使用Fragment来显示BiometricPrompt，并在旋转/ onCreate时恢复它的状态。

1.首先，在应用程序的布局文件中添加一个Fragment：

2.创建BiometricFragment类：

public class BiometricFragment extends Fragment {

private BiometricPrompt mBiometricPrompt; private BiometricPrompt.PromptInfo mPromptInfo;

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

   if (savedInstanceState != null) {
       // 恢复BiometricPrompt状态
       mBiometricPrompt = savedInstanceState.getParcelable("biometricPrompt");
       mPromptInfo = savedInstanceState.getParcelable("promptInfo");
   } else {
       // 创建新的BiometricPrompt
       mBiometricPrompt = new BiometricPrompt(this,
               new Executor() {
                   @Override
                   public void execute(Runnable command) {

                   }
               },
               new BiometricPrompt.AuthenticationCallback() {
                   @Override
                   public void onAuthenticationSucceeded(BiometricPrompt.AuthenticationResult result) {
                       // 指纹验证成功
                       Log.d("BiometricFragment", "onAuthenticationSucceeded");
                   }

                   @Override
                   public void onAuthenticationError(int errorCode, CharSequence errString) {
                       // 指纹验证失败
                       Log.d("BiometricFragment", "onAuthenticationError");
                   }
               });

       // 设置提示信息
       mPromptInfo = new BiometricPrompt.PromptInfo.Builder()
               .setTitle("指纹验证")
               .setSubtitle("请使用您的指纹进行验证")
               .setNegativeButtonText("取消")
               .build();
   }

   // 调用BiometricPrompt.authenticate
   mBiometricPrompt.authenticate(mPromptInfo);

}

@Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState);

   // 保存当前BiometricPrompt状态
   outState.putParcelable("biometricPrompt", mBiometricPrompt);
   outState.putParcelable("promptInfo