使用 cursorloader 启动时应用程序崩溃
The app crashes when start when using cursorloader
该应用程序在首次启动时崩溃并在使用 CursorLoaders 回调方法时给我这些错误（在此之前我在主 UI 中加载数据库 table 但在这种情况下没有任何反应但是当更改为 CursorLoader 以在后台加载和更改 UI 时，出现了这个问题），我不知道导致应用程序崩溃的代码行，但我认为导入有帮助，请帮忙？
03-30 02:10:06.441 1564-1591/android.process.acore E/DatabaseUtils﹕ Writing exception to parcel
java.lang.IllegalArgumentException: Invalid column name
at android.database.sqlite.SQLiteQueryBuilder.computeProjection(SQLiteQueryBuilder.java:632)
at android.database.sqlite.SQLiteQueryBuilder.buildQuery(SQLiteQueryBuilder.java:447)
at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:393)
at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:6493)
at com.android.providers.contacts.ContactsProvider2.queryLocal(ContactsProvider2.java:6443)
at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:5038)
at android.content.ContentProvider$Transport.query(ContentProvider.java:211)
at android.content.ContentProviderNative.onTransact(ContentProviderNative.java:112)
at android.os.Binder.execTransact(Binder.java:446)
03-30 02:10:06.446 24098-24122/com.example.android.pets E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.example.android.pets, PID: 24098
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:304)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.IllegalArgumentException: Invalid column name
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:167)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:137)
at android.content.ContentProviderProxy.query(ContentProviderNative.java:421)
at android.content.ContentResolver.query(ContentResolver.java:478)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:64)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:42)
at android.content.AsyncTaskLoader.onLoadInBackground(AsyncTaskLoader.java:312)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:69)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:57)
at android.os.AsyncTask.call(AsyncTask.java:292)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
这是 https://github.com/NayirMicheal/petsapp 上整个 link 应用程序的 link，此应用程序创建宠物数据库并将这些宠物保存到数据库中，然后从数据库中检索它们，然后使用列表视图通过 CursorLoader 和 CursorAdapter 显示检索到 UI 中的数据
这是 mainActivity
的代码
package com.example.android.pets;
import android.content.ContentValues;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;
import com.example.android.pets.data.PetContract;
import com.example.android.pets.data.PetDbHelper;
public class CatalogActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {
private static final int URI_LOADER = 0;
private PetDbHelper mDbHelper;
SQLiteDatabase db;
ListView lvItems;
PetCursorAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_catalog);
lvItems = (ListView) findViewById(R.id.lstview);
View emptyView = findViewById(R.id.empty_view);
lvItems.setEmptyView(emptyView);
adapter = new PetCursorAdapter(this, null);
lvItems.setAdapter(adapter);
// Setup FAB to open EditorActivity
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(CatalogActivity.this, EditorActivity.class);
startActivity(intent);
}
});
mDbHelper = new PetDbHelper(this);
db=mDbHelper.getWritableDatabase();
getLoaderManager().initLoader(URI_LOADER, null, this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu options from the res/menu/menu_catalog.xml file.
// This adds menu items to the app bar.
getMenuInflater().inflate(R.menu.menu_catalog, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// User clicked on a menu option in the app bar overflow menu
switch (item.getItemId()) {
// Respond to a click on the "Insert dummy data" menu option
case R.id.action_insert_dummy_data:
insertdummy();
return true;
// Respond to a click on the "Delete all entries" menu option
case R.id.action_delete_all_entries:
// Do nothing for now
return true;
}
return super.onOptionsItemSelected(item);
}
private void insertdummy() {
ContentValues values=new ContentValues();
values.put(PetContract.PetEntry.COLUMN_PET_NAME, "toto");
values.put(PetContract.PetEntry.COLUMN_PET_BREED,"terrier");
values.put(PetContract.PetEntry.COLUMN_PET_GENDER, PetContract.PetEntry.GENDER_MALE);
values.put(PetContract.PetEntry.COLUMN_PET_WEIGHT, 7);
Uri URI_ID= getContentResolver().insert(PetContract.PetEntry.CONTENT_URI, values);
if(URI_ID==null)
Toast.makeText(getApplicationContext(), R.string.fail_save,Toast.LENGTH_LONG).show();
else
Toast.makeText(getApplicationContext(), R.string.success_save, Toast.LENGTH_LONG).show();
}
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {PetContract.PetEntry._ID,
PetContract.PetEntry.COLUMN_PET_NAME,
PetContract.PetEntry.COLUMN_PET_BREED};
String selection = null;
String selectionArgs[] =null;
return new CursorLoader(getApplicationContext(), ContactsContract.Data.CONTENT_URI,
projection, selection, selectionArgs, null);
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
adapter.swapCursor(cursor);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
adapter.swapCursor(null);
}
}
我想你必须在这里使用 PetContract :
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {PetContract.PetEntry._ID,
PetContract.PetEntry.COLUMN_PET_NAME,PetContract.PetEntry.COLUMN_PET_BREED};
String selection = null;
String selectionArgs[] =null;
return new CursorLoader(this, PetContract.CONTENT_URI,
projection, selection, selectionArgs, null);
}
我还将 getApplicationContext() 更改为 this 以获得 Activity 上下文。我不确定，但这就是我在装载机中所做的。尝试一下，看看它是否有效，但我认为主要错误在合同部分。
该应用程序在首次启动时崩溃并在使用 CursorLoaders 回调方法时给我这些错误（在此之前我在主 UI 中加载数据库 table 但在这种情况下没有任何反应但是当更改为 CursorLoader 以在后台加载和更改 UI 时，出现了这个问题），我不知道导致应用程序崩溃的代码行，但我认为导入有帮助，请帮忙？
03-30 02:10:06.441 1564-1591/android.process.acore E/DatabaseUtils﹕ Writing exception to parcel
java.lang.IllegalArgumentException: Invalid column name
at android.database.sqlite.SQLiteQueryBuilder.computeProjection(SQLiteQueryBuilder.java:632)
at android.database.sqlite.SQLiteQueryBuilder.buildQuery(SQLiteQueryBuilder.java:447)
at android.database.sqlite.SQLiteQueryBuilder.query(SQLiteQueryBuilder.java:393)
at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:6493)
at com.android.providers.contacts.ContactsProvider2.queryLocal(ContactsProvider2.java:6443)
at com.android.providers.contacts.ContactsProvider2.query(ContactsProvider2.java:5038)
at android.content.ContentProvider$Transport.query(ContentProvider.java:211)
at android.content.ContentProviderNative.onTransact(ContentProviderNative.java:112)
at android.os.Binder.execTransact(Binder.java:446)
03-30 02:10:06.446 24098-24122/com.example.android.pets E/AndroidRuntime﹕ FATAL EXCEPTION: AsyncTask #1
Process: com.example.android.pets, PID: 24098
java.lang.RuntimeException: An error occured while executing doInBackground()
at android.os.AsyncTask.done(AsyncTask.java:304)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355)
at java.util.concurrent.FutureTask.setException(FutureTask.java:222)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.IllegalArgumentException: Invalid column name
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:167)
at android.database.DatabaseUtils.readExceptionFromParcel(DatabaseUtils.java:137)
at android.content.ContentProviderProxy.query(ContentProviderNative.java:421)
at android.content.ContentResolver.query(ContentResolver.java:478)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:64)
at android.content.CursorLoader.loadInBackground(CursorLoader.java:42)
at android.content.AsyncTaskLoader.onLoadInBackground(AsyncTaskLoader.java:312)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:69)
at android.content.AsyncTaskLoader$LoadTask.doInBackground(AsyncTaskLoader.java:57)
at android.os.AsyncTask.call(AsyncTask.java:292)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587)
at java.lang.Thread.run(Thread.java:818)
这是 https://github.com/NayirMicheal/petsapp 上整个 link 应用程序的 link，此应用程序创建宠物数据库并将这些宠物保存到数据库中，然后从数据库中检索它们，然后使用列表视图通过 CursorLoader 和 CursorAdapter 显示检索到 UI 中的数据 这是 mainActivity
的代码package com.example.android.pets;
import android.content.ContentValues;
import android.app.LoaderManager;
import android.content.CursorLoader;
import android.content.Loader;
import android.content.Intent;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.support.design.widget.FloatingActionButton;
import android.support.v7.app.AppCompatActivity;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.Toast;
import com.example.android.pets.data.PetContract;
import com.example.android.pets.data.PetDbHelper;
public class CatalogActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {
private static final int URI_LOADER = 0;
private PetDbHelper mDbHelper;
SQLiteDatabase db;
ListView lvItems;
PetCursorAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_catalog);
lvItems = (ListView) findViewById(R.id.lstview);
View emptyView = findViewById(R.id.empty_view);
lvItems.setEmptyView(emptyView);
adapter = new PetCursorAdapter(this, null);
lvItems.setAdapter(adapter);
// Setup FAB to open EditorActivity
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(CatalogActivity.this, EditorActivity.class);
startActivity(intent);
}
});
mDbHelper = new PetDbHelper(this);
db=mDbHelper.getWritableDatabase();
getLoaderManager().initLoader(URI_LOADER, null, this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu options from the res/menu/menu_catalog.xml file.
// This adds menu items to the app bar.
getMenuInflater().inflate(R.menu.menu_catalog, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// User clicked on a menu option in the app bar overflow menu
switch (item.getItemId()) {
// Respond to a click on the "Insert dummy data" menu option
case R.id.action_insert_dummy_data:
insertdummy();
return true;
// Respond to a click on the "Delete all entries" menu option
case R.id.action_delete_all_entries:
// Do nothing for now
return true;
}
return super.onOptionsItemSelected(item);
}
private void insertdummy() {
ContentValues values=new ContentValues();
values.put(PetContract.PetEntry.COLUMN_PET_NAME, "toto");
values.put(PetContract.PetEntry.COLUMN_PET_BREED,"terrier");
values.put(PetContract.PetEntry.COLUMN_PET_GENDER, PetContract.PetEntry.GENDER_MALE);
values.put(PetContract.PetEntry.COLUMN_PET_WEIGHT, 7);
Uri URI_ID= getContentResolver().insert(PetContract.PetEntry.CONTENT_URI, values);
if(URI_ID==null)
Toast.makeText(getApplicationContext(), R.string.fail_save,Toast.LENGTH_LONG).show();
else
Toast.makeText(getApplicationContext(), R.string.success_save, Toast.LENGTH_LONG).show();
}
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {PetContract.PetEntry._ID,
PetContract.PetEntry.COLUMN_PET_NAME,
PetContract.PetEntry.COLUMN_PET_BREED};
String selection = null;
String selectionArgs[] =null;
return new CursorLoader(getApplicationContext(), ContactsContract.Data.CONTENT_URI,
projection, selection, selectionArgs, null);
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
adapter.swapCursor(cursor);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
adapter.swapCursor(null);
}
}
我想你必须在这里使用 PetContract :
@Override
public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
String[] projection = {PetContract.PetEntry._ID,
PetContract.PetEntry.COLUMN_PET_NAME,PetContract.PetEntry.COLUMN_PET_BREED};
String selection = null;
String selectionArgs[] =null;
return new CursorLoader(this, PetContract.CONTENT_URI,
projection, selection, selectionArgs, null);
}
我还将 getApplicationContext() 更改为 this 以获得 Activity 上下文。我不确定，但这就是我在装载机中所做的。尝试一下，看看它是否有效，但我认为主要错误在合同部分。