有人能帮我理解这段代码有什么问题吗？
我希望能够将与查询关联的所有联系人添加到 ArrayList。
但是仅使用“添加”命令会使循环显然覆盖它并再次使大小为 1。但是使用带有索引的“添加”方法会导致此错误。 'IndexOutOfBoundsError'。
请。帮帮我。
这是错误日志。
08-14 21:36:29.893 20439-20439/? E/Zygote﹕ MountEmulatedStorage()
08-14 21:36:29.893 20439-20439/? E/Zygote﹕ v2
08-14 21:36:29.943 20439-20439/? E/SELinux﹕ [DEBUG] get_category: variable
seinfo: default sensitivity: NULL, cateogry: NULL
08-14 21:36:44.973 20439-20439/com.cmpe277.personalassistant E/MA﹕
search_intent_has_started
08-14 21:36:45.103 20439-20439/com.cmpe277.personalassistant E/DU﹕
startQuery has launched
08-14 21:36:45.103 20439-20439/com.cmpe277.personalassistant E/DU﹕ query =
chemist
08-14 21:36:45.383 20439-20439/com.cmpe277.personalassistant
E/CLoaderCallbacks﹕ Nothing is null?!
08-14 21:36:53.293 20439-20439/com.cmpe277.personalassistant E/MA﹕
search_intent_has_started
08-14 21:36:53.393 20439-20439/com.cmpe277.personalassistant E/DU﹕
startQuery has launched
08-14 21:36:53.393 20439-20439/com.cmpe277.personalassistant E/DU﹕ query =
leela ashok
08-14 21:36:53.533 20439-20439/com.cmpe277.personalassistant
E/CLoaderCallbacks﹕ Nothing is null?!
08-14 21:36:53.563 20439-20439/com.cmpe277.personalassistant
E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.cmpe277.personalassistant, PID: 20439
java.lang.IndexOutOfBoundsException: Invalid index 1, size is 0
at
java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
at java.util.ArrayList.add(ArrayList.java:147)
at
com.cmpe277.personalassistant.ContactablesLoaderCallbacks.onLoadFinished(ContactablesLoaderCallbacks.java:117)
at com.cmpe277.personalassistant.ContactablesLoaderCallbacks.onLoadFinished(ContactablesLoaderCallbacks.java:22)
at android.app.LoaderManagerImpl$LoaderInfo.callOnLoadFinished(LoaderManager.java:483)
at android.app.LoaderManagerImpl$LoaderInfo.onLoadComplete(LoaderManager.java:451)
at android.content.Loader.deliverResult(Loader.java:144)
at android.content.CursorLoader.deliverResult(CursorLoader.java:109)
at android.content.CursorLoader.deliverResult(CursorLoader.java:42)
at android.content.AsyncTaskLoader.dispatchOnLoadComplete(AsyncTaskLoader.java:265)
at android.content.AsyncTaskLoader$LoadTask.onPostExecute(AsyncTaskLoader.java:92)
at android.os.AsyncTask.finish(AsyncTask.java:632)
at android.os.AsyncTask.access$600(AsyncTask.java:177)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:645)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5832)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
这是我的代码:
package com.kishore_kumar.callbacks;
import android.app.Activity;
import android.app.LoaderManager;
import android.content.Context;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract.CommonDataKinds;
import android.util.Log;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.Arrays;
/**
* Helper class to handle all the callbacks that occur when interacting with
loaders. Most of the
* interesting code in this sample app will be in this file.
*/
public class ContactablesLoaderCallbacks implements
LoaderManager.LoaderCallbacks<Cursor> {
Context mContext;
int counter = 0;
public static final String QUERY_KEY = "query";
public static final String TAG = "CLoaderCallbacks";
public ContactablesLoaderCallbacks(Context context) {
mContext = context;
}
@Override
public Loader<Cursor> onCreateLoader(int loaderIndex, Bundle args) {
// Where the Contactables table excels is matching text queries,
// not just data dumps from Contacts db. One search term is used to query
// display name, email address and phone number. In this case, the
query was extracted
// from an incoming intent in the handleIntent() method, via the
// intent.getStringExtra() method.
// BEGIN_INCLUDE(uri_with_query)
String query = args.getString(QUERY_KEY);
Uri uri = Uri.withAppendedPath(
CommonDataKinds.Contactables.CONTENT_FILTER_URI, query);
// END_INCLUDE(uri_with_query)
// BEGIN_INCLUDE(cursor_loader)
// Easy way to limit the query to contacts with phone numbers.
String selection =
CommonDataKinds.Contactables.HAS_PHONE_NUMBER + " = " + 1;
// Sort results such that rows for the same contact stay together.
String sortBy = CommonDataKinds.Contactables.LOOKUP_KEY;
return new CursorLoader(
mContext, // Context
uri, // URI representing the table/resource to be queried
null, // projection - the list of columns to return. Null
means "all"
selection, // selection - Which rows to return (condition rows
must match)
null, // selection args - can be provided separately and
subbed into selection.
sortBy); // string specifying sort order
// END_INCLUDE(cursor_loader)
}
@Override
public void onLoadFinished(Loader<Cursor> arg0, Cursor cursor) {
TextView tv = (TextView)
((Activity)mContext).findViewById(R.id.sample_output);
if(tv == null) {
Log.e(TAG, "TextView is null?!");
} else if (mContext == null) {
Log.e(TAG, "Context is null?");
} else {
Log.e(TAG, "Nothing is null?!");
}
// Reset text in case of a previous query
tv.setText(mContext.getText(R.string.intro_message) + "\n\n");
if (cursor.getCount() == 0) {
return;
}
// Pulling the relevant value from the cursor requires knowing the
column index to pull
// it from.
// BEGIN_INCLUDE(get_columns)
int phoneColumnIndex =
cursor.getColumnIndex(CommonDataKinds.Phone.NUMBER);
int emailColumnIndex =
cursor.getColumnIndex(CommonDataKinds.Email.ADDRESS);
int nameColumnIndex =
cursor.getColumnIndex(CommonDataKinds.Contactables.DISPLAY_NAME);
int lookupColumnIndex =
cursor.getColumnIndex(CommonDataKinds.Contactables.LOOKUP_KEY);
int typeColumnIndex =
cursor.getColumnIndex(CommonDataKinds.Contactables.MIMETYPE);
// END_INCLUDE(get_columns)
cursor.moveToFirst();
// Lookup key is the easiest way to verify a row of data is for the same
// contact as the previous row.
String lookupKey = "";
do {
// BEGIN_INCLUDE(lookup_key)
String currentLookupKey = cursor.getString(lookupColumnIndex);
if (!lookupKey.equals(currentLookupKey)) {
String displayName = cursor.getString(nameColumnIndex);
tv.append(displayName + "\n");
lookupKey = currentLookupKey;
}
// END_INCLUDE(lookup_key)
// BEGIN_INCLUDE(retrieve_data)
// The data type can be determined using the mime type column.
String mimeType = cursor.getString(typeColumnIndex);
if (mimeType.equals(CommonDataKinds.Phone.CONTENT_ITEM_TYPE)) {
tv.append("\tPhone Number: " +
cursor.getString(phoneColumnIndex) + "\n");
//@TeneCursum this is roughly about where the error gets thrown out
ArrayList<String> mylist = new ArrayList<String>();
mylist.add(counter, cursor.getString(phoneColumnIndex)); //this
adds an element to the list.
tv.append("size = "+mylist.size());
counter++;
} else if (mimeType.equals(CommonDataKinds.Email.CONTENT_ITEM_TYPE))
{
tv.append("");
}
// END_INCLUDE(retrieve_data)
// Look at DDMS to see all the columns returned by a query to
Contactables.
// Behold, the firehose!
for(String column : cursor.getColumnNames()) {
Log.d(TAG, column + column + ": " +
cursor.getString(cursor.getColumnIndex(column)) + "\n");
}
} while (cursor.moveToNext());
}
@Override
public void onLoaderReset(Loader<Cursor> cursorLoader) {
}
}
我是初学者。所以请帮助我理解。
最佳答案
放ArrayList<String> mylist = new ArrayList<String>();在 do { 之前构造。问题是您正在递增计数器，但每次都在创建一个新列表。 do-while 第二次执行时，counter = 1并且数组是新的，所以它的大小为 0。因此，添加 myList.add(1, object)会失败。
关于java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java :255) Error，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32014513/