如何在不使用任何库的情况下，在你的安卓 App 中添加指纹认证？
原文:https://www . geesforgeks . org/如何在不使用任何库的情况下在您的安卓应用中添加指纹认证/
生物指纹认证是保护应用敏感信息或优质内容的一种方法。如今，所有支付应用程序都在其应用程序中使用这一功能。它非常容易实现。下面给出了一个示例视频，以了解我们将在本文中做什么。请注意，我们将使用 Java 和 Kotlin 语言来实现这个项目
分步实施
第一步:创建新项目
要在安卓工作室创建新项目，请参考如何在安卓工作室创建/启动新项目。注意，选择柯特林/Java 作为编程语言
步骤 2:在清单中添加生物识别许可
转到 AndroidMenifest.xml 文件，并在那里添加以下权限。
步骤 3:使用 activity_main.xml 文件
转到 activity_main.xml 文件，参考以下代码。下面是 activity_main.xml 文件的代码。它只有一个按钮，点击它将创建指纹扫描仪对话框。
可扩展标记语言
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<Button
android:id="@+id/start_authentication"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Authenticate"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>
步骤 4:使用主活动文件
转到主活动文件，参考以下代码。以下是主活动文件的代码。代码中添加了注释，以更详细地理解代码。
我的锅
import android.app.KeyguardManager
import android.content.Context
import android.content.DialogInterface
import android.content.pm.PackageManager
import android.hardware.biometrics.BiometricPrompt
import android.os.Build
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.os.CancellationSignal
import android.widget.Button
import android.widget.Toast
import androidx.annotation.RequiresApi
import androidx.core.app.ActivityCompat
class MainActivity : AppCompatActivity() {
// create a CancellationSignal variable and assign a value null to it
private var cancellationSignal: CancellationSignal? = null
// create an authenticationCallback
private val authenticationCallback: BiometricPrompt.AuthenticationCallback
get() = @RequiresApi(Build.VERSION_CODES.P)
object : BiometricPrompt.AuthenticationCallback() {
// here we need to implement two methods
// onAuthenticationError and onAuthenticationSucceeded
// If the fingerprint is not recognized by the app it will call
// onAuthenticationError and show a toast
override fun onAuthenticationError(errorCode: Int, errString: CharSequence?) {
super.onAuthenticationError(errorCode, errString)
notifyUser("Authentication Error : $errString")
}
// If the fingerprint is recognized by the app then it will call
// onAuthenticationSucceeded and show a toast that Authentication has Succeed
// Here you can also start a new activity after that
override fun onAuthenticationSucceeded(result: BiometricPrompt.AuthenticationResult?) {
super.onAuthenticationSucceeded(result)
notifyUser("Authentication Succeeded")
// or start a new Activity
}
}
@RequiresApi(Build.VERSION_CODES.P)
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
checkBiometricSupport()
// create a biometric dialog on Click of button
findViewById<Button>(R.id.start_authentication).setOnClickListener {
// This creates a dialog of biometric auth and
// it requires title , subtitle ,
// and description
// In our case there is a cancel button by
// clicking it, it will cancel the process of
// fingerprint authentication
val biometricPrompt = BiometricPrompt.Builder(this)
.setTitle("Title of Prompt")
.setSubtitle("Subtitle")
.setDescription("Uses FP")
.setNegativeButton("Cancel", this.mainExecutor, DialogInterface.OnClickListener { dialog, which ->
notifyUser("Authentication Cancelled")
}).build()
// start the authenticationCallback in mainExecutor
biometricPrompt.authenticate(getCancellationSignal(), mainExecutor, authenticationCallback)
}
}
// it will be called when authentication is cancelled by the user
private fun getCancellationSignal(): CancellationSignal {
cancellationSignal = CancellationSignal()
cancellationSignal?.setOnCancelListener {
notifyUser("Authentication was Cancelled by the user")
}
return cancellationSignal as CancellationSignal
}
// it checks whether the app the app has fingerprint permission
@RequiresApi(Build.VERSION_CODES.M)
private fun checkBiometricSupport(): Boolean {
val keyguardManager = getSystemService(Context.KEYGUARD_SERVICE) as KeyguardManager
if (!keyguardManager.isDeviceSecure) {
notifyUser("Fingerprint authentication has not been enabled in settings")
return false
}
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.USE_BIOMETRIC) != PackageManager.PERMISSION_GRANTED) {
notifyUser("Fingerprint Authentication Permission is not enabled")
return false
}
return if (packageManager.hasSystemFeature(PackageManager.FEATURE_FINGERPRINT)) {
true
} else true
}
// this is a toast method which is responsible for showing toast
// it takes a string as parameter
private fun notifyUser(message: String) {
Toast.makeText(this, message, Toast.LENGTH_SHORT).show()
}
}
Java 语言(一种计算机语言，尤用于创建网站)
import android.app.KeyguardManager;
import android.content.Context;
import android.content.DialogInterface;
import android.content.pm.PackageManager;
import android.hardware.biometrics.BiometricPrompt;
import android.os.Build;
import android.os.Bundle;
import android.os.CancellationSignal;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
public class MainActivity extends AppCompatActivity {
// create a CancellationSignal
// variable and assign a
// value null to it
private CancellationSignal cancellationSignal = null;
// create an authenticationCallback
private BiometricPrompt.AuthenticationCallback authenticationCallback;
@RequiresApi(api = Build.VERSION_CODES.P)
@Override
protected void
onCreate(@Nullable Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
authenticationCallback = new BiometricPrompt.AuthenticationCallback() {
// here we need to implement two methods
// onAuthenticationError and
// onAuthenticationSucceeded If the
// fingerprint is not recognized by the
// app it will call onAuthenticationError
// and show a toast
@Override
public void onAuthenticationError(
int errorCode, CharSequence errString)
{
super.onAuthenticationError(errorCode, errString);
notifyUser("Authentication Error : " + errString);
}
// If the fingerprint is recognized by the
// app then it will call
// onAuthenticationSucceeded and show a
// toast that Authentication has Succeed
// Here you can also start a new activity
// after that
@Override
public void onAuthenticationSucceeded(BiometricPrompt.AuthenticationResult result)
{
super.onAuthenticationSucceeded(result);
notifyUser("Authentication Succeeded");
// or start a new Activity
}
};
checkBiometricSupport();
// create a biometric dialog on Click of button
(Button) findViewById(R.id.start_authentication).setOnClickListener(new View.OnClickListener() {
@RequiresApi(api = Build.VERSION_CODES.P)
@Override
public void onClick(View view)
{
// This creates a dialog of biometric
// auth and it requires title , subtitle
// , and description In our case there
// is a cancel button by clicking it, it
// will cancel the process of
// fingerprint authentication
BiometricPrompt biometricPrompt = new BiometricPrompt
.Builder(getApplicationContext())
.setTitle("Title of Prompt")
.setSubtitle("Subtitle")
.setDescription("Uses FP")
.setNegativeButton("Cancel", getMainExecutor(), new DialogInterface.OnClickListener() {
@Override
public void
onClick(DialogInterface dialogInterface, int i)
{
notifyUser("Authentication Cancelled");
}
}).build();
// start the authenticationCallback in
// mainExecutor
biometricPrompt.authenticate(
getCancellationSignal(),
getMainExecutor(),
authenticationCallback);
}
});
}
// it will be called when
// authentication is cancelled by
// the user
private CancellationSignal getCancellationSignal()
{
cancellationSignal = new CancellationSignal();
cancellationSignal.setOnCancelListener(
new CancellationSignal.OnCancelListener() {
@Override public void onCancel()
{
notifyUser("Authentication was Cancelled by the user");
}
});
return cancellationSignal;
}
// it checks whether the
// app the app has fingerprint
// permission
@RequiresApi(Build.VERSION_CODES.M)
private Boolean checkBiometricSupport()
{
KeyguardManager keyguardManager = (KeyguardManager)getSystemService(Context.KEYGUARD_SERVICE);
if (!keyguardManager.isDeviceSecure()) {
notifyUser("Fingerprint authentication has not been enabled in settings");
return false;
}
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.USE_BIOMETRIC)!= PackageManager.PERMISSION_GRANTED) {
notifyUser("Fingerprint Authentication Permission is not enabled");
return false;
}
if (getPackageManager().hasSystemFeature(PackageManager.FEATURE_FINGERPRINT)) {
return true;
}
else
return true;
}
// this is a toast method which is responsible for
// showing toast it takes a string as parameter
private void notifyUser(String message)
{
Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}
}
输出:
GitHub 回购 这里 。
