a minimalist example of Android accessibility service

gistfile1.txt

$ adb logcat -s RecorderService
--------- beginning of /dev/log/system
--------- beginning of /dev/log/main
V/RecorderService( 1841): onServiceConnected
...
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_CLICKED [class] android.widget.Button [package] com.example [time] 7710428 [text] Activity1
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_FOCUSED [class] android.widget.EditText [package] com.example [time] 7710521 [text]
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_WINDOW_STATE_CHANGED [class] com.example.Activity1 [package] com.example [time] 7710536 [text] TestRecord
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_FOCUSED [class] android.widget.EditText [package] com.example [time] 7710539 [text]
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_CLICKED [class] android.widget.EditText [package] com.example [time] 7725471 [text]
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_TEXT_CHANGED [class] android.widget.EditText [package] com.example [time] 7728589 [text] f
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_TEXT_CHANGED [class] android.widget.EditText [package] com.example [time] 7728804 [text] fg
V/RecorderService( 1841): onAccessibilityEvent: [type] TYPE_VIEW_TEXT_CHANGED [class] android.widget.EditText [package] com.example [time] 7728994 [text] fgj
...

RecorderService.java

import android.accessibilityservice.AccessibilityService;
import android.accessibilityservice.AccessibilityServiceInfo;
import android.util.Log;
import android.view.accessibility.AccessibilityEvent;

public class RecorderService extends AccessibilityService {

    static final String TAG = "RecorderService";

    private String getEventType(AccessibilityEvent event) {
        switch (event.getEventType()) {
            case AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED:
                return "TYPE_NOTIFICATION_STATE_CHANGED";
            case AccessibilityEvent.TYPE_VIEW_CLICKED:
                return "TYPE_VIEW_CLICKED";
            case AccessibilityEvent.TYPE_VIEW_FOCUSED:
                return "TYPE_VIEW_FOCUSED";
            case AccessibilityEvent.TYPE_VIEW_LONG_CLICKED:
                return "TYPE_VIEW_LONG_CLICKED";
            case AccessibilityEvent.TYPE_VIEW_SELECTED:
                return "TYPE_VIEW_SELECTED";
            case AccessibilityEvent.TYPE_WINDOW_STATE_CHANGED:
                return "TYPE_WINDOW_STATE_CHANGED";
            case AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED:
                return "TYPE_VIEW_TEXT_CHANGED";
        }
        return "default";
    }

    private String getEventText(AccessibilityEvent event) {
        StringBuilder sb = new StringBuilder();
        for (CharSequence s : event.getText()) {
            sb.append(s);
        }
        return sb.toString();
    }

    @Override
    public void onAccessibilityEvent(AccessibilityEvent event) {
        Log.v(TAG, String.format(
                "onAccessibilityEvent: [type] %s [class] %s [package] %s [time] %s [text] %s",
                getEventType(event), event.getClassName(), event.getPackageName(),
                event.getEventTime(), getEventText(event)));
    }

    @Override
    public void onInterrupt() {
        Log.v(TAG, "onInterrupt");
    }

    @Override
    protected void onServiceConnected() {
        super.onServiceConnected();
        Log.v(TAG, "onServiceConnected");
        AccessibilityServiceInfo info = new AccessibilityServiceInfo();
        info.flags = AccessibilityServiceInfo.DEFAULT;
        info.eventTypes = AccessibilityEvent.TYPES_ALL_MASK;
        info.feedbackType = AccessibilityServiceInfo.FEEDBACK_GENERIC;
        setServiceInfo(info);
    }

}