我正在尝试创建一个Login功能,以便我可以验证用户。我将用户名,密码变量传递给AsyncTask类,但我不知道获取结果以便使用它们。有帮助吗? (由于网站限制,我发布了部分源代码)
btnLogin.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
if(txtUsername.getText().toString().trim().length() > 0 && txtPassword.getText().toString().trim().length() > 0)
{
// Retrieve the text entered from the EditText
String Username = txtUsername.getText().toString();
String Password = txtPassword.getText().toString();
/*Toast.makeText(MainActivity.this,
Username +" + " + Password+" \n Ready for step to post data", Toast.LENGTH_LONG).show();*/
String[] params = {Username, Password};
// we are going to use asynctask to prevent network on main thread exception
new PostDataAsyncTask().execute(params);
// Redirect to dashboard / home screen.
login.dismiss();
}
else
{
Toast.makeText(MainActivity.this,
"Please enter Username and Password", Toast.LENGTH_LONG).show();
}
}
});
然后我使用AsynkTask进行检查,但不知道如何获得结果并将它们存储在变量中。有什么帮助吗?
public class PostDataAsyncTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
// do stuff before posting data
}
@Override
protected String doInBackground(String... params) {
try {
// url where the data will be posted
String postReceiverUrl = "http://server.com/Json/login.php";
Log.v(TAG, "postURL: " + postReceiverUrl);
String line = null;
String fail = "notok";
// HttpClient
HttpClient httpClient = new DefaultHttpClient();
// post header
HttpPost httpPost = new HttpPost(postReceiverUrl);
// add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("UserName", params[0]));
nameValuePairs.add(new BasicNameValuePair("Password", params[1]));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// execute HTTP post request
HttpResponse response = httpClient.execute(httpPost);
HttpEntity resEntity = response.getEntity();
line = resEntity.toString();
Log.v(TAG, "Testing response: " + line);
if (resEntity != null) {
String responseStr = EntityUtils.toString(resEntity).trim();
Log.v(TAG, "Response: " + responseStr);
Intent Hotels_btn_pressed = new Intent(MainActivity.this, Hotels.class);
startActivity(Hotels_btn_pressed);
// you can add an if statement here and do other actions based on the response
Toast.makeText(MainActivity.this,
"Error! User does not exist", Toast.LENGTH_LONG).show();
}else{
finish();
}
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String lenghtOfFile) {
// do stuff after posting data
}
}
答案 0 :(得分:0)
不是最好的代码重构,只是为了给你一个提示。
我会创建一个界面(让我们称之为&#39; LogInListener&#39;):
public interface LoginListener {
void onSuccessfulLogin(String response);
void onFailedLogin(String response);
}
&#39; MainActivity&#39; class将实现该接口并将其自身设置为监听器&quot; PostDataAsyncTask&#39;。因此,从主活动创建异步任务将如下所示:
String[] params = {Username, Password};
// we are going to use asynctask to prevent network on main thread exception
PostDataAsyncTask postTask = new PostDataAsyncTask(this);
postTask.execute(params);
我会移动&#39; PostDataAsyncTask&#39;将类分成新文件:
public class PostDataAsyncTask extends AsyncTask<String, String, String> {
private static final String ERROR_RESPONSE = "notok";
private LoginListener listener = null;
public PostDataAsyncTask(LoginListener listener) {
this.listener = listener;
}
@Override
protected String doInBackground(String... params) {
String postResponse = "";
try {
// url where the data will be posted
String postReceiverUrl = "http://server.com/Json/login.php";
// HttpClient
HttpClient httpClient = new DefaultHttpClient();
// post header
HttpPost httpPost = new HttpPost(postReceiverUrl);
// add your data
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("UserName", params[0]));
nameValuePairs.add(new BasicNameValuePair("Password", params[1]));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// execute HTTP post request
HttpResponse response = httpClient.execute(httpPost);
HttpEntity resEntity = response.getEntity();
postResponse = EntityUtils.toString(resEntity).trim();
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return postResponse;
}
@Override
protected void onPostExecute(String postResponse) {
if (postResponse.isEmpty() || postResponse.equals(ERROR_RESPONSE) ) {
listener.onFailedLogin(postResponse);
} else {
listener.onSuccessfulLogin(postResponse);
}
}
}
所以,&#39; doInBackground&#39;将响应返回给&#39; onPostExecute&#39; (在UI线程上运行)和&#39; onPostExecute&#39;将结果(成功或失败)路由到MainActivity,MainActivity实现了&#39; LogInListener&#39;方法:
@Override
public void onSuccessfulLogin(String response) {
// you have access to the ui thread here - do whatever you want on suscess
// I'm just assuming that you'd like to start that activity
Intent Hotels_btn_pressed = new Intent(this, Hotels.class);
startActivity(Hotels_btn_pressed);
}
@Override
public void onFailedLogin(String response) {
Toast.makeText(MainActivity.this,
"Error! User does not exist", Toast.LENGTH_LONG).show();
}
我只是假设你在成功时想做的事情:开始一项新活动,并在失败时显示祝酒。