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java - 十六进制数据不会在我的 BLE 扫描仪应用程序中打印

问题描述

我正在尝试使用 Android Studio (JAVA) 制作一个 BLE 扫描仪。我正在使用这里的模型代码：https ://github.com/joelwass/Android-BLE-Scan-Example

我已经编辑了代码以过滤我当前用作广播器的单个设备（CC2640R2 开发板）。

我希望能够打印从广播中接收到的十六进制数据流，以便我可以使用它来定义不同类型的开发板以及其他信息包。

根据我的研究，我研究了getBytes()函数，但仍未找到它的工作方式。

MainActivity.java

package com.example.joelwasserman.androidbletutorial;

import android.Manifest;
import android.app.AlertDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanRecord;
import android.bluetooth.le.ScanResult;
import android.content.Context;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.location.Location;
import android.location.LocationManager;
import android.os.AsyncTask;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.method.ScrollingMovementMethod;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.util.UUID;

public class MainActivity extends AppCompatActivity {

    BluetoothManager btManager;
    BluetoothAdapter btAdapter;
    BluetoothLeScanner btScanner;
    Button startScanningButton;
    Button stopScanningButton;
    TextView peripheralTextView;
    private final static int REQUEST_ENABLE_BT = 1;
    private static final int PERMISSION_REQUEST_COARSE_LOCATION = 1;

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

        peripheralTextView = (TextView) findViewById(R.id.PeripheralTextView);
        peripheralTextView.setMovementMethod(new ScrollingMovementMethod());

        startScanningButton = (Button) findViewById(R.id.StartScanButton);
        startScanningButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                startScanning();
            }
        });

        stopScanningButton = (Button) findViewById(R.id.StopScanButton);
        stopScanningButton.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                stopScanning();
            }
        });
        stopScanningButton.setVisibility(View.INVISIBLE);

        btManager = (BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);
        btAdapter = btManager.getAdapter();
        btScanner = btAdapter.getBluetoothLeScanner();


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

        // Make sure we have access coarse location enabled, if not, prompt the user to enable it
        if (this.checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            final AlertDialog.Builder builder = new AlertDialog.Builder(this);
            builder.setTitle("This app needs location access");
            builder.setMessage("Please grant location access so this app can detect peripherals.");
            builder.setPositiveButton(android.R.string.ok, null);
            builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
                @Override
                public void onDismiss(DialogInterface dialog) {
                    requestPermissions(new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, PERMISSION_REQUEST_COARSE_LOCATION);
                }
            });
            builder.show();
        }
    }

    // Device scan callback.
    private ScanCallback leScanCallback = new ScanCallback() {
        @Override
        public void onScanResult(int callbackType, ScanResult result) {


            if(new String("SimpleBLEBroadcaster").equals(result.getDevice().getName()))
                peripheralTextView.append("Device Name: " + result.getDevice().getName() + " rssi: " + result.getRssi() + "\n" + ScanRecord.getBytes() );
        }
    };

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_REQUEST_COARSE_LOCATION: {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    System.out.println("coarse location permission granted");
                } else {
                    final AlertDialog.Builder builder = new AlertDialog.Builder(this);
                    builder.setTitle("Functionality limited");
                    builder.setMessage("Since location access has not been granted, this app will not be able to discover beacons when in the background.");
                    builder.setPositiveButton(android.R.string.ok, null);
                    builder.setOnDismissListener(new DialogInterface.OnDismissListener() {

                        @Override
                        public void onDismiss(DialogInterface dialog) {
                        }

                    });
                    builder.show();
                }
                return;
            }
        }
    }

    public void startScanning() {
        System.out.println("start scanning");
        peripheralTextView.setText("");
        startScanningButton.setVisibility(View.INVISIBLE);
        stopScanningButton.setVisibility(View.VISIBLE);
        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                btScanner.startScan(leScanCallback);
            }
        });
    }

    public void stopScanning() {
        System.out.println("stopping scanning");
        peripheralTextView.append("Stopped Scanning");
        startScanningButton.setVisibility(View.VISIBLE);
        stopScanningButton.setVisibility(View.INVISIBLE);
        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                btScanner.stopScan(leScanCallback);
            }
        });
    }
}

我从中得到的错误是：Error:(97, 140) error: non-static method getBytes() cannot be referenced from a static context

任何有关如何正确打印十六进制流的帮助将不胜感激！

乔什

标签： javaandroid-studiohexbluetooth-lowenergy

解决方案

该方法getBytes()只能在 的实例上调用ScanRecord。您可以从ScanResult：

peripheralTextView.append("Device Name: " + result.getDevice().getName() + " rssi: " + result.getRssi() + "\n" + result.getScanRecord().getBytes() );

我不知道 aScanRecord代表什么，但至少你的代码是这样编译的。在这种情况下，您可能想将字节表示为字符串？

peripheralTextView.append("Device Name: " + result.getDevice().getName() + " rssi: " + result.getRssi() + "\n" + new String(result.getScanRecord().getBytes(), StandardCharsets.UTF_8) );

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