如何在android中更改蓝牙适配器的扫描模式？

Question

目前我正在开发蓝牙应用程序，我需要将扫描模式从SCAN_MODE_CONNECTABLE_DISCOVERABLE更改为SCAN_MODE_CONNECTABLE，只需点击一个按钮即可。

我设置可被发现使用以下意图：

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

---

在那里我已经设置DISOVERABLE_DURATION=300;

现在我想跳过它们之间的可发现性，并且只想将其状态更改为SCAN_MODE_CONNECTABLE。

请给我提供一个合适的解决方案../

Answer 1

开始与SCAN_MODE_NONE新意图停止扫描，然后用SCAN_MODE_CONNECTABLE再次开始只在连接模式再次扫描。

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），并选择使用EXTRA_DISCOVERABLE_DURATION来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。

证据，采取一目了然通过Android Source，重点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; 
} 

在源指出，“应用程序不能设置扫描模式”。手动扫描API which is not possible for third-party applications以外的模式需要权限WRITE_SECURE_SETTINGS。

Answer 3

那么这是一个很老的问题，但是你可以切换蓝牙扫描模式，没有任何用户的许可和（就我测试过的）无限的时间。 这将需要在Android API上使用反射，所以这不是官方的API。当然，你使用它在你自己的风险:) 下面是代码我使用，使BT适配器发现：

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; 
} 

而且你需要权限：

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

后该设备应在扫描模式下，通过传递int scanMode参数来选择。它正在开发Android API 23.