问题
i want to start a new activity after login success. that is when login goes correct a new activity should start automatically...i dont know where to mention startactivity. please help me with this, im a newbie to android. this is my code...
public class BackgroundTask extends AsyncTask<String,Void,String> {
AlertDialog alertDialog;
Context ctx;
BackgroundTask(Context ctx)
{
this.ctx =ctx;
}
@Override
protected void onPreExecute() {
alertDialog = new AlertDialog.Builder(ctx).create();
alertDialog.setTitle("Login Information....");
}
@Override
protected String doInBackground(String... params) {
String reg_url = "";
String login_url = "";
String method = params[0];
if (method.equals("register")) {
String name = params[1];
String user_name = params[2];
String user_pass = params[3];
try {
URL url = new URL(reg_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
//httpURLConnection.setDoInput(true);
OutputStream OS = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&" +
URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
OS.close();
InputStream IS = httpURLConnection.getInputStream();
IS.close();
//httpURLConnection.connect();
httpURLConnection.disconnect();
return "Registration Success...";
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
else if(method.equals("login"))
{
String login_name = params[1];
String login_pass = params[2];
try {
URL url = new URL(login_url);
HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
OutputStream outputStream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
String data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&"+
URLEncoder.encode("login_pass","UTF-8")+"="+URLEncoder.encode(login_pass,"UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
String response = "";
String line = "";
while ((line = bufferedReader.readLine())!=null)
{
response+= line;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return response;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(String result) {
if(result.equals("Registration Success..."))
{
Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
}
else
{
alertDialog.setMessage(result);
alertDialog.show();
}
}
}
回答1:
You can put intent in your onPostExecute method like this :
@Override
protected void onPostExecute(String result) {
if(result == null)
{
// do what you want to do
}
else if(result.equals("Registration Success..."))
{
Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
}
else if(result.contains("Login Success")) // msg you get from success like "Login Success"
{
Intent i = new Intent(ctx,NewActivity.class);
ctx.startActivity(i);
alertDialog.setMessage(result);
alertDialog.show();
}
}
Edit : If you want to call new activity after login success then put intent in else part.
回答2:
try this
Intent intent = new Intent(MainActivity.this, Second.class);
startActivity(intent);
回答3:
call in your onPostexecute
protected void onPostExecute(String response) {
try {Intent intent = new Intent(context, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(intent);
}catch(Exception e){}}
回答4:
In postExecute() method you have to check the method variable, please check below code.
public class BackgroundTask extends AsyncTask<String,Void,String> {
AlertDialog alertDialog;
Context ctx;
String method;
BackgroundTask(Context ctx)
{
this.ctx =ctx;
}
@Override
protected void onPreExecute() {
alertDialog = new AlertDialog.Builder(ctx).create();
alertDialog.setTitle("Login Information....");
}
@Override
protected String doInBackground(String... params) {
String reg_url = "http://thecapitalcitychurch.16mb.com/new/register.php";
String login_url = "http://thecapitalcitychurch.16mb.com/new/login.php";
method = params[0];
if (method.equals("register")) {
String name = params[1];
String user_name = params[2];
String user_pass = params[3];
try {
URL url = new URL(reg_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
//httpURLConnection.setDoInput(true);
OutputStream OS = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
String data = URLEncoder.encode("user", "UTF-8") + "=" + URLEncoder.encode(name, "UTF-8") + "&" +
URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(user_name, "UTF-8") + "&" +
URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(user_pass, "UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
OS.close();
InputStream IS = httpURLConnection.getInputStream();
IS.close();
//httpURLConnection.connect();
httpURLConnection.disconnect();
return "Registration Success...";
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
else if(method.equals("login"))
{
String login_name = params[1];
String login_pass = params[2];
try {
URL url = new URL(login_url);
HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
httpURLConnection.setDoInput(true);
OutputStream outputStream = httpURLConnection.getOutputStream();
BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
String data = URLEncoder.encode("login_name","UTF-8")+"="+URLEncoder.encode(login_name,"UTF-8")+"&"+
URLEncoder.encode("login_pass","UTF-8")+"="+URLEncoder.encode(login_pass,"UTF-8");
bufferedWriter.write(data);
bufferedWriter.flush();
bufferedWriter.close();
outputStream.close();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"iso-8859-1"));
String response = "";
String line = "";
while ((line = bufferedReader.readLine())!=null)
{
response+= line;
}
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return response;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
@Override
protected void onPostExecute(String result) {
if(result.equals("Registration Success..."))
{
Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
}
else
{
alertDialog.setMessage(result);
alertDialog.show();
}
if(method.equals("login") && result.equals("Login Success..."))
{
Intent intent=new Intent(ctx, Dashboard.class);
ctx.startActivity(intent);
}
}
}
回答5:
As you want to start another activity once your login call gets succeed then you can start another activity either from the call back of login response or from the onpostExecute method of AsyncTask.
For implementing callback in API flow, you just need to create an interface which has few methods without body(only declaration) and these methods must have implemented in the class which implements that interface. Pass this interface object as a constructor of asyncTask. Once login call gets succeed you need to call the method of that interface and inside that method you can start another activity.
来源：https://stackoverflow.com/questions/32437527/how-to-start-a-new-activity-after-login-success