数据库第一次没有填满

Question

我将通过 JSON 从服务器获取一些数据并将它们存储在我的 sqlite 数据库中。

当我使用下面的代码时，在 第一次 时间，Toast 消息显示我的 table 行是零.

但是当我运行我的应用程序秒时间时，它显示了当前的数字（JSON 数据计数）。

此外，在 second 时间，我删除了它们将数据存储到 sqlite 数据库和运行 app 中的行为了确保在第一次时数据存储在数据库中。

请让我知道哪里错了...

关于活动：

public class AboutActivity extends ActionBarActivity implements OnClickListener, OnItemClickListener {

DBHandler dbh;
private static final String TAG_IMAGES = "images";
private static final String TAG_GUID = "GUID";
private static final String TAG_IMG_LINK = "img_link";
private static final String TAG_IMG_DESC = "img_desc";
private static final String TAG_URL = "http://xxx/x.php";
private JSONArray jArray = null;
private JSONParser jParser;
private JSONObject jObject;
private ProgressDialog pDialog;

String[] GUID;
String[] imgLink;
String[] imgDesc;
String[] imgPath;
AboutSlideShowModel model;

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

    dbh = new DBHandler(AboutActivity.this);

    getAllDataFromServer myClass =  new getAllDataFromServer();
    myClass.execute();
    Toast.makeText(AboutActivity.this, dbh.getCount() + "", 5000).show();
}

private class getAllDataFromServer extends AsyncTask<Void, Void, Void>
{
    @Override
    protected void onPreExecute() 
    {
        pDialog = new ProgressDialog(AboutActivity.this);
        pDialog.setMessage("Be patient ...");
        pDialog.show();
        super.onPreExecute();
    }

    @Override
    protected Void doInBackground(Void... params) 
    {
        jParser = new JSONParser();
        jObject = jParser.getJSONFromUrl(TAG_URL);
        try
        {
            jArray = jObject.getJSONArray(TAG_IMAGES);
            GUID = new String[jArray.length()];
            imgLink = new String[jArray.length()];
            imgPath = new String[jArray.length()];
            imgDesc = new String[jArray.length()];
            for(int i=0; i<jArray.length(); i++)
            {
                JSONObject tempJson = jArray.getJSONObject(i);
                GUID[i] = tempJson.getString(TAG_GUID);
                imgLink[i] = tempJson.getString(TAG_IMG_LINK);
                imgDesc[i] = tempJson.getString(TAG_IMG_DESC);
                new SaveImageIntoStorage(AboutActivity.this, imgLink[i], GUID[i] + ".jpg", "SlideShow").saveImage();
                imgPath[i] = Environment.getExternalStorageDirectory() + "/Slideshow/" + GUID[i] + ".jpg";
                model = new AboutSlideShowModel(GUID[i], imgLink[i], imgPath[i], imgDesc[i]);
                dbh.insertSingleAboutSlideShow(model);
            }
        }
        catch(JSONException e)
        {
            e.printStackTrace();
        }
        return null;
    }

    @Override
    protected void onPostExecute(Void result) 
    {
        pDialog.dismiss();
        super.onPostExecute(result);
    }
    }
}

AboutSlideShowModel:

public class AboutSlideShowModel 
{
public int ID;
public String GUID;
public String IMG_LINK;
public String IMG_PATH;
public String Description;

public AboutSlideShowModel() {}

public AboutSlideShowModel(int ID, String GUID, String IMG_LINK, String    IMG_PATH, String Description)
{
    this.GUID = GUID;
    this.IMG_LINK = IMG_LINK;
    this.IMG_PATH = IMG_PATH;
    this.Description = Description;
    this.ID = ID;
}

public AboutSlideShowModel(String GUID, String IMG_LINK, String IMG_PATH, String Description)
{
    this.GUID = GUID;
    this.IMG_LINK = IMG_LINK;
    this.IMG_PATH = IMG_PATH;
    this.Description = Description;
}

public void setID(int ID)
{
    this.ID = ID;
}

public void setGUID(String GUID)
{
    this.GUID = GUID;
}

public void setIMG_LINK(String IMG_LINK)
{
    this.IMG_LINK = IMG_LINK;
}

public void setIMG_PATH(String IMG_PATH)
{
    this.IMG_PATH = IMG_PATH;
}

public void setDescription(String Description)
{
    this.Description = Description;
}

public int getID()
{
    return this.ID;
}

public String getGUID()
{
    return this.GUID;
}

public String getIMG_LINK()
{
    return this.IMG_LINK;
}

public String getIMG_PATH()
{
    return this.IMG_PATH;
}

public String getDescription()
{
    return this.Description;
}
}

数据库处理程序：

public class DBHandler extends SQLiteOpenHelper 
{
private static final String DB_NAME = "db";
private static final int DB_VERSION = 1;

private static final String KEY_ID = "id";
private static final String KEY_GUID = "guid";
private static final String KEY_IMAGE_PATH = "image_path";
private static final String KEY_IMAGE_LINK = "image_link";
private static final String KEY_DESCRIPTION = "description";

private static final String TBL_ABOUT_SLIDESHOW = "tbl_about_slideshow";

private static final String CREATE_TBL_ABOUT_SLIDESHOW = "CREATE TABLE IF NOT EXISTS "
        + TBL_ABOUT_SLIDESHOW + "("
        + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
        + KEY_GUID + " TEXT," 
        + KEY_IMAGE_LINK + " TEXT," 
        + KEY_IMAGE_PATH + " TEXT," 
        + KEY_DESCRIPTION + " TEXT" + ")";

public DBHandler(Context context) 
{
    super(context, DB_NAME, null, DB_VERSION);
}

@Override
public void onCreate(SQLiteDatabase db) 
{
    db.execSQL(CREATE_TBL_ABOUT_SLIDESHOW);
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) 
{
    db.execSQL("DROP TABLE IF EXISTS " + TBL_ABOUT_SLIDESHOW);
    onCreate(db);
}

public void insertSingleAboutSlideShow(AboutSlideShowModel model)
{
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_GUID, model.getGUID());
    values.put(KEY_IMAGE_LINK, model.getIMG_LINK());
    values.put(KEY_IMAGE_PATH, model.getIMG_PATH());
    values.put(KEY_DESCRIPTION, model.getDescription());
    // Inserting Row
    db.insert(TBL_ABOUT_SLIDESHOW, null, values);
    db.close(); // Closing database connection
}
public int getCount()
{
    SQLiteDatabase db = this.getReadableDatabase();
    Cursor c = db.rawQuery("SELECT * FROM " + TBL_ABOUT_SLIDESHOW, null);
    if(c.getCount() <= 0)
        return 0;
    return c.getCount();
}
}

Answer 1

你的任务是异步执行的，所以当你的toast执行的时候，AsyncTask还没有取回数据。如果您在 onPostExecute 方法中检查您的数据库，您可能会看到您要查找的结果。

数据库第一次没有填满

Database doesn't fill at the first time

android

json

sqlite

android-asynctask