有例外

Question

我指的是開發者文檔失敗藍牙低功耗設備掃描來掃描BLE裝置 -

http://developer.android.com/guide/topics/connectivity/bluetooth-le.html

在我的活動類LookUpActivity，我叫一個方法findBLE()上的按鈕，點進

//This will scan BLE devices 
public void findBLE() 
{ 
    Intent intent = new Intent(LookUpActivity.this, DeviceScanActivity.class); 
    startActivity(intent); 
} 

但有以下異常 -

Could not find class 'com.testapp.main.DeviceScanActivity$1', 
referenced from method com.testapp.main.DeviceScanActivity.<init> 


com.testapp.main fatal error : com.testapp.main.DeviceScanActivity$1 
java.lang.NoClassDefFoundError: com.testapp.main.DeviceScanActivity$1 
at com.testapp.main.DeviceScanActivity.<init>(DeviceScanActivity.java:179) 

DeviceScanActivity.java ---

/** 
* Activity for scanning and displaying available Bluetooth LE devices. 
*/ 
@SuppressLint("NewApi") 
public class DeviceScanActivity extends ListActivity { 
    private LeDeviceListAdapter mLeDeviceListAdapter; 
    private BluetoothAdapter mBluetoothAdapter; 
    private boolean mScanning; 
    private Handler mHandler; 

    private static final int REQUEST_ENABLE_BT = 1; 
    // Stops scanning after 10 seconds. 
    private static final long SCAN_PERIOD = 10000; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     mHandler = new Handler(); 
    } 

    @Override 
    protected void onResume() { 
     super.onResume(); 

     // Ensures Bluetooth is enabled on the device. If Bluetooth is not currently enabled, 
     // fire an intent to display a dialog asking the user to grant permission to enable it. 
     if (!mBluetoothAdapter.isEnabled()) { 
      if (!mBluetoothAdapter.isEnabled()) { 
       Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE); 
       startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT); 
      } 
     } 

     // Initializes list view adapter. 
     mLeDeviceListAdapter = new LeDeviceListAdapter(); 
     setListAdapter(mLeDeviceListAdapter); 
     scanLeDevice(true); 
    } 

    @Override 
    protected void onActivityResult(int requestCode, int resultCode, Intent data) { 
     // User chose not to enable Bluetooth. 
     if (requestCode == REQUEST_ENABLE_BT && resultCode == Activity.RESULT_CANCELED) { 
      finish(); 
      return; 
     } 
     super.onActivityResult(requestCode, resultCode, data); 
    } 

    @Override 
    protected void onPause() { 
     super.onPause(); 
     scanLeDevice(false); 
     mLeDeviceListAdapter.clear(); 
    } 

    private void scanLeDevice(final boolean enable) { 
     if (enable) { 
      // Stops scanning after a pre-defined scan period. 
      mHandler.postDelayed(new Runnable() { 
       @Override 
       public void run() { 
        mScanning = false; 
        mBluetoothAdapter.stopLeScan(mLeScanCallback); 
       } 
      }, SCAN_PERIOD); 

      mScanning = true; 
      mBluetoothAdapter.startLeScan(mLeScanCallback); 
     } else { 
      mScanning = false; 
      mBluetoothAdapter.stopLeScan(mLeScanCallback); 
     } 
    } 

    // Adapter for holding devices found through scanning. 
    private class LeDeviceListAdapter extends BaseAdapter { 
     private ArrayList<BluetoothDevice> mLeDevices; 
     private LayoutInflater mInflator; 

     public LeDeviceListAdapter() { 
      super(); 
      mLeDevices = new ArrayList<BluetoothDevice>(); 
      mInflator = DeviceScanActivity.this.getLayoutInflater(); 
     } 

     public void addDevice(BluetoothDevice device) { 
      if(!mLeDevices.contains(device)) { 
       mLeDevices.add(device); 
      } 
     } 

     public BluetoothDevice getDevice(int position) { 
      return mLeDevices.get(position); 
     } 

     public void clear() { 
      mLeDevices.clear(); 
     } 

     @Override 
     public int getCount() { 
      return mLeDevices.size(); 
     } 

     @Override 
     public Object getItem(int i) { 
      return mLeDevices.get(i); 
     } 

     @Override 
     public long getItemId(int i) { 
      return i; 
     } 

     @Override 
     public View getView(int i, View view, ViewGroup viewGroup) { 
      ViewHolder viewHolder; 
      // General ListView optimization code. 
      if (view == null) { 
       view = mInflator.inflate(R.layout.mapentries, null); 
       viewHolder = new ViewHolder(); 
       viewHolder.deviceAddress = (TextView) view.findViewById(R.id.entriestitle); 
       //viewHolder.deviceName = (TextView) view.findViewById(R.id.device_name); 
       view.setTag(viewHolder); 
      } else { 
       viewHolder = (ViewHolder) view.getTag(); 
      } 

      BluetoothDevice device = mLeDevices.get(i); 
      final String deviceName = device.getName(); 
      /* if (deviceName != null && deviceName.length() > 0) 
       viewHolder.deviceName.setText(deviceName); 
      else 
       viewHolder.deviceName.setText(R.string.unknown_device);*/ 

      viewHolder.deviceAddress.setText(device.getAddress()); 

      return view; 
     } 
    } 

    // Device scan callback. 
    private BluetoothAdapter.LeScanCallback mLeScanCallback = 
      new BluetoothAdapter.LeScanCallback() { //This is line 179 causing error... 

     @Override 
     public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) { 
      runOnUiThread(new Runnable() { 
       @Override 
       public void run() { 
        mLeDeviceListAdapter.addDevice(device); 
        mLeDeviceListAdapter.notifyDataSetChanged(); 
       } 
      }); 
     } 
    }; 

    static class ViewHolder { 
     //TextView deviceName; 
     TextView deviceAddress; 
    } 
} 

UPDATE：

爲了更具體，我下載了從BLE確切的項目代碼---

http://developer.android.com/samples/BluetoothLeGatt/project.html

再次得到了相同即使使用項目中提到的代碼也是例外。

這一次的錯誤console--

FATAL EXCEPTION: main 
java.lang.NoClassDefFoundError: 
com.example.android.bluetoothlegatt 
.DeviceScanActivity$1 
at com.example.android.bluetoothlegatt.DeviceScanActivity. 
<init> (DeviceScanActivity.java:250) 

Answer 1

您必須執行完整的檢查，以查看該設備是否支持藍牙低功耗（BLE）。該設備可能運行Android 4.3或更高版本，但缺乏BLE所需的硬件。 Nexus 7（2012）就是這種設備的一個例子。代碼如下：

private boolean bleCheck() { 
    boolean result = false; 
    if (getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) { 
     mBluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE); 
     if (mBluetoothManager != null) { 
     mBluetoothAdapter = mBluetoothManager.getAdapter(); 
     if (mBluetoothAdapter != null) { 
      if (mBluetoothAdapter.isEnabled()) { 
      result = true; 
      } 
     } 
     } 
    } 
    return result; 
    }