Question

我目前正在开发Android应用程序，并想知道如何检测屏幕截图。我尝试使用FileObserver，但问题是检测到所有事件（当设备进入睡眠状态，消息等）。如何只检测截图？

提前谢谢！

Answer 1

您是如何使用FileObserver检测屏幕截图的？使用FileObserver时，仅监视屏幕截图目录中的文件创建事件。

    String path = Environment.getExternalStorageDirectory()
            + File.separator + Environment.DIRECTORY_PICTURES
            + File.separator + "Screenshots" + File.separator;
    Log.d(TAG, path);

    FileObserver fileObserver = new FileObserver(path, FileObserver.CREATE) {
        @Override
        public void onEvent(int event, String path) {
            Log.d(TAG, event + " " + path);
        }
    };

    fileObserver.startWatching();

请勿忘记声明相应的权限以访问SD卡中的内容。

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

另一种检测屏幕截图的方法是使用ContentObserver，因为在屏幕截图后会有一条记录插入系统媒体数据库。以下是使用ContentObserver监控事件的代码段。使用ContentObserver，无需声明write/read external storage权限，但您必须对文件名执行一些过滤，以确保它是一个屏幕截图事件。

    HandlerThread handlerThread = new HandlerThread("content_observer");
    handlerThread.start();
    final Handler handler = new Handler(handlerThread.getLooper()) {

        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
        }
    };

    getContentResolver().registerContentObserver(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            true,
            new ContentObserver(handler) {
                @Override
                public boolean deliverSelfNotifications() {
                    Log.d(TAG, "deliverSelfNotifications");
                    return super.deliverSelfNotifications();
                }

                @Override
                public void onChange(boolean selfChange) {
                    super.onChange(selfChange);
                }

                @Override
                public void onChange(boolean selfChange, Uri uri) {
                    Log.d(TAG, "onChange " + uri.toString());
                    if (uri.toString().matches(MediaStore.Images.Media.EXTERNAL_CONTENT_URI.toString() + "/[0-9]+")) {

                        Cursor cursor = null;
                        try {
                            cursor = getContentResolver().query(uri, new String[] {
                                    MediaStore.Images.Media.DISPLAY_NAME,
                                    MediaStore.Images.Media.DATA
                            }, null, null, null);
                            if (cursor != null && cursor.moveToFirst()) {
                                final String fileName = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DISPLAY_NAME));
                                final String path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
                                // TODO: apply filter on the file name to ensure it's screen shot event
                                Log.d(TAG, "screen shot added " + fileName + " " + path);
                            }
                        } finally {
                            if (cursor != null)  {
                                cursor.close();
                            }
                        }
                    }
                    super.onChange(selfChange, uri);
                }
            }
    );

<强>更新

如果您使用第二种方法，则必须在Android M版本之后请求READ_EXTERNAL_STORAGE，否则它将抛出SecurityException。有关如何请求运行时权限的更多信息，请参阅here。

Answer 2

我已经改进了alijandro评论中的代码，使其易于使用，并在内容观察者检测到来自摄像头的图像时修复问题（应该只是截图）。然后将其包装到委托类中以方便使用。

•ScreenshotDetectionDelegate.java

public class ScreenshotDetectionDelegate {
    private WeakReference<Activity> activityWeakReference;
    private ScreenshotDetectionListener listener;

    public ScreenshotDetectionDelegate(Activity activityWeakReference, ScreenshotDetectionListener listener) {
        this.activityWeakReference = new WeakReference<>(activityWeakReference);
        this.listener = listener;
    }

    public void startScreenshotDetection() {
        activityWeakReference.get()
                .getContentResolver()
                .registerContentObserver(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, true, contentObserver);
    }

    public void stopScreenshotDetection() {
        activityWeakReference.get().getContentResolver().unregisterContentObserver(contentObserver);
    }

    private ContentObserver contentObserver = new ContentObserver(new Handler()) {
        @Override
        public boolean deliverSelfNotifications() {
            return super.deliverSelfNotifications();
        }

        @Override
        public void onChange(boolean selfChange) {
            super.onChange(selfChange);
        }

        @Override
        public void onChange(boolean selfChange, Uri uri) {
            super.onChange(selfChange, uri);
            if (isReadExternalStoragePermissionGranted()) {
                String path = getFilePathFromContentResolver(activityWeakReference.get(), uri);
                if (isScreenshotPath(path)) {
                    onScreenCaptured(path);
                }
            } else {
                onScreenCapturedWithDeniedPermission();
            }
        }
    };

    private void onScreenCaptured(String path) {
        if (listener != null) {
            listener.onScreenCaptured(path);
        }
    }

    private void onScreenCapturedWithDeniedPermission() {
        if (listener != null) {
            listener.onScreenCapturedWithDeniedPermission();
        }
    }

    private boolean isScreenshotPath(String path) {
        return path != null && path.toLowerCase().contains("screenshots");
    }

    private String getFilePathFromContentResolver(Context context, Uri uri) {
        try {
            Cursor cursor = context.getContentResolver().query(uri, new String[]{
                    MediaStore.Images.Media.DISPLAY_NAME,
                    MediaStore.Images.Media.DATA
            }, null, null, null);
            if (cursor != null && cursor.moveToFirst()) {
                String path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
                cursor.close();
                return path;
            }
        } catch (IllegalStateException ignored) {
        }
        return null;
    }

    private boolean isReadExternalStoragePermissionGranted() {
        return ContextCompat.checkSelfPermission(activityWeakReference.get(), Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED;
    }

    public interface ScreenshotDetectionListener {
        void onScreenCaptured(String path);

        void onScreenCapturedWithDeniedPermission();
    }
}

•ScreenshotDetectionActivity.java

import android.Manifest;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.widget.Toast;

public abstract class ScreenshotDetectionActivity extends AppCompatActivity implements ScreenshotDetectionDelegate.ScreenshotDetectionListener {
    private static final int REQUEST_CODE_READ_EXTERNAL_STORAGE_PERMISSION = 3009;

    private ScreenshotDetectionDelegate screenshotDetectionDelegate = new ScreenshotDetectionDelegate(this, this);

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        checkReadExternalStoragePermission();
    }

    @Override
    protected void onStart() {
        super.onStart();
        screenshotDetectionDelegate.startScreenshotDetection();
    }

    @Override
    protected void onStop() {
        super.onStop();
        screenshotDetectionDelegate.stopScreenshotDetection();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode) {
            case REQUEST_CODE_READ_EXTERNAL_STORAGE_PERMISSION:
                if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
                    showReadExternalStoragePermissionDeniedMessage();
                }
                break;
            default:
                super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }
    }

    @Override
    public void onScreenCaptured(String path) {
        // Do something when screen was captured
    }

    @Override
    public void onScreenCapturedWithDeniedPermission() {
        // Do something when screen was captured but read external storage permission has denied
    }

    private void checkReadExternalStoragePermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            requestReadExternalStoragePermission();
        }
    }

    private void requestReadExternalStoragePermission() {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, REQUEST_CODE_READ_EXTERNAL_STORAGE_PERMISSION);
    }

    private void showReadExternalStoragePermissionDeniedMessage() {
        Toast.makeText(this, "Read external storage permission has denied", Toast.LENGTH_SHORT).show();
    }
}

•MainActivity.java

import android.os.Bundle;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends ScreenshotDetectionActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    public void onScreenCaptured(String path) {
        Toast.make(this, path, Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onScreenCapturedWithDeniedPermission() {
        Toast.make(this, "Please grant read external storage permission for screenshot detection", Toast.LENGTH_SHORT).show();
    }
}

Answer 3

您可以创建仅监视屏幕截图目录的FileObserver，以及仅用于创建文件或目录的触发事件。有关详情，请点击here。

Answer 4

我为android截图制作了git项目。

我使用了Content Observer。

从API 14到最新版本

工作正常

您可以查看here

1.ScreenShotContentObserver .class
（原始截图删除 - ＆gt;通知截图并给出截图位图）

public class ScreenShotContentObserver extends ContentObserver {


private final String TAG = this.getClass().getSimpleName();
private static final String[] PROJECTION = new String[]{
        MediaStore.Images.Media.DISPLAY_NAME, MediaStore.Images.Media.DATA,
        MediaStore.Images.Media.DATE_ADDED, MediaStore.Images.ImageColumns._ID
};
private static final long DEFAULT_DETECT_WINDOW_SECONDS = 10;
private static final String SORT_ORDER = MediaStore.Images.Media.DATE_ADDED + " DESC";

public static final String FILE_POSTFIX = "FROM_ASS";
private static final String WATERMARK = "Scott";
private ScreenShotListener mListener;
private ContentResolver mContentResolver;
private String lastPath;

public ScreenShotContentObserver(Handler handler, ContentResolver contentResolver, ScreenShotListener listener) {
    super(handler);
    mContentResolver = contentResolver;
    mListener = listener;
}

@Override
public boolean deliverSelfNotifications() {
    Log.e(TAG, "deliverSelfNotifications");
    return super.deliverSelfNotifications();
}

@Override
synchronized public void onChange(boolean selfChange) {
    super.onChange(selfChange);
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
        //above API 16 Pass~!(duplicated call...)
        return;
    }
    Log.e(TAG, "[Start] onChange : " + selfChange);
    try {
        process(MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
        Log.e(TAG, "[Finish] general");
    } catch (Exception e) {
        Log.e(TAG, "[Finish] error : " + e.toString(), e);
    }
}

@Override
synchronized public void onChange(boolean selfChange, Uri uri) {
    super.onChange(selfChange, uri);
    Log.e(TAG, "[Start] onChange : " + selfChange + " / uri : " + uri.toString());

    if (uri.toString().startsWith(MediaStore.Images.Media.EXTERNAL_CONTENT_URI.toString())) {
        try {
            process(uri);
            Log.e(TAG, "[Finish] general");
        } catch (Exception e) {
            Log.e(TAG, "[Finish] error : " + e.toString(), e);
        }
    } else {
        Log.e(TAG, "[Finish] not EXTERNAL_CONTENT_URI ");
    }
}

public void register() {
    Log.d(TAG, "register");
    mContentResolver.registerContentObserver(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, true, this);
}

public void unregister() {
    Log.d(TAG, "unregister");
    mContentResolver.unregisterContentObserver(this);
}

 private boolean process(Uri uri) throws Exception {
    Data result = getLatestData(uri);
    if (result == null) {
        Log.e(TAG, "[Result] result is null!!");
        return false;
    }
    if (lastPath != null && lastPath.equals(result.path)) {
        Log.e(TAG, "[Result] duplicate!!");
        return false;
    }
    long currentTime = System.currentTimeMillis() / 1000;
    if (matchPath(result.path) && matchTime(currentTime, result.dateAdded)) {
        lastPath = result.path;
        Uri screenUri = Uri.parse(MediaStore.Images.Media.EXTERNAL_CONTENT_URI.toString() + "/" + result.id);
        Log.e(TAG, "[Result] This is screenshot!! : " + result.fileName + " | dateAdded : " + result.dateAdded + " / " + currentTime);
        Bitmap bitmap = MediaStore.Images.Media.getBitmap(mContentResolver, screenUri);
        Bitmap copyBitmap = bitmap.copy(bitmap.getConfig(), true);
        bitmap.recycle();
        int temp = mContentResolver.delete(screenUri, null, null);
        Log.e(TAG, "Delete Result : " + temp);
        if (mListener != null) {
            mListener.onScreenshotTaken(copyBitmap, result.fileName);
        }
        return true;
    } else {
        Log.e(TAG, "[Result] No ScreenShot : " + result.fileName);
    }
    return false;
}

private Data getLatestData(Uri uri) throws Exception {
    Data data = null;
    Cursor cursor = null;
    try {
        cursor = mContentResolver.query(uri, PROJECTION, null, null, SORT_ORDER);
        if (cursor != null && cursor.moveToFirst()) {
            long id = cursor.getLong(cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID));
            String fileName = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DISPLAY_NAME));
            String path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            long dateAdded = cursor.getLong(cursor.getColumnIndex(MediaStore.Images.Media.DATE_ADDED));

            if (fileName.contains(FILE_POSTFIX)) {
                if (cursor.moveToNext()) {
                    id = cursor.getLong(cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID));
                    fileName = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DISPLAY_NAME));
                    path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
                    dateAdded = cursor.getLong(cursor.getColumnIndex(MediaStore.Images.Media.DATE_ADDED));
                } else {
                    return null;
                }
            }

            data = new Data();
            data.id = id;
            data.fileName = fileName;
            data.path = path;
            data.dateAdded = dateAdded;
            Log.e(TAG, "[Recent File] Name : " + fileName);
        }
    } finally {
        if (cursor != null) {
            cursor.close();
        }
    }
    return data;
}

private boolean matchPath(String path) {
    return (path.toLowerCase().contains("screenshots/") && !path.contains(FILE_POSTFIX));
}

private boolean matchTime(long currentTime, long dateAdded) {
    return Math.abs(currentTime - dateAdded) <= DEFAULT_DETECT_WINDOW_SECONDS;
}

class Data {
    long id;
    String fileName;
    String path;
    long dateAdded;
}  
 }

Util.class

public static void saveImage(Context context, Bitmap bitmap, String title) throws Exception {
OutputStream fOut = null;
title = title.replaceAll(" ", "+");
int index = title.lastIndexOf(".png");
String fileName = title.substring(0, index) + ScreenShotContentObserver.FILE_POSTFIX + ".png";
final String appDirectoryName = "Screenshots";
final File imageRoot = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), appDirectoryName);
imageRoot.mkdirs();
final File file = new File(imageRoot, fileName);
fOut = new FileOutputStream(file);

bitmap.compress(Bitmap.CompressFormat.PNG, 100, fOut);
fOut.flush();
fOut.close();

ContentValues values = new ContentValues();
values.put(MediaStore.Images.Media.TITLE, "XXXXX");
values.put(MediaStore.Images.Media.DESCRIPTION, "description here");
values.put(MediaStore.Images.Media.DATE_TAKEN, System.currentTimeMillis());
values.put(MediaStore.Images.ImageColumns.BUCKET_ID, file.hashCode());
values.put(MediaStore.Images.ImageColumns.BUCKET_DISPLAY_NAME, file.getName());
values.put("_data", file.getAbsolutePath());
ContentResolver cr = context.getContentResolver();
Uri newUri = cr.insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, newUri));
}

仅使用FileObserver Android检测屏幕截图

4 个答案: