我是 android 的新手,无法将结果从数据库获取到屏幕上的 TextView
中。目前我的应用程序在点击按钮后返回一条消息。我在屏幕上有两个 TextView
元素 txtViewBegin
和 txtViewEind
。从 mySql
(通过 php
)我得到一个像这样的字符串 22-02-2014 24-05-2017
,我把它拆分成一个字符串数组 (.split(""))
。
我可以使用后台工作程序中的 setTextView
(onPostExecute 吗?)
或者我应该在我的 MainActivity
中这样做吗?仍然是菜鸟。对不起。
这是我的BackgroundWorker
:
public class BackgroundWorker extends AsyncTask<String,Void,String> {
Context context;
AlertDialog alertDialog;
BackgroundWorker(Context ctx){
context = ctx;
}
@Override
protected String doInBackground(String... params) {
String type = params[0];
String login_url= "http://*************/****.php";
if(type.equals("Draai")){
try {
URL url = new URL(login_url);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(false);
httpURLConnection.setDoInput(true);
//OutputStream outputStream = httpURLConnection.getOutputStream();
//BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream,"UTF-8"));
//String post_data = URLEncoder.encode("user_name""UTF-8")// HIER KUN JE VARIABELEN INGEVEN DIE WORDEN GEIMPLEMENTEERD IN HET PHP DOCUMENT
//bufferedWriter.write();
//bufferedWriter.flush();
// bufferedWriter.close();
//outputStream.close();
InputStream inputStream = httpURLConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"));
String result ="";
String line="";
while ((line=bufferedReader.readLine()) != null){
result += line;
}
String[] separated = result.split(" ");
bufferedReader.close();
inputStream.close();
httpURLConnection.disconnect();
return result;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e){
e.printStackTrace();
}
}
return null;
}
@Override
protected void onPreExecute() {
alertDialog = new AlertDialog.Builder(context).create();
alertDialog.setTitle("TijdsDuur");
}
@Override
protected void onPostExecute(String result) {
alertDialog.setMessage(result);
alertDialog.show();
}
@Override
protected void onProgressUpdate(Void... values) {
super.onProgressUpdate(values);
}
}
和我的MainActivity
:
public class MainActivity extends AppCompatActivity {
TextView ViewBegin, ViewEind;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ViewBegin = (TextView) findViewById(R.id.txtViewBegin);
ViewEind = (TextView) findViewById(R.id.txtViewEind);
}
public void onDraai(View view){
String type = "Draai";
BackgroundWorker backgroundWorker = new BackgroundWorker(this);
backgroundWorker.execute(type);
}
}
最佳答案
1.) 在您的 BackgroundWorker
接口(interface)
public interface DataCallBack{
void onDataReceived(String s);
}
2.) 在您的 Activity
public class MainActivity extends AppCompatActivity implements BackgroundWorker.DataCallBack {
3.) 任务完成后,用要显示的数据通知您的 Activity
你的 MainActivity
看起来像
public class MainActivity extends AppCompatActivity implements BackgroundWorker.DataCallBack {
TextView ViewBegin, ViewEind;
// .....code
@Override
void onDataReceived(String s){
if(s!=null){
String[] separated = result.split(" ");
ViewBegin.setText(separated[0]);
ViewEind.setText(separated[1]);
}
}
// .....code
}
你的 BackgroundWorker
类看起来像
public class BackgroundWorker extends AsyncTask<String,Void,String> {
Context context;
AlertDialog alertDialog;
DataCallBack callback;
BackgroundWorker(Context ctx){
context = ctx;
// initialize the callback reference
callback = (DataCallBack) cxt;
}
public interface DataCallBack{
void onDataReceived(String s);
}
// .....code
@Override
protected void onPostExecute(String result) {
callback.onDataReceived(result);
// ^^^ send data to Activity
alertDialog.setMessage(result);
alertDialog.show();
}
// .....code
}
关于php - 如何将 BackgroundWorker 的结果设置为 TextView,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/42161153/