Question

我正在编写一个应用程序来打开蓝牙，扫描附近的蓝牙可发现设备，包括已配对但未配对，以便将它们添加到列表中。

这是我的代码：

public class Main extends Activity {

    private BluetoothAdapter ba;
    private Set<BluetoothDevice>pairedDevices;

    private ListView lv;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        lv = (ListView)findViewById(R.id.bluetooth_device_listview);

        initiate();
    }

    public void initiate() {

        ba = BluetoothAdapter.getDefaultAdapter();

        if (ba == null) {

            // Device does not support Bluetooth
            AlertDialog.Builder localBuilder = new AlertDialog.Builder(this);

            localBuilder.setTitle("No Bluetooth Support");
            localBuilder.setMessage("Device does not support Bluetooth feature.\nThis"
                    + "will quit the application.");
            localBuilder.setCancelable(false);

            localBuilder.setPositiveButton("OK", new DialogInterface.OnClickListener()
            {
              public void onClick(DialogInterface paramAnonymousDialogInterface, int     paramAnonymousInt)
              { 
                Main.this.finish();
              }
            });

            localBuilder.create().show();
        }
    }

    public void turnOn(View view) {

        if (!ba.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, 0);

            if(ba.isEnabled())
                Toast.makeText(getApplicationContext(), "Turned On", 
                        Toast.LENGTH_SHORT).show();

            scan();

        } else
            Toast.makeText(getApplicationContext(), "Already On", 
                    Toast.LENGTH_LONG).show();
    }

    public void scan() {        

        final ArrayList<String> deviceList = new ArrayList<String>();

        if (ba.isDiscovering()) ba.cancelDiscovery();

        ba.startDiscovery();

        // Get a list of paired devices

        pairedDevices = ba.getBondedDevices();

        for(BluetoothDevice bt : pairedDevices)
            deviceList.add(bt.getName() + "\n" + bt.getAddress() + "\n" + "Paired");

        /*********************************************************************/

        // Scan for other devices

        final BroadcastReceiver receiver = new BroadcastReceiver() {

            public void onReceive(Context context, Intent intent) {

                String action = intent.getAction();

                if (BluetoothDevice.ACTION_FOUND.equals(action)) {

                    BluetoothDevice device =     intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

                    deviceList.add(device.getName() + "\n" + device.getAddress()
                            + "\n" + "Not Paired");
                }
            }
        };

        final ArrayAdapter<String> adapter = new ArrayAdapter<String>
        (this, android.R.layout.simple_list_item_1, deviceList);

        lv.setAdapter(adapter);

        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        registerReceiver(receiver, filter);
    }
}

代码看起来很好，但它没有找到或添加任何附近的设备列表，当我退出应用程序时，我得到以下异常日志：

12-12 12:53:59.818: E/ActivityThread(5097): Activity net.adeveloper.testdeviate.Main has leaked IntentReceiver net.adeveloper.testdeviate.Main$2@4055c128 that was originally registered here. Are you missing a call to unregisterReceiver()?
12-12 12:53:59.818: E/ActivityThread(5097): android.app.IntentReceiverLeaked: Activity net.adeveloper.testdeviate.Main has leaked IntentReceiver net.adeveloper.testdeviate.Main$2@4055c128 that was originally registered here. Are you missing a call to unregisterReceiver()?
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.LoadedApk$ReceiverDispatcher.<init>(LoadedApk.java:799)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.LoadedApk.getReceiverDispatcher(LoadedApk.java:575)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.ContextImpl.registerReceiverInternal(ContextImpl.java:865)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:852)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.ContextImpl.registerReceiver(ContextImpl.java:846)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.content.ContextWrapper.registerReceiver(ContextWrapper.java:318)
12-12 12:53:59.818: E/ActivityThread(5097):     at net.adeveloper.testdeviate.Main.scan(Main.java:132)
12-12 12:53:59.818: E/ActivityThread(5097):     at net.adeveloper.testdeviate.Main.turnOn(Main.java:83)
12-12 12:53:59.818: E/ActivityThread(5097):     at java.lang.reflect.Method.invokeNative(Native Method)
12-12 12:53:59.818: E/ActivityThread(5097):     at java.lang.reflect.Method.invoke(Method.java:507)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.view.View$1.onClick(View.java:2187)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.view.View.performClick(View.java:2533)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.view.View$PerformClick.run(View.java:9320)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.os.Handler.handleCallback(Handler.java:587)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.os.Handler.dispatchMessage(Handler.java:92)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.os.Looper.loop(Looper.java:150)
12-12 12:53:59.818: E/ActivityThread(5097):     at android.app.ActivityThread.main(ActivityThread.java:4385)
12-12 12:53:59.818: E/ActivityThread(5097):     at java.lang.reflect.Method.invokeNative(Native Method)
12-12 12:53:59.818: E/ActivityThread(5097):     at java.lang.reflect.Method.invoke(Method.java:507)
12-12 12:53:59.818: E/ActivityThread(5097):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
12-12 12:53:59.818: E/ActivityThread(5097):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
12-12 12:53:59.818: E/ActivityThread(5097):     at dalvik.system.NativeStart.main(Native Method)

有什么想法解决问题吗？

要将配对设备添加到列表视图，我必须添加一个按钮并将其与scan（）方法相关联。这令人沮丧，我想在点击“开启”按钮时填充列表。此外，找不到配对设备仍然存在。

Answer 1

根据下面的答案，你应该覆盖BroadcastReceiver中的onStop方法并调用unregisterReceiver（）来摆脱那些logcat错误。

https://stackoverflow.com/a/14357640/3250699

但是，我认为这不会解决发现问题。为了确保开始发现，您可以尝试检查ba.startDiscovery（）上的返回吗？根据Android Docs，方法...＆＃34; [startDiscovery（）]成功时返回true，错误时返回false＆＃34;。

文档还提到＆＃34;需要BLUETOOTH_ADMIN。＆＃34;所以请确保在AndroidManifest.xml中设置此权限

Android SDK文档： http://developer.android.com/reference/android/bluetooth/BluetoothAdapter.html#startDiscovery()

Answer 2

您忘记取消注册BroadcastReceiver。这里有一些建议：

1.您可以在onCreate（）中注册BroadcastReceiver，并在onDestroy（）中取消注册BroadcastReceiver。

2.尝试注册BroadcastReceiver后开始发现蓝牙设备。

3.请注意，BroadcastRecevier会返回相同的BluetoothDevice，这与蓝牙发现的机制有关。通常你需要按mac地址过滤。

我很困惑你的意思是什么：当我点击＆＃34;打开＆＃34;我想填写列表。按钮。此外，找不到配对设备仍然存在。？

当你点击＆＃34;打开＆＃34;按钮，你只需做一件事，你检查蓝牙是否打开。然后使用startActivityForResult弹出系统窗口，提醒用户需要打开蓝牙，然后发现在线蓝牙设备并获取配对设备。你不会修改配对的蓝牙设备列表，也许你会发现更多或更少的不成对的蓝牙设备。

Answer 3

对于最新的Android版本，您还需要添加 <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 到AndroidManifest.xml。

请参见this reference

Answer 4

我也遇到过这个问题。但问题不在代码中，这是因为我没有向应用程序授予位置权限。授予权限后，它会显示附近所有可用的设备

找不到蓝牙设备

4 个答案: