I’m currently loading a webpage using a thread and I need a progress bar to display while the page loads up. Whats the best way to implement this? My code to load the webpage is this
private Thread checkUpdate = new Thread() {
@Override
public void run() {
try {
/**
* establish a URL connection
*/
URL updateURL = new URL("http://www.mtsu.edu/alertupdates/");
URLConnection conn = updateURL.openConnection();
/**
* create an Input stream and buffered array to
* prepare for parsing.
*/
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
/**
* read in the html and parse it to bytes.
*/
int current = 0;
while((current = bis.read()) != -1){
baf.append((byte)current);
}
/**
* Convert the Bytes read to a String.
*/
html = new String(baf.toByteArray());
int position = html.indexOf("<h1>");
int position2 = html.indexOf("<!--",position);
html = html.substring(position, position2);
mHandler.post(showUpdate);
} catch (Exception e){}
}
};
Here is my attempt at Using AsyncTask and the entire code of my project.
package com.MTSUAndroid;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.net.URL;
import java.net.URLConnection;
import java.util.Calendar;
import org.apache.http.util.ByteArrayBuffer;
import android.app.Activity;
import android.app.ProgressDialog;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.widget.Button;
import android.widget.ProgressBar;
import android.widget.TextView;
import android.widget.Toast;
import android.text.Html;
import android.view.Gravity;
import android.view.View;
import java.lang.String;
import android.content.Context;
public class Alerts extends Activity {
/**
* private variables to hold the html strings for parsing.
*/
private String html = "";
private Handler mHandler;
private TextView text1;
private TextView timestamp;
private Button home;
private Button refresh;
private ProgressDialog myProgress;
private int myProgressStatus = 0;
private Handler myHandler = new Handler();
/**
* overriding on create with a new handler for threading
*/
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.alerts);
initialControls();
//mHandler = new Handler();
//checkUpdate.start();
}
public void connectivityMessage(String msg){
Context context = getApplicationContext();
Toast toast = Toast.makeText(context, "", Toast.LENGTH_LONG);
toast.setGravity(Gravity.CENTER, 0, 0);
toast.setText(msg);
toast.show();
}
/**
* InitialControls function to set up all the initial controls for the GUI
* Such as buttons, etc...
*/
private void initialControls(){
text1 = (TextView)findViewById(R.id.textView1);
home = (Button)findViewById(R.id.home_button);
//myProgress = (ProgressBar)findViewById(R.id.progressBar1);
home.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
finish();
}
});
/**
* TimeStamp for the alerts refresh button
*/
timestamp = (TextView)findViewById(R.id.timestamp);
refresh = (Button)findViewById(R.id.update);
/**
* implementing the refresh button/loading the website
*/
refresh.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
try {
/**
* establish a URL connection
*/
URL updateURL = new URL("http://www.mtsu.edu/alertupdates/");
URLConnection conn = updateURL.openConnection();
/**
* create an Input stream and buffered array to
* prepare for parsing.
*/
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
/**
* read in the html and parse it to bytes.
*/
int current = 0;
while((current = bis.read()) != -1){
baf.append((byte)current);
}
/**
* Convert the Bytes read to a String.
*/
html = new String(baf.toByteArray());
int position = html.indexOf("<h1>");
int position2 = html.indexOf("<!--",position);
html = html.substring(position, position2);
mHandler.post(showUpdate);
/**
* using calendar class for the refresh button
*/
Calendar c = Calendar.getInstance();
int seconds = c.get(Calendar.SECOND);
int minutes = c.get(Calendar.MINUTE);
int hours = c.get(Calendar.HOUR);
int years = c.get(Calendar.YEAR);
int months = 1 + c.get(Calendar.MONTH);
int days = c.get(Calendar.DAY_OF_MONTH);
try{
if (c.get(Calendar.AM_PM) == 0)
{
String AM = "";
AM = "AM";
if (hours == 0)
{
hours = 12;
}
timestamp.setText("Refreshed on " + days + "-"
+ months + "-" + years + " " + hours + ":" + minutes + ":" + seconds + " " + AM);
timestamp.setTextSize(17f);
timestamp.setTextColor(Color.GREEN);
}
else
{
String PM = "";
PM = "PM";
timestamp.setText("Refreshed on " + days + "-"
+ months + "-" + years + " " + hours + ":" + minutes + ":" + seconds + " " + PM);
timestamp.setTextSize(17f);
timestamp.setTextColor(Color.GREEN);
}
}
catch (Exception e){}
}
/**
* Catch exception E to catch all errors.
*/
catch (Exception e) {}
}
}
);}
/**
* creating a new thread to run the URL.
*/
private Thread checkUpdate = new Thread() {
@Override
public void run() {
try {
/**
* establish a URL connection
*/
URL updateURL = new URL("http://www.mtsu.edu/alertupdates/");
URLConnection conn = updateURL.openConnection();
/**
* create an Input stream and buffered array to
* prepare for parsing.
*/
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
/**
* read in the html and parse it to bytes.
*/
int current = 0;
while((current = bis.read()) != -1){
baf.append((byte)current);
}
/**
* Convert the Bytes read to a String.
*/
html = new String(baf.toByteArray());
int position = html.indexOf("<h1>");
int position2 = html.indexOf("<!--",position);
html = html.substring(position, position2);
mHandler.post(showUpdate);
} catch (Exception e){}
}
};
/**
* set the textView to the freshly parsed html for viewing
*/
private Runnable showUpdate = new Runnable(){
@Override
public void run(){
text1.setText(Html.fromHtml(html));
}
};
public class myTask extends AsyncTask<Void,Void,Void>{
ProgressDialog progress;
public myTask(ProgressDialog progress) {
this.progress = progress;
}
@Override
protected void onPreExecute() {
progress = ProgressDialog.show(Alerts.this, "Loading data..", "Please Wait");
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
try {
/**
* establish a URL connection
*/
URL updateURL = new URL("http://www.mtsu.edu/alertupdates/");
URLConnection conn = updateURL.openConnection();
/**
* create an Input stream and buffered array to
* prepare for parsing.
*/
InputStream is = conn.getInputStream();
BufferedInputStream bis = new BufferedInputStream(is);
ByteArrayBuffer baf = new ByteArrayBuffer(50);
/**
* read in the html and parse it to bytes.
*/
int current = 0;
while((current = bis.read()) != -1){
baf.append((byte)current);
}
/**
* Convert the Bytes read to a String.
*/
html = new String(baf.toByteArray());
int position = html.indexOf("<h1>");
int position2 = html.indexOf("<!--",position);
html = html.substring(position, position2);
mHandler.post(showUpdate);
} catch (Exception e){}
return null;
}
protected void onPostExecute() {
progress.dismiss();
}
}
}
An AsyncTask will help handle progress for you. Read here: http://developer.android.com/reference/android/os/AsyncTask.html