生物识别提示:生物识别片段和活动内存泄漏

Question

您好，我发现了 2 个我想解决的内存泄漏。

收到回调onAuthenticationSucceeded(BiometricPrompt.AuthenticationResult result)后，我想setResult()并调用活动B上的finish()返回活动A。
虽然这确实工作正常，但它似乎会导致 2 个内存泄漏 调用finish().

2 泄漏金丝雀截图

下面是重现内存泄漏(活动 B(的相关代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_b);;
BiometricPrompt biometricPrompt = biometricPromptInstance();
biometricPrompt.authenticate(buildPromptInfo());
}
private BiometricPrompt biometricPromptInstance(){
Executor executor = ContextCompat.getMainExecutor(this);;
BiometricPrompt.AuthenticationCallback callback = new BiometricPrompt.AuthenticationCallback() {
@Override
public void onAuthenticationError(int errorCode, @NonNull CharSequence errString) {
}
@Override
public void onAuthenticationSucceeded(@NonNull BiometricPrompt.AuthenticationResult result) {
setResult(RESULT_OK);
//Causing leak:  ////////////////////////////////////////////////
finish();
/////////////////////////////////////////////////////////////////
}
@Override
public void onAuthenticationFailed() {
}
};
return new BiometricPrompt(this, executor, callback);
}
private BiometricPrompt.PromptInfo buildPromptInfo(){
return new BiometricPrompt.PromptInfo.Builder()
.setTitle("Login")
.setSubtitle("Log in using your biometric credential")
.setNegativeButtonText("Cancel")
.build();
}

Answer 1

问题在于执行器的初始化，

// initialize biometric executor
executor = ContextCompat.getMainExecutor(this)

更新到

// initialize biometric executor
executor = ContextCompat.getMainExecutor(applicationContext)

在内部，Google 正在使用处理程序在新线程中执行操作。上下文关联不应是您的活动(或片段(。

/**
* Return an {@link Executor} that will run enqueued tasks on the main
* thread associated with this context. This is the thread used to dispatch
* calls to application components (activities, services, etc).
*/
public static Executor getMainExecutor(Context context) {
if (Build.VERSION.SDK_INT >= 28) {
return context.getMainExecutor();
}
return new MainHandlerExecutor(new Handler(context.getMainLooper()));
}
private static class MainHandlerExecutor implements Executor {
private final Handler mHandler;
MainHandlerExecutor(@NonNull Handler handler) {
mHandler = handler;
}
@Override
public void execute(Runnable command) {
if (!mHandler.post(command)) {
throw new RejectedExecutionException(mHandler + " is shutting down");
}
}
}