轉(zhuǎn)載注明出處：http://www.reibang.com/p/7ead15eeaaef

前言

Android系統(tǒng)沒(méi)有直接對(duì)截屏事件監(jiān)聽(tīng)的接口组橄，只能自己動(dòng)手來(lái)豐衣足食荞膘，一般有三種方法。

• 利用FileObserver監(jiān)聽(tīng)某個(gè)目錄中資源變化情況
• 利用ContentObserver監(jiān)聽(tīng)全部資源的變化
• 監(jiān)聽(tīng)截屏快捷按鍵

由于廠商自定義Android系統(tǒng)的多樣性晨炕，再加上快捷鍵的不同以及第三方應(yīng)用衫画，監(jiān)聽(tīng)截屏快捷鍵這事基本不靠譜毫炉，可以直接忽略瓮栗。

本文使用的測(cè)試手機(jī)，一加2（One Plus 2)瞄勾。

FileObserver

添加權(quán)限：

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

代碼示例：

public class ScreenshotActivity extends AppCompatActivity {

    private final String TAG = "Screenshot";
    
    private static final String PATH = Environment.getExternalStorageDirectory() + File.separator 
            + Environment.DIRECTORY_PICTURES + File.separator + "Screenshots" + File.separator;
    
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_screenshot);
    
        mFileObserver = new CustomFileObserver(PATH);
    }

    @Override
    protected void onResume() {
        super.onResume();
        mFileObserver.startWatching();
        Log.d(TAG, PATH);
    }

    @Override
    protected void onStop() {
        super.onStop();
        mFileObserver.stopWatching();
    }
    
    /**
     * 目錄監(jiān)聽(tīng)器
     */
    private class CustomFileObserver extends FileObserver {

        private String mPath;
    
        public CustomFileObserver(String path) {
            super(path);
            this.mPath = path;
        }
    
        public CustomFileObserver(String path, int mask) {
            super(path, mask);
            this.mPath = path;
        }
    
        @Override
        public void onEvent(int event, String path) {
            Log.d(TAG, path + " " + event);
            // 監(jiān)聽(tīng)到事件费奸，做一些過(guò)濾去重處理操作
        }
    }
}

打印的日志：

一加2

D/Screenshot: Screenshot_2016-12-16-17-49-18.png 256
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 32
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 2
D/Screenshot: Screenshot_2016-12-16-17-49-18.png 8

三星 S4

D/Screenshot: Screenshot_2016-12-16-19-01-08.png 256
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 32
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 2
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 8
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 32
D/Screenshot: Screenshot_2016-12-16-19-01-08.png 16

可以通過(guò)指定構(gòu)造函數(shù)中的mask，監(jiān)聽(tīng)某一個(gè)事件进陡。

幾點(diǎn)注意事項(xiàng)：

• 每一次截屏愿阐，有多個(gè)事件回調(diào)
• 每一次截屏，不同的手機(jī)趾疚，事件回調(diào)可能有些不同缨历，參考上述日志
• 不同的手機(jī)，默認(rèn)截屏圖片儲(chǔ)存的文件夾可能不同
• FileObserver只能監(jiān)聽(tīng)文件夾中子文件和子文件夾的變化情況糙麦，不能監(jiān)聽(tīng)子文件夾內(nèi)部的資源變化
• 需要<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>權(quán)限辛孵，否則可能收不到事件

基于第三點(diǎn)和第四點(diǎn)，這種方法并不能適用于所有的機(jī)型赡磅。

注意：如果自己寫(xiě)Demo沒(méi)有收到事件魄缚，檢查一下權(quán)限和監(jiān)聽(tīng)的目錄

ContentObserver

ContentObserver用來(lái)監(jiān)聽(tīng)指定uri的所有資源變化，我們可以用它來(lái)監(jiān)聽(tīng)圖片資源變化情況焚廊，然后做過(guò)濾冶匹。

添加權(quán)限

<uses-permission android:name="MediaStore.Images.Media.INTERNAL_CONTENT_URI"/>
<uses-permission android:name="MediaStore.Images.Media.EXTERNAL_CONTENT_URI"/>

代碼示例：

public class ScreenshotActivity extends AppCompatActivity {
    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"
    };

    /** 讀取媒體數(shù)據(jù)庫(kù)時(shí)需要讀取的列 */
    private static final String[] MEDIA_PROJECTIONS =  {
            MediaStore.Images.ImageColumns.DATA,
            MediaStore.Images.ImageColumns.DATE_TAKEN,
    };
    
        /** 內(nèi)部存儲(chǔ)器內(nèi)容觀察者 */
    private ContentObserver mInternalObserver;

    /** 外部存儲(chǔ)器內(nèi)容觀察者 */
    private ContentObserver mExternalObserver;

    private HandlerThread mHandlerThread;
    private Handler mHandler;
    
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_screenshot);
    
        mHandlerThread = new HandlerThread("Screenshot_Observer");
        mHandlerThread.start();
        mHandler = new Handler(mHandlerThread.getLooper());

        // 初始化
        mInternalObserver = new MediaContentObserver(MediaStore.Images.Media.INTERNAL_CONTENT_URI, mHandler);
        mExternalObserver = new MediaContentObserver(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, mHandler);
    
        // 添加監(jiān)聽(tīng)
        this.getContentResolver().registerContentObserver(
            MediaStore.Images.Media.INTERNAL_CONTENT_URI,
            false,
            mInternalObserver
        );
        this.getContentResolver().registerContentObserver(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            false,
            mExternalObserver
        );
    }
    
    protected void onDestroy() {
        super.onDestroy();
        
        // 注銷(xiāo)監(jiān)聽(tīng)
        this.getContentResolver().unregisterContentObserver(mInternalObserver);
        this.getContentResolver().unregisterContentObserver(mExternalObserver);
    }
    
    private void handleMediaContentChange(Uri contentUri) {
        Cursor cursor = null;
        try {
            // 數(shù)據(jù)改變時(shí)查詢數(shù)據(jù)庫(kù)中最后加入的一條數(shù)據(jù)
            cursor = this.getContentResolver().query(
                    contentUri,
                    MEDIA_PROJECTIONS,
                    null,
                    null,
                    MediaStore.Images.ImageColumns.DATE_ADDED + " desc limit 1"
            );

            if (cursor == null) {
                return;
            }
            if (!cursor.moveToFirst()) {
                return;
            }

            // 獲取各列的索引
            int dataIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
            int dateTakenIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATE_TAKEN);

            // 獲取行數(shù)據(jù)
            String data = cursor.getString(dataIndex);
            long dateTaken = cursor.getLong(dateTakenIndex);

            // 處理獲取到的第一行數(shù)據(jù)
            handleMediaRowData(data, dateTaken);

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

        } finally {
            if (cursor != null && !cursor.isClosed()) {
                cursor.close();
            }
        }
    }
    
    /**
     * 處理監(jiān)聽(tīng)到的資源
     */
    private void handleMediaRowData(String data, long dateTaken) {
        if (checkScreenShot(data, dateTaken)) {
            Log.d(TAG, data + " " + dateTaken);
        } else {
            Log.d(TAG, "Not screenshot event");
        }
    }
    
    /**
     * 判斷是否是截屏
     */
    private boolean checkScreenShot(String data, long dateTaken) {

        data = data.toLowerCase();
        // 判斷圖片路徑是否含有指定的關(guān)鍵字之一, 如果有, 則認(rèn)為當(dāng)前截屏了
        for (String keyWork : KEYWORDS) {
            if (data.contains(keyWork)) {
                return true;
            }
        }
        return false;
    }

    /**
     * 媒體內(nèi)容觀察者(觀察媒體數(shù)據(jù)庫(kù)的改變)
     */
    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);
            Log.d(TAG, mContentUri.toString());
            handleMediaContentChange(mContentUri);
        }
    }
}

日志：

D/Screenshot: content://media/external/images/media
D/Screenshot: /storage/emulated/0/Pictures/Screenshots/Screenshot_2016-12-19-11-24-02.png 1482117842287

注意事項(xiàng):

• ContentObserver會(huì)監(jiān)聽(tīng)到所有圖片資源的變化情況，要做好去重過(guò)濾工作
• 根據(jù)uri去讀取ContentProvider內(nèi)容時(shí)候咆瘟，記得關(guān)閉cursor嚼隘，防止內(nèi)存泄漏
• 關(guān)鍵字可擴(kuò)展，大大增加的監(jiān)聽(tīng)的范圍袒餐，比FileObserver好用多了嗓蘑，但是去重過(guò)濾會(huì)比FileObserver復(fù)雜一些。

總結(jié)

目前這是在網(wǎng)上搜索到的關(guān)于截屏監(jiān)聽(tīng)方法的總結(jié)匿乃，如果大家還有什么比較好的監(jiān)聽(tīng)方法桩皿，歡迎分享。

參考：

• Detect only screenshot with FileObserver Android
• Android系統(tǒng)截屏監(jiān)聽(tīng)的實(shí)現(xiàn)