我在学校有一个项目的Android应用程序。该应用程序的目标是获取GPS位置，扫描可用的WiFi网络，并将该信息捆绑到要发布的字符串（也由应用程序）。 gps和wifi部分是从头开始编写的，推特代码是我的一个队友发现的一些开源代码。我们都没有任何以前的Android编程经验，所以我们一直在学习我们只需要飞行的东西。 应用程序现在有效，但还不够好。它通常可以关闭一些推文，但它最终总会得到一个ANR。我想这可能来自GPS或WIFI代码，因为那是我们自己写的东西。我们用twitter代码编写了一个单独的应用程序来测试它，这似乎工作正常，所以我认为这不会导致问题。
一些有更多经验的Android程序员可以查看一些代码并指出他们看到的任何问题，特别是可能导致这个应用程序到ANR的原因吗？如果有人愿意建议比我们现有的更好的架构/框架，我会感兴趣。 当应用程序正常工作时，我们最终发送的推文看起来像这样：
这是我们活动类的相关代码......
private Intent in;
public static TextView textView1;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_spectral_tweets);
mConsumer = new CommonsHttpOAuthConsumer(CONSUMER_KEY, CONSUMER_SECRET);
mProvider = new DefaultOAuthProvider(
"http://api.twitter.com/oauth/request_token",
"http://api.twitter.com/oauth/access_token",
"http://api.twitter.com/oauth/authorize");
prefs = PreferenceManager.getDefaultSharedPreferences(this);
String token = prefs.getString("token", null);
String tokenSecret = prefs.getString("tokenSecret", null);
if (token != null && tokenSecret != null) {
mConsumer.setTokenWithSecret(token, tokenSecret);
oauthClient = new OAuthSignpostClient(CONSUMER_KEY,
CONSUMER_SECRET, token, tokenSecret);
twitter = new Twitter(TWITTER_USER, oauthClient);
} else {
Log.d(TAG, "onCreate. Not Authenticated Yet " );
new OAuthAuthorizeTask().execute();
}
in = new Intent(this, BackgroundService.class);
textView1 = (TextView) findViewById(R.id.textView1);
changeText("On Create");
}
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_spectral_tweets, menu);
return true;
}
/**
* Changes textView1 to string msg
*/
public static void changeText(String msg) {
textView1.setText(msg);
}
/**
* tell the service to start displaying GPS/WIFI updates
*/
public void startMessages(View view) {
startService(in);
}
/**
* tell the service to stop displaying GPS/WIFI updates
*/
public void stopMessages(View view) {
changeText("stopped");
stopService(in);
}
/**
* When the BACK key is pressed ask the user if they want to quit
* if they do then stop the service and exit the program
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK)) {
@SuppressWarnings("unused")
AlertDialog alertbox = new AlertDialog.Builder(this)
.setMessage("Do you want to exit the application?")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
// stop the service and end the program
public void onClick(DialogInterface arg0, int arg1) {
stopService(in);
finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
// return to program
public void onClick(DialogInterface arg0, int arg1) {}
})
.show();
}
return super.onKeyDown(keyCode, event);
}
这是我们服务中处理gps和wifi内容的代码......
public class BackgroundService extends Service implements LocationListener
{
private static Timer repeater = new Timer();
private static LocationManager lm;
private getInfoAndTweet getAndTweet = this.new getInfoAndTweet();
private static final int MIN_TIME_MILLISECONDS = 0;
private static final int MIN_DIST_METERS = 0;
private static final int frequency = 30 * 1000;
private double temp_long = 0.0;
private double temp_lat = 0.0;
private int temp_count = 0;
private boolean thread_running = false;
@Override
public IBinder onBind(Intent arg0) {
return null;
}
public void onCreate()
{
super.onCreate();
lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, MIN_TIME_MILLISECONDS, MIN_DIST_METERS, this);
Toast.makeText(getApplicationContext(), "Location display is on", Toast.LENGTH_SHORT).show();
startService();
}
public void onDestroy()
{
repeater.cancel();
lm.removeUpdates(this);
unregisterReceiver(getAndTweet.receiver);
Toast.makeText(getApplicationContext(), "Location display is off", Toast.LENGTH_SHORT).show();
temp_lat = 0;
temp_long = 0;
temp_count = 0;
}
private void startService()
{
repeater.scheduleAtFixedRate(getAndTweet, 0, frequency);
}
/* this class will contain all of the GPS and WIFI classes so that none of that stuff clogs up the main thread */
private class getInfoAndTweet extends TimerTask
{
WifiManager wifi;
BroadcastReceiver receiver;
DecimalFormat lat = new DecimalFormat("00.000000");
DecimalFormat lon = new DecimalFormat("000.000000");
String gps_info;
String wifi_info;
String final_string;
private final String hashtag = "#ajd7v-34 ";
int count = 0;
private class WIFIscanner extends BroadcastReceiver
{
private final ArrayList<Integer> channel_numbers = new ArrayList<Integer> (Arrays.asList(0, 2412, 2417, 2422, 2427, 2432, 2437, 2442, 2447, 2452, 2457, 2462));
List <ScanResult> results;
Map<Integer, String> levels = new HashMap<Integer, String>();
String empty_channel = "__________"; // 10 spaces
public WIFIscanner()
{
init_levels();
}
public void onReceive(Context context, Intent intent)
{
wifi_info = "";
results = wifi.getScanResults();
ScanResult sr;
Iterator<ScanResult> it = results.iterator();
ScanResult channel_info[] = new ScanResult[12];
for (int i = 1; i < 12; i++)
{
channel_info[i] = null;
}
while (it.hasNext())
{
sr = it.next();
int channel = channel_numbers.indexOf(Integer.valueOf(sr.frequency));
if (channel_info[channel] == null)
{
channel_info[channel] = sr;
}
else
{
if (channel_info[channel].level < sr.level)
{
channel_info[channel] = sr;
}
}
}
for (int i = 1; i < 12; i++)
{
if (channel_info[i] != null)
{
wifi_info += (levels.get(channel_info[i].level) == null ? "0" : levels.get(channel_info[i].level)) + channel_info[i].BSSID.replace(":", "").substring(2, 11);
}
else
{
wifi_info += empty_channel;
}
}
final_string = hashtag + wifi_info + gps_info;
if (temp_count != 0)
{
if(Twitter_Test_AppActivity.twitter != null) {
Twitter_Test_AppActivity.twitter.setStatus(final_string);
Twitter_Test_AppActivity.changeText("Auto Tweet Sent: " + count + "\t" + final_string);
} else {
Twitter_Test_AppActivity.changeText("Tweet not sent");
}
}
else
{
Twitter_Test_AppActivity.changeText(count + "\tno new GPS info");
}
thread_running = false;
}
}
public void run()
{
thread_running = true;
wifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
if (receiver == null)
{
receiver = new WIFIscanner();
}
registerReceiver(receiver, new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION));
String latitude = lat.format(temp_lat / temp_count).replace(".", "");
String longitude = lon.format(temp_long / temp_count).replace(".", "");
gps_info = ((temp_lat / temp_count) > 0 ? "+" : "") + latitude + ((temp_long / temp_count) > 0 ? "+" : "") + longitude;
wifi.startScan();
count++;
}
}
public void onLocationChanged(Location location) {
if (thread_running)
{
temp_lat += location.getLatitude();
temp_long += location.getLongitude();
temp_count ++;
}
}
public void onProviderDisabled(String provider) {
Toast.makeText(getApplicationContext(), "GPS disabled", Toast.LENGTH_SHORT).show();
}
public void onProviderEnabled(String provider) {
Toast.makeText(getApplicationContext(), "GPS enabled", Toast.LENGTH_SHORT).show();
}
public void onStatusChanged(String provider, int status, Bundle extras) {}
}
EDIT 当我想到这一点时，我发现在主线程上运行的推特代码也可能导致我的ANR。在学校的网络并不是最好的，我的笔记本电脑有时甚至无法上手（不是我的笔记本电脑的故障，在其他地方都很好）。一个缓慢或不良的网络连接可能导致我的主线程在尝试发送推文时挂断，导致手机响应我的应用程序？
答案 0 :(得分：0)
首先，TimerTask不是存储数据的最佳位置。仅使用TimerTask定期执行Service。
其次，最好将所有Context相关组件的所有内部类（如Activity或Service）作为static类。这将保护您的代码免受内存泄漏的影响。
另外，您最好只注册一次BroadcastRreceiver，而不是在每次定时任务调用中都这样做。
我真的建议你阅读一些东西，例如Reto Meier的书“Android应用程序开发”。