net.kenevans.android.bleexplorer.DeviceScanActivity.java Source code

Java tutorial

Introduction

Here is the source code for net.kenevans.android.bleexplorer.DeviceScanActivity.java

Source

/*
 * Copyright (C) 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.
 */

package net.kenevans.android.bleexplorer;

import android.Manifest;
import android.annotation.SuppressLint;
import android.app.ActionBar;
import android.app.Activity;
import android.app.ListActivity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothManager;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;

/**
 * Activity for scanning and displaying available Bluetooth LE devices.
 */
@SuppressLint("InflateParams")
public class DeviceScanActivity extends ListActivity implements IConstants {
    private LeDeviceListAdapter mLeDeviceListAdapter;
    private BluetoothAdapter mBluetoothAdapter;
    private boolean mScanning;
    private Handler mHandler;
    private boolean mCoarseLocationPermissionAsked = false;
    private boolean mAllowScan;

    private static final int REQUEST_ENABLE_BT = 1;
    // Stops scanning after 10 seconds.
    private static final long SCAN_PERIOD = 10000;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        ActionBar actionBar = getActionBar();
        if (actionBar != null) {
            actionBar.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_LONG).show();
            finish();
        }

        // Initializes a Bluetooth adapter. For API level 18 and above, get a
        // reference to BluetoothAdapter through BluetoothManager.
        mBluetoothAdapter = null;
        final BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        if (bluetoothManager == null) {
            Toast.makeText(this, R.string.error_bluetooth_manager, Toast.LENGTH_LONG).show();
            finish();
            return;
        }
        try {
            mBluetoothAdapter = bluetoothManager.getAdapter();
        } catch (NullPointerException ex) {
            Toast.makeText(this, R.string.error_bluetooth_adapter, Toast.LENGTH_LONG).show();
        }

        // Checks if Bluetooth is supported on the device.
        if (mBluetoothAdapter == null) {
            String msg = getString(R.string.bluetooth_not_supported);
            Utils.errMsg(this, msg);
            Toast.makeText(this, msg, Toast.LENGTH_LONG).show();
            finish();
        }

        // Set result CANCELED in case the user backs out
        setResult(Activity.RESULT_CANCELED);
    }

    @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();
            startScan();
            break;
        case R.id.menu_stop:
            endScan();
            break;
        }
        return true;
    }

    @Override
    protected void onResume() {
        super.onResume();
        Log.d(TAG, "onResume: mScanning=" + mScanning);

        // 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()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        }

        // Initializes list view adapter.
        if (mBluetoothAdapter.isEnabled()) {
            mLeDeviceListAdapter = new LeDeviceListAdapter();
            setListAdapter(mLeDeviceListAdapter);
            startScan();
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
            @NonNull int[] grantResults) {
        switch (requestCode) {
        case PERMISSION_ACCESS_COARSE_LOCATION:
            // COARSE_LOCATION
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                mAllowScan = true;
                startScan();
            } else if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_DENIED) {
                mAllowScan = false;
            }
            break;
        }
    }

    @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
    protected void onPause() {
        super.onPause();
        Log.d(TAG, "onPause: mScanning=" + mScanning);
        if (mBluetoothAdapter.isEnabled()) {
            endScan();
        }
        if (mLeDeviceListAdapter != null) {
            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);
    }

    private void endScan() {
        Log.d(TAG, "endScan");
        // Stop
        if (mScanning) {
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        }
        mScanning = false;
        invalidateOptionsMenu();
    }

    private void startScan() {
        Log.d(TAG, "startScan");

        // Check for coarse location permission
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            // Permission is not granted
            mAllowScan = false;
            if (!mCoarseLocationPermissionAsked) {
                Log.d(TAG, "startScan: requestPermission");
                mCoarseLocationPermissionAsked = true;
                ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.ACCESS_COARSE_LOCATION },
                        PERMISSION_ACCESS_COARSE_LOCATION);
            } else {
                Log.d(TAG, "startScan: infoMsg");
                String msg = getString(R.string.permission_coarse_location);
                if (mCoarseLocationPermissionAsked) {
                    Utils.infoMsg(this, msg);
                }
            }
        } else {
            mAllowScan = true;
        }

        if (mAllowScan) {
            // Stops scanning after a pre-defined scan period.
            mHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mScanning = false;
                    mBluetoothAdapter.stopLeScan(mLeScanCallback);
                    invalidateOptionsMenu();
                }
            }, SCAN_PERIOD);

            mScanning = true;
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        }
        invalidateOptionsMenu();
    }

    // Adapter for holding devices found through scanning.
    private class LeDeviceListAdapter extends BaseAdapter {
        private final ArrayList<BluetoothDevice> mLeDevices;
        private final LayoutInflater mInflator;

        private LeDeviceListAdapter() {
            super();
            mLeDevices = new ArrayList<>();
            mInflator = DeviceScanActivity.this.getLayoutInflater();
        }

        private void addDevice(BluetoothDevice device) {
            if (!mLeDevices.contains(device)) {
                mLeDevices.add(device);
            }
        }

        private BluetoothDevice getDevice(int position) {
            return mLeDevices.get(position);
        }

        private 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 = mInflator.inflate(R.layout.listitem_device, null);
                viewHolder = new ViewHolder();
                viewHolder.deviceAddress = view.findViewById(R.id.device_address);
                viewHolder.deviceName = 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();
                }
            });
        }
    };

    static class ViewHolder {
        TextView deviceName;
        TextView deviceAddress;
    }
}