NoSuchMethod异常

Question

我使用的是BLE startLescan，但现在它已经过时了。现在，我已经更改了我的API level to 23 (from 20)，并为此使用了BluetoothLeScanner。我的开始扫描功能是：

public void startScan(){
    mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();

     mBluetoothLeScanner.startScan(new ScanCallback() {
            @Override
            public void onScanResult(int callbackType, ScanResult result) {
                super.onScanResult(callbackType, result);

                String s = "\nRssi : "+result.getRssi()+"" +
                        "\nName (Get Device) : "+result.getDevice().getName()+"" +
                        "\nBytes"+result.getScanRecord().getBytes()+"" +
                        "\nGet Device : " + result.getDevice()+"" +
                        "\nAddress : "+result.getDevice().getAddress()+"" +
                        "\nService UUIds : "+result.getScanRecord().getServiceUuids().get(0)+"" +       //Unique
                        "\nName (Scan Record) : "+result.getScanRecord().getDeviceName()+"" +
                        "\nUuids device : "+result.getDevice().getUuids()+"" +
                        "\nDescribe contents : "+result.describeContents();

                //This will show you all the data in logs.
                Log.e("All Data",s);



            }

            @Override
            public void onBatchScanResults(List<ScanResult> results) {
                super.onBatchScanResults(results);
            }

            @Override
            public void onScanFailed(int errorCode) {
                super.onScanFailed(errorCode);
            }
        });

当我到达第一行时，

java抛出一个nosuchmethod异常： 方法查找失败的选择器"getBluetoothLeScanner“与签名”()Landroid/蓝牙/le/蓝牙刷扫描仪；

Answer 1

如果您的设备有API版本20或更低，它将无法使用新的API。因此，您需要实现两种扫描方法，并根据设备os版本检查应该使用哪个版本。(Kitkat不支持新的扫描API!)

Answer 2

在这种情况下，需要一个BluetoothAdapter实例。做这样的事：

Context mContext = getBaseContext();
BluetoothAdapter mBluetoothAdapter = (BluetoothManager) mContext.getSystemService(Context.BLUETOOTH_SERVICE).getAdapter();
BluetoothLeScanner mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();

mBluetoothLeScanner.startScan(new ScanCallback() {….

}