Android App内监听截图加二维码功能代码

Android截屏功能是一个常用的功能，可以方便的用来分享或者发送给好友，本文介绍了如何实现app内截屏监控功能，当发现用户在我们的app内进行了截屏操作时，进行对图片的二次操作，例如添加二维码，公司loGo等一系列*。

项目地址

测试截图：

截屏原理

android系统并没有提供截屏通知相关的api，需要我们自己利用系统能提供的相关特性变通实现。Android系统有一个媒体数据库，每拍一张照片，或使用系统截屏截取一张图片，都会把这张图片的详细信息加入到这个媒体数据库，并发出内容改变通知，我们可以利用内容观察者（ContentObserver）监听媒体数据库的变化，当数据库有变化时，获取最后插入的一条图片数据，如果该图片符合特定的规则，则认为被截屏了。

判断依据

当ContentObserver监听到媒体数据库的数据改变, 在有数据改变时 获取最后插入数据库的一条图片数据, 如果符合以下规则, 则认为截屏了:

• 时间判断，图片的生成时间在开始监听之后,并与当前时间相隔10秒内：开始监听后生成的图片才有意义，相隔10秒内说明是刚刚生成的
• 尺寸判断，图片的尺寸没有超过屏幕的尺寸：图片尺寸超过屏幕尺寸，不可能是截屏图片
• 路径判断，图片路径符合包含特定的关键词：这一点是关键，截屏图片的保存路径通常包含“screenshot”

这些判断是为了增加截屏检测结果的可靠性，防止误报，防止遗漏。其中截屏图片的路径正常Android系统保存的路径格式， 例如我的是：“外部存储器/storage/emulated/0/Pictures/Screenshots/Screenshot_2017-08-03-15-42-58.png”，但Android系统碎片化严重，加上其他第三方截屏APP等，所以路径关键字除了检查是否包含“screenshot”外，还可以适当增加其他关键字，详见最后的监听器完整代码。这种监听截屏的方法也不是100%准确，例如某些被root的机器使用第三方截屏APP自定义保存路径，还比如通过ADB命令在电脑上获取手机屏幕快照均不能监听到，但这也是目前可行性最高的方法，对于绝大多数用户都比较靠谱。

代码描述

监听截屏

public class ScreenShotListenManager {  private static final String TAG = "ScreenShotListenManager";    private static final String[] MEDIA_PROJECTioNS = {      MediaStore.Images.ImageColumns.DATA,      MediaStore.Images.ImageColumns.DATE_TAKEN,  };    private static final String[] MEDIA_PROJECTIONS_API_16 = {      MediaStore.Images.ImageColumns.DATA,      MediaStore.Images.ImageColumns.DATE_TAKEN,      MediaStore.Images.ImageColumns.WIDTH,      MediaStore.Images.ImageColumns.HEIGHT,  };    private static final String[] KEYWordS = {      "screenshot", "screen_shot", "screen-shot", "screen shot",      "screencapture", "screen_capture", "screen-capture", "screen capture",      "screencap", "screen_cap", "screen-cap", "screen cap"  };  private static Point sScreenRealSize;    private final static List<String> sHasCallbackPaths = new ArrayList<String>();  private Context mContext;  private OnScreenShotListener mListener;  private long mStartListenTime;    private MediaContentObserver mInternalObserver;    private MediaContentObserver mExternalObserver;    private final Handler mUiHandler = new Handler(Looper.getMainLooper());  private ScreenShotListenManager(Context context) {    if (context == null) {      throw new IllegalArgumentException("The context must not be null.");    }    mContext = context;    // 获取屏幕真实的分辨率    if (sScreenRealSize == null) {      sScreenRealSize = getRealScreenSize();      if (sScreenRealSize != null) {        Log.d(TAG, "Screen Real Size: " + sScreenRealSize.x + " * " + sScreenRealSize.y);      } else {        Log.w(TAG, "Get screen real size failed.");      }    }  }  public static ScreenShotListenManager newInstance(Context context) {    assertInMainThread();    return new ScreenShotListenManager(context);  }    public void startListen() {    assertInMainThread();//    sHasCallbackPaths.clear();    // 记录开始监听的时间戳    mStartListenTime = System.currentTimeMillis();    // 创建内容观察者    mInternalObserver = new MediaContentObserver(MediaStore.Images.Media.INTERNAL_CONTENT_URI, mUiHandler);    mExternalObserver = new MediaContentObserver(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, mUiHandler);    // 注册内容观察者    mContext.getContentResolver().reGISterContentObserver(        MediaStore.Images.Media.INTERNAL_CONTENT_URI,        false,        mInternalObserver    );    mContext.getContentResolver().registerContentObserver(        MediaStore.Images.Media.EXTERNAL_CONTENT_URI,        false,        mExternalObserver    );  }    public void stopListen() {    assertInMainThread();    // 注销内容观察者    if (mInternalObserver != null) {      try {        mContext.getContentResolver().unregisterContentObserver(mInternalObserver);      } catch (Exception e) {        e.printStackTrace();      }      mInternalObserver = null;    }    if (mExternalObserver != null) {      try {        mContext.getContentResolver().unregisterContentObserver(mExternalObserver);      } catch (Exception e) {        e.printStackTrace();      }      mExternalObserver = null;    }    // 清空数据    mStartListenTime = 0;//    sHasCallbackPaths.clear();    //切记！！！:必须设置为空 可能mListener 会隐式持有Activity导致释放不掉    mListener = null;  }    private void handleMediaContentChange(Uri contentUri) {    Cursor cursor = null;    try {      // 数据改变时查询数据库中最后加入的一条数据      cursor = mContext.getContentResolver().query(          contentUri,          Build.VERSION.SDK_INT < 16 ? MEDIA_PROJECTIONS : MEDIA_PROJECTIONS_API_16,          null,          null,          MediaStore.Images.ImageColumns.DATE_ADDED + " desc limit 1"      );      if (cursor == null) {        Log.e(TAG, "Deviant logic.");        return;      }      if (!cursor.moveToFirst()) {        Log.d(TAG, "Cursor no data.");        return;      }      // 获取各列的索引      int dataIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);      int dateTakenIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATE_TAKEN);      int widthIndex = -1;      int heightIndex = -1;      if (Build.VERSION.SDK_INT >= 16) {        widthIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.WIDTH);        heightIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.HEIGHT);      }      // 获取行数据      String data = cursor.getString(dataIndex);      long dateTaken = cursor.getLong(dateTakenIndex);      int width = 0;      int height = 0;      if (widthIndex >= 0 && heightIndex >= 0) {        width = cursor.getInt(widthIndex);        height = cursor.getInt(heightIndex);      } else {        // API 16 之前, 宽高要手动获取        Point size = getImageSize(data);        width = size.x;        height = size.y;      }      // 处理获取到的第一行数据      handleMediaRowData(data, dateTaken, width, height);    } catch (Exception e) {      e.printStackTrace();    } finally {      if (cursor != null && !cursor.isClosed()) {        cursor.close();      }    }  }  private Point getImageSize(String imagePath) {    BitmapFactory.Options options = new BitmapFactory.Options();    options.inJustDecodeBounds = true;    BitmapFactory.decodeFile(imagePath, options);    return new Point(options.outWidth, options.outHeight);  }    private void handleMediaRowData(String data, long dateTaken, int width, int height) {    if (checkScreenShot(data, dateTaken, width, height)) {      Log.d(TAG, "ScreenShot: path = " + data + "; size = " + width + " * " + height          + "; date = " + dateTaken);      if (mListener != null && !checkCallback(data)) {        mListener.onShot(data);      }    } else {      // 如果在观察区间媒体数据库有数据改变，又不符合截屏规则，则输出到 log 待分析      Log.w(TAG, "Media content changed, but not screenshot: path = " + data          + "; size = " + width + " * " + height + "; date = " + dateTaken);    }  }    private boolean checkScreenShot(String data, long dateTaken, int width, int height) {        // 如果加入数据库的时间在开始监听之前, 或者与当前时间相差大于10秒, 则认为当前没有截屏    if (dateTaken < mStartListenTime || (System.currentTimeMillis() - dateTaken) > 10 * 1000) {      return false;    }        if (sScreenRealSize != null) {      // 如果图片尺寸超出屏幕, 则认为当前没有截屏      if (!((width <= sScreenRealSize.x && height <= sScreenRealSize.y)          || (height <= sScreenRealSize.x && width <= sScreenRealSize.y))) {        return false;      }    }        if (TextUtils.isEmpty(data)) {      return false;    }    data = data.toLowerCase();    // 判断图片路径是否含有指定的关键字之一, 如果有, 则认为当前截屏了    for (String keyWork : KEYWORDS) {      if (data.contains(keyWork)) {        return true;      }    }    return false;  }    private boolean checkCallback(String imagePath) {    if (sHasCallbackPaths.contains(imagePath)) {      Log.d(TAG, "ScreenShot: imgPath has done"          + "; imagePath = " + imagePath);      return true;    }    // 大概缓存15~20条记录便可    if (sHasCallbackPaths.size() >= 20) {      for (int i = 0; i < 5; i++) {        sHasCallbackPaths.remove(0);      }    }    sHasCallbackPaths.add(imagePath);    return false;  }    private Point getRealScreenSize() {    Point screenSize = null;    try {      screenSize = new Point();      WindowManager windowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);      Display defaultDisplay = windowManager.getDefaultDisplay();      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {        defaultDisplay.getRealSize(screenSize);      } else {        try {          Method mGetRawW = Display.class.getMethod("getRawWidth");          Method mGetRawH = Display.class.getMethod("getRawHeight");          screenSize.set(              (Integer) mGetRawW.invoke(defaultDisplay),              (Integer) mGetRawH.invoke(defaultDisplay)          );        } catch (Exception e) {          screenSize.set(defaultDisplay.getWidth(), defaultDisplay.getHeight());          e.printStackTrace();        }      }    } catch (Exception e) {      e.printStackTrace();    }    return screenSize;  }  public Bitmap createScreenShotBitmap(Context context, String screenFilePath) {    View v = LayoutInflater.from(context).inflate(R.layout.share_screenshot_layout, null);    ImageView iv = (ImageView) v.findViewById(R.id.iv);    Bitmap bitmap = BitmapFactory.decodeFile(screenFilePath);    iv.setImageBitmap(bitmap);    //整体布局    Point point = getRealScreenSize();    v.measure(View.MeasureSpec.makeMeasureSpec(point.x, View.MeasureSpec.EXACTLY),        View.MeasureSpec.makeMeasureSpec(point.y, View.MeasureSpec.EXACTLY));    v.layout(0, 0, point.x, point.y);//    Bitmap result = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.RGB_565);    Bitmap result = Bitmap.createBitmap(v.getWidth(), v.getHeight() + dp2px(context, 140), Bitmap.Config.ARGB_8888);    canvas c = new Canvas(result);    c.drawColor(Color.WHITE);    // Draw view to canvas    v.draw(c);    return result;  }  private int dp2px(Context ctx, float dp) {    float scale = ctx.getResources().getDisplayMetrics().density;    return (int) (dp * scale + 0.5f);  }    public void setListener(OnScreenShotListener listener) {    mListener = listener;  }  public interface OnScreenShotListener {    void onShot(String imagePath);  }  private static void assertInMainThread() {    if (Looper.myLooper() != Looper.getMainLooper()) {      StackTraceElement[] elements = Thread.currentThread().getStackTrace();      String methodMsg = null;      if (elements != null && elements.length >= 4) {        methodMsg = elements[3].toString();      }      throw new IllegalStateException("Call the method must be in main thread: " + methodMsg);    }  }    private class MediaContentObserver extends ContentObserver {    private Uri mContentUri;    public MediaContentObserver(Uri contentUri, Handler handler) {      super(handler);      mContentUri = contentUri;    }    @Override    public void onChange(boolean selfChange) {      super.onChange(selfChange);      handleMediaContentChange(mContentUri);    }  }}