Використання Accessibility API для доступу до View/Window інших додатків. Застосування API в розробці додатків

для людей з обмеженими здібностями або додатків для автоматизації користувальницьких дій/UX

Create Your Accessibility Service

An accessibility service can be bundled with a normal application, or created as a standalone Android project. The steps to creating the service are the same in either situation. Within your project, create a class that

extends AccessibilityService.

package com.example.android.apis.accessibility;

import android.accessibilityservice.AccessibilityService;

public class MyAccessibilityService extends AccessibilityService {

…

@Override

public void onAccessibilityEvent(AccessibilityEvent event) {

}

@Override

public void onInterrupt() {

}

…

}

Like any other service, you also declare it in the manifest file. Remember to specify that it handles the android.accessibilityservice intent, so that

the service is called when applications fire an AccessibilityEvent.

<application …>

…

<service android:name=”.MyAccessibilityService”>

<intent-filter>

<action android:name=”android.accessibilityservice.AccessibilityService” />

</intent-filter>

. . .

</service>

…

</application>

Accessibility need enable manually!!!

Configure Your Accessibility Service @Override public void onServiceConnected() { // Set the type of events that this service wants to listen to. Others// won’t be passed to this service.

info.eventTypes = AccessibilityEvent.TYPE_VIEW_CLICKED |AccessibilityEvent.TYPE_VIEW_FOCUSED;

// If you only want this service to work with specific applications, set their// package names here. Otherwise, when the service is activated, it will listen// to events from all applications.

info.packageNames = new String[]{“com.example.android.myFirstApp”, “com.example.android.mySecondApp”};

// Set the type of feedback your service will provide.info.feedbackType = AccessibilityServiceInfo.FEEDBACK_SPOKEN;

// Default services are invoked only if no package-specific ones are present// for the type of AccessibilityEvent generated. This service *is*// application-specific, so the flag isn’t necessary. If this was a// general-purpose service, it would be worth considering setting the// DEFAULT flag.// info.flags = AccessibilityServiceInfo.DEFAULT;

info.notificationTimeout = 100;this.setServiceInfo(info);}

Starting with Android 4.0, there is a second option available: configure the service using an XML file. Certain configuration options like canRetrieveWindowContent are only available if you configure your service using XML. The same configuration options above, defined using XML, would look like this:

<accessibility-serviceandroid:accessibilityEventTypes=”typeViewClicked|typeViewFocused”android:packageNames=”com.example.android.myFirstApp, com.example.android.mySecondApp”android:accessibilityFeedbackType=”feedbackSpoken”android:notificationTimeout=”100″android:settingsActivity=”com.example.android.apis.accessibility.TestBackActivity”android:canRetrieveWindowContent=”true”/>

If you go the XML route, be sure to reference it in your manifest, by adding a <meta-data> tag to your service declaration, pointing at the XML file. If you stored your XML file in res/xml/serviceconfig.xml, the new tag would look like this:

<service android:name=”.MyAccessibilityService”><intent-filter><action android:name=”android.accessibilityservice.AccessibilityService” /></intent-filter><meta-data android:name=”android.accessibilityservice”android:resource=”@xml/serviceconfig” /></service>

Respond to AccessibilityEvents

Now that your service is set up to run and listen for events, write some code so it knows what to do when an AccessibilityEvent actually arrives! Start by overriding the

onAccessibilityEvent(AccessibilityEvent) method. In that method, use getEventType() to determine the type of event, and getContentDescription() to extract any label text associated with the fiew that

fired the event.

@Override

public void onAccessibilityEvent(AccessibilityEvent event) {

final int eventType = event.getEventType();

String eventText = null;

switch(eventType) {

case AccessibilityEvent.TYPE_VIEW_CLICKED:

eventText = “Focused: “;

break;

case AccessibilityEvent.TYPE_VIEW_FOCUSED:

eventText = “Focused: “;

break;

}

eventText = eventText + event.getContentDescription();

}

Advanced service to access the window hierarchy

Query the View Heirarchy for More Context

This step is optional, but highly useful. One of the new features in Android 4.0 (API Level 14) is the ability for an AccessibilityService to query the view hierarchy, collecting information about the the UI component that generated an event, and its parent and children. In order to do this, make sure that you set the following line in your XML configuration:

android:canRetrieveWindowContent=”true”

Once that’s done, get an AccessibilityNodeInfo object using getSource(). This call only returns an object if the window where the event originated is still the active window. If not, it will return null, so behave accordingly. The following example is a snippet of code that, when it receives an event, does the following:

1. Immediately grab the parent of the view where the event originated2. In that view, look for a label and a check box as children views3. If it finds them, create a string to report to the user, indicating the label and whether it was checked or not.4. If at any point a null value is returned while traversing the view hierarchy, the method quietly gives up.

// Alternative onAccessibilityEvent, that uses AccessibilityNodeInfo

@Override

public void onAccessibilityEvent(AccessibilityEvent event) {

AccessibilityNodeInfo source = event.getSource();

if (source == null) {

return;

}

CharSequence taskLabel = source.getText();

final boolean isComplete = source.isChecked();

}

Grab window hierarchy

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {

currentNode = event.getSource();

if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN)

rootNode = getRootInActiveWindow();//Node from root window

}

And then....

Get list of View's in current window

...scanNode(rootNode, EditText.class.getName());...

private void scanNode(final AccessibilityNodeInfo node, final String mask) {try{

if (node == null)return;for (int i = 0; i < node.getChildCount(); i++) {final AccessibilityNodeInfo tmpnode = node.getChild(i);if (tmpnode == null)break;if (tmpnode.getChildCount() > 0)scanNode(tmpnode, mask);else if (tmpnode.getClassName().equals(mask)) {eventList.add(tmpnode);}

}} catch (Exception ex){ex.printStackTrace();}

}

Perform actions in View

for (AccessibilityNodeInfo info : editsList) {

info.performAction(AccessibilityNodeInfo.ACTION_FOCUS);

info.performAction(AccessibilityNodeInfo.ACTION_LONG_CLICK);

SetTextToClipboard(''Hello MMDAY Lviv);

info.performAction(AccessibilityNodeInfo.ACTION_PASTE);

}

Advanced Accessibility Service in action

Sergey KomlachLamantine Software a.s

2014sergey.komlach@stickypassword.com