我是初学程序员，我被分配了一个项目来制作库存应用程序。该应用程序使用Content Provider和Cursor Loader;在我实现了Content Provider和CurorLoader后，它曾经工作正常，但是，当我尝试将图像添加到listview中的项目时，它在启动时开始崩溃。
这是DbHelper类：
public class InventoryDbHelper extends SQLiteOpenHelper {
public static final String LOG_TAG = InventoryDbHelper.class.getSimpleName();
private static final String DATABASE_NAME = "inventory.db";
private static final int DATABASE_VERSION = 1;
public InventoryDbHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String SQL_CREATE_INVENTORY_TABLE = "CREATE TABLE " + InventoryEntry.TABLE_NAME + " ("
+ InventoryEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, "
+ InventoryEntry.COLUMN_INVENTORY_NAME + " TEXT NOT NULL, "
+ InventoryEntry.COLUMN_INVENTORY_SUPPLIER + " TEXT NOT NULL, "
+ InventoryEntry.COLUMN_INVENTORY_PRICE + " INTEGER NOT NULL, "
+ InventoryEntry.COLUMN_INVENTORY_QUANTITY + " INTEGER NOT NULL DEFAULT 0, "
+ InventoryEntry.COLUMN_INVENTORY_IMAGE + " TEXT NOT NULL DEFAULT 'No images', "
+ ");";
db.execSQL(SQL_CREATE_INVENTORY_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + InventoryEntry.TABLE_NAME);
onCreate(db);
}
这是合同：
public final class InventoryContract {
private InventoryContract() {}
public static final String CONTENT_AUTHORITY = "com.mesharialmutairi.inventoryapp";
public static final Uri BASE_CONTENT_URI = Uri.parse("content://" + CONTENT_AUTHORITY);
public static final String PATH_INVENTORIES = "inventories";
public static final class InventoryEntry implements BaseColumns {
public static final Uri CONTENT_URI = Uri.withAppendedPath(BASE_CONTENT_URI, PATH_INVENTORIES);
public static final String CONTENT_LIST_TYPE = ContentResolver.CURSOR_DIR_BASE_TYPE + "/" + CONTENT_AUTHORITY + "/" + PATH_INVENTORIES;
public static final String CONTENT_ITEM_TYPE = ContentResolver.CURSOR_ITEM_BASE_TYPE + "/" + CONTENT_AUTHORITY + "/" + PATH_INVENTORIES;
public final static String TABLE_NAME = "inventories";
public final static String _ID = BaseColumns._ID;
public final static String COLUMN_INVENTORY_IMAGE = "image";
public final static String COLUMN_INVENTORY_NAME = "name";
public final static String COLUMN_INVENTORY_SUPPLIER = "supplier";
public final static String COLUMN_INVENTORY_PRICE = "price";
public final static String COLUMN_INVENTORY_QUANTITY = "quantity";
public static Uri buildInventoryURI(long id) {
return ContentUris.withAppendedId(CONTENT_URI, id);
}
}
这是提供者：
public class InventoryProvider extends ContentProvider{
public static final String TAG = InventoryProvider.class.getSimpleName();
private static final int INVENTORIES = 100;
private static final int INVENTORY_ID = 101;
private static final UriMatcher iUriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
static {
iUriMatcher.addURI(InventoryContract.CONTENT_AUTHORITY, InventoryContract.PATH_INVENTORIES, INVENTORIES);
iUriMatcher.addURI(InventoryContract.CONTENT_AUTHORITY, InventoryContract.PATH_INVENTORIES + "/#", INVENTORY_ID);
}
private InventoryDbHelper inventoryDbHelper;
@Override
public boolean onCreate() {
Log.i(TAG, "DB helper is prepared");
inventoryDbHelper = new InventoryDbHelper(getContext());
return true;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
SQLiteDatabase database = inventoryDbHelper.getReadableDatabase();
Cursor cursor;
int match = iUriMatcher.match(uri);
switch (match) {
case INVENTORIES:
cursor = database.query(InventoryEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
case INVENTORY_ID:
selection = InventoryEntry._ID + "=?";
selectionArgs = new String[] { String.valueOf(ContentUris.parseId(uri)) };
cursor = database.query(InventoryEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, sortOrder);
break;
default:
throw new IllegalArgumentException("Cannot query unknown URI " + uri);
}
cursor.setNotificationUri(getContext().getContentResolver(), uri);
return cursor;
}
@Override
public Uri insert(Uri uri, ContentValues contentValues) {
final int match = iUriMatcher.match(uri);
switch (match) {
case INVENTORIES:
return insertInventory(uri, contentValues);
default:
throw new IllegalArgumentException("Insertion is not supported for " + uri);
}
}
private Uri insertInventory(Uri uri, ContentValues values) {
String name = values.getAsString(InventoryEntry.COLUMN_INVENTORY_NAME);
if (name == null) {
throw new IllegalArgumentException("Inventory requires a name");
}
String supplier = values.getAsString(InventoryEntry.COLUMN_INVENTORY_SUPPLIER);
if (supplier == null) {
throw new IllegalArgumentException("Inventory requires a supplier");
}
Integer price = values.getAsInteger(InventoryEntry.COLUMN_INVENTORY_PRICE);
if (price != null && price < 0) {
throw new IllegalArgumentException("Inventory requires a valid price");
}
Integer quantity = values.getAsInteger(InventoryEntry.COLUMN_INVENTORY_QUANTITY);
if (quantity != null && quantity < 0) {
throw new IllegalArgumentException("Inventory requires a valid quantity");
}
SQLiteDatabase database = inventoryDbHelper.getWritableDatabase();
long id = database.insert(InventoryEntry.TABLE_NAME, null, values);
if (id == -1) {
Log.e(TAG, "Failed to insert row for " + uri);
return null;
}
getContext().getContentResolver().notifyChange(uri, null);
return ContentUris.withAppendedId(uri, id);
}
@Override
public int update(Uri uri, ContentValues contentValues, String selection, String[] selectionArgs) {
final int match = iUriMatcher.match(uri);
switch (match) {
case INVENTORIES:
return updateInventory(uri, contentValues, selection, selectionArgs);
case INVENTORY_ID:
selection = InventoryEntry._ID + "=?";
selectionArgs = new String[] { String.valueOf(ContentUris.parseId(uri)) };
return updateInventory(uri, contentValues, selection, selectionArgs);
default:
throw new IllegalArgumentException("Update is not supported for " + uri);
}
}
private int updateInventory(Uri uri, ContentValues values, String selection, String[] selectionArgs) {
if (values.containsKey(InventoryEntry.COLUMN_INVENTORY_NAME)) {
String name = values.getAsString(InventoryContract.InventoryEntry.COLUMN_INVENTORY_NAME);
if (name == null) {
throw new IllegalArgumentException("Inventory requires a name");
}
}
if (values.containsKey(InventoryEntry.COLUMN_INVENTORY_SUPPLIER)) {
String supplier = values.getAsString(InventoryContract.InventoryEntry.COLUMN_INVENTORY_SUPPLIER);
if (supplier == null) {
throw new IllegalArgumentException("Inventory requires a supplier");
}
}
if (values.containsKey(InventoryEntry.COLUMN_INVENTORY_PRICE)) {
Integer price = values.getAsInteger(InventoryContract.InventoryEntry.COLUMN_INVENTORY_PRICE);
if (price != null && price < 0) {
throw new IllegalArgumentException("Inventory requires valid price");
}
}
if (values.containsKey(InventoryEntry.COLUMN_INVENTORY_QUANTITY)) {
Integer quantity = values.getAsInteger(InventoryEntry.COLUMN_INVENTORY_QUANTITY);
if (quantity != null && quantity < 0) {
throw new IllegalArgumentException("Inventory requires valid quantity");
}
}
if (values.size() == 0) {
return 0;
}
SQLiteDatabase database = inventoryDbHelper.getWritableDatabase();
int rowsUpdated = database.update(InventoryEntry.TABLE_NAME, values, selection, selectionArgs);
if (rowsUpdated != 0) {
getContext().getContentResolver().notifyChange(uri, null);
}
return rowsUpdated;
}
@Override
public int delete(Uri uri, String selection, String [] selectionArgs) {
SQLiteDatabase database = inventoryDbHelper.getWritableDatabase();
int rowsDeleted;
final int match = iUriMatcher.match(uri);
switch (match) {
case INVENTORIES:
rowsDeleted = database.delete(InventoryEntry.TABLE_NAME, selection, selectionArgs);
break;
case INVENTORY_ID:
selection = InventoryEntry._ID + "=?";
selectionArgs = new String[] {String.valueOf(ContentUris.parseId(uri)) };
rowsDeleted = database.delete(InventoryEntry.TABLE_NAME, selection,selectionArgs);
break;
default:
throw new IllegalArgumentException("Deletion is not supported for " + uri);
}
if (rowsDeleted != 0) {
getContext().getContentResolver().notifyChange(uri, null);
}
return rowsDeleted;
}
@Override
public String getType(Uri uri) {
final int match = iUriMatcher.match(uri);
switch (match) {
case INVENTORIES:
return InventoryEntry.CONTENT_LIST_TYPE;
case INVENTORY_ID:
return InventoryEntry.CONTENT_ITEM_TYPE;
default:
throw new IllegalArgumentException("Unknown URI " + uri + " with match " + match);
}
}
这是MainActivity：
public class MainActivity extends AppCompatActivity implements LoaderManager.LoaderCallbacks<Cursor> {
private static final int INVENTORY_LOADER = 0;
InventoryCursorAdapter iCursoradapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener(){
@Override
public void onClick(View view) {
Intent intent = new Intent(MainActivity.this, EditorActivity.class);
startActivity(intent);
}
});
ListView inventoryListView = (ListView) findViewById(R.id.list);
View emptyView = findViewById(R.id.empty_view);
inventoryListView.setEmptyView(emptyView);
iCursoradapter = new InventoryCursorAdapter(this, null);
inventoryListView.setAdapter(iCursoradapter);
inventoryListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> adapterView, View view, int position, long id) {
Intent intent = new Intent(MainActivity.this, EditorActivity.class);
Uri currentInventoryUri = ContentUris.withAppendedId(InventoryEntry.CONTENT_URI, id);
intent.setData(currentInventoryUri);
startActivity(intent);
}
});
getLoaderManager().initLoader(INVENTORY_LOADER, null, this);
}
private void insertInventory() {
ContentValues values = new ContentValues();
values.put(InventoryEntry.COLUMN_INVENTORY_NAME, "Sunglasses");
values.put(InventoryEntry.COLUMN_INVENTORY_SUPPLIER, "Elegance");
values.put(InventoryEntry.COLUMN_INVENTORY_PRICE, "75");
values.put(InventoryEntry.COLUMN_INVENTORY_QUANTITY, "3");
Uri newUri = getContentResolver().insert(InventoryEntry.CONTENT_URI, values);
}
private void deleteAllInventories() {
int rowsDeleted = getContentResolver().delete(InventoryEntry.CONTENT_URI, null, null);
Log.v("MainActivity", rowsDeleted + " rows deleted from inventory database");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_catalog, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.action_insert_dummy_data:
insertInventory();
return true;
case R.id.action_delete_all_entries:
deleteAllInventories();
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle bundle) {
String[] projection = {
InventoryEntry._ID,
InventoryEntry.COLUMN_INVENTORY_NAME,
InventoryEntry.COLUMN_INVENTORY_SUPPLIER,
InventoryEntry.COLUMN_INVENTORY_PRICE,
InventoryEntry.COLUMN_INVENTORY_QUANTITY,
InventoryEntry.COLUMN_INVENTORY_IMAGE};
return new CursorLoader(this, InventoryEntry.CONTENT_URI, projection, null, null, null);
}
@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
iCursoradapter.swapCursor(data);
}
@Override
public void onLoaderReset(Loader<Cursor> loader) {
iCursoradapter.swapCursor(null);
}
这是CursorAdapter：
public class InventoryCursorAdapter extends CursorAdapter {
private static final String TAG = InventoryCursorAdapter.class.getSimpleName();
public InventoryCursorAdapter(Context context, Cursor c) {
super(context, c, 0);
}
@Override
public View newView(Context context, Cursor cursor, ViewGroup parent) {
return LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
}
@Override
public void bindView(View view, Context context, Cursor cursor) {
TextView nameTextView = (TextView) view.findViewById(R.id.name);
TextView supplierTextView = (TextView) view.findViewById(R.id.supplier);
TextView priceTextView = (TextView) view.findViewById(R.id.price);
TextView quantityTextView = (TextView) view.findViewById(R.id.quantity);
ImageView imageImageView = (ImageView) view.findViewById(R.id.image);
int nameColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_INVENTORY_NAME);
int supplierColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_INVENTORY_SUPPLIER);
int priceColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_INVENTORY_PRICE);
int quantityColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_INVENTORY_QUANTITY);
int imageColumnIndex = cursor.getColumnIndex(InventoryEntry.COLUMN_INVENTORY_IMAGE);
int id = cursor.getInt(cursor.getColumnIndex(InventoryEntry._ID));
String inventoryName = cursor.getString(nameColumnIndex);
String inventorySupplier = cursor.getString(supplierColumnIndex);
String inventoryPrice = cursor.getString(priceColumnIndex);
int quantity = cursor.getInt(quantityColumnIndex);
Uri imageUri = Uri.parse(cursor.getString(imageColumnIndex));
final Uri currentInventoryUri = ContentUris.withAppendedId(InventoryEntry.CONTENT_URI, id);
Log.d(TAG, "genero Uri: " + currentInventoryUri + " Inventory name: " + inventoryName + " id: " + id);
if (TextUtils.isEmpty(inventorySupplier)) {
inventorySupplier = context.getString(R.string.unknown_supplier);
}
nameTextView.setText(inventoryName);
supplierTextView.setText(inventorySupplier);
priceTextView.setText(inventoryPrice);
quantityTextView.setText(quantity);
Glide.with(context).load(imageUri).placeholder(R.mipmap.ic_launcher).error(ic_insert_placeholder).crossFade().centerCrop().into(imageImageView);
}
答案 0 :(得分：1)
我最初的想法是删除SQL create table语句中的最后一个逗号。但是您应该从Android监视器检查并共享错误堆栈，如果不能通过该步骤解决，则至少可以识别大多数问题。祝你好运，听起来像你在做Udacity android初学者课程。这很有趣我几乎在下一堂课的一半。保持动力。
答案 1 :(得分：0)
+ InventoryEntry.COLUMN_INVENTORY_IMAGE + " TEXT NOT NULL DEFAULT 'No images', "
+ ");";
尝试将其更改为
+ InventoryEntry.COLUMN_INVENTORY_IMAGE + " TEXT NOT NULL DEFAULT 'No images'");";