过去3个小时我一直试图实现这个对话框，我无法弄清楚为什么它没有突然出现，我认为最好让全班同学了解我的问题：
Registration.java
public class Registration extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
}
//on submit press
public void SubmitRegistration(View view) {
// start an asynch request
class RequestTask extends AsyncTask<String, String, String>{
@Override
public String doInBackground(String... uri) {
HttpClient httpclient = new DefaultHttpClient();
HttpResponse response;
String responseString = null;
try {
response = httpclient.execute(new HttpGet(uri[0]));
StatusLine statusLine = response.getStatusLine();
if(statusLine.getStatusCode() == HttpStatus.SC_OK){
ByteArrayOutputStream out = new ByteArrayOutputStream();
response.getEntity().writeTo(out);
out.close();
responseString = out.toString();
} else{
//Closes the connection.
response.getEntity().getContent().close();
throw new IOException(statusLine.getReasonPhrase());
}
} catch (ClientProtocolException e) {
//TODO Handle problems..
} catch (IOException e) {
//TODO Handle problems..
}
return responseString;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
//Do anything with response..
}
}
// assign text in fields to string values
EditText first = (EditText)findViewById(R.id.first);
String first2 = first.getText().toString();
EditText last = (EditText)findViewById(R.id.last);
String last2 = last.getText().toString();
EditText display = (EditText)findViewById(R.id.display);
String display2 = display.getText().toString();
//calculates the number of characters in the display field
int length2 = display2.length();
EditText email = (EditText)findViewById(R.id.email);
String email2 = email.getText().toString();
EditText password = (EditText)findViewById(R.id.password);
String password2 = password.getText().toString();
EditText vpassword = (EditText)findViewById(R.id.vpassword);
String vpassword2 = vpassword.getText().toString();
//calculates the number of characters in the password field
int length = vpassword2.length();
// verifying the following in order: Passwords match? A Password field is empty?
//Password and Display Name less than 6 characters long? Email contains an @ sign and a period?
if(!vpassword2.equals(password2)) {
Toast.makeText(getApplicationContext(), "Passwords do not match!", Toast.LENGTH_SHORT).show();
}
else if (password2.isEmpty() || vpassword2.isEmpty()){
Toast.makeText(getApplicationContext(), "Password field is empty", Toast.LENGTH_SHORT).show();
}
else if (length < 6 || length2 < 6 ) {
Toast.makeText(getApplicationContext(), "Password and Display Name must be at least 6 characters long", Toast.LENGTH_LONG).show();
}
else if (!email2.contains("@") || !email2.contains(".")){
Toast.makeText(getApplicationContext(), "Must enter valid email address.", Toast.LENGTH_SHORT).show();
}
//start else
else {
//send php with all the data to server for validation and insertion into table
String output = null;
try {
output = new RequestTask()
.execute("http://www.alkouri.com/android/registercheck.php?first=" + first2 + "&last=" + last2 + "&display=" + display2 + "&email=" + email2 + "&password=" + password2)
.get();
//example: www.alkouri.com/android/registercheck.php?first=Adam&last=Alkouri&display=arugala&email=arugala@blackbaud.com&password=123
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ExecutionException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
//if the response from website contains "duplicate" (which means there is a duplicate email address in the DB) then it will display toast.
if (output.contains("Duplicate")) {
Toast.makeText(getApplicationContext(), "Email address already in system, press back button if you forgot password and click on Forgot Password ", Toast.LENGTH_LONG).show();
}
//if the response from website contains "You have registered successfully" then it will send popup message and go to login screen
else if (output.contains("You have")){
//start dialogue
AlertDialog.Builder alertbox = new AlertDialog.Builder(Registration.this);
alertbox.setMessage("You have succesfully registered. Please check your email for further instructions."); // Please Restart Application // "Please restart the app and download your purchase again".
alertbox.setPositiveButton("YES", new DialogInterface.OnClickListener() {
//create button in dialogue
public void onClick(DialogInterface arg0, int arg1)
{
//on clicking "ok" in the dialogue box, current activity will close and return to last activity (login screen).
finish();
}
});
alertbox.show();
}
}//end else
} //end button click task
}//end class
所以，在最底层，直接在最后一个吐司下面，我想要一个对话框弹出。
这是为了让用户知道他们已经注册，他们应该检查他们的电子邮件以获得进一步的指示。
吐司出现得很好，但是当我实施以下任何一个例子时，没有任何东西弹出。
我没有在LogCat中出现任何错误，只是没有任何错误弹出....
I have tried the following examples that I Have seen online:
public class FireMissilesDialogFragment extends DialogFragment {
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setMessage(R.string.dialog_fire_missiles)
.setPositiveButton(R.string.fire, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// FIRE ZE MISSILES!
}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// User cancelled the dialog
}
});
// Create the AlertDialog object and return it
return builder.create();
}
}
http://stackoverflow.com/questions/2115758/how-to-display-alert-dialog-in-android
AlertDialog.Builder builder1 = new AlertDialog.Builder(context);
builder1.setMessage("Write your message here.");
builder1.setCancelable(true);
builder1.setPositiveButton("Yes",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
builder1.setNegativeButton("No",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert11 = builder1.create();
alert11.show();
我做错了什么？
答案 0 :(得分：1)
AlertDialog.Builder alertbox = new AlertDialog.Builder(MainMenuActivity.this);
alertbox.setMessage("Please restart the app and download your data again."); // Please Restart Application // "Please restart the app and download your purchase again".
alertbox.setPositiveButton("YES", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface arg0, int arg1)
{
//code
}
});
alertbox.setNegativeButton("NO", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface arg0, int arg1)
{
//code
}
});
alertbox.show();
答案 1 :(得分：0)
你需要在onCreate（）方法中为你的提交按钮添加一个OnclickListener，并从那里调用你的其他函数。
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
//Call your submitregistration function function here
}
});
}
答案 2 :(得分：0)
output = new RequestTask()
.execute("http://www.mywebsite.com/android/registercheck.php?first=" + first2 + "&last=" + last2 + "&display=" + display2 + "&email=" + email2 + "&password=" + password2)
.get();
调用get不会使其异步。它会阻止ui线程等待结果。
将AsyncTask移出onClick
class RequestTask extends AsyncTask<String, String, String>{
http://developer.android.com/reference/android/os/AsyncTask.html#get()
public final Result get ()
Added in API level 3
Waits if necessary for the computation to complete, and then retrieves its result.
同时将变量声明为实例变量，并在onCreate中初始化您的视图。
EditText first ;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.register);
first = (EditText)findViewById(R.id.first);
在按钮上单击从editText
获取文本调用asynctask
new RequestTask().execute(params); // no get
doInbackground计算的结果是onPostExecute的参数。根据结果，您可以在onPostExecute。