Android BLE NoClassDefFoundError

Question

我正在尝试在我的应用中使用BLE，但我坚持使用private ScanCallback mScanCallback = new ScanCallback() 。这是我收到此错误的函数：

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

    if (!bleCheck()) {
        Toast.makeText(getApplicationContext(), "BLE not Supported",
                Toast.LENGTH_SHORT).show();
        finish();
    }
    mHandler = new Handler();
    if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
        Toast.makeText(this, "BLE Not Supported",
                Toast.LENGTH_SHORT).show();
        finish();
    }
    BluetoothManager btManager = (BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);

    BluetoothAdapter btAdapter = btManager.getAdapter();
    if (btAdapter != null && !btAdapter.isEnabled()) {
        Intent enableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableIntent,REQUEST_ENABLE_BT);
    }

}

private boolean bleCheck() {
    boolean result = false;
    if (getPackageManager().
            hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)){
        result = true;
    }
    return result;
}

@Override
protected void onResume() {
    super.onResume();
    if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
        Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
    } else {
        if (Build.VERSION.SDK_INT >= 21) {
            mLEScanner = mBluetoothAdapter.getBluetoothLeScanner();
            settings = new ScanSettings.Builder()
                    .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                    .build();
            filters = new ArrayList<ScanFilter>();
        }
        scanLeDevice(true);
    }
}


@Override
protected void onPause() {
    super.onPause();
    if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
        scanLeDevice(false);
    }
}

@Override
protected void onDestroy() {
    if (mGatt == null) {
        return;
    }
    mGatt.close();
    mGatt = null;
    super.onDestroy();
}

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

private void scanLeDevice(final boolean enable) {
    if (enable) {
        mHandler.postDelayed(new Runnable() {
            @Override
            public void run() {
                if (Build.VERSION.SDK_INT < 21) {
                    mBluetoothAdapter.stopLeScan(mLeScanCallback);
                } else {
                    mLEScanner.stopScan(mScanCallback);

                }
            }
        }, SCAN_PERIOD);
        if (Build.VERSION.SDK_INT < 21) {
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        } else {
            mLEScanner.startScan(filters, settings, mScanCallback);
        }
    } else {
        if (Build.VERSION.SDK_INT < 21) {
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        } else {
            mLEScanner.stopScan(mScanCallback);
        }
    }
}


private ScanCallback mScanCallback = new ScanCallback() {
    @Override
    public void onScanResult(int callbackType, ScanResult result) {
        Log.i("callbackType", String.valueOf(callbackType));
        Log.i("result", result.toString());
        Toast.makeText(getApplicationContext(),result.toString(),Toast.LENGTH_SHORT).show();
        BluetoothDevice btDevice = result.getDevice();
        connectToDevice(btDevice);
    }

    @Override
    public void onBatchScanResults(List<ScanResult> results) {
        for (ScanResult sr : results) {
            Log.i("ScanResult - Results", sr.toString());
        }
    }

    @Override
    public void onScanFailed(int errorCode) {
        Log.e("Scan Failed", "Error Code: " + errorCode);
    }
};

private BluetoothAdapter.LeScanCallback mLeScanCallback =
        new BluetoothAdapter.LeScanCallback() {
            @Override
            public void onLeScan(final BluetoothDevice device, int rssi,
                                 byte[] scanRecord) {
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        Log.i("onLeScan", device.toString());
                        connectToDevice(device);
                    }
                });
            }
        };

public void connectToDevice(BluetoothDevice device) {
    if (mGatt == null) {
        mGatt = device.connectGatt(this, false, gattCallback);
        scanLeDevice(false);// will stop after first device detection
    }
}

private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
    @Override
    public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
        Log.i("onConnectionStateChange", "Status: " + status);
        switch (newState) {
            case BluetoothProfile.STATE_CONNECTED:
                Log.i("gattCallback", "STATE_CONNECTED");
                gatt.discoverServices();
                break;
            case BluetoothProfile.STATE_DISCONNECTED:
                Log.e("gattCallback", "STATE_DISCONNECTED");
                break;
            default:
                Log.e("gattCallback", "STATE_OTHER");
        }

    }

    @Override
    public void onServicesDiscovered(BluetoothGatt gatt, int status) {
        List<BluetoothGattService> services = gatt.getServices();
        Log.i("onServicesDiscovered", services.toString());
        gatt.readCharacteristic(services.get(1).getCharacteristics().get
                (0));
    }

    @Override
    public void onCharacteristicRead(BluetoothGatt gatt,
                                     BluetoothGattCharacteristic
                                             characteristic, int status) {
        Log.i("onCharacteristicRead", characteristic.toString());
        gatt.disconnect();
    }
};

请告诉我我在哪里做错了。

我的代码：

JMP SOMELABEL
. . . 
SOMELABEL:

}