接收广播错误蓝牙发现

本文介绍了接收广播错误蓝牙发现 - 错误onRecieve（）方法，通过startDiscovery接收意图（）方法的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

您好我是新来的Andr​​oid编程，我面临着设备扫描活动的一个问题。我想扫描所有蓝牙设备在附近，并且打印出来的UI。但我得到相同的运行时错误在Receiving广播错误的蓝牙发现。请请请帮我调试我的code。

公共类MainActivity扩展ActionBarActivity {    BluetoothAdapter mBluetoothAdapter;    私人INT REQUEST_ENABLE_BT = 1000;    公众的ArrayList＆LT;串GT; deviceArrayList =新的ArrayList＆LT;＆GT;（）;    公众的ArrayList＆LT;＆BluetoothDevice类GT; DEVICELIST =新的ArrayList＆LT;＆GT;（）;    @覆盖    保护无效的onCreate（捆绑savedInstanceState）{        super.onCreate（savedInstanceState）;        的setContentView（R.layout.activity_main）;    }    @覆盖    保护无效onResume（）{        // TODO自动生成方法存根        super.onResume（）;        mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter（）;        如果（mBluetoothAdapter == NULL）{            //设备不支持蓝牙            Toast.makeText（这一点，设备不支持蓝牙!!!，Toast.LENGTH_LONG）.show（）;            返回;        }        如果（！mBluetoothAdapter.isEnabled（））{            意图enableBtIntent =新意图（BluetoothAdapter.ACTION_REQUEST_ENABLE）;            startActivityForResult（enableBtIntent，REQUEST_ENABLE_BT）;        }        scanStart（）;    }    公共无效scanStart（）{        // TODO自动生成方法存根        //添加配对设备到ArrayList中        addPairedDevices（）;        如果（mBluetoothAdapter.isDiscovering（））{            mBluetoothAdapter.cancelDiscovery（）;        }        如果（mBluetoothAdapter.startDiscovery（）==真）{            Toast.makeText（这一点，搜索...，Toast.LENGTH_LONG）.show（）;        }        其他{            Toast.makeText（这一点，蓝牙适配器了NULL值，Toast.LENGTH_SHORT）.show（）;        }        //注册的BroadcastReceiver        IntentFilter的过滤器=新的IntentFilter（BluetoothDevice.ACTION_FOUND）;        this.registerReceiver（requestReciever，过滤器）; //不要忘记的onDestroy期间注销        尝试{            视频下载（12000）;        }赶上（InterruptedException的E）{            // TODO自动生成catch块            e.printStackTrace（）;        }        在UI //打印设备列表        ListView控件LV =新的ListView（这一点）;        ArrayAdapter＆LT;串GT; listAdapter =新ArrayAdapter＆LT;＆GT;（这一点，R.layout.print_device_list，deviceArrayList）;        lv.setAdapter（listAdapter）;        的setContentView（LV）;        如果（deviceArrayList.size（）＆下; = 0）{            Toast.makeText（这一点，未找到设备...，Toast.LENGTH_LONG）.show（）;        }    }    公共无效addPairedDevices（）{        // TODO自动生成方法存根        //获取配对设备        SET＆LT;＆BluetoothDevice类GT; pairedDevices = mBluetoothAdapter.getBondedDevices（）;        //如果有配对设备        如果（pairedDevices.size（）大于0）{            //循环配对设备            对于（BluetoothDevice类设备：pairedDevices）{                //添加名称和地址到一个数组适配器在ListView显示                deviceArrayList.add（device.getName（）+\\ n+ device.getAddress（）+\\ n+ device.getUuids（）[0] .getUuid（））;                deviceList.add（设备）;            }        }    }    私人广播接收器requestReciever =新的广播接收器（）{        公共无效的onReceive（上下文的背景下，意图意图）{            如果（意向== NULL）{                返回;            }            字符串行动= intent.getAction（）;            如果（BluetoothDevice.ACTION_FOUND.equals（动作））{                Log.d（BT，设备中找到）;                BluetoothDevice类设备= intent.getParcelableExtra（BluetoothDevice.EXTRA_DEVICE）;                如果（设备！= NULL）{                    如果（device.getName（）=空＆放大器;！＆放大器; device.getName（）长度（）大于0）{                        deviceArrayList.add（device.getName（）+\\ n+ device.getAddress（）+\\ n+ device.getUuids（）[0] .getUuid（））;                        deviceList.add（设备）;                    }                }            }        };    };    @覆盖    保护无效的onActivityResult（INT申请code，INT结果code，意图数据）{        // TODO自动生成方法存根        super.onActivityResult（要求code，结果code，数据）;        如果（要求code == REQUEST_ENABLE_BT）{            如果（结果code == Activity.RESULT_CANCELED）{                Toast.makeText（这一点，UESR想不打开蓝牙!!!，Toast.LENGTH_LONG）.show（）;                返回;            }        }    }    @覆盖    保护无效的onDestroy（）{        // TODO自动生成方法存根        super.onDestroy（）;        如果（mBluetoothAdapter！= NULL）{            mBluetoothAdapter.cancelDiscovery（）;        }        如果（requestReciever！= NULL）            unregisterReceiver（requestReciever）;        Toast.makeText（这一点，蓝牙应用程序已停止，Toast.LENGTH_LONG）.show（）;    }}

解决方案

device.getUuids（） - 在这里你有一个空，这就是为什么你在这里有一个错误。检查这个变量beforе使用它。

Hi I am new to android programming and i am facing a problem in device scan activity. I want to scan all bluetooth devices in vicinity and print them on UI. But i am getting the same run time error as in Receiving broadcast error for Bluetooth discovery. Please, please please help me to debug my code.

public class MainActivity extends ActionBarActivity { BluetoothAdapter mBluetoothAdapter; private int REQUEST_ENABLE_BT = 1000; public ArrayList<String> deviceArrayList = new ArrayList<>(); public ArrayList<BluetoothDevice> deviceList = new ArrayList<>(); @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); if (mBluetoothAdapter == null) { // Device does not support Bluetooth Toast.makeText(this, "Device Doesn't Support Bluetooth!!!", Toast.LENGTH_LONG).show(); return; } if (!mBluetoothAdapter.isEnabled()) { Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT ); } scanStart(); } public void scanStart() { // TODO Auto-generated method stub //Adding Paired Devices into ArrayList addPairedDevices(); if(mBluetoothAdapter.isDiscovering()){ mBluetoothAdapter.cancelDiscovery(); } if(mBluetoothAdapter.startDiscovery() == true){ Toast.makeText(this, "Searching...", Toast.LENGTH_LONG).show(); } else{ Toast.makeText(this, "Bluetooth Adapter got Null Value", Toast.LENGTH_SHORT).show(); } // Register the BroadcastReceiver IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); this.registerReceiver(requestReciever, filter); // Don't forget to unregister during onDestroy try { Thread.sleep(12000); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } //Printing Device List on UI ListView lv = new ListView(this); ArrayAdapter<String> listAdapter = new ArrayAdapter<>(this, R.layout.print_device_list, deviceArrayList); lv.setAdapter(listAdapter); setContentView(lv); if(deviceArrayList.size()<=0){ Toast.makeText(this, "No Devices Found...", Toast.LENGTH_LONG).show(); } } public void addPairedDevices() { // TODO Auto-generated method stub // get paired devices Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices(); // If there are paired devices if (pairedDevices.size() > 0) { // Loop through paired devices for (BluetoothDevice device : pairedDevices) { // Add the name and address to an array adapter to show in a ListView deviceArrayList.add(device.getName() + "\n" + device.getAddress() + "\n" + device.getUuids()[0].getUuid()); deviceList.add(device); } } } private BroadcastReceiver requestReciever = new BroadcastReceiver(){ public void onReceive(Context context, Intent intent) { if (intent == null) { return; } String action = intent.getAction(); if(BluetoothDevice.ACTION_FOUND.equals(action)){ Log.d("BT", "Device Found"); BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); if(device!=null){ if(device.getName() != null && device.getName().length() > 0){ deviceArrayList.add(device.getName()+"\n"+device.getAddress()+"\n"+device.getUuids()[0].getUuid()); deviceList.add(device); } } } }; }; @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { // TODO Auto-generated method stub super.onActivityResult(requestCode, resultCode, data); if(requestCode == REQUEST_ENABLE_BT){ if(resultCode == Activity.RESULT_CANCELED){ Toast.makeText(this, "Uesr Doesn't want to switch on Bluetooth!!!", Toast.LENGTH_LONG).show(); return; } } } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); if(mBluetoothAdapter != null){ mBluetoothAdapter.cancelDiscovery(); } if(requestReciever!=null) unregisterReceiver(requestReciever); Toast.makeText(this, "Bluetooth App Stopped", Toast.LENGTH_LONG).show(); } }

解决方案

device.getUuids() - here you have a Null, that is why you have an error here. Check this variable beforе using it.