截屏分享，上次那个是偷懒，现在这个是监听系统的（升级版本）

截屏分享：思路分析

1.监听截屏按键（第一种）；

2.监听文件变化（第二种）；

3.监听全局资源变化（第三种）；

第一种肯定是不行的，各家厂商跟快捷键不一样，还有安卓版本不一样截屏按键也不一样；

第二种可以满足功能，但是有缺陷，就是适配效果不是那么好；

第三种百分90可以的，自己试过，截屏生成文件需要时间，一般三秒到五秒左右；看手机性能了；

我只贴第三种功能：

public class FileContextObserver 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","Pictures","screenshots","pictures"
                ,"Screenshots"
        };

        /** 读取媒体数据库时需要读取的列 */
        private static final String[] MEDIA_PROJECTIONS =  {
                MediaStore.Images.ImageColumns.DATA,
                MediaStore.Images.ImageColumns.DATE_TAKEN,
        };

        /** 内部存储器内容观察者 */
        private ContentObserver mInternalObserver;

        /** 外部存储器内容观察者 */
        private ContentObserver mExternalObserver;

        private HandlerThread mHandlerThread;
        private Handler mHandler;
        private ImageView obsevre_imageView;
        private Bitmap bm;
        private Handler mFileObserver=new Handler(){
            @Override
            public void handleMessage(Message msg) {
                super.handleMessage(msg);
                if (msg.what==1){
                    Log.d("otouzi", data +"第msg个");
                    obsevre_imageView.setImageBitmap(bm);
                }
            }
        };

        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_file_context_observer);
            obsevre_imageView= (ImageView) findViewById(R.id.obsevre_imageView);
            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);

            // 添加监听
            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();

            // 注销监听
            this.getContentResolver().unregisterContentObserver(mInternalObserver);
            this.getContentResolver().unregisterContentObserver(mExternalObserver);
        }

        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 = this.getContentResolver().query(
                        contentUri,
                        MEDIA_PROJECTIONS,
                        null,
                        null,
                        MediaStore.Images.ImageColumns.DATE_ADDED + " desc limit 1"
                );

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

                // 获取行数据
                String data = cursor.getString(dataIndex);
                long dateTaken = cursor.getLong(dateTakenIndex);
                Log.d("otouzi", data + " " + dateTaken+"第四个");
                // 处理获取到的第一行数据
                handleMediaRowData(data, dateTaken);

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

            } finally {
                if (cursor != null && !cursor.isClosed()) {
                    cursor.close();
                }
            }
        }

        /**
         * 处理监听到的资源
         */
        private void handleMediaRowData(final String data, long dateTaken) {
            if (checkScreenShot(data, dateTaken)) {

                mFileObserver.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        bm = BitmapFactory.decodeFile(data);
                        mFileObserver.sendEmptyMessage(1);
                    }
                },3000);

                Log.d("otouzi", data + " " + dateTaken+"第一个");
            } else {
                Log.d("otouzi", "Not screenshot event"+"第二个");
            }
        }

        /**
         * 判断是否是截屏
         */
        private boolean checkScreenShot(String data, long dateTaken) {

            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;
        }

        /**
         * 媒体内容观察者(观察媒体数据库的改变)
         */
        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("otouzi", mContentUri.toString()+"第三个");
//                obsevre_imageView.setImageURI(mContentUri);
                handleMediaContentChange(mContentUri);
            }
        }

}

原文链接：http://www.apkbus.com/blog-340477-72743.html