如何实现包含“this”和“MainActivity.this”的Android本机代码。使用 import com.codename1.impl.android.AndroidNativeUtil;

Question

我正在实现下面的本机 Android 代码来调用生物识别身份验证，并使用设备引脚/图案/密码作为备份。我在 android studio 中使用了以下代码，它适用于模拟器和物理设备。本质上，当应用程序启动以及按下按钮时会出现提示。

    import androidx.annotation.NonNull;
    import androidx.appcompat.app.AppCompatActivity;
    import androidx.biometric.BiometricPrompt;
    import androidx.core.content.ContextCompat;
    import android.app.Activity;
    import android.os.Bundle;
    import android.util.Log;
    import android.widget.Button;
    import android.widget.Toast;
    import java.util.concurrent.Executor;
    
       public class MainActivity extends AppCompatActivity {

    private Executor executor;
    private BiometricPrompt biometricPrompt;
    private BiometricPrompt.PromptInfo promptInfo;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        executor = ContextCompat.getMainExecutor(this);
        biometricPrompt = new BiometricPrompt(MainActivity.this,
                executor, new BiometricPrompt.AuthenticationCallback() {
            @Override
            public void onAuthenticationError(int errorCode,
                                              @NonNull CharSequence errString) {
                super.onAuthenticationError(errorCode, errString);
                Toast.makeText(getApplicationContext(),
                                "Authentication error: " + errString, Toast.LENGTH_SHORT)
                        .show();
            }

            @Override
            public void onAuthenticationSucceeded(
                    @NonNull BiometricPrompt.AuthenticationResult result) {
                super.onAuthenticationSucceeded(result);
                Toast.makeText(getApplicationContext(),
                        "Authentication succeeded!", Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onAuthenticationFailed() {
                super.onAuthenticationFailed();
                Toast.makeText(getApplicationContext(), "Authentication failed",
                                Toast.LENGTH_SHORT)
                        .show();
            }
        });

        promptInfo = new BiometricPrompt.PromptInfo.Builder()
                .setTitle("Biometric login for my app")
                .setSubtitle("Log in using your biometric credential")
                .setAllowedAuthenticators(androidx.biometric.BiometricManager.Authenticators.BIOMETRIC_WEAK | androidx.biometric.BiometricManager.Authenticators.BIOMETRIC_STRONG | androidx.biometric.BiometricManager.Authenticators.DEVICE_CREDENTIAL)

                .build();

        biometricPrompt.authenticate(promptInfo);

        // Prompt appears when user clicks "Log in".
        // Consider integrating with the keystore to unlock cryptographic operations,
        // if needed by your app.
        Button biometricLoginButton = findViewById(R.id.b_launchAuth);
        biometricLoginButton.setOnClickListener(view -> {
            Log.d("b_launchAuth", "Pressed - Enter");
            biometricPrompt.authenticate(promptInfo);
            Log.d("b_launchAuth", "Pressed - Exit");
        });

    }
}

上面的代码需要添加构建提示： - "android.gradleDep=implementation("androidx.biometric:biometric:1.1.0")"

上面的代码引用了“this”（作为上下文：）和MainActivity.this（作为活动：）。我已导入 com.codename1.impl.android.AndroidNativeUtil 并尝试用 AndroidNativeUtil.getContext() 替换“this”，用 AndroidNativeUtil.getActivity() 替换“MainActivity.this”，但是我无法成功构建。

如果我注释掉除：-

之外的所有内容

executor = ContextCompat.getMainExecutor(AndroidNativeUtil.getActivity());

或

executor = ContextCompat.getMainExecutor(AndroidNativeUtil.getContext());

然后我就可以成功构建了。我的问题似乎与 MainActivity.this 相关。

我当前的 cn1 MyNativeImpl.java 代码如下：-

package com.jamesco.maventestnew;

import android.util.Log;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.biometric.BiometricPrompt;
import androidx.core.content.ContextCompat;
import android.os.Bundle;
import android.widget.Button;
import android.widget.Toast;
import java.util.concurrent.Executor;
import com.codename1.impl.android.AndroidNativeUtil;

public class MyNativeImpl {

    private Executor executor;
    private BiometricPrompt biometricPrompt;
    private BiometricPrompt.PromptInfo promptInfo;

    public boolean isSupported() {
        return true;
    }

    public boolean nativeAuth(){

        boolean AuthOK = false;

       
        executor = ContextCompat.getMainExecutor(AndroidNativeUtil.getContext());
        biometricPrompt = new BiometricPrompt(AndroidNativeUtil.getActivity(),
                executor, new BiometricPrompt.AuthenticationCallback() {
            @Override
            public void onAuthenticationError(int errorCode,
                                              @NonNull CharSequence errString) {
                super.onAuthenticationError(errorCode, errString);
                //Do nothing for now

            }

            @Override
            public void onAuthenticationSucceeded(
                    @NonNull BiometricPrompt.AuthenticationResult result) {
                super.onAuthenticationSucceeded(result);
                AuthOK = true;

            }

            @Override
            public void onAuthenticationFailed() {
                super.onAuthenticationFailed();

            }
        });


        promptInfo = new BiometricPrompt.PromptInfo.Builder()
                .setTitle("Biometric login for my app")
                .setSubtitle("Log in using your biometric credential")
                .setAllowedAuthenticators(androidx.biometric.BiometricManager.Authenticators.BIOMETRIC_WEAK | androidx.biometric.BiometricManager.Authenticators.BIOMETRIC_STRONG | androidx.biometric.BiometricManager.Authenticators.DEVICE_CREDENTIAL)
                .build();

        biometricPrompt.authenticate(promptInfo);

        return AuthOK;

    }

}

这里是按要求指向错误日志的链接

Answer 1

您在聊天中发送的日志的错误是：

MyNativeImpl.java:78: error: no suitable constructor found for BiometricPrompt(Activity,Executor,<anonymous AuthenticationCallback>)
        biometricPrompt = new BiometricPrompt(AndroidNativeUtil.getActivity(),
                          ^
    constructor BiometricPrompt.BiometricPrompt(FragmentActivity,Executor,AuthenticationCallback) is not applicable
      (argument mismatch; Activity cannot be converted to FragmentActivity)
    constructor BiometricPrompt.BiometricPrompt(Fragment,Executor,AuthenticationCallback) is not applicable
      (argument mismatch; Activity cannot be converted to Fragment)

问题是生物识别代码假定为

Fragment

或

FragmentActivity

。

我过去没有使用过片段，所以我只是在这里猜测，但我认为这样的事情可能会解决这个特定问题：

public class BiometricFragment extends Fragment {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true); 

        // write the biometric code here...
    }
}

您可以使用此未经测试的代码从本机代码启动它......：

BiometricFragment biometricFragment = new BiometricFragment();
            getFragmentManager().beginTransaction()
                .add(biometricFragment, "biometric_fragment")
                .commit();