Android AOSP - android源代码中扫描间隔和扫描window的定义

Question

我已经下载了 Lollipop 5.0 的 AOSP 源代码。在 api 级别 21 中，在蓝牙低功耗扫描设置下，有三个用于扫描蓝牙设备的选项 - SCAN_MODE_BALANCED, SCAN_MODE_LOW_LATENCY, SCAN_MODE_LOW_POWER。是否基于不同的扫描间隔和扫描 window 值？如果是这样，我在哪里可以找到源代码目录中为这些宏定义的值。

Answer 1

我不确定这是否准确，或者您是否可以使用它来找到您需要的值，但我发现了一些 code from Google regarding scanning settings:

  // Constants for Scan Cycle
  // Low Power: 2.5 minute period with 1.5 seconds active (1% duty cycle)
  /* @VisibleForTesting */ static final int LOW_POWER_IDLE_MILLIS = 148500;
  /* @VisibleForTesting */ static final int LOW_POWER_ACTIVE_MILLIS = 1500;

  // Balanced: 15 second period with 1.5 second active (10% duty cycle)
  /* @VisibleForTesting */ static final int BALANCED_IDLE_MILLIS = 13500;
  /* @VisibleForTesting */ static final int BALANCED_ACTIVE_MILLIS = 1500;

  // Low Latency: 1.67 second period with 1.5 seconds active (90% duty cycle)
  /* @VisibleForTesting */ static final int LOW_LATENCY_IDLE_MILLIS = 167;
  /* @VisibleForTesting */ static final int LOW_LATENCY_ACTIVE_MILLIS = 1500;

Answer 2

我在搜索关键字 "SCAN_MODE_BALANCED" 时在 http://androidxref.com/5.0.0_r2/xref/packages/apps/Bluetooth/src/com/android/bluetooth/gatt/ScanManager.java 中发现以下值：

    /**
     * Scan params corresponding to regular scan setting
     */
    private static final int SCAN_MODE_LOW_POWER_WINDOW_MS = 500;
    private static final int SCAN_MODE_LOW_POWER_INTERVAL_MS = 5000;
    private static final int SCAN_MODE_BALANCED_WINDOW_MS = 2000;
    private static final int SCAN_MODE_BALANCED_INTERVAL_MS = 5000;
    private static final int SCAN_MODE_LOW_LATENCY_WINDOW_MS = 5000;
    private static final int SCAN_MODE_LOW_LATENCY_INTERVAL_MS = 5000;

    /**
     * Scan params corresponding to batch scan setting
     */
    private static final int SCAN_MODE_BATCH_LOW_POWER_WINDOW_MS = 1500;
    private static final int SCAN_MODE_BATCH_LOW_POWER_INTERVAL_MS = 150000;
    private static final int SCAN_MODE_BATCH_BALANCED_WINDOW_MS = 1500;
    private static final int SCAN_MODE_BATCH_BALANCED_INTERVAL_MS = 15000;
    private static final int SCAN_MODE_BATCH_LOW_LATENCY_WINDOW_MS = 1500;
    private static final int SCAN_MODE_BATCH_LOW_LATENCY_INTERVAL_MS = 5000;

也可以查看 ScanManager.ScanNative.configureRegularScanParams()。根据扫描设置（ScanSettings.SCAN_MODE_LOW_POWER、ScanSettings.SCAN_MODE_BALANCED、ScanSettings.SCAN_MODE_LOW_LATENCY）设置两个参数scanWindow和scanInterval，转换成BLE单元，然后传递给gattSetScanParametersNative ().

希望对您有所帮助。

Android AOSP - android源代码中扫描间隔和扫描window的定义

Android AOSP - Definition of scan interval and scan window in android source code

android

bluetooth-lowenergy

android-source