如何在自定义Dialog类中设置Interface和listener，以将Facebook的登录回调传递给MainActivity中的firebase auth？

问题描述

我在实现自定义对话框类时遇到了一些问题，该类从Facebook获得响应并将其传递回主要活动。

这是我的自定义课程：

class LoginDialog(var c: Activity) : Dialog(c),View.OnClickListener {

val mContext = c
private lateinit var realFbButton: LoginButton
private lateinit var listener: LoginListener

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    requestWindowFeature(Window.FEATURE_NO_TITLE)
    getWindow()?.setBackgroundDrawableResource(android.R.color.transparent);
    setContentView(R.layout.login_dialog)

    // here image to cover the real facebook LoginButton
    val loginFbButton: ImageView = findViewById(R.id.facebookButton)
    loginFbButton.setOnClickListener(this)

    // the real facebook login button I wanna click to start the facebook auth process
    realFbButton = findViewById(R.id.facebooOfficalButton)
    realFbButton.setOnClickListener(this)

}

override fun onClick(v: View) {
    when (v.id) {
        R.id.facebookButton -> {realFbButton.performClick()
            // Initialize Facebook Login button
            //TODO: (nothing necessary)
        }
        R.id.facebooOfficalButton -> {
            realFbButton.setReadPermissions("email","public_profile")

            // register callback after LoginButton has been pushed
            realFbButton.registerCallback(callbackManager,object :
                FacebookCallback<LoginResult>{
                override fun onSuccess(result: LoginResult?) {
                    try{
                        Toast.makeText(context,"success",Toast.LENGTH_LONG).show()
                        // listener to pass result
                        listener.passLoginListener(result)
                    }
                    catch(e: Exception){
                        Toast.makeText(context,"exception" + e,Toast.LENGTH_LONG).show()

                    }
                    TODO("Not yet implemented")
                }

                override fun onCancel() {
                    TODO("Not yet implemented")
                }

                override fun onError(error: FacebookException?) {
                    TODO("Not yet implemented")
                }
            })
        }
        else -> {
            Toast.makeText(mContext,"id not recognized: " + v,Toast.LENGTH_LONG).show()
        }
    }
    dismiss()
}

fun setLoginListener(listener: LoginListener?) {
    this.listener = listener!!
}


interface LoginListener{
    public fun passLoginListener(callBack: LoginResult?)

}

}

在我的主要活动中：

   // interface implementation
   class CentralActivity : AppCompatActivity(),LoginDialog.LoginListener{/* my full class is  here
   ...*/}

   
   override fun passLoginListener(callBack: LoginResult?) {/*here call to handleFacebookAccessToken(token: AccessToken)*/}
  
   // in onCreate overriden method:
   val dialog = LoginDialog(this@CentralActivity)
   dialog.setLoginListener(this@CentralActivity) // this activate the listener

但是它不起作用：即使使用调试器，我也可以绝对告诉任何东西都不能通过接口传递给活动，也不会触发“成功”响应（与其他响应一样）。

我该怎么做才能正确地做到这一点？

解决方法

我解决了这个问题，希望这种经历可以为其他人节省一些宝贵的时间：）

1. 监听器需要正确初始化为自定义类，其中“ c”是从我的主要活动传递来的活动：

   //in onCreate,inside the custom dialog class:
   listener = c as LoginDialog.LoginListener
   

2. 由于回调需要一些时间才能返回，因此将响应传递给主要活动是没有用的：相反，最好将按钮传递给

    override fun onClick(v: View) {
   
    when (v.id) {
        R.id.facebookButton -> {realFbButton.performClick()
            //TODO: nothing here
        }
        R.id.facebooOfficalButton -> {
            realFbButton.setReadPermissions("email","public_profile")
            this.listener.passLoginListener(realFbButton) // here we go passing the button to the interface and to the main activity
        }
        else -> {
            Toast.makeText(mContext,"id not recognized: " + v,Toast.LENGTH_LONG).show()
        }
    }
    dismiss()
   

在主要活动中，

3. 让我们将其设置为等待结果： 这是听众

    override fun passLoginListener(fbb: LoginButton): LoginButton {
    // get the LoginButton and set up the receiver
    fbb.registerCallback(callbackManager,object :
        FacebookCallback<LoginResult> {
        override fun onSuccess(result: LoginResult?) {
   
            try{
                Toast.makeText(applicationContext,"success",Toast.LENGTH_LONG).show()
                handleFacebookAccessToken(result!!.accessToken) 
            }
            catch(e: Exception){
                Toast.makeText(applicationContext,"exception" + e,Toast.LENGTH_LONG).show()
   
            }
        }
   
        override fun onCancel() {
            TODO("Not yet implemented")
        }
   
        override fun onError(error: FacebookException?) {
            TODO("Not yet implemented")
        }
    })
    return fbb
    }
   

现在onActivityResult方法可以正常工作

    override fun onActivityResult(requestCode: Int,resultCode: Int,data: Intent?) {
    super.onActivityResult(requestCode,resultCode,data)

    // Pass the activity result back to the Facebook SDK
    callbackManager.onActivityResult(requestCode,data)}

现在，对于在onCreate中初始化的Firebase身份验证

    //firebase auth in onCreate
    auth = Firebase.auth

，并在此处进行了更新（有关此信息，请参见正式的Firebase文档）

private fun handleFacebookAccessToken(token: AccessToken) {
    Log.d("Tag","handleFacebookAccessToken:$token")
    Toast.makeText(applicationContext,"in handle fb login " + token,Toast.LENGTH_LONG).show()

    val credential = FacebookAuthProvider.getCredential(token.token)
    auth.signInWithCredential(credential)
        .addOnCompleteListener(this) { task ->
            if (task.isSuccessful) {
                // Sign in success,update UI with the signed-in user's information
                Log.d("Tag","signInWithCredential:success")
                val user = auth.currentUser
                updateUI(user)
            } else {
                // If sign in fails,display a message to the user.
                Log.w("Tag","signInWithCredential:failure",task.exception)
                Toast.makeText(baseContext,"Authentication failed.",Toast.LENGTH_SHORT).show()
                updateUI(null)
            }

            // ...
        }
}
    

希望有帮助！