<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"   xmlns:tools="http://schemas.android.com/tools"   android:layout_width="match_parent"   android:layout_height="match_parent"   android:gravity="center"   android:orientation="vertical"   android:paddingBottom="@dimen/activity_vertical_margin"   android:paddingLeft="@dimen/activity_horizontal_margin"   android:paddingRight="@dimen/activity_horizontal_margin"   android:paddingTop="@dimen/activity_vertical_margin"   tools:context="com.liu.finger.MainActivity">    <TextView     android:id="@+id/textView"     android:layout_width="wrap_content"     android:layout_height="wrap_content"     android:text="Hello World!"     android:textSize="18sp" />    <Button     android:id="@+id/btn_activity_main_finger"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:layout_alignParentStart="true"     android:layout_below="@+id/textView"     android:layout_marginTop="54dp"     android:text="指紋識別" /> </LinearLayout> 

package com.liu.finger;  import android.Manifest; import android.app.KeyguardManager; import android.content.Context; import android.content.Intent; import android.content.pm.PackageManager; import android.hardware.fingerprint.FingerprintManager; import android.os.Bundle; import android.os.CancellationSignal; import android.support.v4.app.ActivityCompat; import android.support.v4.app.FragmentActivity; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.Toast;    public class MainActivity extends FragmentActivity {   FingerprintManager manager;   KeyguardManager mKeyManager;   private final static int REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS = 0;   private final static String TAG = "finger_log";    @Override   protected void onCreate(Bundle savedInstanceState) {     super.onCreate(savedInstanceState);     setContentView(R.layout.activity_main);     manager = (FingerprintManager) this.getSystemService(Context.FINGERPRINT_SERVICE);     mKeyManager = (KeyguardManager) this.getSystemService(Context.KEYGUARD_SERVICE);     Button btn_finger = (Button) findViewById(R.id.btn_activity_main_finger);     btn_finger.setOnClickListener(new View.OnClickListener() {       @Override       public void onClick(View v) {         if (isFinger()) {           Toast.makeText(MainActivity.this, "請進行指紋識別", Toast.LENGTH_LONG).show();           Log(TAG, "keyi");           startListening(null);         }       }     });    }    public boolean isFinger() {      //android studio 上，沒有這個會報錯     if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {       Toast.makeText(this, "沒有指紋識別權限", Toast.LENGTH_SHORT).show();       return false;     }     Log(TAG, "有指紋權限");     //判斷硬件是否支持指紋識別     if (!manager.isHardwareDetected()) {       Toast.makeText(this, "沒有指紋識別模塊", Toast.LENGTH_SHORT).show();       return false;     }    Log(TAG, "有指紋模塊");     //判斷 是否開啟鎖屏密碼      if (!mKeyManager.isKeyguardSecure()) {       Toast.makeText(this, "沒有開啟鎖屏密碼", Toast.LENGTH_SHORT).show();       return false;     }     Log(TAG, "已開啟鎖屏密碼");     //判斷是否有指紋錄入     if (!manager.hasEnrolledFingerprints()) {       Toast.makeText(this, "沒有錄入指紋", Toast.LENGTH_SHORT).show();       return false;     }     Log(TAG, "已錄入指紋");      return true;   }    CancellationSignal mCancellationSignal = new CancellationSignal();   //回調方法   FingerprintManager.AuthenticationCallback mSelfCancelled = new FingerprintManager.AuthenticationCallback() {     @Override     public void onAuthenticationError(int errorCode, CharSequence errString) {       //但多次指紋密碼驗證錯誤后，進入此方法；并且，不能短時間內調用指紋驗證       Toast.makeText(MainActivity.this, errString, Toast.LENGTH_SHORT).show();       showAuthenticationScreen();     }      @Override     public void onAuthenticationHelp(int helpCode, CharSequence helpString) {        Toast.makeText(MainActivity.this, helpString, Toast.LENGTH_SHORT).show();     }      @Override     public void onAuthenticationSucceeded(FingerprintManager.AuthenticationResult result) {        Toast.makeText(MainActivity.this, "指紋識別成功", Toast.LENGTH_SHORT).show();     }      @Override     public void onAuthenticationFailed() {       Toast.makeText(MainActivity.this, "指紋識別失敗", Toast.LENGTH_SHORT).show();     }   };     public void startListening(FingerprintManager.CryptoObject cryptoObject) {     //android studio 上，沒有這個會報錯     if (ActivityCompat.checkSelfPermission(this, Manifest.permission.USE_FINGERPRINT) != PackageManager.PERMISSION_GRANTED) {       Toast.makeText(this, "沒有指紋識別權限", Toast.LENGTH_SHORT).show();       return;     }     manager.authenticate(cryptoObject, mCancellationSignal, 0, mSelfCancelled, null);     }    /**    * 鎖屏密碼    */   private void showAuthenticationScreen() {      Intent intent = mKeyManager.createConfirmDeviceCredentialIntent("finger", "測試指紋識別");     if (intent != null) {       startActivityForResult(intent, REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS);     }   }    @Override   protected void onActivityResult(int requestCode, int resultCode, Intent data) {     if (requestCode == REQUEST_CODE_CONFIRM_DEVICE_CREDENTIALS) {       // Challenge completed, proceed with using cipher       if (resultCode == RESULT_OK) {         Toast.makeText(this, "識別成功", Toast.LENGTH_SHORT).show();       } else {         Toast.makeText(this, "識別失敗", Toast.LENGTH_SHORT).show();       }     }   }    private void Log(String tag, String msg) {     Log.d(tag, msg);   } }