Android AOSP——android源码中扫描间隔和扫描窗口的定义

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窗口值？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

我在 http://androidxref.com/5.0.0_r2/xref/packages/apps/Bluetooth/src/com/android/bluetooth/gatt/ScanManager.java 中找到以下值在搜索关键字“SCAN_MODE_BALANCED”时:

    /**
     * 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;

另请查看 ScanManager.ScanNative.configureRegularScanParams()。根据扫描设置设置两个参数 scanWindow 和 scanInterval (ScanSettings.SCAN_MODE_LOW_POWER, ScanSettings.SCAN_MODE_BALANCED, ScanSettings.SCAN_MODE_LOW_LATENCY), 转换成BLE单位，然后传递给gattSetScanParametersNative()。

希望这对您有所帮助。