1

我想将数据库中的记录计数以整数形式显示到我的应用程序中，然后显示它......我该怎么做？？？

我不能这样做

这是数据库代码

public int counttable()
{
    int count=0;
    openOrCreateDatabase();

    count=db.execSQL("select count(*) from "+TableNameis+";");

    return count;

}

我知道数据类型不匹配...有人可以建议我该怎么做吗？我如何将计数值存储在整数变量中。

仪表板.java

public class Dashboard extends Activity {

EditText edt_pending, edt_completed,edt_synched;

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);

    setContentView(R.layout.dashboard);

    edt_pending=(EditText)findViewById(R.id.editpending);
    edt_completed=(EditText)findViewById(R.id.editcompleted);
    edt_synched=(EditText)findViewById(R.id.editsynched);

    WayDataBase way=new WayDataBase(Dashboard.this);
    int count=way.counttable();

    edt_completed.setText(count);


}

}

日志猫

04-08 07:15:02.216: E/AndroidRuntime(16026): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.android.lthomepage/com.android.lthomepage.Dashboard}: android.content.res.Resources$NotFoundException: String resource ID #0x1 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread.access$600(ActivityThread.java:141) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.os.Handler.dispatchMessage(Handler.java:99) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.os.Looper.loop(Looper.java:137) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread.main(ActivityThread.java:5039) 04-08 07:15:02.216: E/AndroidRuntime(16026): at java.lang.reflect.Method.invokeNative(Native Method) 04-08 07:15:02.216: E/AndroidRuntime(16026): at java.lang.reflect.Method.invoke(Method.java:511) 04-08 07:15:02.216: E/AndroidRuntime(16026): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793) 04-08 07:15:02.216: E/AndroidRuntime(16026): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560) 04-08 07:15:02.216: E/AndroidRuntime(16026): at dalvik.system.NativeStart.main(Native Method) 04-08 07:15:02.216: E/AndroidRuntime(16026): Caused by: android.content.res.Resources$NotFoundException: String resource ID #0x1 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.content.res.Resources.getText(Resources.java:230) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.widget.TextView.setText(TextView.java:3640) 04-08 07:15:02.216: E/AndroidRuntime(16026): at com.android.lthomepage.Dashboard.onCreate(Dashboard.java:27) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.Activity.performCreate(Activity.java:5104) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080) 04-08 07:15:02.216: E/AndroidRuntime(16026): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)

4

3 回答 3

1

您可以使用Cursor#getCount()来获取编号。的记录。

public int counttable()
{
    int count=0;
    openOrCreateDatabase();

    // count=db.execSQL("select * from "+TableNameis+";"); - This statement is invalid

    // Use this instead
    count=db.rawQuery(selectionQuery, null).getCount(); 

    return count;

}
于 2013-04-08T06:54:48.963 回答
1

试试这个代码：

public int counttable()
{
int count=0;
openOrCreateDatabase();
Cursor c = db.rawQuery("select * from your_table_name",null);
count=c.getCount();
return count;
}

还，

edt_completed.setText(String.valueOf(count));

使用SELECT查询就足够了，然后计算Cursor的大小..

于 2013-04-08T06:56:06.663 回答
0

  1. 像这样为 DatabaseCreate 创建一个类..

    公共类 WayDataBase 扩展 SQLiteOpenHelper {

    private static String DATABASE_NAME = "Database Name";
private SQLiteDatabase myDataBase;
private Context myContext;
private String DATABASE_PATH = "/data/data/"Package Name"/databases/";


// Constructor  

public WayDataBase (Context context) 
{

    super(context, DATABASE_NAME, null, 1);
    this.myContext = context;
}

// Create DataBase 

public void createDatabase() throws IOException
{

    boolean dbExist = checkDataBase();

    if(dbExist)
    {
    }
    else
    {

        this.getReadableDatabase();

        try 
        {
            this.close();   
            copyDataBase();
        } 
        catch (IOException e) 
        {
            throw new Error("Error copying database");
        }
    }

}

// check Database Existing or not

private boolean checkDataBase() 
{
    SQLiteDatabase checkDB = null;

    try
    {
        String myPath = DATABASE_PATH + DATABASE_NAME;
        checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);

    }
    catch(SQLiteException e)
    {
    }

    if(checkDB != null)
    {

        checkDB.close();

    }

    return checkDB != null ? true : false;

}

// Copy DataBase from assets to SD card 

private void copyDataBase() throws IOException
{

    String outFileName = DATABASE_PATH + DATABASE_NAME;


    OutputStream myOutput = new FileOutputStream(outFileName);
    InputStream myInput = myContext.getAssets().open(DATABASE_NAME);

    byte[] buffer = new byte[1024];
    int length;
    while ((length = myInput.read(buffer)) > 0) 
    {
        myOutput.write(buffer, 0, length);
    }

    myInput.close();
    myOutput.flush();
    myOutput.close();
}

// Open DataBase

public void openDatabase() throws SQLException
{

    String myPath = DATABASE_PATH + DATABASE_NAME;
    myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READWRITE);

}
public int counttable()
{
    int count=0;
    openDatabase();
    Cursor c = myDataBase.rawQuery("SELECT * FROM table_name",null);
    return count;
}

    }

现在在您的活动中

公共类仪表板扩展活动{

私有 WayDataBase 方式；

EditText edt_pending, edt_completed,edt_synched;

protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);

    requestWindowFeature(Window.FEATURE_NO_TITLE);

    setContentView(R.layout.dashboard);

    edt_pending=(EditText)findViewById(R.id.editpending);
    edt_completed=(EditText)findViewById(R.id.editcompleted);
    edt_synched=(EditText)findViewById(R.id.editsynched);


    way= new WayDataBase(this);
    try 
    {
        way.createDatabase();

    } catch (IOException ioe) 
    {
        throw new Error("Unable to create database");
    }


    int count=way.counttable();

    edt_completed.setText(count+"");


}

}

于 2013-04-08T07:06:21.987 回答