当我使用使用数据库的活动并将产品详细信息添加到数据库时，我的应用崩溃了
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
我已经实现了所需的库... 我的数据库活动
public class Database extends SQLiteAssetHelper {
private static final String DB_NAME = "app.db" ;
private static final int DB_VER = 1 ;
public Database(Context context) {
super(context, DB_NAME, null, DB_VER);
}
public List<Order> getCarts() {
SQLiteDatabase db = getReadableDatabase();
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
String[] sqlSelect = {"ProductName", "ProductId", "Quantity", "Price", "Discount"};
String sqlTable = "OrderDetail";
qb.setTables(sqlTable);
Cursor cursor = qb.query(db, sqlSelect, null, null, null, null, null);
final List<Order> result = new ArrayList<>();
if (cursor.moveToFirst()) {
//13:30
do {
result.add(new Order(cursor.getString(cursor.getColumnIndex("ProductId")),
cursor.getString(cursor.getColumnIndex("ProductName")),
cursor.getString(cursor.getColumnIndex("Quantity")),
cursor.getString(cursor.getColumnIndex("Price")),
cursor.getString(cursor.getColumnIndex("Discount"))
));
}while(cursor.moveToNext());
}
return result;
}
public void addToCart (Order order){
SQLiteDatabase db=getReadableDatabase(); //here is the crash line
String query = String.format("INSERT INTO OrderDetail(ProductId,Quantity,ProductName,Price,Discount) VALUES ('%s','%s','%s','%s','%s');",
order.getProductId(),
order.getProductName(),
order.getDiscount(),
order.getPrice(),
order.getQuantity());
db.execSQL(query);
}
public void cleanCart()
{
SQLiteDatabase db=getReadableDatabase();
String query = String.format("DELETE FROM OrderDetail");
db.execSQL(query);
}
}
logcat：
Process: com.OverRout.KFood, PID: 2637
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:209)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:193)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:463)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:185)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:177)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:808)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:793)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:696)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:671)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:264)
at com.OverRout.KFood.Database.Database.addToCart(Database.java:45)
at com.OverRout.KFood.food_detail$1.onClick(food_detail.java:47)
at android.view.View.performClick(View.java:5637)
at android.view.View$PerformClick.run(View.java:22429)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)
答案 0 :(得分：0)
使用SQLiteAssetHelper时，导致此错误的原因（也是应消除的第一个原因）是将从资产中复制的数据库不在预期的位置。
SQLiteAssetHelper希望要复制的数据库文件位于资产文件夹内的 databases 文件夹中。
因此，很可能您没有将文件 app.db 复制到资产/数据库文件夹/目录中。
如果不是，那么您会在日志中获取包含其他异常的日志，例如：-
2019-01-08 06:13:53.259 1882-1882/? W/SQLiteAssetHelper: copying database from assets...
2019-01-08 06:13:53.261 1882-1882/? E/SQLiteAssetHelper: Couldn't open app.db for writing (will try read-only):
com.readystatesoftware.sqliteasset.SQLiteAssetHelper$SQLiteAssetException: Missing databases/app.db file (or .zip, .gz archive) in assets, or target folder not writable
at android.content.res.AssetManager.nativeOpenAsset(Native Method)
at android.content.res.AssetManager.open(AssetManager.java:744)
at android.content.res.AssetManager.open(AssetManager.java:721)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.copyDatabaseFromAssets(SQLiteAssetHelper.java:436)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.createOrOpenDatabase(SQLiteAssetHelper.java:400)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getWritableDatabase(SQLiteAssetHelper.java:176)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:254)
at ptfc.populatetablefromcursor.Database.addToCart(Database.java:44)
at ptfc.populatetablefromcursor.MainActivity.onCreate(MainActivity.java:22)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6680)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
2019-01-08 06:13:53.262 1882-1882/? E/SQLiteLog: (14) cannot open file at line 36667 of [0c55d17973]
2019-01-08 06:13:53.262 1882-1882/? E/SQLiteLog: (14) os_unix.c:36667: (2) open(/data/user/0/ptfc.populatetablefromcursor/databases/app.db) -
2019-01-08 06:13:53.264 1882-1882/? E/SQLiteDatabase: Failed to open database '/data/user/0/ptfc.populatetablefromcursor/databases/app.db'.
android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14 SQLITE_CANTOPEN): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:211)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:195)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:503)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:204)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:196)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:880)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:865)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:766)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:714)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:264)
at ptfc.populatetablefromcursor.Database.addToCart(Database.java:44)
at ptfc.populatetablefromcursor.MainActivity.onCreate(MainActivity.java:22)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6680)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
2019-01-08 06:13:53.264 1882-1882/? D/AndroidRuntime: Shutting down VM
然后您将获得运行时异常：-（基本上根据您显示的日志）
--------- beginning of crash
2019-01-08 06:13:53.268 1882-1882/? E/AndroidRuntime: FATAL EXCEPTION: main
Process: ptfc.populatetablefromcursor, PID: 1882
java.lang.RuntimeException: Unable to start activity ComponentInfo{ptfc.populatetablefromcursor/ptfc.populatetablefromcursor.MainActivity}: android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14 SQLITE_CANTOPEN): Could not open database
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2914)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6680)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Caused by: android.database.sqlite.SQLiteCantOpenDatabaseException: unknown error (code 14 SQLITE_CANTOPEN): Could not open database
at android.database.sqlite.SQLiteConnection.nativeOpen(Native Method)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:211)
at android.database.sqlite.SQLiteConnection.open(SQLiteConnection.java:195)
at android.database.sqlite.SQLiteConnectionPool.openConnectionLocked(SQLiteConnectionPool.java:503)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:204)
at android.database.sqlite.SQLiteConnectionPool.open(SQLiteConnectionPool.java:196)
at android.database.sqlite.SQLiteDatabase.openInner(SQLiteDatabase.java:880)
at android.database.sqlite.SQLiteDatabase.open(SQLiteDatabase.java:865)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:766)
at android.database.sqlite.SQLiteDatabase.openDatabase(SQLiteDatabase.java:714)
at com.readystatesoftware.sqliteasset.SQLiteAssetHelper.getReadableDatabase(SQLiteAssetHelper.java:264)
at ptfc.populatetablefromcursor.Database.addToCart(Database.java:44)
at ptfc.populatetablefromcursor.MainActivity.onCreate(MainActivity.java:22)
at android.app.Activity.performCreate(Activity.java:7136)
at android.app.Activity.performCreate(Activity.java:7127)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1271)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2894)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3049)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:78)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:108)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:68)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1809)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6680)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)