我已经制作了自己的应用程序，尝试连接到自己宣传为蓝牙LE外设的Raspberry Pi 3。我知道PI没有任何问题，因为我可以使用iOS应用程序连接到它。 Raspberry Pi设备未显示在列表中。
所以我查看了Google's code（以及他们的documentation）并且我一直在修改它以尝试发现设备：
@RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public class DeviceScanActivity extends ListActivity {
private LeDeviceListAdapter mLeDeviceListAdapter;
private BluetoothAdapter mBluetoothAdapter;
private boolean mScanning;
private Handler mHandler;
private static final int REQUEST_ENABLE_BT = 1;
private static final int REQUEST_LOCATION_PERMISSION = 2;
// Stops scanning after 10 seconds.
private static final long SCAN_PERIOD = 10000;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActionBar().setTitle(R.string.title_devices);
mHandler = new Handler();
// Use this check to determine whether BLE is supported on the device. Then you can
// selectively disable BLE-related features.
if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
Toast.makeText(this, R.string.ble_not_supported, Toast.LENGTH_SHORT).show();
finish();
}
// Initializes a Bluetooth adapter. For API level 18 and above, get a reference to
// BluetoothAdapter through BluetoothManager.
final BluetoothManager bluetoothManager =
(BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
mBluetoothAdapter = bluetoothManager.getAdapter();
// Checks if Bluetooth is supported on the device.
if (mBluetoothAdapter == null) {
Toast.makeText(this, R.string.error_bluetooth_not_supported, Toast.LENGTH_SHORT).show();
finish();
return;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
if (!mScanning) {
menu.findItem(R.id.menu_stop).setVisible(false);
menu.findItem(R.id.menu_scan).setVisible(true);
menu.findItem(R.id.menu_refresh).setActionView(null);
} else {
menu.findItem(R.id.menu_stop).setVisible(true);
menu.findItem(R.id.menu_scan).setVisible(false);
menu.findItem(R.id.menu_refresh).setActionView(
R.layout.actionbar_indeterminate_progress);
}
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.menu_scan:
mLeDeviceListAdapter.clear();
scanLeDevice(true);
break;
case R.id.menu_stop:
scanLeDevice(false);
break;
}
return true;
}
@Override
protected void onResume() {
super.onResume();
// Ensures Bluetooth is enabled on the device. If Bluetooth is not currently enabled,
// fire an intent to display a dialog asking the user to grant permission to enable it.
if (!mBluetoothAdapter.isEnabled()) {
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
}
// Initializes list view adapter.
mLeDeviceListAdapter = new LeDeviceListAdapter();
setListAdapter(mLeDeviceListAdapter);
scanLeDevice(true);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// User chose not to enable Bluetooth.
if (requestCode == REQUEST_ENABLE_BT && resultCode == Activity.RESULT_CANCELED) {
finish();
return;
}
super.onActivityResult(requestCode, resultCode, data);
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case REQUEST_LOCATION_PERMISSION:{
// If request is cancelled, the result arrays are empty.
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission was granted, yay! Do the
// contacts-related task you need to do.
scanLeDevice(true);
} else {
// permission denied, boo! Disable the
// functionality that depends on this permission.
}
}
}
}
@Override
protected void onPause() {
super.onPause();
scanLeDevice(false);
mLeDeviceListAdapter.clear();
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
final BluetoothDevice device = mLeDeviceListAdapter.getDevice(position);
if (device == null) return;
final Intent intent = new Intent(this, DeviceControlActivity.class);
intent.putExtra(DeviceControlActivity.EXTRAS_DEVICE_NAME, device.getName());
intent.putExtra(DeviceControlActivity.EXTRAS_DEVICE_ADDRESS, device.getAddress());
if (mScanning) {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
mScanning = false;
}
startActivity(intent);
}
public boolean checkForPermission(String permission) {
if (permission == null) return false;
if (ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED) {
// Should we show an explanation?
if (ActivityCompat.shouldShowRequestPermissionRationale(this, permission)) {
// Show an explanation to the user *asynchronously* -- don't block
// this thread waiting for the user's response! After the user
// sees the explanation, try again to request the permission.
} else {
// No explanation needed, we can request the permission.
ActivityCompat.requestPermissions(this, new String[]{permission}, getCodeForPermissionRequest(permission));
// MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
// app-defined int constant. The callback method gets the
// result of the request.
}
return false;
}
return true;
}
private int getCodeForPermissionRequest(String permission) {
if (permission.equals(Manifest.permission.ACCESS_FINE_LOCATION)) return REQUEST_LOCATION_PERMISSION;
return 0;
}
private void startScan() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
mBluetoothAdapter.getBluetoothLeScanner().startScan(mLeScannerCallback);
} else {
mBluetoothAdapter.startLeScan(mLeScanCallback);
}
}
private void stopScan() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
mBluetoothAdapter.getBluetoothLeScanner().stopScan(mLeScannerCallback);
} else {
mBluetoothAdapter.stopLeScan(mLeScanCallback);
}
}
private void scanLeDevice(final boolean enable) {
if (!checkForPermission(Manifest.permission.ACCESS_FINE_LOCATION)) return;
if (enable) {
// Stops scanning after a pre-defined scan period.
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
mScanning = false;
stopScan();
invalidateOptionsMenu();
}
}, SCAN_PERIOD);
mScanning = true;
startScan();
} else {
mScanning = false;
stopScan();
}
invalidateOptionsMenu();
}
// Adapter for holding devices found through scanning.
private class LeDeviceListAdapter extends BaseAdapter {
private ArrayList<BluetoothDevice> mLeDevices;
private LayoutInflater mInflater;
public LeDeviceListAdapter() {
super();
mLeDevices = new ArrayList<>();
mInflater = DeviceScanActivity.this.getLayoutInflater();
}
public void addDevice(BluetoothDevice device) {
if(!mLeDevices.contains(device)) {
mLeDevices.add(device);
}
}
public BluetoothDevice getDevice(int position) {
return mLeDevices.get(position);
}
public void clear() {
mLeDevices.clear();
}
@Override
public int getCount() {
return mLeDevices.size();
}
@Override
public Object getItem(int i) {
return mLeDevices.get(i);
}
@Override
public long getItemId(int i) {
return i;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
ViewHolder viewHolder;
// General ListView optimization code.
if (view == null) {
view = mInflater.inflate(R.layout.listitem_device, null);
viewHolder = new ViewHolder();
viewHolder.deviceAddress = (TextView) view.findViewById(R.id.device_address);
viewHolder.deviceName = (TextView) view.findViewById(R.id.device_name);
view.setTag(viewHolder);
} else {
viewHolder = (ViewHolder) view.getTag();
}
BluetoothDevice device = mLeDevices.get(i);
final String deviceName = device.getName();
if (deviceName != null && deviceName.length() > 0)
viewHolder.deviceName.setText(deviceName);
else
viewHolder.deviceName.setText(R.string.unknown_device);
viewHolder.deviceAddress.setText(device.getAddress());
return view;
}
}
// Device scan callback.
private BluetoothAdapter.LeScanCallback mLeScanCallback =
new BluetoothAdapter.LeScanCallback() {
@Override
public void onLeScan(final BluetoothDevice device, int rssi, byte[] scanRecord) {
runOnUiThread(new Runnable() {
@Override
public void run() {
mLeDeviceListAdapter.addDevice(device);
mLeDeviceListAdapter.notifyDataSetChanged();
}
});
}
};
private android.bluetooth.le.ScanCallback mLeScannerCallback = new ScanCallback() {
@Override
public void onScanResult(int callbackType, final ScanResult result) {
super.onScanResult(callbackType, result);
runOnUiThread(new Runnable() {
@Override
public void run() {
mLeDeviceListAdapter.addDevice(result.getDevice());
mLeDeviceListAdapter.notifyDataSetChanged();
}
});
}
};
static class ViewHolder {
TextView deviceName;
TextView deviceAddress;
}
}
我的Gradle文件如下：
buildscript {
repositories {
jcenter()
}
dependencies {
classpath 'com.android.tools.build:gradle:2.3.3'
}
}
apply plugin: 'com.android.application'
repositories {
jcenter()
}
dependencies {
compile "com.android.support:support-v4:25.3.1"
compile "com.android.support:support-v13:25.3.1"
compile "com.android.support:cardview-v7:25.3.1"
compile "com.android.support:appcompat-v7:25.3.1"
}
// The sample build uses multiple directories to
// keep boilerplate and common code separate from
// the main sample code.
List<String> dirs = [
'main', // main sample code; look here for the interesting stuff.
'common', // components that are reused by multiple samples
'template'] // boilerplate code that is generated by the sample template process
android {
compileSdkVersion 25
buildToolsVersion "25.0.3"
defaultConfig {
minSdkVersion 18
targetSdkVersion 25
}
compileOptions {
sourceCompatibility JavaVersion.VERSION_1_7
targetCompatibility JavaVersion.VERSION_1_7
}
sourceSets {
main {
dirs.each { dir ->
java.srcDirs "src/${dir}/java"
res.srcDirs "src/${dir}/res"
}
}
androidTest.setRoot('tests')
androidTest.java.srcDirs = ['tests/src']
}
}
我的清单：
<?xml version="1.0" encoding="UTF-8"?>
<!--
Copyright 2013 The Android Open Source Project
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.bluetoothlegatt"
android:versionCode="1"
android:versionName="1.0">
<!-- Min/target SDK versions (<uses-sdk>) managed by build.gradle -->
<!-- Declare this required feature if you want to make the app available to BLE-capable
devices only. If you want to make your app available to devices that don't support BLE,
you should omit this in the manifest. Instead, determine BLE capability by using
PackageManager.hasSystemFeature(FEATURE_BLUETOOTH_LE) -->
<uses-feature android:name="android.hardware.bluetooth_le" android:required="true"/>
<uses-feature android:name="android.hardware.location.gps"/>
<uses-permission android:name="android.permission.BLUETOOTH"/>
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<application android:label="@string/app_name"
android:icon="@drawable/ic_launcher"
android:theme="@android:style/Theme.Holo.Light">
<activity android:name=".DeviceScanActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
<activity android:name=".DeviceControlActivity"/>
<service android:name=".BluetoothLeService" android:enabled="true"/>
</application>
</manifest>