我正在尝试开发一个应用程序来扫描 BLE 设备。但是，它只扫描一次。我尝试使用 while 循环来循环它，但它卡在那里。扫描部分在proceed函数:
package com.example.user.myfriend;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.os.Handler;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import org.w3c.dom.Text;
public class MainActivity extends ActionBarActivity {
BluetoothAdapter mBluetoothAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
hello();
}
public void hello() {
if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
Intent enableBluetooth = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBluetooth, 1);
}
proceed();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if (resultCode == RESULT_OK) {
proceed();
}
}
super.onActivityResult(requestCode, resultCode, data);
}
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
public void onLeScan(final BluetoothDevice device, final int rssi, final byte[] scanRecord) {
int startByte = 2;
boolean patternFound = false;
while (startByte <= 5) {
if (((int) scanRecord[startByte + 2] & 0xff) == 0x02 && //Identifies an iBeacon
((int) scanRecord[startByte + 3] & 0xff) == 0x15) { //Identifies correct data length
patternFound = true;
break;
}
startByte++;
}
if (patternFound) {
//Convert to hex String
byte[] uuidBytes = new byte[16];
System.arraycopy(scanRecord, startByte + 4, uuidBytes, 0, 16);
String hexString = bytesToHex(uuidBytes);
//Here is your UUID
String uuid = hexString.substring(0, 8) + "-" +
hexString.substring(8, 12) + "-" +
hexString.substring(12, 16) + "-" +
hexString.substring(16, 20) + "-" +
hexString.substring(20, 32);
//Here is your Major value
int major = (scanRecord[startByte + 20] & 0xff) * 0x100 + (scanRecord[startByte + 21] & 0xff);
//Here is your Minor value
int minor = (scanRecord[startByte + 22] & 0xff) * 0x100 + (scanRecord[startByte + 23] & 0xff);
if (major == 1) {
RelativeLayout hai = (RelativeLayout) findViewById(R.id.hai);
hai.setBackgroundColor(Color.YELLOW);
}
if (major == 2) {
RelativeLayout hai = (RelativeLayout) findViewById(R.id.hai);
hai.setBackgroundColor(Color.RED);
}
}
}
};
private static String bytesToHex(byte[] bytes) {
final char[] hexArray = "0123456789ABCDEF".toCharArray();
char[] hexChars = new char[bytes.length * 2];
for (int j = 0; j < bytes.length; j++) {
int v = bytes[j] & 0xFF;
hexChars[j * 2] = hexArray[v >>> 4];
hexChars[j * 2 + 1] = hexArray[v & 0x0F];
}
return new String(hexChars);
}
public void proceed() {
boolean scanning = true;
mBluetoothAdapter.startLeScan(mLeScanCallback);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
// @Override
public void run() {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
}
}, 50000000);
}
如何让应用循环扫描？
最佳答案
如果“通过循环扫描？”你的意思是检测附近所有的广播设备，你已经做到了。代码行:
mBluetoothAdapter.startLeScan(mLeScanCallback)
使扫描开始。在扫描期间，回调“mLeScanCallback”将在发现每个广播设备时被调用。扫描将一直有效，直到
mBluetoothAdapter.stopScan(mLeScanCallback)
被调用。在您的情况下，这将在很长一段时间后被调用:50000000 毫秒。
也许您在该区域只有 1 个广播设备，因此您在测试时只能收到 1 个回调。
关于android - 在android studio中扫描ble模块(蓝牙4.0)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30685802/