机android语音api集成在一起.twilio SDK似乎没有像它正确集成一样，我无法访问脚本中的twilio类和方法。这些是我得到的错误。

Running Gradle task 'assembleDebug'...
/home/kudziesimz/voip20/android/app/src/main/java/com/workerbees  /voip20/MainActivity.java:23: error: package android.support.annotation does not exist
import android.support.annotation.NonNull;
                             ^
/home/kudziesimz/voip20/android/app/src/main/java/com/workerbees   /voip20/MainActivity.java:295: error: cannot find symbol
public void onRequestPermissionsResult(int requestCode, @NonNull   String[] permissions, @NonNull int[] grantResults) {
                                                         ^
symbol:   class NonNull
location: class MainActivity
/home/kudziesimz/voip20/android/app/src/main/java/com/workerbees /voip20/MainActivity.java:295: error: cannot find symbol
   public void onRequestPermissionsResult(int requestCode, @NonNull  String[] permissions, @NonNull int[] grantResults) {
                                                                                         ^
symbol:   class NonNull
location: class MainActivity
/home/kudziesimz/voip20/android/app/src/main/java/com/workerbees   /voip20/MainActivity.java:117: error: cannot find symbol
    soundPoolManager =   SoundPoolManager.getInstance(this.MainActivity);
                                                        ^
 symbol: variable MainActivity
/home/kudziesimz/voip20/android/app/src/main/java/com/workerbees /voip20/MainActivity.java:186: …