Question

我试图在该区域内阅读可用的信标。在API级别21下我使用BluetoothAdapter.LeScanCallback而在21级以上我使用ScanCallback

当我在Kitkat上运行我的应用程序时，它是scaned beacon。但是当我在Lollipop上运行我的应用程序时，它已经强制关闭并显示此错误

java.lang.NoClassDefFoundError: test.abc.com.mybeacon.Beacon$2

'Beacon'是我的活动类

这是我的代码：

    private BluetoothLeScanner mBluetoothLeScanner;
    private ScanCallback mScanCallback;
    protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_beacon);

        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
                //JellyBean/Kitkat
               mBluetoothAdapter.startLeScan(mLeScanCallback);
            } else {
                //lollipop+
                mScanCallback = new ScanCallback() {
                @Override
                public void onScanResult(int callbackType, ScanResult   result) {


                 processResult(result);
                    }
              };
               startScan();
            }

     }

     private void startScan() {
            mBluetoothLeScanner.startScan(mScanCallback);
        }

     private void stopScan() {
           mBluetoothLeScanner.stopScan(mScanCallback);
        }
        private void processResult(ScanResult result) {

            Log.d("res"," "+result.getDevice().getName().toString());
        }
}

Answer 1

您尝试使用Kitkat及更低版本在设备上实例化ScanCallback，但他们并不知道ScanCallback类，因为它已添加到Lollipop中。我建议在onCreate方法中实例化ScanCallback，在那里你可以检查设备是否正在运行Lollipop或更新。

编辑：只是为了澄清，这确实会失败并出现相同的错误，或者您是否会收到其他错误？

    private BluetoothLeScanner mBluetoothLeScanner;
    private ScanCallback mScanCallback;

    protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_beacon);

            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
                //JellyBean/Kitkat
               mBluetoothAdapter.startLeScan(mLeScanCallback);
            } else {
                //lollipop+
                mScanCallback = new ScanCallback() {
                    @Override
                    public void onScanResult(int callbackType, ScanResult result) {
                        processResult(result);
                    }
               };
               startScan();
            }

     }

     private void startScan() {
            mBluetoothLeScanner.startScan(mScanCallback);
     }

     private void processResult(ScanResult result) {
            Log.d("res"," "+result.getDevice().getName().toString());
     }
}

应用程序在读取ScannCallback时关闭

1 个答案: