android 致命异常：AsyncTask #2
android FATAL EXCEPTION: AsyncTask #2
我正在编写 android 应用程序，但在使用异步任务时它失败了，我有一个异步任务，错误出现在它的 doInBackground() 方法中，其他一切看起来都不错，但 doInBackground() 方法不起作用适当地 。在 doInBackground() 方法中，我编写了调试时从数据库中获取记录的代码，我发现记录是在 array-list 中获取的，但它们没有被馈送到
onPostExecute(String result) 请帮帮我...
private class LoadMoreAsync extends AsyncTask<Context, Void, String> {
private String strAddress;
public LoadMoreAsync(Context mContext,String strAddress) {
/*this.strCardNo = strCardNo;
this.strFirstName = strFirstName;
this.strMiddleName = strMiddleName;*/
this.strAddress = strAddress;
/*this.strCardNo = strCardNo;*/
}
@Override
protected void onPreExecute() {
super.onPreExecute();
ToastUtils.showToast(mContext, "Loading More...");
}
@Override
protected String doInBackground(Context... arg0) {
mVoterArray = new ArrayList<AddressInfo>();
mVoterArray = extDbUtil.getAddresslist(strAddress , limit += 20);
if (mVoterArray.isEmpty() || mVoterArray == null)
return null;
else
return "";
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
IOUtils.stopLoading();
if (result == null) {
ToastUtils.showToast(mContext, "No Record Found!!");
} else {
int position = mListView.getLastVisiblePosition();
mListAdapter = new ListAdapterNew2(mContext,
android.R.layout.simple_list_item_1, mVoterArray);
mListView.setAdapter(mListAdapter);
mListView.setSelectionFromTop(position, 0);
mListAdapter.notifyDataSetChanged();
}
}
}
代码 extDbUtil.getAddresslist(strAddress , limit += 20);方法是
public ArrayList<AddressInfo> getAddresslist(String strAddress,int limit) {
open();
ArrayList<AddressInfo> mAddressArray = new ArrayList<AddressInfo>();
String mQuery = "SELECT Address1,TotalMale,TotalFemale,TotalVoters, SrNo FROM "
+ TABLE_ADDRESS;
String Where = "";
if (!strAddress.equals("NA")) {
Where = " WHERE EAddress1 Like '%" + strAddress + "%'";
}
Log.i("SearchQuery", mQuery + Where + " LIMIT " + limit);
Cursor mCursor = mDatabase.rawQuery(mQuery + Where + " LIMIT " + limit,
null);
if (mCursor != null) {
if (mCursor.moveToFirst()) {
do {
AddressInfo mAddress = new AddressInfo();
mAddress.setSrNO(mCursor.getString(mCursor
.getColumnIndex("SrNo")));
mAddress.setAddress(mCursor.getString(mCursor
.getColumnIndex("Address1")));
mAddress.setTotalMale(mCursor.getString(mCursor
.getColumnIndex("TotalMale")));
mAddress.setTotalFemal(mCursor.getString(mCursor
.getColumnIndex("TotalFemale")));
mAddress.setTotalVoter(mCursor.getString(mCursor
.getColumnIndex("TotalVoters")));
} while (mCursor.moveToNext());
}
}
mCursor.close();
CleanUp();
return mAddressArray;
}
即将出现的错误是
01-03 22:59:05.310: D/memalloc(15369): ion: Mapped buffer base:0x51d44000 size:4096 offset:0 fd:87
01-03 22:59:05.310: I/SearchQuery(15369): SELECT Address1,TotalMale,TotalFemale,TotalVoters, SrNo FROM Addresses WHERE EAddress1 Like '%R%' LIMIT 20
01-03 22:59:05.330: W/dalvikvm(15369): threadid=16: thread exiting with uncaught exception (group=0x41a09600)
01-03 22:59:05.340: D/memalloc(15369): ion: Mapped buffer base:0x555da000 size:196608 offset:0 fd:84
01-03 22:59:05.340: D/memalloc(15369): ion: Mapped buffer base:0x51d4b000 size:4096 offset:0 fd:90
01-03 22:59:05.340: E/AndroidRuntime(15369): FATAL EXCEPTION: AsyncTask #3
01-03 22:59:05.340: E/AndroidRuntime(15369): java.lang.RuntimeException: An error occured while executing doInBackground()
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask.done(AsyncTask.java:299)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.lang.Thread.run(Thread.java:864)
01-03 22:59:05.340: E/AndroidRuntime(15369): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.Handler.<init>(Handler.java:121)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast$TN.<init>(Toast.java:322)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast.<init>(Toast.java:91)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast.makeText(Toast.java:238)
01-03 22:59:05.340: E/AndroidRuntime(15369): at com.phoenix.rajtantra.SearchByAdd$List_Async.doInBackground(SearchByAdd.java:284)
01-03 22:59:05.340: E/AndroidRuntime(15369): at com.phoenix.rajtantra.SearchByAdd$List_Async.doInBackground(SearchByAdd.java:1)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask.call(AsyncTask.java:287)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
01-03 22:59:05.340: E/AndroidRuntime(15369): ... 5 more
01-03 22:59:05.540: D/memalloc(15369): ion: Mapped buffer base:0x5570a000 size:1536000 offset:0 fd:92
01-03 22:59:05.540: D/memalloc(15369): ion: Mapped buffer base:0x53c33000 size:4096 offset:0 fd:94
如果您阅读堆栈跟踪，它会告诉您根本原因：
Caused by: java.lang.RuntimeException: Can't create handler inside thread
that has not called Looper.prepare()
another answer here on SO 详细介绍了这个问题。
您检查的方式，是否有任何数据错误。与其使用另一个字符串，不如检查 ArrayList 本身。在此处进行更改
private class LoadMoreAsync extends AsyncTask<Context, Void, Void>
这里：
@Override
protected String doInBackground(Context... arg0) {
// This just gets data from DB on background Thread
mVoterArray = new ArrayList<AddressInfo>();
mVoterArray = extDbUtil.getAddresslist(strAddress , limit += 20);
return null;
}
@Override
protected void onPostExecute(Void v) {
super.onPostExecute();
// If the mVoterArray isnt null and if it isnt empty, then there is some data in there.
if (mVoterArray != null && !mVoterArray.isEmpty()) {
int position = mListView.getLastVisiblePosition();
mListAdapter = new ListAdapterNew2(mContext,
android.R.layout.simple_list_item_1, mVoterArray);
mListView.setAdapter(mListAdapter);
mListView.setSelectionFromTop(position, 0);
mListAdapter.notifyDataSetChanged();
} else {
ToastUtils.showToast(mContext, "No Record Found!!");
}
}
编辑 1：
在您的 getAdressList() 方法中，您正在创建一个 AddressInfo 对象。但是您永远不会将它添加到您的 ArrayList 中。这就是为什么你总是得到没有数据的吐司。
do {
AddressInfo mAddress = new AddressInfo();
mAddress.setSrNO(mCursor.getString(mCursor
.getColumnIndex("SrNo")));
mAddress.setAddress(mCursor.getString(mCursor
.getColumnIndex("Address1")));
mAddress.setTotalMale(mCursor.getString(mCursor
.getColumnIndex("TotalMale")));
mAddress.setTotalFemal(mCursor.getString(mCursor
.getColumnIndex("TotalFemale")));
mAddress.setTotalVoter(mCursor.getString(mCursor
.getColumnIndex("TotalVoters")));
// Add AddressInfo obejct ot ArrayList!
mAddressArray.add(mAddress);
} while (mCursor.moveToNext());
我正在编写 android 应用程序，但在使用异步任务时它失败了，我有一个异步任务，错误出现在它的 doInBackground() 方法中，其他一切看起来都不错，但 doInBackground() 方法不起作用适当地 。在 doInBackground() 方法中，我编写了调试时从数据库中获取记录的代码，我发现记录是在 array-list 中获取的，但它们没有被馈送到
onPostExecute(String result) 请帮帮我...
private class LoadMoreAsync extends AsyncTask<Context, Void, String> {
private String strAddress;
public LoadMoreAsync(Context mContext,String strAddress) {
/*this.strCardNo = strCardNo;
this.strFirstName = strFirstName;
this.strMiddleName = strMiddleName;*/
this.strAddress = strAddress;
/*this.strCardNo = strCardNo;*/
}
@Override
protected void onPreExecute() {
super.onPreExecute();
ToastUtils.showToast(mContext, "Loading More...");
}
@Override
protected String doInBackground(Context... arg0) {
mVoterArray = new ArrayList<AddressInfo>();
mVoterArray = extDbUtil.getAddresslist(strAddress , limit += 20);
if (mVoterArray.isEmpty() || mVoterArray == null)
return null;
else
return "";
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
IOUtils.stopLoading();
if (result == null) {
ToastUtils.showToast(mContext, "No Record Found!!");
} else {
int position = mListView.getLastVisiblePosition();
mListAdapter = new ListAdapterNew2(mContext,
android.R.layout.simple_list_item_1, mVoterArray);
mListView.setAdapter(mListAdapter);
mListView.setSelectionFromTop(position, 0);
mListAdapter.notifyDataSetChanged();
}
}
}
代码 extDbUtil.getAddresslist(strAddress , limit += 20);方法是
public ArrayList<AddressInfo> getAddresslist(String strAddress,int limit) {
open();
ArrayList<AddressInfo> mAddressArray = new ArrayList<AddressInfo>();
String mQuery = "SELECT Address1,TotalMale,TotalFemale,TotalVoters, SrNo FROM "
+ TABLE_ADDRESS;
String Where = "";
if (!strAddress.equals("NA")) {
Where = " WHERE EAddress1 Like '%" + strAddress + "%'";
}
Log.i("SearchQuery", mQuery + Where + " LIMIT " + limit);
Cursor mCursor = mDatabase.rawQuery(mQuery + Where + " LIMIT " + limit,
null);
if (mCursor != null) {
if (mCursor.moveToFirst()) {
do {
AddressInfo mAddress = new AddressInfo();
mAddress.setSrNO(mCursor.getString(mCursor
.getColumnIndex("SrNo")));
mAddress.setAddress(mCursor.getString(mCursor
.getColumnIndex("Address1")));
mAddress.setTotalMale(mCursor.getString(mCursor
.getColumnIndex("TotalMale")));
mAddress.setTotalFemal(mCursor.getString(mCursor
.getColumnIndex("TotalFemale")));
mAddress.setTotalVoter(mCursor.getString(mCursor
.getColumnIndex("TotalVoters")));
} while (mCursor.moveToNext());
}
}
mCursor.close();
CleanUp();
return mAddressArray;
}
即将出现的错误是
01-03 22:59:05.310: D/memalloc(15369): ion: Mapped buffer base:0x51d44000 size:4096 offset:0 fd:87
01-03 22:59:05.310: I/SearchQuery(15369): SELECT Address1,TotalMale,TotalFemale,TotalVoters, SrNo FROM Addresses WHERE EAddress1 Like '%R%' LIMIT 20
01-03 22:59:05.330: W/dalvikvm(15369): threadid=16: thread exiting with uncaught exception (group=0x41a09600)
01-03 22:59:05.340: D/memalloc(15369): ion: Mapped buffer base:0x555da000 size:196608 offset:0 fd:84
01-03 22:59:05.340: D/memalloc(15369): ion: Mapped buffer base:0x51d4b000 size:4096 offset:0 fd:90
01-03 22:59:05.340: E/AndroidRuntime(15369): FATAL EXCEPTION: AsyncTask #3
01-03 22:59:05.340: E/AndroidRuntime(15369): java.lang.RuntimeException: An error occured while executing doInBackground()
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask.done(AsyncTask.java:299)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask.run(FutureTask.java:137)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask$SerialExecutor.run(AsyncTask.java:230)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.lang.Thread.run(Thread.java:864)
01-03 22:59:05.340: E/AndroidRuntime(15369): Caused by: java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.Handler.<init>(Handler.java:121)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast$TN.<init>(Toast.java:322)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast.<init>(Toast.java:91)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.widget.Toast.makeText(Toast.java:238)
01-03 22:59:05.340: E/AndroidRuntime(15369): at com.phoenix.rajtantra.SearchByAdd$List_Async.doInBackground(SearchByAdd.java:284)
01-03 22:59:05.340: E/AndroidRuntime(15369): at com.phoenix.rajtantra.SearchByAdd$List_Async.doInBackground(SearchByAdd.java:1)
01-03 22:59:05.340: E/AndroidRuntime(15369): at android.os.AsyncTask.call(AsyncTask.java:287)
01-03 22:59:05.340: E/AndroidRuntime(15369): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
01-03 22:59:05.340: E/AndroidRuntime(15369): ... 5 more
01-03 22:59:05.540: D/memalloc(15369): ion: Mapped buffer base:0x5570a000 size:1536000 offset:0 fd:92
01-03 22:59:05.540: D/memalloc(15369): ion: Mapped buffer base:0x53c33000 size:4096 offset:0 fd:94
如果您阅读堆栈跟踪，它会告诉您根本原因：
Caused by: java.lang.RuntimeException: Can't create handler inside thread
that has not called Looper.prepare()
another answer here on SO 详细介绍了这个问题。
您检查的方式，是否有任何数据错误。与其使用另一个字符串，不如检查 ArrayList 本身。在此处进行更改
private class LoadMoreAsync extends AsyncTask<Context, Void, Void>
这里：
@Override
protected String doInBackground(Context... arg0) {
// This just gets data from DB on background Thread
mVoterArray = new ArrayList<AddressInfo>();
mVoterArray = extDbUtil.getAddresslist(strAddress , limit += 20);
return null;
}
@Override
protected void onPostExecute(Void v) {
super.onPostExecute();
// If the mVoterArray isnt null and if it isnt empty, then there is some data in there.
if (mVoterArray != null && !mVoterArray.isEmpty()) {
int position = mListView.getLastVisiblePosition();
mListAdapter = new ListAdapterNew2(mContext,
android.R.layout.simple_list_item_1, mVoterArray);
mListView.setAdapter(mListAdapter);
mListView.setSelectionFromTop(position, 0);
mListAdapter.notifyDataSetChanged();
} else {
ToastUtils.showToast(mContext, "No Record Found!!");
}
}
编辑 1：
在您的 getAdressList() 方法中，您正在创建一个 AddressInfo 对象。但是您永远不会将它添加到您的 ArrayList 中。这就是为什么你总是得到没有数据的吐司。
do {
AddressInfo mAddress = new AddressInfo();
mAddress.setSrNO(mCursor.getString(mCursor
.getColumnIndex("SrNo")));
mAddress.setAddress(mCursor.getString(mCursor
.getColumnIndex("Address1")));
mAddress.setTotalMale(mCursor.getString(mCursor
.getColumnIndex("TotalMale")));
mAddress.setTotalFemal(mCursor.getString(mCursor
.getColumnIndex("TotalFemale")));
mAddress.setTotalVoter(mCursor.getString(mCursor
.getColumnIndex("TotalVoters")));
// Add AddressInfo obejct ot ArrayList!
mAddressArray.add(mAddress);
} while (mCursor.moveToNext());