Question

目前我正在使用蓝牙应用，我需要点击按钮将扫描模式从SCAN_MODE_CONNECTABLE_DISCOVERABLE更改为SCAN_MODE_CONNECTABLE。

我使用以下意图将其设置为可发现：

Intent discoverableIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE); discoverableIntent .putExtra( BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, DISOVERABLE_DURATION);
startActivityForResult(discoverableIntent, REQUEST_DISCOVERABLE_BT);

我已设置DISOVERABLE_DURATION=300;

现在我想跳过其中的Discoverability，并希望仅将其状态更改为SCAN_MODE_CONNECTABLE。

请给我一个合适的解决方案../

Answer 1

使用SCAN_MODE_NONE启动新意图以停止扫描，然后再次使用SCAN_MODE_CONNECTABLE以可连接模式再次扫描。

Answer 2

您无法使用第三方（非内核/非系统）应用程序在4.2及更高版本中设置Android设备的扫描模式。您只能启用发现（SCAN_MODE_CONNECTABLE_DISCOVERABLE），并可选择使用EXTRA_DISCOVERABLE_DURATION设置特定的持续时间。您可以通过设置duration parameter to 1来有效取消发现。

有关证据，请浏览Android Source，重点关注 BluetoothAdapter.java ：

/**
 * Set the Bluetooth scan mode of the local Bluetooth adapter.
 * <p>The Bluetooth scan mode determines if the local adapter is
 * connectable and/or discoverable from remote Bluetooth devices.
 * <p>For privacy reasons, discoverable mode is automatically turned off
 * after <code>duration</code> seconds. For example, 120 seconds should be
 * enough for a remote device to initiate and complete its discovery
 * process.
 * <p>Valid scan mode values are:
 * {@link #SCAN_MODE_NONE},
 * {@link #SCAN_MODE_CONNECTABLE},
 * {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE}.
 * <p>If Bluetooth state is not {@link #STATE_ON}, this API
 * will return false. After turning on Bluetooth,
 * wait for {@link #ACTION_STATE_CHANGED} with {@link #STATE_ON}
 * to get the updated value.
 * <p>Requires {@link android.Manifest.permission#WRITE_SECURE_SETTINGS}
 * <p>Applications cannot set the scan mode. They should use
 * <code>startActivityForResult(
 * BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE})
 * </code>instead.
 *
 * @param mode valid scan mode
 * @param duration time in seconds to apply scan mode, only used for
 *                 {@link #SCAN_MODE_CONNECTABLE_DISCOVERABLE}
 * @return     true if the scan mode was set, false otherwise
 * @hide
 */
public boolean setScanMode(int mode, int duration) {
    if (getState() != STATE_ON) return false;
    try {
        synchronized(mManagerCallback) {
            if (mService != null) return mService.setScanMode(mode, duration);
        }
    } catch (RemoteException e) {Log.e(TAG, "", e);}
    return false;
}

如源中所述，＆＃34;应用程序无法设置扫描模式＆＃34;。需要权限WRITE_SECURE_SETTINGS才能在API外部手动扫描模式which is not possible for third-party applications。

Answer 3

这是一个很老的问题，但是你可以在没有用户许可的情况下切换蓝牙的扫描模式，并且（对于我已经测试过的）无限时间。这需要在Android API上使用反射，因此这不是官方API。当然，你自己冒险使用它:) 下面是我用来使BT适配器可被发现的代码：

private boolean setBluetoothScanMode(int scanMode){
    Method method = null;
    final BluetoothAdapter btAdapter = btManager.getAdapter();

    if(!btAdapter.isEnabled()){
        Log.d(LCAT, "BT adapter is off, turning on");
        btAdapter.enable();
    }

    try {
        method = btAdapter.getClass().getMethod("setScanMode", int.class);
    } catch (SecurityException e) {
        return false;
    } catch (NoSuchMethodException e) {
        return false;
    }

    try {
      method.invoke(btAdapter, scanMode);
    } catch (IllegalArgumentException e) {
        return false;
    } catch (IllegalAccessException e) {
        return false;
    } catch (InvocationTargetException e) {
        return false;
    }
    return true;
}

您还需要权限：

<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<uses-permission android:name="android.permission.WRITE_SETTINGS" />

此设备应处于扫描模式后，您可以通过传递int scanMode参数来选择。它正在使用Android API 23.

如何在android中更改蓝牙适配器的扫描模式？

3 个答案: