我正在尝试将一些数据插入到我创建的表中。我有这门课：
public class DataBase extends SQLiteOpenHelper {
private static final String DB_NAME = "db_mydatabase";
private static final int DB_VERSION = 1;
private static final String TBL_USERS = "users";
private static final String TBL_USERSE_CREATE = "CREATE TABLE IF NOT EXISTS "
+ TBL_USERS + "(id integer PRIMARY KEY AUTOINCREMENT, "
+ "usr varchar(128) NOT NULL UNIQUE, psw varchar(512));";
public DataBase(Context context) {
super(context, DB_NAME, null, DB_VERSION);
}
public List<String> GetUsersList() {
List<String> users = new ArrayList<String>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor c = db.rawQuery("SELECT id, usr FROM " + TBL_USERS, null);
if (c != null ) {
if (c.moveToFirst()) {
do {
String firstName = c.getString(c.getColumnIndex("USR"));
users.add(firstName);
} while (c.moveToNext());
}
}
return users;
}
public void CreateNewUser(String username, String password) {
SQLiteDatabase db = this.getWritableDatabase();
db.execSQL("INSERT INTO " + TBL_USERS + " (usr, psw) VALUES ('" + username + "', '" + password + "')");
//If I comment this line, it doesn't crashes anymore, but I don't see why
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(TBL_USERSE_CREATE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("DROP TABLE IF EXISTS " + TBL_USERS);
onCreate(db);
}
}
因此，当我按下REGISTER按钮时，EditText中的用户名和密码将被发送到CreateNewUser。我的Activity类看起来像这样：
public class RegisterActivity extends Activity {
List<String> values;
DataBase dtb;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
ListView listView = (ListView) findViewById(R.id.listView1);
dtb = new DataBase(MainActivity.MainContext);
values = dtb.GetUsersList();
listView.setAdapter(new ArrayAdapter<String>(MainActivity.MainContext, R.layout.listitem, values));
Button Create = (Button) findViewById(R.id.Create);
Create.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
EditText username = (EditText)findViewById(R.id.Username);
EditText password = (EditText)findViewById(R.id.Password);
if (username.getText().length()>0 && password.getText().length()>0) {
if (values.indexOf(username.getText())<0) {
dtb.CreateNewUser(username.getText().toString(), password.getText().toString());
values = dtb.GetUsersList();
}
}
}
});
}
}
我是SQLite程序员的初学者，我得到了这个可理解的严重错误并崩溃了
> **04-24 12:30:51.340: E/CursorWindow(7986): Bad request for field slot 0,-1. numRows = 1, numColumns = 2** 04-24 12:30:51.350: > D/AndroidRuntime(7986): Shutting down VM 04-24 12:30:51.350: > W/dalvikvm(7986): threadid=3: thread exiting with uncaught exception > (group=0x4001b188) 04-24 12:30:51.350: E/AndroidRuntime(7986): > Uncaught handler: thread main exiting due to uncaught exception > **04-24 12:30:51.380: E/AndroidRuntime(7986): java.lang.IllegalStateException: get field slot from row 0 col -1 > failed** 04-24 12:30:51.380: E/AndroidRuntime(7986): at > android.database.CursorWindow.getString_native(Native Method) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.database.CursorWindow.getString(CursorWindow.java:329) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:49) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > com.bma.myagenda.DataBase.GetUsersList(DataBase.java:32) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > com.bma.myagenda.RegisterActivity$1.onClick(RegisterActivity.java:46) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > android.view.View.performClick(View.java:2364) 04-24 12:30:51.380: > E/AndroidRuntime(7986): at > android.view.View.onTouchEvent(View.java:4179) 04-24 12:30:51.380: > E/AndroidRuntime(7986): at > android.widget.TextView.onTouchEvent(TextView.java:6541) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.View.dispatchTouchEvent(View.java:3709) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > android.app.Activity.dispatchTouchEvent(Activity.java:2061) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.os.Handler.dispatchMessage(Handler.java:99) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > android.os.Looper.loop(Looper.java:123) 04-24 12:30:51.380: > E/AndroidRuntime(7986): at > android.app.ActivityThread.main(ActivityThread.java:4363) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > java.lang.reflect.Method.invokeNative(Native Method) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > java.lang.reflect.Method.invoke(Method.java:521) 04-24 12:30:51.380: > E/AndroidRuntime(7986): at > com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) > 04-24 12:30:51.380: E/AndroidRuntime(7986): at > com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 04-24 > 12:30:51.380: E/AndroidRuntime(7986): at > dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：1)
尝试用以下代码替换插入代码：
public void CreateNewUser(String username, String password) {
SQLiteDatabase db = this.getWritableDatabase();
ContentValues initialValues = new ContentValues();
initialValues.put(usr, username);
initialValues.put(psw, password);
db.insert(TBL_USERS, null, initialValues);
}
答案 1 :(得分：1)
变化
String firstName = c.getString(c.getColumnIndex("USR"));
到
String firstName = c.getString(1);
错误
CursorWindow(7986): Bad request for field slot 0,-1. numRows = 1, numColumns = 2
...java.lang.IllegalStateException: get field slot from row 0 col -1 failed
表示您在Cursor的第一行中请求索引为-1的列。从Cursor请求数据的代码中唯一的部分是c.getString(columnIndex)。这意味着你到达那里的columnIndex必须是-1。现在，如果您阅读了Cursor.getColumnIndex "USR"，您会看到：
返回给定列名的从零开始的索引，如果该列不存在，则返回-1。
意味着没有名为"usr"的列。如果查看表定义，可以看到将其命名为String firstName = c.getString(c.getColumnIndex("usr"));
。所以要修复你的错误，你可以做到
Cursor但是（这是可选的并且可能会导致错误）：由于您SELECT id, usr FROM .. id的请求，因此我们保证0是列usr和{{1}您的1中的列Cursor就是1，您可以直接使用if (c != null ) {
while(c.moveToNext()) {
String firstName = c.getString(1);
users.add(firstName);
}
c.close();
}
。
还有其他一些可以改进的事情：
if () do {} while () a）您可以将while() {}简化为简单Cursor
b）一旦您不需要，您应该关闭INSERT。你至少可以防止这种警告。
您还应该使用execSQL的bindArgs版本进行'针对错误/注入攻击的保存。尝试在用户名中输入'，您会看到它会以您的方式崩溃。使用bindArgs会阻止它，因为它会自动转义db.execSQL("INSERT INTO " + TBL_USERS + " (usr, psw) VALUES (?, ?)", new String[]{ username, password });
。
Cursor如果我评论这一行，它不会再崩溃，但我不明白为什么
这是因为varchar(128)为空，然后您没有找到导致错误的代码。
最后一件事：{{1}}在SQLite中没有任何影响，因为：
请注意，SQLite会忽略括号后面的数字参数（例如：“VARCHAR（255）”） - SQLite不会对字符串，BLOB或数值的长度施加任何长度限制。 documentation
答案 2 :(得分：1)
变化：
String firstName = c.getString(c.getColumnIndex("USR"));
要：
String firstName = c.getString(c.getColumnIndex("usr")); //USR != usr