问题描述
我正在尝试使用 Android Studio (JAVA) 制作 BLE 扫描仪。我正在使用这里的模型代码：https://github.com/joelwass/Android-BLE-Scan-Example
我已编辑代码以筛选我目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，我已经研究了 getBytes() 函数，但仍然没有找到它的工作方式。
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：错误：(97,140) 错误：不能从静态上下文中引用非静态方法 getBytes()>
任何有关如何正确打印十六进制流的帮助将不胜感激！
乔希
解决方法
方法 getBytes() 只能在 ScanRecord 的实例上调用。您可以从 ScanResult:
peripheralTextView.append("Device Name: " + result.getDevice().getName() + " rssi: " + result.getRssi() + "\n" + result.getScanRecord().getBytes() );
我不知道 ScanRecord 代表什么，但至少您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) );
所以我设法使用此处找到的 https://stackoverflow.com/users/344480/matthias 答案解决了这个问题：