使用字符串 doInBackground(String... args)

Question

我正在努力将我的数据保存到 MySQL 数据库中。我读到您需要使用新线程来打开数据库。我已经看到了使用 AsyncTask 的示例。我将如何访问 doInBackground 方法。我尝试了各种不同的方法调用，要么得到错误，要么程序不使用 AsyncTask。这是我的代码。我尝试了不同版本的 AddtoSQLDB db = new AddtoSQLDB() 和 CreateNewProduct cn = new CreateNewProduct()。

public class AddToMySQLDB extends Activity {

JSONParser jsonParser = new JSONParser();

// TODO Auto-generated method stub

// url to create new product
private static String url_create_product = "http://api.androidhive.info/android_connect/create_product.php";

// JSON Node names
private static final String TAG_SUCCESS = "success";
private ProgressDialog pDialog;
static String name = "";
static String company = "";
static String timeIn = "";
static String signature;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (android.os.Build.VERSION.SDK_INT > 9) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                .permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }

}

public static void setVariable(String sDate, String visitorsName2, String visitorsCompany2, byte[] signature2) {
    name = visitorsName2;
    company = visitorsCompany2;
    timeIn = sDate;

}
class CreateNewProduct extends AsyncTask<String, String, String>
{

    @Override
    protected String doInBackground(String... args) {
        // TODO Auto-generated method stub
        // getting JSON Object
        // Note that create product url accepts POST method
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        params.add(new BasicNameValuePair("name", name));
        params.add(new BasicNameValuePair("timeIn", timeIn));
        params.add(new BasicNameValuePair("signature", signature));
        JSONObject json = jsonParser.makeHttpRequest(url_create_product,
                "POST", params);

        // check log cat fro response
        Log.d("Create Response", json.toString());

        // check for success tag
        try {
            int success = json.getInt(TAG_SUCCESS);

            if (success == 1) {
                // successfully created product
/*                  Intent i = new Intent(getApplicationContext(),
                        AllProductsActivity.class);
                startActivity(i);*/

                // closing this screen

            } else {
                // failed to create product
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return null;
    }

}
protected void onPostExecute(String file_url) {
    // dismiss the dialog once done
    pDialog.dismiss();
}


protected void onPostExecute(String file_url) {
    // dismiss the dialog once done
    pDialog.dismiss();
}

}

}

Answer 1

你需要execute你的AsyncTask：

CreateNewProduct cn = new CreateNewProduct();
cn.execute(""); //pass the params you want for doInBackground here