Manifest.xm:
<uses-permission android:name="android.permission.INTERNET"/>
**************************
res/layout/main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello" />
<LinearLayout
android:id="@+id/linearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="下載" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="重整" />
</LinearLayout>
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher" />
</LinearLayout>
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public class Cq_Handler_vogella03Activity extends Activity {
/** Called when the activity is first created. */
private static ProgressDialog dialog;
private static ImageView mImageView;
private static Bitmap downloadBitmap;
private static Handler handler;
private Thread downloadThread;
private Button downloadBtn;
private Button resetBtn;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
//Create a handler to update the UI
handler = new Handler();
mImageView = (ImageView) findViewById(R.id.imageView1);
//Did we already download the image?
if (downloadBitmap != null) {
mImageView.setImageBitmap(downloadBitmap);
}
//Check if the thread is already running
downloadThread = (Thread) getLastNonConfigurationInstance();
if (downloadThread != null && downloadThread.isAlive()) {
dialog = ProgressDialog.show(this, "下載狀況", "下載中...");
}
//Setup buttons
downloadBtn = (Button) findViewById(R.id.button1);
resetBtn = (Button) findViewById(R.id.button2);
downloadBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
downloadPicture(v);
}
});
resetBtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
resetPicture(v);
}
});
}
public void downloadPicture (View view) {
dialog = ProgressDialog.show(this, "下載狀況", "下載中...");
downloadThread = new MyThread();
downloadThread.start();
}
public void resetPicture(View view) {
if (downloadBitmap != null) {
downloadBitmap = null;
}
mImageView.setImageResource(R.drawable.ic_launcher);
}
//SAVE the thread
@Override
public Object onRetainNonConfigurationInstance() {
// TODO Auto-generated method stub
//return super.onRetainNonConfigurationInstance();
return downloadThread;
}
// Dismiss dialog if activity is destroyed
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
if (dialog != null && dialog.isShowing()) {
dialog.dismiss();
dialog = null;
}
super.onDestroy();
}
// Utility method to download image from the internet
static private Bitmap downloadBitmap (String url) throws IOException {
HttpUriRequest request = new HttpGet(url.toString());
HttpClient httpClient = new DefaultHttpClient();
HttpResponse response = httpClient.execute(request);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
byte [] bytes = EntityUtils.toByteArray(entity);
Bitmap bitmap = BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
return bitmap;
}else {
throw new IOException("Download failed, HTTP response code " + statusCode + " - "
+ statusLine.getReasonPhrase());
}
}
static public class MyThread extends Thread {
@Override
public void run() {
// TODO Auto-generated method stub
//super.run();
try {
//Simulate a slow network
try {
new Thread().sleep(5000);
}catch (InterruptedException e) {
e.printStackTrace();
}
downloadBitmap = downloadBitmap("http://www.vogella.com/img/lars/LarsVogelArticle7.png");
handler.post(new MyRunnable());
}catch (IOException e) {
e.printStackTrace();
}finally {
}
}
}// end of MyThread
static public class MyRunnable implements Runnable {
@Override
public void run() {
// TODO Auto-generated method stub
mImageView.setImageBitmap(downloadBitmap);
dialog.dismiss();
}
}// end of MyRunnable
}
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