按照java doc上的例子，进度条不显示
Use Cases
Basic usage
There are 3 types of progress indication:
- 1. indefinite when it's not known how much time will be needed to complete
- 2. definite with time estimate for completion (UI shows time that remains)
- 3. definite without time estimate where the UI shows percentage completed.
The default location of the progress indication is the status bar which aggregates all tasks running in the IDE that show progress. However it's possible to exclude the task from the default location and show the progress in one's custom dialog component. In such a case the same task should not appear in the status line component as well.
It's possible to request cancelling the task from status line progress aggregator if the task allows cancelling.
Progress tasks that get started as a result of explicit user action takes precedence in the status line docked component over tasks that are triggered by the system. (say filesystem refresh for example)
The most common usecase of the API looks like this:
ProgressHandle handle = ProgressHandleFactory.creatHandle("My custom task");...
// we have 100 workunits
// at this point the task appears in status bar.
handle.start(100);
...
handle.progress(10);
...
handle.progress("half way through", 50);
...
handle.progress(99);
// at this point the task is finished and removed from status bar
// it's not realy necessary to count all the way to the limit, finish can be called earlier.
// however it has to be called at the end of the processing.
handle.finish();
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http://rubenlaguna.com/wp/2010/01/18/cancellable-tasks-and-progress-indicators-netbeans-platform/
Progress indicator (indeterminate mode) which allows to cancel the task
The easiest way of having a cancellable progress indicator (Progress API) for a task in Netbeans Platform Application is the one below but it’s only worth for tasks that don’t update the progress indicator (indeterminate mode) until the task is finished. If you want to update the progress indicator (ProgressHandle) inside the task itself look at the second example.
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Logger;
import org.netbeans.api.progress.ProgressHandle;
import org.netbeans.api.progress.ProgressHandleFactory;
import org.openide.util.RequestProcessor;
import org.openide.util.TaskListener;
public final class MyCancellableActionNoProgressInformation implements ActionListener {
//The RequestProcessor has to have allowInterrupt set to true!!
private final static RequestProcessor RP = new RequestProcessor("interruptible tasks", 1, true);
private final static Logger LOG = Logger.getLogger(MyCancellableActionNoProgressInformation.class.getName());
public void actionPerformed(ActionEvent e) {
Runnable runnable = new Runnable() {
private final int NUM = 60000;
public void run() {
for (int i = 0; i < NUM; i++) {
doSomething(i);
if (Thread.interrupted()) {
LOG.info("the task was CANCELLED");
return;
}
}
}
private void doSomething(int i) {
LOG.info("doSomething with " + i);
return;
}
};
final RequestProcessor.Task theTask = RP.create(runnable);
final ProgressHandle ph = ProgressHandleFactory.createHandle("performing some task", theTask);
theTask.addTaskListener(new TaskListener() {
public void taskFinished(org.openide.util.Task task) {
//make sure that we get rid of the ProgressHandle
//when the task is finished
ph.finish();
}
});
//start the progresshandle the progress UI will show 500s after
ph.start();
//this actually start the task
theTask.schedule(0);
}
}
leads to
INFO [com.rubenlaguna.en4j.mainmodule.ImportEvernoteFile]: doSomething with 6620
INFO [com.rubenlaguna.en4j.mainmodule.ImportEvernoteFile]: doSomething with 6621
INFO [com.rubenlaguna.en4j.mainmodule.ImportEvernoteFile]: doSomething with 6622
INFO [com.rubenlaguna.en4j.mainmodule.ImportEvernoteFile]: the task was CANCELLED
Progress indicator (determinate mode) which allows to cancel the task
This example show a ProgressHandle that it’s updated from the Runnable and it’s stil cancelable. In this case you are also somewhat to use the more cumbersome catch(InterruptedException) instead of just checking Thread.interrupted(). For some reason I couldn’t get the Thread.interrupted() to work in this case. Doing a Thread.sleep(0) will always throw a InterruptedException if the thread was interrupted (canceling a task will interrupt the thread if the RequestProcessor is created with the interruptThread=true).
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Logger;
import org.netbeans.api.progress.ProgressHandle;
import org.netbeans.api.progress.ProgressHandleFactory;
import org.openide.util.Cancellable;
import org.openide.util.RequestProcessor;
import org.openide.util.Task;
import org.openide.util.TaskListener;
public final class MyCancellableAction implements ActionListener {
private final static RequestProcessor RP = new RequestProcessor("interruptible tasks", 1, true);
private final static Logger LOG = Logger.getLogger(MyCancellableAction.class.getName());
private RequestProcessor.Task theTask = null;
public void actionPerformed(ActionEvent e) {
final ProgressHandle ph = ProgressHandleFactory.createHandle("task thats shows progress", new Cancellable() {
public boolean cancel() {
return handleCancel();
}
});
Runnable runnable = new Runnable() {
private final int NUM = 60000;
public void run() {
try {
ph.start(); //we must start the PH before we swith to determinate
ph.switchToDeterminate(NUM);
for (int i = 0; i < NUM; i++) {
doSomething(i);
ph.progress(i);
Thread.sleep(0); //throws InterruptedException is the task was cancelled
}
} catch (InterruptedException ex) {
LOG.info("the task was CANCELLED");
return;
}
}
private void doSomething(int i) {
LOG.info("doSomething with " + i);
return;
}
};
theTask = RP.create(runnable); //the task is not started yet
theTask.addTaskListener(new TaskListener() {
public void taskFinished(Task task) {
ph.finish();
}
});
theTask.schedule(0); //start the task
}
private boolean handleCancel() {
LOG.info("handleCancel");
if (null == theTask) {
return false;
}
return theTask.cancel();
}
}
leads to
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5400
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5401
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5402
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5403
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5404
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5405
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: handleCancel
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: doSomething with 5406
INFO [com.rubenlaguna.en4j.mainmodule.MyCancellableAction]: the task was CANCELLED
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