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对此有困难。我想使用数据库将数据从添加提醒页面获取到包含列表视图的提醒页面。

这是数据库文件

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;

public class MOSDatabase extends SQLiteOpenHelper  {

    private static final int DATABASE_VERSION = 2;
    public static final String TABLE_NAME = "ReminderTable";


    private static final String TABLE_CREATE = "create table " + TABLE_NAME + " (" +
            "PTITLE" + " TEXT ," + //HEADING FOR MINUTE SELECTED IN TIMEPICKER
            "PA" + " TEXT ," + //PAYMENT VALUE
            "PDAY" + " TEXT ," + //DAY SELECTED IN DATEPICKER
            "PMONTH" + " TEXT ," + //MONTH SELECTED IN DATEPICKER
            "PYEAR" + " TEXT ," + //YEAR SELECTED IN DATEPICKER
            "RDAY" + " TEXT ," + //REMINDER DAY
            "RMONTH" + " TEXT ," + //REMINDER MONTH
            "RYEAR" + " TEXT ," + //REMINDER YEAR
            "RMIN" + " TEXT ," + //REMINDER MIN
            "RHOUR" + " TEXT);"; //REMINDER HOUR

    MOSDatabase(Context context){
        super(context, "MOSDatabase", null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
        db.execSQL(TABLE_CREATE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
        db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
        this.onCreate(db);
    }


}

这是我的提醒页面中使用的 CustomAdapter

    import java.util.ArrayList;

import android.content.Context;
import android.content.SharedPreferences;
import android.database.Cursor;
import android.graphics.Color;
import android.graphics.Typeface;
import android.preference.PreferenceManager;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;

public class CustomAdapter extends ArrayAdapter<String> {


    Cursor C;
    SharedPreferences prefs;
    String color;
    String text_color;
    String bgcolor;


    public CustomAdapter(Context context, int textViewResourceId) {
        super(context, textViewResourceId);
        // TODO Auto-generated constructor stub
    }


    public ArrayList<String> paymentTitle;
    public ArrayList<String> paymentDate;
    public ArrayList<String> reminderTime;
    public ArrayList<String> reminderDate;
    public ArrayList<String> paymentAmount;


   // Typeface myTypeface = Typeface.createFromAsset(getContext().getAssets(), "Roboto-Light.ttf");


    public CustomAdapter(Context context, int resource, ArrayList<String> pt, ArrayList<String> pd, ArrayList<String> rd, ArrayList<String> rt, ArrayList<String> pa) {

        super(context, resource, pt);

        this.paymentTitle = pt;
        this.paymentDate = pd;
        this.reminderDate = rd;
        this.reminderTime = rt;
        this.paymentAmount = pa;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {

        View v = convertView;

        if (v == null) {

            LayoutInflater vi;
            vi = LayoutInflater.from(getContext());
            v = vi.inflate(R.layout.item_row, null);

        }

        //Get the corresponding string for the position of arraylist
        String paymentTimeStr = paymentTitle.get(position).toString();
        String paymentDateStr = paymentDate.get(position).toString();
        String reminderDateStr = reminderDate.get(position).toString();
        String reminderTimeStr = reminderTime.get(position).toString();
        String paymentValueStr = paymentAmount.get(position).toString();


        //FIND THE TEXTVIEWS FROM YOUR INDIVIDUAL LAYOUT
        TextView payDateTV = (TextView) v.findViewById(R.id.txtPaymentDate);
        TextView payTitleTV = (TextView) v.findViewById(R.id.txtTitle);
        TextView reminderDateTV = (TextView) v.findViewById(R.id.txtReminderDate);
        TextView reminderTimeTV = (TextView) v.findViewById(R.id.txtReminderTime);
        TextView paymentValueTV = (TextView) v.findViewById(R.id.txtAmount);


        if (payDateTV != null) {
            payDateTV.setText(paymentDateStr);
        }

        if (payTitleTV != null) {
            payTitleTV.setText(paymentTimeStr);
        }

        if (reminderDateTV != null) {
            reminderDateTV.setText(reminderDateStr);
        }

        if (reminderTimeTV != null) {
            reminderTimeTV.setText(reminderTimeStr);
        }

        if (paymentValueTV != null) {
            paymentValueTV.setText(paymentValueStr);
        }

        return v;

    }
}

这是提醒页面

public class Reminders extends Activity
{
    TextView title;
    Button add, edit, remove;
    ListView mListView;

    ArrayList<String> paymentTitle = new ArrayList<String>();
    ArrayList<String> paymentDate = new ArrayList<String>();
    ArrayList<String> reminderDate = new ArrayList<String>();
    ArrayList<String> reminderTime = new ArrayList<String>();
    ArrayList<String> paymentVal = new ArrayList<String>();

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.reminders);
        initializeVariables();

        MOSDatabase mDatabase = new MOSDatabase(this);

        //DEFINE CUSTOM ADAPTER
        CustomAdapter aa = new CustomAdapter(this, R.layout.item_row, paymentTitle, paymentDate, reminderDate, reminderTime, paymentVal);

        //SET CUSTOM ADAPTER FOR LISTVIEW
        mListView.setAdapter(aa);

        // READING A DB
        SQLiteDatabase readableDB = mDatabase.getReadableDatabase();
        Cursor C = readableDB.query("ReminderTable", new String[] { "PTITLE", "PA", "PDAY", "PMONTH", "PYEAR", "RDAY", "RMONTH",
                "RYEAR", "RMIN", "RHOUR" }, null, null, null, null, null);

        if (C == null)
        {
            title.setText("No Upcoming Payments");
        }
        else{
            C.moveToFirst();
            do {
                String reminderDateStr = "";
                String reminderTimeStr = "";
                String paymentDateStr = "";
                String paymentTitleStr = "";
                String paymentValue = "";

                //Build strings of each record to then be set to the listview
                reminderDateStr = C.getString(5) + "/" + C.getString(6)+ "/" +C.getString(7);
                reminderTimeStr = C.getString(8) + ":" + C.getString(9);
                paymentDateStr = C.getString(2) + "/" + C.getString(3) + "/" + C.getString(4);
                paymentTitleStr = C.getString(0);
                paymentValue = C.getString(1);

                //Add the new strings to the corresponding array
                paymentTitle.add(paymentTitleStr);
                reminderTime.add(reminderTimeStr);
                paymentDate.add(paymentDateStr);
                reminderDate.add(reminderDateStr);
                paymentVal.add(paymentValue);

            } while (C.moveToNext());
        }



        //CLOSE CURSOR AND DATABASE TO AVOID MEMORY LEAKS
        C.close();
        readableDB.close();

        //TELL ADAPTER THERE IS NEW DATA SO UPDATE THE LISTVIEW ACCORDINGLY
        aa.notifyDataSetChanged();

    }

    private void initializeVariables()
    {
        title = (TextView) findViewById(R.id.txtTitle);
        add = (Button) findViewById(R.id.bAdd);
        edit = (Button) findViewById(R.id.bEdit);
        remove = (Button) findViewById(R.id.bRemove);
        mListView = (ListView) findViewById(R.id.LVReminder);
    }

    public void addClicked(View view)
    {
        Intent openNewPayment = new Intent("com.studentbudget.ADDREMINDER");
        startActivity(openNewPayment);
        finish();
    }
}

当我运行我的应用程序并单击提醒链接时，它没有打开并崩溃。这是日志：

08-04 23:02:59.798  10548-10548/com.studentbudget E/AndroidRuntime: FATAL EXCEPTION: main
        java.lang.RuntimeException: Unable to start activity ComponentInfo{com.studentbudget/com.studentbudget.Reminders}: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
        at android.app.ActivityThread.access$600(ActivityThread.java:141)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)
        Caused by: android.database.CursorIndexOutOfBoundsException: Index 0 requested, with a size of 0
        at android.database.AbstractCursor.checkPosition(AbstractCursor.java:424)
        at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:136)
        at android.database.AbstractWindowedCursor.getString(AbstractWindowedCursor.java:50)
        at com.studentbudget.Reminders.onCreate(Reminders.java:66)
        at android.app.Activity.performCreate(Activity.java:5133)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
        ... 11 more

第 66 行是这样的：

reminderDateStr = C.getString(5) + "/" + C.getString(6)+ "/" +C.getString(7);

我试过改变它，所以它是remindDateStr = "Test"; 它起作用了，所以 C.getString(num) 方法有问题，我不知道它是什么。

感谢任何帮助我解决此问题的人。

4

4 回答 4

1 
reminderDateStr = C.getString(C.getColumnIndex("RDAY")) + "/" +
                  C.getString(C.getColumnIndex("RMONTH"))+ "/" + 
                  C.getString(C.getColumnIndex("RYEAR"));

希望它可以帮助你。

于 2013-08-05T05:06:27.620 回答
1

大概就是这一行：

C.moveToFirst();

结合

while (C.moveToNext());

使用这两行最终会超出光标的范围。

而不是这样做，只需使用

while (c.moveToNext()) {
    // Retrieve data here
}

c.close();
于 2013-08-05T18:44:42.337 回答
1

你得到一个 0 大小的光标，你尝试阅读它。我建议将您的光标阅读代码更改为：

if (C == null || !C.moveToFirst())
    {
        title.setText("No Upcoming Payments");
    }
    else{
        do {
            String reminderDateStr = "";
            ...
            //Build strings of each record to then be set to the listview
            ...
            //Add the new strings to the corresponding array
       } while (C.moveToNext());
    }
于 2013-08-05T19:16:59.290 回答
1

C.moveToFirst()false如果游标中没有条目，则返回。检查它，因为这将导致CursorIndexOutOfBoundsException如果没有条目。

还要始终检查是否存在该行并获取正确的光标索引，例如C.getColumnIndex("RDAY")

if(C.moveToFirst()) {
    do {
        String reminderDateStr = "";
        String reminderTimeStr = "";
        String paymentDateStr = "";
        String paymentTitleStr = "";
        String paymentValue = "";

        //Build strings of each record to then be set to the listview
        reminderDateStr = C.getString(C.getColumnIndex("RDAY")) + "/" + C.getString(C.getColumnIndex("RMONTH"))+ "/" +C.getString(C.getColumnIndex("RYEAR"));
        reminderTimeStr = C.getString(C.getColumnIndex("RHOUR")) + ":" + C.getString(C.getColumnIndex("RMIN"));
        paymentDateStr = C.getString(C.getColumnIndex("PDAY")) + "/" + C.getString(C.getColumnIndex("PMONTH")) + "/" + C.getString(C.getColumnIndex("PYEAR"));
        paymentTitleStr = C.getString(C.getColumnIndex("PTITLE"));
        paymentValue = C.getString(C.getColumnIndex("PA"));

        //Add the new strings to the corresponding array
        paymentTitle.add(paymentTitleStr);
        reminderTime.add(reminderTimeStr);
        paymentDate.add(paymentDateStr);
        reminderDate.add(reminderDateStr);
        paymentVal.add(paymentValue);

    } while (C.moveToNext());
}
于 2013-08-05T19:17:59.480 回答