基礎知識
支援系統和機型
iOS系統的指紋識別功能最低支援的機型為iPhone 5s
,最低支援系統為iOS 8
,雖然安裝iOS 7
系統的5s機型可以使用系統提供的指紋解鎖功能,但由於API
並未開放,所以理論上第三方軟體不可使用。
依賴框架
LocalAuthentication.framework
#import <LocalAuthentication/LocalAuthentication.h>
注意事項
做iOS 8
以下版本適配時,務必進行API驗證,避免呼叫相關API引起崩潰。
使用類
LAContext
指紋驗證操作物件
程式碼
- (void)authenticateUser
{
//初始化上下文物件
LAContext* context = [[LAContext alloc] init];
//錯誤物件
NSError* error = nil;
NSString* result = @"Authentication is needed to access your notes.";
//首先使用canEvaluatePolicy 判斷裝置支援狀態
if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {
//支援指紋驗證
[context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:result reply:^(BOOL success, NSError *error) {
if (success) {
//驗證成功,主執行緒處理UI
}
else
{
NSLog(@"%@",error.localizedDescription);
switch (error.code) {
case LAErrorSystemCancel:
{
NSLog(@"Authentication was cancelled by the system");
//切換到其他APP,系統取消驗證Touch ID
break;
}
case LAErrorUserCancel:
{
NSLog(@"Authentication was cancelled by the user");
//使用者取消驗證Touch ID
break;
}
case LAErrorUserFallback:
{
NSLog(@"User selected to enter custom password");
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
//使用者選擇輸入密碼,切換主執行緒處理
}];
break;
}
default:
{
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
//其他情況,切換主執行緒處理
}];
break;
}
}
}
}];
}
else
{
//不支援指紋識別,LOG出錯誤詳情
switch (error.code) {
case LAErrorTouchIDNotEnrolled:
{
NSLog(@"TouchID is not enrolled");
break;
}
case LAErrorPasscodeNotSet:
{
NSLog(@"A passcode has not been set");
break;
}
default:
{
NSLog(@"TouchID not available");
break;
}
}
NSLog(@"%@",error.localizedDescription);
}
}
typedef NS_ENUM(NSInteger, LAError)
{
//授權失敗
LAErrorAuthenticationFailed = kLAErrorAuthenticationFailed,
//使用者取消Touch ID授權
LAErrorUserCancel = kLAErrorUserCancel,
//使用者選擇輸入密碼
LAErrorUserFallback = kLAErrorUserFallback,
//系統取消授權(例如其他APP切入)
LAErrorSystemCancel = kLAErrorSystemCancel,
//系統未設定密碼
LAErrorPasscodeNotSet = kLAErrorPasscodeNotSet,
//裝置Touch ID不可用,例如未開啟
LAErrorTouchIDNotAvailable = kLAErrorTouchIDNotAvailable,
//裝置Touch ID不可用,使用者未錄入
LAErrorTouchIDNotEnrolled = kLAErrorTouchIDNotEnrolled,
} NS_ENUM_AVAILABLE(10_10, 8_0);
操作流程
首先判斷系統版本,iOS 8
及以上版本執行-(void)authenticateUser
方法,方法自動判斷裝置是否支援和開啟Touch ID
。
iOS 9
感謝秋兒指出iOS 9加入了三種新的錯誤型別。
/// Authentication was not successful, because there were too many failed Touch ID attempts and
/// Touch ID is now locked. Passcode is required to unlock Touch ID, e.g. evaluating
/// LAPolicyDeviceOwnerAuthenticationWithBiometrics will ask for passcode as a prerequisite.
LAErrorTouchIDLockout NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorTouchIDLockout,
/// Authentication was canceled by application (e.g. invalidate was called while
/// authentication was in progress).
LAErrorAppCancel NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorAppCancel,
/// LAContext passed to this call has been previously invalidated.
LAErrorInvalidContext NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorInvalidContext
其中,LAErrorTouchIDLockout
是在8.0中也會出現的情況,但並未歸為單獨的錯誤型別,這個錯誤出現,源自使用者多次連續使用Touch ID失敗,Touch ID被鎖,需要使用者輸入密碼解鎖,這個錯誤的互動LocalAuthentication.framework
已經封裝好了,不需要開發者關心。
LAErrorAppCancel
和LAErrorSystemCancel
相似,都是當前軟體被掛起取消了授權,但是前者是使用者不能控制的掛起,例如突然來了電話,電話應用進入前臺,APP被掛起。後者是使用者自己切到了別的應用,例如按home鍵掛起。
LAErrorInvalidContext
很好理解,就是授權過程中,LAContext物件被釋放掉了,造成的授權失敗。