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/*
* Copyright (C) 2015 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.
*/
package com.example.android.bluetoothadvertisements;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanFilter;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.os.Bundle;
import android.os.Handler;
import android.support.v4.app.ListFragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
/**
* Scans for Bluetooth Low Energy Advertisements matching a filter and displays them to the user.
*/
public class ScannerFragment extends ListFragment {
private static final String TAG = ScannerFragment.class.getSimpleName();
/**
* Stops scanning after 5 seconds.
*/
private static final long SCAN_PERIOD = 5000;
private BluetoothAdapter mBluetoothAdapter;
private BluetoothLeScanner mBluetoothLeScanner;
private ScanCallback mScanCallback;
private ScanResultAdapter mAdapter;
private Handler mHandler;
/**
* Must be called after object creation by MainActivity.
*
* @param btAdapter the local BluetoothAdapter
*/
public void setBluetoothAdapter(BluetoothAdapter btAdapter) {
this.mBluetoothAdapter = btAdapter;
mBluetoothLeScanner = mBluetoothAdapter.getBluetoothLeScanner();
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setHasOptionsMenu(true);
setRetainInstance(true);
// Use getActivity().getApplicationContext() instead of just getActivity() because this
// object lives in a fragment and needs to be kept separate from the Activity lifecycle.
//
// We could get a LayoutInflater from the ApplicationContext but it messes with the
// default theme, so generate it from getActivity() and pass it in separately.
mAdapter = new ScanResultAdapter(getActivity().getApplicationContext(),
LayoutInflater.from(getActivity()));
mHandler = new Handler();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
final View view = super.onCreateView(inflater, container, savedInstanceState);
setListAdapter(mAdapter);
return view;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
getListView().setDivider(null);
getListView().setDividerHeight(0);
setEmptyText(getString(R.string.empty_list));
// Trigger refresh on app's 1st load
startScanning();
}
@Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
super.onCreateOptionsMenu(menu, inflater);
inflater.inflate(R.menu.scanner_menu, menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.refresh:
startScanning();
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/**
* Start scanning for BLE Advertisements (& set it up to stop after a set period of time).
*/
public void startScanning() {
if (mScanCallback == null) {
Log.d(TAG, "Starting Scanning");
// Will stop the scanning after a set time.
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
stopScanning();
}
}, SCAN_PERIOD);
// Kick off a new scan.
mScanCallback = new SampleScanCallback();
mBluetoothLeScanner.startScan(buildScanFilters(), buildScanSettings(), mScanCallback);
String toastText = getString(R.string.scan_start_toast) + " "
+ TimeUnit.SECONDS.convert(SCAN_PERIOD, TimeUnit.MILLISECONDS) + " "
+ getString(R.string.seconds);
Toast.makeText(getActivity(), toastText, Toast.LENGTH_LONG).show();
} else {
Toast.makeText(getActivity(), R.string.already_scanning, Toast.LENGTH_SHORT);
}
}
/**
* Stop scanning for BLE Advertisements.
*/
public void stopScanning() {
Log.d(TAG, "Stopping Scanning");
// Stop the scan, wipe the callback.
mBluetoothLeScanner.stopScan(mScanCallback);
mScanCallback = null;
// Even if no new results, update 'last seen' times.
mAdapter.notifyDataSetChanged();
}
/**
* Return a List of {@link ScanFilter} objects to filter by Service UUID.
*/
private List<ScanFilter> buildScanFilters() {
List<ScanFilter> scanFilters = new ArrayList<>();
ScanFilter.Builder builder = new ScanFilter.Builder();
builder.setServiceUuid(Constants.Service_UUID);
scanFilters.add(builder.build());
return scanFilters;
}
/**
* Return a {@link ScanSettings} object set to use low power (to preserve battery life).
*/
private ScanSettings buildScanSettings() {
ScanSettings.Builder builder = new ScanSettings.Builder();
builder.setScanMode(ScanSettings.SCAN_MODE_LOW_POWER);
return builder.build();
}
/**
* Custom ScanCallback object - adds to adapter on success, displays error on failure.
*/
private class SampleScanCallback extends ScanCallback {
@Override
public void onBatchScanResults(List<ScanResult> results) {
super.onBatchScanResults(results);
for (ScanResult result : results) {
mAdapter.add(result);
}
mAdapter.notifyDataSetChanged();
}
@Override
public void onScanResult(int callbackType, ScanResult result) {
super.onScanResult(callbackType, result);
mAdapter.add(result);
mAdapter.notifyDataSetChanged();
}
@Override
public void onScanFailed(int errorCode) {
super.onScanFailed(errorCode);
Toast.makeText(getActivity(), "Scan failed with error: " + errorCode, Toast.LENGTH_LONG)
.show();
}
}
}
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