Question

我有以下应用程序，我试图开发。它是一个存款，取款跟踪器，可以跟踪账户。所有数据都使用mysql存储在数据库中。我想在我的数据库中获得总计列，但是当我点击按钮显示总数时我一直收到错误

这是我的代码

public class MainActivity extends Activity {
    String total;
    SQLiteDatabase db;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        db=openOrCreateDatabase("MyDB1",MODE_PRIVATE, null);
        db.execSQL("CREATE TABLE IF NOT EXISTS DepWith(total VARCHAR);");
    }
    public void data(View view)
    {
        EditText edittext1;
        edittext1 = (EditText)findViewById(R.id.Deposit);
        total=edittext1.getText().toString();
        int total1 = Integer.parseInt(total);

        db.execSQL("INSERT INTO DepWith VALUES('"+total+"');");


    }
    public void showdata(View view)
    {
        Cursor c=db.rawQuery("SELECT * from DepWith", null);
        int count= c.getCount();
        c.moveToFirst();
        TableLayout tableLayout = new TableLayout(getApplicationContext());
        tableLayout.setVerticalScrollBarEnabled(true);
        TableRow tableRow;
        TextView textView,textView1,textView2,textView3,textView4,textView5;
        tableRow = new TableRow(getApplicationContext());
        textView=new TextView(getApplicationContext());
        textView.setText("Total");
        textView.setTextColor(Color.RED);
        textView.setTypeface(null, Typeface.BOLD);
        textView.setPadding(20, 20, 20, 20);
        tableRow.addView(textView);
        tableLayout.addView(tableRow);
        for (Integer j = 0; j < count; j++)
        {
            tableRow = new TableRow(getApplicationContext());
            textView1 = new TextView(getApplicationContext());
            textView1.setText(c.getString(c.getColumnIndex("total")));

            textView1.setPadding(20, 20, 20, 20);

            tableRow.addView(textView1);

            tableLayout.addView(tableRow);
            c.moveToNext() ;
        }
        setContentView(tableLayout);
        db.close();
    }
    public void close(View view)
    {
        System.exit(0);
    }

    public void AddTotal(View view)
    {
        TextView tt;
        tt=(TextView)findViewById(R.id.tt);
        db=openOrCreateDatabase("MyDB1",MODE_PRIVATE, null);

        Cursor resultSet = db.rawQuery("Select sum(total) from DepWith",null);
        resultSet.moveToFirst();
        String results = resultSet.getString(0);

        tt.setText( results);
    }
}

这是我得到的崩溃错误

 java.lang.IllegalStateException: Could not execute method of the activity
            at android.view.View$1.onClick(View.java:3823)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.reflect.InvocationTargetException
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at android.view.View$1.onClick(View.java:3818)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: android.database.sqlite.SQLiteException: no such table: DepWith (code 1): , while compiling: Select sum(total) from DepWith
            at android.database.sqlite.SQLiteConnection.nativePrepareStatement(Native Method)
            at android.database.sqlite.SQLiteConnection.acquirePreparedStatement(SQLiteConnection.java:889)
            at android.database.sqlite.SQLiteConnection.prepare(SQLiteConnection.java:500)
            at android.database.sqlite.SQLiteSession.prepare(SQLiteSession.java:588)
            at android.database.sqlite.SQLiteProgram.<init>(SQLiteProgram.java:58)
            at android.database.sqlite.SQLiteQuery.<init>(SQLiteQuery.java:37)
            at android.database.sqlite.SQLiteDirectCursorDriver.query(SQLiteDirectCursorDriver.java:44)
            at android.database.sqlite.SQLiteDatabase.rawQueryWithFactory(SQLiteDatabase.java:1314)
            at android.database.sqlite.SQLiteDatabase.rawQuery(SQLiteDatabase.java:1253)
            at com.example.app.MainActivity.AddTotal(MainActivity.java:86)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at android.view.View$1.onClick(View.java:3818)
            at android.view.View.performClick(View.java:4438)
            at android.view.View$PerformClick.run(View.java:18422)
            at android.os.Handler.handleCallback(Handler.java:733)
            at android.os.Handler.dispatchMessage(Handler.java:95)
            at android.os.Looper.loop(Looper.java:136)
            at android.app.ActivityThread.main(ActivityThread.java:5017)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
            at dalvik.system.NativeStart.main(Native Method)

Answer 1

在您的AddTotal()中，您打开的数据库与onCreate()中的数据库不同：

SQLiteDatabase db = openOrCreateDatabase("DepWith",MODE_PRIVATE,null);

VS

db=openOrCreateDatabase("MyDB1",MODE_PRIVATE, null);

DepWith数据库没有该表。

您无需在db中初始化其他AddTotal - 只需删除该行，然后使用db中初始化的onCreate()。

Answer 2

您创建MyDB1

db=openOrCreateDatabase("MyDB1",MODE_PRIVATE, null);

然后尝试打开DepWith这是一个表

SQLiteDatabase db = openOrCreateDatabase("DepWith",MODE_PRIVATE,null);  

    Cursor resultSet = db.rawQuery("Select sum(total) from DepWith",null);

Android SQLite一个列的总数

2 个答案: