使用光標加載器時，應用程序崩潰時啓動

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該應用程序在第一次啓動時發生崩潰，並在使用CursorLoaders回調方法時給我那些錯誤（在此之前，我在主UI中加載數據庫表並且在此情況下沒有發生任何事情，更改爲CursorLoader加載和更改背景中出現此問題的UI），我不知道導致應用程序崩潰的代碼行，但我認爲這些導入有幫助，請幫忙？使用光標加載器時，應用程序崩潰時啓動

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$3.done(AsyncTask.java:304) 
     at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:355) 
     at java.util.concurrent.FutureTask.setException(FutureTask.java:222) 
     at java.util.concurrent.FutureTask.run(FutureTask.java:242) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
     at java.util.concurrent.ThreadPoolExecutor$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$2.call(AsyncTask.java:292) 
     at java.util.concurrent.FutureTask.run(FutureTask.java:237) 
     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1112) 
     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:587) 
     at java.lang.Thread.run(Thread.java:818)

這是應用程序的全部鏈路的鏈路上https://github.com/NayirMicheal/petsapp，該應用創建的寵物的數據庫和保存那些寵物進入數據庫，然後使用列表視圖throught CursorLoader從數據庫retriving回以及顯示檢索到的UI數據和CursorAdapter的，這裏是在mainActivity

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); 
} 
}

來源

2017-03-30 Nayir Micheal

你能否包括你的合同類和你的助手類？該錯誤似乎與您的列。 –

https://www.github.com/NayirMicheal/petsapp這是一個鏈接到整個應用程序的完整結構 –

這個問題將是非常巨大的，不能被閱讀，我認爲錯誤是在主要活動，因爲它的工作正確的時候加載在主UI的數據庫數據，但試圖加載它使用CursorLoader使這次崩潰 –

我認爲你必須使用PetContract這裏的代碼：

@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); 
}

我還將getApplicationContext（）更改爲此爲了獲得活動上下文。我不確定這一點，但這正是我在裝載機上所做的。嘗試一下，看看它是否有效，但我認爲主要錯誤將在合同部分。

來源

2017-03-30 01:05:15

感謝問題是在這一行PetContract.CONTENT_URI –

使用光標加載器時，應用程序崩潰時啓動

回答

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