DeviceListActivity.java

* Copyright (C) 2009 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.BluetoothChat;

import java.util.Set;

import android.app.Activity;

import android.bluetooth.BluetoothAdapter; import android.bluetooth.BluetoothDevice; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent;

import android.content.IntentFilter; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.Window;

import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.ListView; import android.widget.TextView;

import android.widget.AdapterView.OnItemClickListener; /**

* This Activity appears as a dialog. It lists any paired devices and devices * detected in the area after discovery. When a device is chosen by the user, * the MAC address of the device is sent back to the parent Activity in the * result Intent.

*/创建一个基于Activity的类DeviceListActivity public class DeviceListActivity extends Activity { // Debugging private static final String TAG = \"DeviceListActivity\"; private static final boolean D = true; // Return Intent extra public static String EXTRA_DEVICE_ADDRESS = \"device_address\"; // Member fields

传建一个本地蓝牙设备对象mBtAdapter private BluetoothAdapter mBtAdapter; Private（数组适配器） ArrayAdapter mPairedDevicesArrayAdapter; private ArrayAdapter mNewDevicesArrayAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Setup the window requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS); setContentView(R.layout.device_list); // Set result CANCELED incase the user backs out setResult(Activity.RESULT_CANCELED); // Initialize the button to perform device discovery

创建扫描按键的对象，并获得控件ID

Button scanButton = (Button) findViewById(R.id.button_scan);

创建扫描按键监听器

scanButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { doDiscovery(); v.setVisibility(View.GONE); } }); // Initialize array adapters. One for already paired devices and // one for newly discovered devices mPairedDevicesArrayAdapter = new ArrayAdapter(this,

R.layout.device_name);

mNewDevicesArrayAdapter = new ArrayAdapter(this, R.layout.device_name);

// Find and set up the ListView for paired devices

ListView pairedListView = (ListView) findViewById(R.id.paired_devices); pairedListView.setAdapter(mPairedDevicesArrayAdapter);

pairedListView.setOnItemClickListener(mDeviceClickListener);

// Find and set up the ListView for newly discovered devices

ListView newDevicesListView = (ListView) findViewById(R.id.new_devices); newDevicesListView.setAdapter(mNewDevicesArrayAdapter);

newDevicesListView.setOnItemClickListener(mDeviceClickListener); // Register for broadcasts when a device is discovered

IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); this.registerReceiver(mReceiver, filter);

// Register for broadcasts when discovery has finished

filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); this.registerReceiver(mReceiver, filter);

// Get the local Bluetooth adapter

mBtAdapter = BluetoothAdapter.getDefaultAdapter();

// Get a set of currently paired devices

Set pairedDevices = mBtAdapter.getBondedDevices(); // If there are paired devices, add each one to the ArrayAdapter if (pairedDevices.size() > 0) { findViewById(R.id.title_paired_devices).setVisibility(View.VISIBLE); for (BluetoothDevice device : pairedDevices) { mPairedDevicesArrayAdapter.add(device.getName() + \"\\n\" + device.getAddress()); } } else { String noDevices = getResources().getText(R.string.none_paired) .toString(); mPairedDevicesArrayAdapter.add(noDevices); }

}

@Override

protected void onDestroy() { super.onDestroy(); }

// Make sure we're not doing discovery anymore if (mBtAdapter != null) { mBtAdapter.cancelDiscovery(); }

// Unregister broadcast listeners this.unregisterReceiver(mReceiver);

/**

* Start device discover with the BluetoothAdapter */

private void doDiscovery() { if (D) Log.d(TAG, \"doDiscovery()\"); }

// Indicate scanning in the title

setProgressBarIndeterminateVisibility(true); setTitle(R.string.scanning);

// Turn on sub-title for new devices

findViewById(R.id.title_new_devices).setVisibility(View.VISIBLE); // If we're already discovering, stop it if (mBtAdapter.isDiscovering()) { mBtAdapter.cancelDiscovery(); }

// Request discover from BluetoothAdapter mBtAdapter.startDiscovery();

// The on-click listener for all devices in the ListViews

private OnItemClickListener mDeviceClickListener = new OnItemClickListener() {

};

public void onItemClick(AdapterView av, View v, int arg2, long arg3) { // Cancel discovery because it's costly and we're about to connect mBtAdapter.cancelDiscovery(); }

// Get the device MAC address, which is the last 17 chars in the // View

String info = ((TextView) v).getText().toString(); String address = info.substring(info.length() - 17); // Create the result Intent and include the MAC address Intent intent = new Intent();

intent.putExtra(EXTRA_DEVICE_ADDRESS, address); // Set result and finish this Activity

setResult(Activity.RESULT_OK, intent); finish();

// The BroadcastReceiver that listens for discovered devices and // changes the title when discovery is finished

private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction();

// When discovery finds a device

if (BluetoothDevice.ACTION_FOUND.equals(action)) { // Get the BluetoothDevice object from the Intent BluetoothDevice device = intent .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); // If it's already paired, skip it, because it's been listed // already if (device.getBondState() != BluetoothDevice.BOND_BONDED) { mNewDevicesArrayAdapter.add(device.getName() + \"\\n\" + device.getAddress()); } // When discovery is finished, change the Activity title }

}

};

}

else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { setProgressBarIndeterminateVisibility(false); setTitle(R.string.select_device); if (mNewDevicesArrayAdapter.getCount() == 0) { String noDevices = getResources().getText( R.string.none_found).toString(); mNewDevicesArrayAdapter.add(noDevices); } }