我是Android开发的新手，目前我正在发布并将数据提取到php文件。我无法找到为什么getData（）函数给出在主活动中不起作用，但它在另一个活动中正常工作。我将相同的功能从仪表板活动复制到主要活动。
这是我的主要活动代码
public class MainActivity extends ActionBarActivity {
private static final String TAG = "MainActivity.java";
private EditText editEmail;
private EditText editPass;
TextView resultView;
@Override
protected void onCreate(Bundle savedInstanceState) {
final Button loginButton;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
resultView = (TextView) findViewById(R.id.result);
getData();
editEmail = (EditText) findViewById(R.id.userEmail);
editPass = (EditText) findViewById(R.id.userPassword);
loginButton = (Button) findViewById(R.id.buttonlogin);
loginButton.setOnClickListener(new Button.OnClickListener() {
public void onClick(View v) {
final String email = editEmail.getText().toString();
final String pass = editPass.getText().toString();
//perform action
if (!isValidEmail(email)) {
editEmail.setError("Please enter valid Email...");
}
else if (!isValidPassword(pass)) {
editPass.setError("Please enter valid Password");
}else{
new PostDataAsyncTask().execute();
startActivity(new Intent(MainActivity.this, DashboardActivity.class));
}
//if (emailEditText.getText().toString().trim().length()==0) {
//Toast.makeText(getBaseContext(), "Email is empty!!!", Toast.LENGTH_SHORT).show();
//return;
// }else{
// Redirect to Another Activity
//startActivity(new Intent(MainActivity.this, DashboardActivity.class));
// }
//if(upassword.getText().toString().trim().length()==0){
// Toast.makeText(getBaseContext(), "Password is empty!!!", Toast.LENGTH_SHORT).show();
//return;
//}
}
});
}
// validating email id
private boolean isValidEmail(String email) {
String EMAIL_PATTERN = "^[_A-Za-z0-9-\\+]+(\\.[_A-Za-z0-9-]+)*@"
+ "[A-Za-z0-9-]+(\\.[A-Za-z0-9]+)*(\\.[A-Za-z]{2,})$";
Pattern pattern = Pattern.compile(EMAIL_PATTERN);
Matcher matcher = pattern.matcher(email);
return matcher.matches();
}
// validating password with retype password
private boolean isValidPassword(String pass) {
if (pass != null && pass.length() > 10) {
return true;
}
return false;
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public class PostDataAsyncTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
// do stuff before posting data
}
@Override
protected String doInBackground(String... strings) {
try {
// 1 = post text data, 2 = post file
int actionChoice = 2;
// post a text data
if(actionChoice==1){
postText();
}
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(String lenghtOfFile) {
// do stuff after posting data
}
}
// this will post our text data
private void postText(){
final String email = editEmail.getText().toString();
final String pass = editPass.getText().toString();
try{
// url where the data will be posted
String postReceiverUrl = "http://xyzweb.com/appservice.php";
Log.v(TAG, "postURL: " + postReceiverUrl);
// 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("first_name", email));
//nameValuePairs.add(new BasicNameValuePair("lastname", pass));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
// execute HTTP post request
HttpResponse response = httpClient.execute(httpPost);
HttpEntity resEntity = response.getEntity();
if (resEntity != null) {
String responseStr = EntityUtils.toString(resEntity).trim();
Log.v(TAG, "Response: " + responseStr);
// you can add an if statement here and do other actions based on the response
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
public void getData(){
String result = "";
InputStream isr = null;
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://xyzweb.com/appservice.php"); //YOUR PHP SCRIPT ADDRESS
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
isr = entity.getContent();
}
catch(Exception e){
Log.e("log_tag", "Error in http connection " + e.toString());
resultView.setText("Couldnt connect to database");
}
//convert response to string
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(isr,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
isr.close();
result=sb.toString();
}
catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
//parse json data
try {
String s = "";
JSONArray jArray = new JSONArray(result);
for(int i=0; i<jArray.length();i++){
JSONObject json = jArray.getJSONObject(i);
s = s +
"Name : "+json.getString("first_name")+"\n\n";
}
resultView.setText(s);
} catch (Exception e) {
// TODO: handle exception
Log.e("log_tag", "Error Parsing Data " + e.toString());
}
}
}
getData()函数发出此错误Couldnt connect to database
$name = urldecode($_POST['first_name']);
//$user = urldecode($_POST['user']);
//$email = urldecode($_POST['email']);
//$pass = urldecode($_POST['pass']);
$postdata = array();
$postdata[]['first_name'] = 'hjgjh';
print(json_encode($postdata));
答案 0 :(得分：2)
getData（）函数执行远程URL。这些类型的请求应由后台线程而不是主线程处理。这可以这样做：
@Override
protected void onCreate(Bundle savedInstanceState) {
final Button loginButton;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
resultView = (TextView) findViewById(R.id.result);
//Call your getData function from AsyncTask
new YourAsyncTask.execute();
...
}
public class YourAsyncTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected String doInBackground(String... strings) {
//Call getData function from here
getData();
return null;
}
@Override
protected void onPostExecute(String lenghtOfFile) {
// do stuff after posting data
}
}