AsyncTask Example Android with ProgressBar
MainActivity.java
activity_main.xml
AndroidManifest.xml do not forget INTERNET uses-permission !!!!!!!
package com.asynctaskexample;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.ProgressBar;
import android.widget.TextView;
public class MainActivity extends Activity {
private TextView textView;
private ProgressBar progressBar;
private DownloadWebPageTask mTask = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView = (TextView) findViewById(R.id.TextView01);
downloadPage();
}
// AsyncTask <TypeOfVarArgParams , ProgressValue , ResultValue> .
private class DownloadWebPageTask extends AsyncTask<String, Integer, String> {
@Override
protected void onPreExecute() {
//textView.setText("Hello !!!");
progressBar = (ProgressBar) findViewById(R.id.progressBar1);
progressBar.setVisibility(View.VISIBLE);
super.onPreExecute();
}
@Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
@Override
protected String doInBackground(String... urls) {
String response = "";
for (String url : urls) {
DefaultHttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
try {
HttpResponse execute = client.execute(httpGet);
InputStream content = execute.getEntity().getContent();
BufferedReader buffer = new BufferedReader(new InputStreamReader(
content));
String s = "";
while ((s = buffer.readLine()) != null) {
response += s;
}
} catch (Exception e) {
e.printStackTrace();
}
}
return response;
}
@Override
protected void onPostExecute(String result) {
progressBar.setVisibility(View.INVISIBLE);
textView.setText(result);
}
}
private void downloadPage() {
if (mTask != null
&& mTask.getStatus() != DownloadWebPageTask.Status.FINISHED) {
mTask.cancel(true);
}
// execute(String[]) you can put array of links to web pages, or array of Integer[]
// if first param is Integer[] etc.
mTask = (DownloadWebPageTask) new DownloadWebPageTask()
.execute(new String[] { "//android.okhelp.cz/android-market.html",
"//android.okhelp.cz/android-market.html" });
}
@Override
protected void onDestroy() {
super.onDestroy();
if (mTask != null
&& mTask.getStatus() != DownloadWebPageTask.Status.FINISHED) {
mTask.cancel(true);
mTask = null;
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}
activity_main.xml
<LinearLayout xmlns:android="//schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ProgressBar
android:id="@+id/progressBar1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/TextView01"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello_world" />
</LinearLayout>
AndroidManifest.xml do not forget INTERNET uses-permission !!!!!!!
<uses-permission android:name="android.permission.INTERNET" />
396LW NO topic_id
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Další témata ....(Topics)
FrameLayou, fragment have to unique id android:id="@+id/your_id_unique"
<FrameLayout xmlns:android="//schemas.android.com/apk/res/android"
xmlns:tools="//schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<fragment
android:id="@+id/your_id_unique"
android:layout_width="match_parent"
android:layout_height="match_parent"
class="cz.okhelp.notepad.AddNoteFragment"
tools:layout="@layout/add_note" />
</FrameLayout>
If You have old PC (Android in emulator with high screen resolution uses a lot of memory) or your testing phone have small screen, You can try this trick.
Rename layout folder for small device screen f.g. from layout into layout-swXXXdp and a large layout-sw600dp into layout.
Your phone with small screnn will do select xml file from renamed layout folder (for small screen).
You can to testing rotation with device en stability of fragments if an application changed orientation.
If you have old pc, you can try to make a new virtual device running on older version of Android, which uses less memory of computer.
For testing of rotation stability - application orientation changed - use on emulator Ctrl+F11, Ctrl+F12 key (Windows).
Important
Before the release of application, you have to rename layout folder to older name layout-sw600dp and layout-swXXXdp to layout.
Rename layout folder for small device screen f.g. from layout into layout-swXXXdp and a large layout-sw600dp into layout.
Your phone with small screnn will do select xml file from renamed layout folder (for small screen).
You can to testing rotation with device en stability of fragments if an application changed orientation.
If you have old pc, you can try to make a new virtual device running on older version of Android, which uses less memory of computer.
For testing of rotation stability - application orientation changed - use on emulator Ctrl+F11, Ctrl+F12 key (Windows).
Important
Before the release of application, you have to rename layout folder to older name layout-sw600dp and layout-swXXXdp to layout.
If you try function for checking internet connection you can disable internet on the emulator:
Settings - Wireless and networks - Mobile networks - Data enabled (checked - unchecked )
Settings - Wireless and networks - Mobile networks - Data enabled (checked - unchecked )
public boolean isNetworkAvailable() {
ConnectivityManager cm = (ConnectivityManager)
getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = cm.getActiveNetworkInfo();
if (networkInfo != null && networkInfo.isConnected()) {
return true;
}
return false;
}
// solution 1
ImageView imageView = (ImageView)findViewById(R.id.myimage);
imageView.setImageDrawable(null);
// or
imageView.setImageResource(0);
// solution 2 hide ImageView
imageView.setVisibility(View.INVISIBLE);
// solution 3 resize ImageView 0, 0
hImageViewSemafor.setLayoutParams(new LinearLayout.LayoutParams(0,0));
// image from res/drawable
int resID = getResources().getIdentifier("my_image",
"drawable", getPackageName());
// view
int resID = getResources().getIdentifier("my_resource",
"id", getPackageName());
// string
int resID = getResources().getIdentifier("my_string",
"string", getPackageName());
Editace: 2012-12-27 15:30:36
Počet článků v kategorii: 396
Url:asynctask-example-android-with-progressbar