AsyncTask: ProgressDialog und sauberes OrientationChange Handling (InnerClass Version)

1<resources>
2 <style name="MyProgressDialog" parent="@android:style/Theme.Dialog">
3 <item name="android:background">@android:color/transparent</item>
4 <item name="android:backgroundDimEnabled">false</item>
5 <item name="android:windowAnimationStyle">@android:style/Animation.Dialog</item>
6 <item name="android:windowBackground">@android:color/transparent</item>
7 <item name="android:windowContentOverlay">@null</item>
8 <item name="android:windowFrame">@null</item>
9 <item name="android:windowIsFloating">true</item>
10 <item name="android:windowSoftInputMode">stateUnspecified|adjustPan</item>
11 <item name="android:windowTitleStyle">@null</item>
12 </style>
13</resources>

1public class MyProgressDialog extends Dialog {
2
3 public MyProgressDialog(Context context) {
4 super(context, R.style.MyProgressDialog);
5 }
6
7 public static MyProgressDialog show(Context context, CharSequence title, CharSequence message) {
8 return show(context, title, message, false);
9 }
10
11 public static MyProgressDialog show(Context context, CharSequence title, CharSequence message, boolean indeterminate) {
12 return show(context, title, message, indeterminate, false, null);
13 }
14
15 public static MyProgressDialog show(Context context, CharSequence title, CharSequence message, boolean indeterminate, boolean cancelable) {
16 return show(context, title, message, indeterminate, cancelable, null);
17 }
18
19 public static MyProgressDialog show(Context context, CharSequence title, CharSequence message, boolean indeterminate, boolean cancelable, final OnCancelListener onCancelListener) {
20 MyProgressDialog dialog = new MyProgressDialog(context);
21 dialog.setCancelable(cancelable);
22 dialog.setOnCancelListener(onCancelListener);
23 dialog.setTitle(title);
24
25 dialog.addContentView(new ProgressBar(context), new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
26 dialog.show();
27
28 return dialog;
29 }
30}

1public class MyActivity extends Activity {
2
3 private class MyAsyncTask extends AsyncTask<..., ..., ...> {
4
5 private Context context;
6 private MyProgressDialog dialog;
7
8 public MyAsyncTask(Context context) {
9 super();
10
11 this.context = context;
12 }
13
14 @Override
15 protected ... doInBackground(...) {
16 // Lang laufender Job ohne UI Nutzung
17 }
18
19 @Override
20 protected ... onPostExecute(...) {
21 if (dialog != null) {
22 try {
23 dialog.dismiss();
24 } catch (Exception exception) {
25 }
26
27 dialog = null;
28 }
29
30 if (context != null) {
31 // Hier UI Nutzung
32 context.eineMethode();
33 }
34
35 // Signalisiert der Activity: AsyncTask laeuft nicht mehr
36 if (context != null) {
37 context.task = null;
38 }
39 }
40
41 @Override
42 protected ... onPreExecute () {
43 // ProgressDialog ausgeben
44 if (context != null) {
45 dialog = MyProgressDialog.show(context, null, null, true, false);
46}
47 }
48 }
49
50 private MyAsyncTask task;
51
52 @Override
53 public void onCreate(Bundle bundle) {
54 // ...
55
56 task = (MyAsyncTask) getLastNonConfigurationInstance();
57 if (task != null) {
58 // Task war aktiv als Activity abgeschossen wurde, Context in AsyncTask setzen und ProgressDialog anzeigen
59 task.context = this;
60 task.dialog = MyProgressDialog.show(this, null, null, true, false);
61 } else {
62 // Task war nicht aktiv, Task starten (z.B. bei einer ListActivity, etc.)
63 task = new MyAsyncTask(this);
64 task.execute();
65 }
66
67 // ...
68 }
69
70 @Override
71 public Object onRetainNonConfigurationInstance() {
72 if (task != null) {
73 // Activity wird abgeschossen waehrend Task laeuft
74 if (task.dialog != null) {
75 // ProgressDialog wegwerfen
76 task.dialog.dismiss();
77 task.dialog = null;
78 }
79
80 // Signalisiert dem AsyncTask: Activity existiert nicht mehr
81 task.context = null;
82 }
83
84 return task;
85 }
86
87 private void eineMethode() {
88 }
89}