在android中的后台加载数据(Loading data in background in android)
我正在尝试执行某些操作，比如创建一个表并在应用程序的初始启动时插入720行需要一些时间，所以我决定在后台运行它。 请看下面的代码，
MainActivity.java
DatabaseHandler dbhandler = new DatabaseHandler(this); this.progressDialog = ProgressDialog.show(this, "Please wait...", "Downloading Passengers Information...", true, false); new DownloadTask().execute(); private class DownloadTask extends AsyncTask<String, Void, Object> { @Override protected Object doInBackground(String... args) { for (int i = 1; i <= 5; i++) { for (int j = 0; j < 11; j++) { value = jedis.hget("passengerInfo", String.valueOf(i + (char) (asciiA) + j)); //this will get the data from hash table passengerInfo created in Redis if (value != null) { addSeat = String.valueOf(i + (char) (asciiA) + j); paxInfo = value.split(","); passName = paxInfo[0]; passAge = Integer.parseInt(paxInfo[1]); passGender = Integer.parseInt(paxInfo[2]); passFoodPref = paxInfo[3]; dbhandler.addPassengerInfo(new PassengerInfo(addSeat, passName, passAge, passGender, passFoodPref)); } else { addSeat = String.valueOf(i + (char) (asciiA) + j); passName = "NA"; passAge = 0; passGender = -1; passFoodPref = "NA"; dbhandler.addPassengerInfo(new PassengerInfo(addSeat, passName, passAge, passGender, passFoodPref)); } } } return null; } @Override protected void onPostExecute(Object result) { // Pass the result data back to the main activity MainActivity.this.data = result; if (MainActivity.this.progressDialog != null) { MainActivity.this.progressDialog.dismiss(); } } }当我运行它时，它在logcat中显示以下错误，
01-23 21:29:06.206: E/AndroidRuntime(704): FATAL EXCEPTION: AsyncTask #1 01-23 21:29:06.206: E/AndroidRuntime(704): java.lang.RuntimeException: An error occured while executing doInBackground()请帮忙 ！
仅供参考：整个Logcat
01-23 21:53:15.807: E/AndroidRuntime(742): at android.os.AsyncTask$3.done(AsyncTask.java:200) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask.setException(FutureTask.java:125) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask.run(FutureTask.java:138) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.lang.Thread.run(Thread.java:1019) 01-23 21:53:15.807: E/AndroidRuntime(742): Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Connection timed out 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.connect(Connection.java:134) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:69) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.sendCommand(Connection.java:79) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.BinaryClient.hget(BinaryClient.java:212) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Client.hget(Client.java:138) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Jedis.hget(Jedis.java:680) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.jedisconnectiontest.com.MainActivity$DownloadTask.doInBackground(MainActivity.java:118) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.jedisconnectiontest.com.MainActivity$DownloadTask.doInBackground(MainActivity.java:1) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.os.AsyncTask$2.call(AsyncTask.java:185) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 01-23 21:53:15.807: E/AndroidRuntime(742): ... 4 more 01-23 21:53:15.807: E/AndroidRuntime(742): Caused by: java.net.SocketTimeoutException: Connection timed out 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.platform.OSNetworkSystem.connect(Native Method) 01-23 21:53:15.807: E/AndroidRuntime(742): at dalvik.system.BlockGuard$WrappedNetworkSystem.connect(BlockGuard.java:357) 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:204) 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:437) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.net.Socket.connect(Socket.java:983) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.connect(Connection.java:129) 01-23 21:53:15.807: E/AndroidRuntime(742): ... 13 more 01-23 21:53:17.737: E/WindowManager(742): Activity android.jedisconnectiontest.com.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40523ac8 that was originally added here 01-23 21:53:17.737: E/WindowManager(742): android.view.WindowLeaked: Activity android.jedisconnectiontest.com.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40523ac8 that was originally added here 01-23 21:53:17.737: E/WindowManager(742): at android.view.ViewRoot.(ViewRoot.java:258) 01-23 21:53:17.737: E/WindowManager(742): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148) 01-23 21:53:17.737: E/WindowManager(742): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91) 01-23 21:53:17.737: E/WindowManager(742): at android.view.Window$LocalWindowManager.addView(Window.java:424) 01-23 21:53:17.737: E/WindowManager(742): at android.app.Dialog.show(Dialog.java:241) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ProgressDialog.show(ProgressDialog.java:107) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ProgressDialog.show(ProgressDialog.java:95) 01-23 21:53:17.737: E/WindowManager(742): at android.jedisconnectiontest.com.MainActivity.onCreate(MainActivity.java:56) 01-23 21:53:17.737: E/WindowManager(742): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 01-23 21:53:17.737: E/WindowManager(742): at android.os.Handler.dispatchMessage(Handler.java:99) 01-23 21:53:17.737: E/WindowManager(742): at android.os.Looper.loop(Looper.java:123) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.main(ActivityThread.java:3683) 01-23 21:53:17.737: E/WindowManager(742): at java.lang.reflect.Method.invokeNative(Native Method) 01-23 21:53:17.737: E/WindowManager(742): at java.lang.reflect.Method.invoke(Method.java:507) 01-23 21:53:17.737: E/WindowManager(742): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 01-23 21:53:17.737: E/WindowManager(742): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 01-23 21:53:17.737: E/WindowManager(742): at dalvik.system.NativeStart.main(Native Method)I'm trying to do certain operations like creating a table and inserting 720 rows at initial launch of the application which takes some time, so I decided to run it in background. Please see the code below,
MainActivity.java
DatabaseHandler dbhandler = new DatabaseHandler(this); this.progressDialog = ProgressDialog.show(this, "Please wait...", "Downloading Passengers Information...", true, false); new DownloadTask().execute(); private class DownloadTask extends AsyncTask<String, Void, Object> { @Override protected Object doInBackground(String... args) { for (int i = 1; i <= 5; i++) { for (int j = 0; j < 11; j++) { value = jedis.hget("passengerInfo", String.valueOf(i + (char) (asciiA) + j)); //this will get the data from hash table passengerInfo created in Redis if (value != null) { addSeat = String.valueOf(i + (char) (asciiA) + j); paxInfo = value.split(","); passName = paxInfo[0]; passAge = Integer.parseInt(paxInfo[1]); passGender = Integer.parseInt(paxInfo[2]); passFoodPref = paxInfo[3]; dbhandler.addPassengerInfo(new PassengerInfo(addSeat, passName, passAge, passGender, passFoodPref)); } else { addSeat = String.valueOf(i + (char) (asciiA) + j); passName = "NA"; passAge = 0; passGender = -1; passFoodPref = "NA"; dbhandler.addPassengerInfo(new PassengerInfo(addSeat, passName, passAge, passGender, passFoodPref)); } } } return null; } @Override protected void onPostExecute(Object result) { // Pass the result data back to the main activity MainActivity.this.data = result; if (MainActivity.this.progressDialog != null) { MainActivity.this.progressDialog.dismiss(); } } }When I run this it show the following error in logcat,
01-23 21:29:06.206: E/AndroidRuntime(704): FATAL EXCEPTION: AsyncTask #1 01-23 21:29:06.206: E/AndroidRuntime(704): java.lang.RuntimeException: An error occured while executing doInBackground()Please help !
FYI: Entire Logcat
01-23 21:53:15.807: E/AndroidRuntime(742): at android.os.AsyncTask$3.done(AsyncTask.java:200) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:274) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask.setException(FutureTask.java:125) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:308) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask.run(FutureTask.java:138) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1088) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:581) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.lang.Thread.run(Thread.java:1019) 01-23 21:53:15.807: E/AndroidRuntime(742): Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Connection timed out 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.connect(Connection.java:134) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.BinaryClient.connect(BinaryClient.java:69) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.sendCommand(Connection.java:79) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.BinaryClient.hget(BinaryClient.java:212) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Client.hget(Client.java:138) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Jedis.hget(Jedis.java:680) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.jedisconnectiontest.com.MainActivity$DownloadTask.doInBackground(MainActivity.java:118) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.jedisconnectiontest.com.MainActivity$DownloadTask.doInBackground(MainActivity.java:1) 01-23 21:53:15.807: E/AndroidRuntime(742): at android.os.AsyncTask$2.call(AsyncTask.java:185) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:306) 01-23 21:53:15.807: E/AndroidRuntime(742): ... 4 more 01-23 21:53:15.807: E/AndroidRuntime(742): Caused by: java.net.SocketTimeoutException: Connection timed out 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.platform.OSNetworkSystem.connect(Native Method) 01-23 21:53:15.807: E/AndroidRuntime(742): at dalvik.system.BlockGuard$WrappedNetworkSystem.connect(BlockGuard.java:357) 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:204) 01-23 21:53:15.807: E/AndroidRuntime(742): at org.apache.harmony.luni.net.PlainSocketImpl.connect(PlainSocketImpl.java:437) 01-23 21:53:15.807: E/AndroidRuntime(742): at java.net.Socket.connect(Socket.java:983) 01-23 21:53:15.807: E/AndroidRuntime(742): at redis.clients.jedis.Connection.connect(Connection.java:129) 01-23 21:53:15.807: E/AndroidRuntime(742): ... 13 more 01-23 21:53:17.737: E/WindowManager(742): Activity android.jedisconnectiontest.com.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40523ac8 that was originally added here 01-23 21:53:17.737: E/WindowManager(742): android.view.WindowLeaked: Activity android.jedisconnectiontest.com.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@40523ac8 that was originally added here 01-23 21:53:17.737: E/WindowManager(742): at android.view.ViewRoot.(ViewRoot.java:258) 01-23 21:53:17.737: E/WindowManager(742): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:148) 01-23 21:53:17.737: E/WindowManager(742): at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:91) 01-23 21:53:17.737: E/WindowManager(742): at android.view.Window$LocalWindowManager.addView(Window.java:424) 01-23 21:53:17.737: E/WindowManager(742): at android.app.Dialog.show(Dialog.java:241) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ProgressDialog.show(ProgressDialog.java:107) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ProgressDialog.show(ProgressDialog.java:95) 01-23 21:53:17.737: E/WindowManager(742): at android.jedisconnectiontest.com.MainActivity.onCreate(MainActivity.java:56) 01-23 21:53:17.737: E/WindowManager(742): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.access$1500(ActivityThread.java:117) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931) 01-23 21:53:17.737: E/WindowManager(742): at android.os.Handler.dispatchMessage(Handler.java:99) 01-23 21:53:17.737: E/WindowManager(742): at android.os.Looper.loop(Looper.java:123) 01-23 21:53:17.737: E/WindowManager(742): at android.app.ActivityThread.main(ActivityThread.java:3683) 01-23 21:53:17.737: E/WindowManager(742): at java.lang.reflect.Method.invokeNative(Native Method) 01-23 21:53:17.737: E/WindowManager(742): at java.lang.reflect.Method.invoke(Method.java:507) 01-23 21:53:17.737: E/WindowManager(742): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 01-23 21:53:17.737: E/WindowManager(742): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 01-23 21:53:17.737: E/WindowManager(742): at dalvik.system.NativeStart.main(Native Method)最满意答案
Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Connection timed out Caused by: java.net.SocketTimeoutException: Connection timed out此错误意味着服务器未在给定的TimeOut值（正常约10秒）之间应答，您的服务器是否已关闭？ 或者你拼错了服务器网址？
Caused by: redis.clients.jedis.exceptions.JedisConnectionException: java.net.SocketTimeoutException: Connection timed out Caused by: java.net.SocketTimeoutException: Connection timed outThis error means that the server did not answer between the given TimeOut value (normal about 10 seconds), is your server down? Or did you misspelled the server url?
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