I have a problem. I need to go from one activity to another. My second activity has a big xml layout, with a lot of elements (I'm speaking about four hundred aprox.), then it takes a few seconds (too much) to show this second Activity.
How can I show a Progress dialog between two activities?
I'm trying to use a background task to do this.
I have this method in my Activity A:
private void goToYear() {
Intent intent = new Intent();
intent.setClass (getBaseContext(), YearActivity.class);
startActivity( intent);
}
And in my Activity B:
public class YearActivity extends Activity {
private String TAG = "YearActivity ::";
private ProgressDialog pd = null;
@Override
public void onCreate( Bundle savedInstanceState) {
super.onCreate( savedInstanceState);
// Show the ProgressDialog on this thread
this.pd = ProgressDialog.show(this, "Working...", "Calculating the screen...", true, false);
// Start a new thread that will download all the data
new MakeYearTask().execute();
}
private void initCalendar () {
this.setContentView( R.layout.calendar_year);
...
...
initialize values
...
...
}
private class MakeYearTask extends AsyncTask<String, Void, Object> {
protected Void doInBackground(String... args) {
Log.i("YearActivity::MakeYearTask", "MakeYearTask Background thread starting");
YearActivity.this.initCalendar();
}
protected void onPostExecute(Object result) {
if (YearActivity.this.pd != null) {
YearActivity.this.pd.dismiss();
}
}
}
}
You can see that I make the setContentView
out of the onCreate
method.
This doesn't work. It gives me one exception, like this:
12-09 19:49:17.729: ERROR/AndroidRuntime(218): java.lang.RuntimeException: An error occured while executing doInBackground()
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.os.AsyncTask$3.done(AsyncTask.java:200)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:234)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:258)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.FutureTask.run(FutureTask.java:122)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:648)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:673)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.lang.Thread.run(Thread.java:1060)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): Caused by: android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.view.ViewRoot.checkThread(ViewRoot.java:2629)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.view.ViewRoot.requestLayout(ViewRoot.java:545)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.view.View.requestLayout(View.java:7657)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.view.ViewGroup.addView(ViewGroup.java:1749)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.view.ViewGroup.addView(ViewGroup.java:1731)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow.generateLayout(PhoneWindow.java:2186)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow.installDecor(PhoneWindow.java:2239)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:309)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.app.Activity.setContentView(Activity.java:1620)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at es.jota.app.YearActivity.initCalendar(YearActivity.java:42)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at es.jota.app.YearActivity.access$0(YearActivity.java:41)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at es.jota.app.YearActivity.initCalendar$MakeYearTask.doInBackground(YearActivity.java:120)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at es.jota.app.YearActivity.initCalendar$MakeYearTask.doInBackground(YearActivity.java:1)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at android.os.AsyncTask$2.call(AsyncTask.java:185)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:256)
12-09 19:49:17.729: ERROR/AndroidRuntime(218): ... 4 more
"Deprecated" refers to functions or elements that are in the process of being replaced by newer ones. ProgressDialog is a modal dialog, which prevents the user from interacting with the app. Instead of using this class, you should use a progress indicator like ProgressBar , which can be embedded in your app's UI.
setProgress(int value) This method is used to update the progress dialog with some specific value.
Android Progress Dialog is a UI which shows the progress of a task like you want user to wait until the previous lined up task is completed and for that purpose you can use progress dialog. The best example is you see when downloading or uploading any file.
This is poor design to start with. If you have such a large amount of data to present to the user which would presumably be scrolled through, you should instead use an AdapterView
subclass, such as a ListView
or GridView
. An XML layout with almost 400 elements is incredibly large.
I understand what you're trying to do (you're attempting to perform the lengthy building of the massive View
hierarchy on a separate Thread
using an AsyncTask
, but what you've found is that it's blown up on you for trying to touch the View
hierarchy on a non-UI Thread
).
Even if you did manage to implement some kind of progress bar in the foreground while the hierarchy is being built, I'm not sure if the system would provide the means to call back progress information while it inflates the View
hierarchy (but I may be wrong).
AdapterView
s were created to solve exactly this kind of problem. With an AdapterView
, typically only a screen's worth of Views
exist in memory at any time. For example, you could have a table with a thousand rows, but with only seven rows fitting onto the screen at once, only eight row View
s might exist in memory at once. Furthermore, the adapter should also recycle the View
s, further optimising performance.
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