这是LoginActivty
public class MainActivity extends Activity {
ProgressDialog prgDialog;
TextView errorMsg;
EditText emailET;
EditText pwdET;
Button button;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_main);
errorMsg = (TextView) findViewById(R.id.login_error);
emailET = (EditText) findViewById(R.id.loginEmail);
pwdET = (EditText) findViewById(R.id.loginPassword);
prgDialog = new ProgressDialog(this);
prgDialog.setMessage("Please wait...");
prgDialog.setCancelable(false);
button = (Button) findViewById(R.id.btnLogin);
final Button button = (Button) findViewById(R.id.btnLogin);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
try {
// Get Email Edit View Value
String email = emailET.getText().toString();
// Get Password Edit View Value
String password = pwdET.getText().toString();
// When Email Edit View and Password Edit View have values
// other than Null
if (Utility.isNotNull(email) && Utility.isNotNull(password)) {
// When Email entered is Valid
if (Utility.validate(email)) {
// call the async task
JSONObject js = new HttpAsyncTask(
getApplicationContext()).execute(email,
password).get();
Toast.makeText(getApplicationContext(),
"Asynctask started", Toast.LENGTH_SHORT)
.show();
}
// When Email is invalid
else {
Toast.makeText(getApplicationContext(),
"Please enter valid email",
Toast.LENGTH_LONG).show();
}
}
// When any of the Edit View control left blank
else {
Toast.makeText(
getApplicationContext(),
"Please fill the form, don't leave any field blank",
Toast.LENGTH_LONG).show();
}
} catch (Exception ex) {
}
}
});
TextView registerScreen = (TextView) findViewById(R.id.link_to_register);
// Listening to register new account link
registerScreen.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Switching to Register screen
Intent i = new Intent(getApplicationContext(),
RegisterActivity.class);
startActivity(i);
}
});
}
}
然后我使用AsyncTask，这是代码
public class HttpAsyncTask extends AsyncTask<String, Integer, JSONObject> {
private static InputStream stream = null;
private static String API;
private JSONObject responseJson = null;
private Context contxt;
private Activity activity;
public HttpAsyncTask(Context context) {
// API = apiURL;
this.contxt = context;
}
// async task to accept string array from context array
@Override
protected JSONObject doInBackground(String... params) {
String path = null;
String response = null;
HashMap<String, String> request = null;
JSONObject requestJson = null;
DefaultHttpClient httpClient = null;
HttpPost httpPost = null;
StringEntity requestString = null;
ResponseHandler<String> responseHandler = null;
// get the username and password
Log.i("Email", params[0]);
Log.i("Password", params[1]);
try {
path = "http://192.168.x.xxx/xxxxService/UserAuthentication";
new URL(path);
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
// set the API request
request = new HashMap<String, String>();
request.put(new String("Email"), params[0]);
request.put(new String("Password"), params[1]);
request.entrySet().iterator();
// Store locations in JSON
requestJson = new JSONObject(request);
httpClient = new DefaultHttpClient();
httpPost = new HttpPost(path);
requestString = new StringEntity(requestJson.toString());
// sets the post request as the resulting string
httpPost.setEntity(requestString);
httpPost.setHeader("Content-type", "application/json");
// Handles the response
responseHandler = new BasicResponseHandler();
response = httpClient.execute(httpPost, responseHandler);
responseJson = new JSONObject(response);
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
try {
responseJson = new JSONObject(response);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
return responseJson;
}
@Override
protected void onPostExecute(JSONObject result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
String myResJson;
try {
myResJson = responseJson.getString("status");
String test = myResJson;
if (test.equals("200")) {
Log.i("Login Success", "Success message");
} else {
Log.e("Login Error", "Error converting result ");
}
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
当我输入正确的电子邮件和密码时，它就到了这一行
Log.i("Login Success", "Success message");
从那里我想打开HomeActivty，但它不允许我使用意图，甚至不能干杯
一旦日志记录成功，我需要帮助实现指向Home Activity。
答案 0 :(得分：0)
你可以从AsyncTask开始这样的活动，你应该使用上下文。
mContext.startActivity(new Intent(CurrentActivity.this, Home.class));
或者尝试这样
Intent intent = new Intent();
intent.setClass(getApplicationContext(),Home.class);
startActivity(intent);
答案 1 :(得分：0)
下面：
JSONObject js = new HttpAsyncTask(
getApplicationContext()).execute(email,
password).get();
因为您通过调用AsyncTask.get()方法AsyncTask在主要主题上获得结果。
首先调用AsyncTask.execute方法启动AsyncTask任务：
new HttpAsyncTask(MainActivity.this).execute(email,password);
然后使用onPreExecute()显示progessbar和onPostExecute以启动下一个活动：
@Override
protected void onPreExecute() {
// show ProgressDialog here
}
@Override
protected void onPostExecute(Void result) {
// parse json here and start Home Activity
//.........your code here
if (test.equals("200")) {
Log.i("Login Success", "Success message");
Intent intent = new Intent(contxt,HomeActivity.class);
contxt.startActivity(intent);
} else {
Log.e("Login Error", "Error converting result ");
}
}
答案 2 :(得分：0)
我知道还有另一个有效的答案来解决您的问题。但为了准确解释为什么你的错误存在，我在下面给出答案。
要为Intent创建startActivity()，可以通过以下方式完成：
Intent i = new Intent(currentActivity, NextActivity.class);
startActivity(i);
请注意Intent的构造函数的第一个参数是android.content.Context，其中Activity是它的子类。因此，在任何情况下，您始终可以将Context传递到自定义类并开始新的Activity或使用此Toast创建Context。
在您的问题中，private Context contxt;中的HttpAsyncTask是您需要做的所有事情。