diff options
Diffstat (limited to 'samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java')
| -rw-r--r-- | samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java | 145 |
1 files changed, 88 insertions, 57 deletions
diff --git a/samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java b/samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java index dbbfe3a1b..c7088be98 100644 --- a/samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java +++ b/samples/ApiDemos/src/com/example/android/apis/accessibility/TaskBackService.java @@ -19,6 +19,7 @@ package com.example.android.apis.accessibility; import com.example.android.apis.R; import android.accessibilityservice.AccessibilityService; +import android.text.TextUtils; import android.util.Log; import android.view.accessibility.AccessibilityEvent; import android.view.accessibility.AccessibilityNodeInfo; @@ -28,26 +29,40 @@ import android.speech.tts.TextToSpeech.OnInitListener; import java.util.Locale; -/** The TaskBackService listens for AccessibilityEvents, and turns them into information it can - * communicate to the user with speech. +/** + * This class demonstrates how an accessibility service can query + * window content to improve the feedback given to the user. */ public class TaskBackService extends AccessibilityService implements OnInitListener { - private final String LOG_TAG = "TaskBackService/onAccessibilityEvent"; - private boolean mTextToSpeechInitialized = false; - private TextToSpeech mTts = null; + /** Tag for logging. */ + private static final String LOG_TAG = "TaskBackService/onAccessibilityEvent"; + + /** Comma separator. */ private static final String SEPARATOR = ", "; + /** The class name of TaskListView - for simplicity we speak only its items. */ + private static final String TASK_LIST_VIEW_CLASS_NAME = + "com.example.android.apis.accessibility.TaskListView"; + + /** Flag whether Text-To-Speech is initialized. */ + private boolean mTextToSpeechInitialized; + /** Handle to the Text-To-Speech engine. */ + private TextToSpeech mTts; - /** Initializes the Text-To-Speech engine as soon as the service is connected. */ + /** + * {@inheritDoc} + */ @Override public void onServiceConnected() { + // Initializes the Text-To-Speech engine as soon as the service is connected. mTts = new TextToSpeech(getApplicationContext(), this); } - /** Processes an AccessibilityEvent, by traversing the View's tree and putting together a - * message to speak to the user. + /** + * Processes an AccessibilityEvent, by traversing the View's tree and + * putting together a message to speak to the user. */ @Override public void onAccessibilityEvent(AccessibilityEvent event) { @@ -56,55 +71,49 @@ public class TaskBackService extends AccessibilityService implements OnInitListe return; } - int eventType = event.getEventType(); - if (eventType != AccessibilityEvent.TYPE_VIEW_CLICKED) { + // This AccessibilityNodeInfo represents the view that fired the + // AccessibilityEvent. The following code will use it to traverse the + // view hierarchy, using this node as a starting point. + // + // NOTE: Every method that returns an AccessibilityNodeInfo may return null, + // because the explored window is in another process and the + // corresponding View might be gone by the time your request reaches the + // view hierarchy. + AccessibilityNodeInfo source = event.getSource(); + if (source == null) { return; } - /* This AccessibilityNodeInfo represents the view that fired the - * AccessibilityEvent. The following code will use it to traverse - * the view hierarchy, using this node as a starting point. - */ - AccessibilityNodeInfo entryNode = event.getSource(); - - /* Every method that returns an AccessibilityNodeInfo may return null, - * because the explored window is in another process and the corresponding - * View might be gone by the time your request reaches the view hierarchy." - */ - if (entryNode == null) { - return; - } // Grab the parent of the view that fired the event. - AccessibilityNodeInfo rowNode = entryNode.getParent(); - + AccessibilityNodeInfo rowNode = getListItemNodeInfo(source); if (rowNode == null) { - return; + return; } - /* Using this parent, get references to both child nodes, - * the label and the checkbox. - */ + // Using this parent, get references to both child nodes, the label and the checkbox. AccessibilityNodeInfo labelNode = rowNode.getChild(0); - AccessibilityNodeInfo completeNode = rowNode.getChild(1); - - if (labelNode == null || completeNode == null) { - return; + if (labelNode == null) { + rowNode.recycle(); + return; } - /* Using these to determine what the task is and whether or not - * it's complete, based on the text inside the label, and the state - * of the checkbox. - */ + AccessibilityNodeInfo completeNode = rowNode.getChild(1); + if (completeNode == null) { + rowNode.recycle(); + return; + } - // Quick check to make sure we're not in the ApiDemos nav. + // Determine what the task is and whether or not it's complete, based on + // the text inside the label, and the state of the check-box. if (rowNode.getChildCount() < 2 || !rowNode.getChild(1).isCheckable()) { + rowNode.recycle(); return; } CharSequence taskLabel = labelNode.getText(); - boolean isComplete = completeNode.isChecked(); + final boolean isComplete = completeNode.isChecked(); - String completeStr = null;; + String completeStr = null; if (isComplete) { completeStr = getString(R.string.task_complete); } else { @@ -112,44 +121,66 @@ public class TaskBackService extends AccessibilityService implements OnInitListe } String taskStr = getString(R.string.task_complete_template, taskLabel, completeStr); - StringBuilder forSpeech = new StringBuilder(taskStr); - - /* The custom listview added extra context to the event by adding - * an AccessibilityRecord to it. Extract that from the event and read it. - */ - int records = event.getRecordCount(); + StringBuilder utterance = new StringBuilder(taskStr); + // The custom ListView added extra context to the event by adding an + // AccessibilityRecord to it. Extract that from the event and read it. + final int records = event.getRecordCount(); for (int i = 0; i < records; i++) { AccessibilityRecord record = event.getRecord(i); CharSequence contentDescription = record.getContentDescription(); - if (contentDescription != null) { - forSpeech.append(SEPARATOR).append(contentDescription); + if (!TextUtils.isEmpty(contentDescription )) { + utterance.append(SEPARATOR); + utterance.append(contentDescription); } } - /* Speak the forSpeech string to the user. QUEUE_ADD adds the string to the end of the - * queue, QUEUE_FLUSH would interrupt whatever was currently being said. - */ - mTts.speak(forSpeech.toString() , TextToSpeech.QUEUE_ADD, null); - Log.d(LOG_TAG, forSpeech.toString()); + // Announce the utterance. + mTts.speak(utterance.toString(), TextToSpeech.QUEUE_FLUSH, null); + Log.d(LOG_TAG, utterance.toString()); + } + + private AccessibilityNodeInfo getListItemNodeInfo(AccessibilityNodeInfo source) { + AccessibilityNodeInfo current = source; + while (true) { + AccessibilityNodeInfo parent = current.getParent(); + if (parent == null) { + return null; + } + if (TASK_LIST_VIEW_CLASS_NAME.equals(parent.getClassName())) { + return current; + } + // NOTE: Recycle the infos. + AccessibilityNodeInfo oldCurrent = current; + current = parent; + oldCurrent.recycle(); + } } + /** + * {@inheritDoc} + */ @Override public void onInterrupt() { - /* do nothing */ + /* do nothing */ } - /** Sets a flag so that the TaskBackService knows that the Text-To-Speech engine has been - * initialized, and can now handle speaking requests. + /** + * {@inheritDoc} */ @Override - public void onInit (int status) { + public void onInit(int status) { + // Set a flag so that the TaskBackService knows that the Text-To-Speech + // engine has been initialized, and can now handle speaking requests. if (status == TextToSpeech.SUCCESS) { mTts.setLanguage(Locale.US); mTextToSpeechInitialized = true; } } + /** + * {@inheritDoc} + */ @Override public void onDestroy() { super.onDestroy(); |