Android 截屏監(jiān)聽（ContentObserver）

前言

網(wǎng)上一般列舉的有三種方法

  1. 利用FileObserver監(jiān)聽某個(gè)目錄中資源變化情況。
  2. 利用ContentObserver監(jiān)聽全部資源的變化。
  3. 監(jiān)聽截屏快捷按鍵 ( 由于廠商自定義Android系統(tǒng)的多樣性，再加上快捷鍵的不同以及第三方應(yīng)用，監(jiān)聽截屏快捷鍵這事基本不靠譜，可以直接忽略 )。

FileObserver對比ContentObserver

FileObserver：通過FileObserver監(jiān)聽截屏文件夾，當(dāng)有新的截屏文件產(chǎn)生時(shí)，調(diào)用設(shè)定的回調(diào)函數(shù)執(zhí)行相關(guān)操作。

實(shí)現(xiàn)簡單，但是不同手機(jī)默認(rèn)的截屏路徑、事件名稱可能不同，需要做適配。

ContentObserver：通過ContentObserver監(jiān)聽圖片多媒體的變化，當(dāng)手機(jī)上有新圖片文件產(chǎn)生時(shí)會通過MediaProvider類向圖片數(shù)據(jù)庫插入一條記錄，監(jiān)聽圖片插入事件來獲得圖片的URI。

事件監(jiān)聽一致，但是需要對插入的圖片進(jìn)行過濾。

本文通過ContentObserver實(shí)現(xiàn)

截屏幫助類

/**
 * @author Alex.yelj
 * 2020-01-16 11:01 Thursday
 * Description: 截屏幫助類
 */
class ScreenShotHelper {

    companion object {

        const val TAG = "ScreenShotLog"

        /**
         * 讀取媒體數(shù)據(jù)庫時(shí)需要讀取的列
         */
        val MEDIA_PROJECTIONS = arrayOf(
            MediaStore.Images.ImageColumns.DATA,
            MediaStore.Images.ImageColumns.DATE_TAKEN
        )

        /**
         * 讀取媒體數(shù)據(jù)庫時(shí)需要讀取的列，其中 width、height 字段在 API 16 之后才有
         */
        val MEDIA_PROJECTIONS_API_16 = arrayOf(
            MediaStore.Images.ImageColumns.DATA,
            MediaStore.Images.ImageColumns.DATE_TAKEN,
            MediaStore.Images.ImageColumns.WIDTH,
            MediaStore.Images.ImageColumns.HEIGHT
        )

        /**
         * 截屏路徑判斷的關(guān)鍵字
         */
        val KEYWORDS = arrayOf(
            "screenshot", "screen_shot", "screen-shot", "screen shot",
            "screencapture", "screen_capture", "screen-capture", "screen capture",
            "screencap", "screen_cap", "screen-cap", "screen cap"
        )

        fun showLog(msg: String) {
            Log.d(TAG, msg)
        }
    }
}

截屏監(jiān)聽器

/**
 * @author Alex.yelj
 * 2020-01-15 17:28 Wednesday
 * Description: 截屏監(jiān)聽
 */
class ScreenShotListener constructor(context: Context?) {

    private var mContext: Context
    private var mScreenRealSize: Point? = null
    private val mHasCallbackPaths: ArrayList<String> = ArrayList()
    private var mListener: OnScreenShotListener? = null
    private var mStartListenTime: Long = 0
    /**
     * 內(nèi)部存儲器內(nèi)容觀察者
     */
    private var mInternalObserver: MediaContentObserver? = null
    /**
     * 外部存儲器內(nèi)容觀察者
     */
    private var mExternalObserver: MediaContentObserver? = null
    /**
     * 運(yùn)行在 UI 線程的 Handler, 用于運(yùn)行監(jiān)聽器回調(diào)
     */
    private var mUiHandler = Handler(Looper.getMainLooper())

    init {
        ScreenShotHelper.showLog("init")
        assertInMainThread()
        requireNotNull(context) { "The context must not be null." }
        mContext = context

        if (mScreenRealSize == null) {
            mScreenRealSize = getRealScreenSize()
            if (mScreenRealSize != null) {
                ScreenShotHelper.showLog("Screen Real Size: " + mScreenRealSize!!.x + " * " + mScreenRealSize!!.y)
            } else {
                ScreenShotHelper.showLog("Get screen real size failed.")
            }
        }
    }

    /**
     * 單例
     */
    companion object : SingletonHolder<ScreenShotListener, Context>(::ScreenShotListener)

    /**
     * 開啟監(jiān)聽
     */
    fun startListener() {
        assertInMainThread()

        // 記錄開始監(jiān)聽的時(shí)間戳
        mStartListenTime = System.currentTimeMillis()

        // 創(chuàng)建內(nèi)容觀察者
        mInternalObserver =
            MediaContentObserver(MediaStore.Images.Media.INTERNAL_CONTENT_URI, mUiHandler)
        mExternalObserver =
            MediaContentObserver(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, mUiHandler)

        // 注冊內(nèi)容觀察者
        mContext.contentResolver.registerContentObserver(
            MediaStore.Images.Media.INTERNAL_CONTENT_URI,
            false,
            mInternalObserver
        )
        mContext.contentResolver.registerContentObserver(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
            false,
            mExternalObserver
        )
    }

    fun stopListener() {
        assertInMainThread()

        // 注銷內(nèi)容觀察者
        if (mInternalObserver != null) {
            try {
                mContext.contentResolver.unregisterContentObserver(mInternalObserver!!)
            } catch (e: Exception) {
                e.printStackTrace()
            }
            mInternalObserver = null
        }
        if (mExternalObserver != null) {
            try {
                mContext.contentResolver.unregisterContentObserver(mExternalObserver!!)
            } catch (e: Exception) {
                e.printStackTrace()
            }
            mExternalObserver = null
        }

        // 清空數(shù)據(jù)
        mStartListenTime = 0
        mListener = null
    }

    /**
     * 處理媒體數(shù)據(jù)庫的內(nèi)容改變
     */
    fun handleMediaContentChange(contentUri: Uri) {
        var cursor: Cursor? = null
        try {
            cursor = mContext.contentResolver.query(
                contentUri,
                if (Build.VERSION.SDK_INT < 16) ScreenShotHelper.MEDIA_PROJECTIONS else ScreenShotHelper.MEDIA_PROJECTIONS_API_16,
                null, null,
                "${MediaStore.Images.ImageColumns.DATE_ADDED} desc limit 1"
            )

            if (cursor == null) {
                ScreenShotHelper.showLog("Deviant logic.")
                return
            }

            if (!cursor.moveToFirst()) {
                ScreenShotHelper.showLog("Cursor no data.")
                return
            }

            // 獲取各列的索引
            val dataIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA)
            val dateTakenIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATE_TAKEN)
            var widthIndex = -1
            var heightIndex = -1
            if (Build.VERSION.SDK_INT >= 16) {
                widthIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.WIDTH)
                heightIndex = cursor.getColumnIndex(MediaStore.Images.ImageColumns.HEIGHT)
            }

            // 獲取行數(shù)據(jù)
            val data = cursor.getString(dataIndex)
            val dateTaken = cursor.getLong(dateTakenIndex)
            var width = 0
            var height = 0
            if (widthIndex >= 0 && heightIndex >= 0) {
                width = cursor.getInt(widthIndex)
                height = cursor.getInt(heightIndex)
            } else {
                val size = getImageSize(data)
                width = size.x
                height = size.y
            }

            // 處理獲取到的第一行數(shù)據(jù)
            handleMediaRowData(data, dateTaken, width, height)
        } catch (e: Exception) {
            ScreenShotHelper.showLog("Exception: ${e.message}")
            e.printStackTrace()
        } finally {
            if (cursor != null && !cursor.isClosed) {
                cursor.close()
            }
        }
    }

    private fun getImageSize(imagePath: String): Point {
        val options = BitmapFactory.Options()
        options.inJustDecodeBounds = true
        BitmapFactory.decodeFile(imagePath, options)
        return Point(options.outWidth, options.outHeight)
    }

    /**
     * 處理獲取到的一行數(shù)據(jù)
     */
    private fun handleMediaRowData(data: String, dateTaken: Long, width: Int, height: Int) {
        if (checkScreenShot(data, dateTaken, width, height)) {
            ScreenShotHelper.showLog("ScreenShot: path = $data; size = $width * $height; date = $dateTaken")
            if (mListener != null && !checkCallback(data)) {
                mListener!!.onScreenShot(data)
            }
        } else {
            // 如果在觀察區(qū)間媒體數(shù)據(jù)庫有數(shù)據(jù)改變，又不符合截屏規(guī)則，則輸出到 log 待分析
            ScreenShotHelper.showLog("Media content changed, but not screenshot: path = $data; size = $width * $height; date = $dateTaken")
        }
    }

    /**
     * 判斷指定的數(shù)據(jù)行是否符合截屏條件
     */
    private fun checkScreenShot(data: String?, dateTaken: Long, width: Int, height: Int): Boolean {
        // 判斷依據(jù)一: 時(shí)間判斷
        // 如果加入數(shù)據(jù)庫的時(shí)間在開始監(jiān)聽之前, 或者與當(dāng)前時(shí)間相差大于10秒, 則認(rèn)為當(dāng)前沒有截屏
        if (dateTaken < mStartListenTime || System.currentTimeMillis() - dateTaken > 10 * 1000) {
            return false
        }

        // 判斷依據(jù)二: 尺寸判斷
        if (mScreenRealSize != null) {
            // 如果圖片尺寸超出屏幕, 則認(rèn)為當(dāng)前沒有截屏
            if (!(width <= mScreenRealSize!!.x && height <= mScreenRealSize!!.y)
                || (height <= mScreenRealSize!!.x && width <= mScreenRealSize!!.y)
            ) {
                return false
            }
        }

        // 判斷依據(jù)三: 路徑判斷
        if (data.isNullOrEmpty()) {
            return false
        }

        val lowerData = data.toLowerCase(Locale.getDefault())
        // 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 (keyWork in ScreenShotHelper.KEYWORDS) {
            if (lowerData.contains(keyWork)) {
                return true
            }
        }
        return false
    }

    /**
     * 判斷是否已回調(diào)過, 某些手機(jī)ROM截屏一次會發(fā)出多次內(nèi)容改變的通知; <br></br>
     * 刪除一個(gè)圖片也會發(fā)通知, 同時(shí)防止刪除圖片時(shí)誤將上一張符合截屏規(guī)則的圖片當(dāng)做是當(dāng)前截屏.
     */
    private fun checkCallback(imagePath: String): Boolean {
        if (mHasCallbackPaths.contains(imagePath)) {
            ScreenShotHelper.showLog("ScreenShot: imgPath has done; imagePath = $imagePath")
            return true
        }
        // 大概緩存15~20條記錄便可
        if (mHasCallbackPaths.size >= 20) {
            for (i in 0..4) {
                mHasCallbackPaths.removeAt(0)
            }
        }
        mHasCallbackPaths.add(imagePath)
        return false
    }

    /**
     * 獲取屏幕分辨率
     */
    private fun getRealScreenSize(): Point? {
        var screenSize: Point? = null
        try {
            screenSize = Point()
            val windowManager = mContext.getSystemService(Context.WINDOW_SERVICE) as WindowManager
            val defaultDisplay = windowManager.defaultDisplay
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                defaultDisplay.getRealSize(screenSize)
            } else {
                try {
                    val mGetRawW = Display::class.java.getMethod("getRawWidth")
                    val mGetRawH = Display::class.java.getMethod("getRawHeight")
                    screenSize.set(
                        mGetRawW.invoke(defaultDisplay) as Int,
                        mGetRawH.invoke(defaultDisplay) as Int
                    )
                } catch (e: Exception) {
                    screenSize.set(defaultDisplay.width, defaultDisplay.height)
                    e.printStackTrace()
                }

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

        return screenSize
    }

    private fun assertInMainThread() {
        if (Looper.myLooper() != Looper.getMainLooper()) {
            val stackTrace = Thread.currentThread().stackTrace
            var methodMsg: String? = null
            if (stackTrace != null && stackTrace.size >= 4) {
                methodMsg = stackTrace[3].toString()
            }
            ScreenShotHelper.showLog("Call the method must be in main thread: $methodMsg")
        }
    }

    /**
     * 媒體內(nèi)容觀察者
     */
    private inner class MediaContentObserver(var contentUri: Uri, handler: Handler) :
        ContentObserver(handler) {

        override fun onChange(selfChange: Boolean) {
            super.onChange(selfChange)
            handleMediaContentChange(contentUri)
        }
    }

    /**
     * 設(shè)置截屏監(jiān)聽器回調(diào)
     */
    fun setListener(listener: OnScreenShotListener) {
        this.mListener = listener
    }

    /**
     * 截屏監(jiān)聽接口
     */
    interface OnScreenShotListener {
        fun onScreenShot(picPath: String)
    }
}

SingletonHolder

open class SingletonHolder<out T, in A>(creator: (A) -> T) {

    private var creator: ((A) -> T)? = creator

    @Volatile
    private var instance: T? = null

    fun getInstance(arg: A): T {
        val i = instance
        if (i != null) {
            return i
        }

        return synchronized(this) {
            val i2 = instance
            if (i2 != null) {
                i2
            } else {
                val created = creator!!(arg)
                instance = created
                creator = null
                created
            }
        }
    }
}

使用

  1. 若要監(jiān)聽整個(gè)APP的所有頁面，則將監(jiān)聽器加入到BaseActivity，在頁面的onResume中開啟監(jiān)聽，在onPause停止監(jiān)聽。
  2. 需要讀取內(nèi)部存儲（READ_EXTERNAL_STORAGE）權(quán)限
/**
 * @author Alex.yelj
 * 2020-01-16 14:56 Thursday
 * Description:
 */
class ScreenShotActivity : AppCompatActivity() {

    private lateinit var screenShotListener: ScreenShotListener
    var isHasScreenShotListener = false

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_screen_shot)

        screenShotListener = ScreenShotListener.getInstance(this)
        
        // 申請權(quán)限
        val permission = arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE)
        if (ActivityCompat.checkSelfPermission(
                this,
                Manifest.permission.READ_EXTERNAL_STORAGE
            ) != PackageManager.PERMISSION_GRANTED
        ) {
            ActivityCompat.requestPermissions(this, permission, 1001)
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == 1001) {
            if (grantResults[0] == PermissionChecker.PERMISSION_GRANTED) {
                customToast("權(quán)限申請成功")
            } else {
                customToast("權(quán)限申請失敗")
            }
        }
    }

    override fun onResume() {
        super.onResume()
        startScreenShotListen()
    }

    override fun onPause() {
        super.onPause()
        stopScreenShotListen()
    }

    private fun startScreenShotListen() {
        if (!isHasScreenShotListener) {
            screenShotListener.setListener(object : ScreenShotListener.OnScreenShotListener {
                override fun onScreenShot(picPath: String) {
                    customToast("監(jiān)聽截屏成功")
                    Log.d(ScreenShotHelper.TAG, picPath)
                }
            })
            screenShotListener.startListener()
            isHasScreenShotListener = true
        }
    }

    private fun stopScreenShotListen() {
        if (isHasScreenShotListener) {
            screenShotListener.stopListener()
            isHasScreenShotListener = false
        }
    }
}

實(shí)測兼容性

image.png

來自這位老哥的GitHub，謝謝！

僅作為學(xué)習(xí)記錄！

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