我有 2 部 Android 5.0.2 的手机，它们都安装了最新的 Radius Beacon 的应用程序：Locate Beacon，同时，我打开了 2 个 IBeacon 发送器，并且可以看到两部手机的 RSSI不断变化。
但是当我尝试编写一些示例代码来模拟上述情况时，我发现 ble scan 回调总是在调用 2 或 3 次后停止被调用，我最初怀疑 'Locate Beacon' 可能使用不同的方式，所以我尝试了 2 种API，一个是旧的4.4，另一个是android 5中引入的新方式，但两者的行为相同（但都在android 5上运行）。
4.4 一：
public class MainActivity extends Activity {
private BluetoothAdapter mBluetoothAdapter;
private static final String LOG_TAG = "BleCollector";
private TextView calledTimesTextView = null;
private int calledTimes = 0;
// Device scan callback.
private BluetoothAdapter.LeScanCallback mLeScanCallback = new BluetoothAdapter.LeScanCallback() {
@Override
public void onLeScan(final BluetoothDevice device, int rssi,
byte[] scanRecord) {
calledTimes++;
runOnUiThread(new Runnable() {
@Override
public void run() {
calledTimesTextView.setText(Integer.toString(calledTimes));
}
});
Log.e(LOG_TAG, "in onScanResult, " + " is coming...");
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
calledTimesTextView = (TextView) findViewById(R.id.CalledTimes);
mBluetoothAdapter = ((BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE))
.getAdapter();
mBluetoothAdapter.startLeScan(mLeScanCallback);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}}
和 5.0.2：
public class MainActivity extends Activity {
private BluetoothAdapter mBluetoothAdapter = null;
private BluetoothLeScanner mLescanner;
private ScanCallback mLeScanCallback;
private static final String LOG_TAG = "BleFingerprintCollector";
private TextView calledTimesTextView = null;
private int calledTimes = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
calledTimesTextView = (TextView) findViewById(R.id.CalledTimes);
this.mBluetoothAdapter = ((BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE))
.getAdapter();
this.mLescanner = this.mBluetoothAdapter.getBluetoothLeScanner();
ScanSettings bleScanSettings = new ScanSettings.Builder().setScanMode(
ScanSettings.SCAN_MODE_LOW_LATENCY).build();
this.mLeScanCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, ScanResult result) {
calledTimes++;
runOnUiThread(new Runnable() {
@Override
public void run() {
calledTimesTextView.setText(Integer
.toString(calledTimes));
}
});
Log.e(LOG_TAG, "in onScanResult, " + " is coming...");
}
@Override
public void onBatchScanResults(List<ScanResult> results) {
}
@Override
public void onScanFailed(int errorCode) {
}
};
this.mLescanner.startScan(null, bleScanSettings, this.mLeScanCallback);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}}
它们非常简单，只是在 UI 中显示一个计数器，最终证明总是停在 2 或 3。
我之前在带有 android 4.4 设备的三星 note 2 上播放过这个 ble 广告接收，它运行良好，每秒调用一次回调。那么有人可以帮忙吗？为什么 Radius 的 Locate Beacon 在这里工作得很好？