Eu modifiquei o código do visualizador MJPEGAndroid e MJPEG para trabalhar usando um AsyncTask (e, portanto, trabalhar no Ice Cream Sandwich (ICS), 4.0.4) e aqui está o meu código.

Se alguém tiver alguma sugestão sobre como otimizar, limpar ou fazer algo mais adequado com o código, por favor me avise. Duas questões que eu gostaria de ajudar a abordar:

Se você tiver o dispositivo em um fluxo, bloqueie a tela e desbloqueie a tela para não retomar a reprodução até que você mate e retome o aplicativo ou gire a tela. Todas as minhas tentativas de usar OnResume () para fazer algo ou outro resultaram em falhas no aplicativo.

Em particular, eu gostaria de obter o AsyncTask de volta em MjpegInputStream.java, mas não foi capaz de fazer isso funcionar.

MjpegActivity.java:

<code>package com.demo.mjpeg;

import java.io.IOException;
import java.net.URI;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;

import com.demo.mjpeg.MjpegView.MjpegInputStream;
import com.demo.mjpeg.MjpegView.MjpegView;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Toast;

public class MjpegActivity extends Activity {
    private static final String TAG = "MjpegActivity";

    private MjpegView mv;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        //sample public cam
        String URL = "http://trackfield.webcam.oregonstate.edu/axis-cgi/mjpg/video.cgi?resolution=800x600&amp%3bdummy=1333689998337";

        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
        WindowManager.LayoutParams.FLAG_FULLSCREEN);

        mv = new MjpegView(this);
        setContentView(mv);        

        new DoRead().execute(URL);
    }

    public void onPause() {
        super.onPause();
        mv.stopPlayback();
    }

    public class DoRead extends AsyncTask<String, Void, MjpegInputStream> {
        protected MjpegInputStream doInBackground(String... url) {
            //TODO: if camera has authentication deal with it and don't just not work
            HttpResponse res = null;
            DefaultHttpClient httpclient = new DefaultHttpClient();     
            Log.d(TAG, "1. Sending http request");
            try {
                res = httpclient.execute(new HttpGet(URI.create(url[0])));
                Log.d(TAG, "2. Request finished, status = " + res.getStatusLine().getStatusCode());
                if(res.getStatusLine().getStatusCode()==401){
                    //You must turn off camera User Access Control before this will work
                    return null;
                }
                return new MjpegInputStream(res.getEntity().getContent());  
            } catch (ClientProtocolException e) {
                e.printStackTrace();
                Log.d(TAG, "Request failed-ClientProtocolException", e);
                //Error connecting to camera
            } catch (IOException e) {
                e.printStackTrace();
                Log.d(TAG, "Request failed-IOException", e);
                //Error connecting to camera
            }

            return null;
        }

        protected void onPostExecute(MjpegInputStream result) {
            mv.setSource(result);
            mv.setDisplayMode(MjpegView.SIZE_BEST_FIT);
            mv.showFps(true);
        }
    }
}
</code>

MjpegInputStream.java:

<code>package com.demo.mjpeg.MjpegView;

import java.io.BufferedInputStream;
import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Properties;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.util.Log;

public class MjpegInputStream extends DataInputStream {
    private static final String TAG = "MjpegInputStream";

    private final byte[] SOI_MARKER = { (byte) 0xFF, (byte) 0xD8 };
    private final byte[] EOF_MARKER = { (byte) 0xFF, (byte) 0xD9 };
    private final String CONTENT_LENGTH = "Content-Length";
    private final static int HEADER_MAX_LENGTH = 100;
    private final static int FRAME_MAX_LENGTH = 40000 + HEADER_MAX_LENGTH;
    private int mContentLength = -1;

    public MjpegInputStream(InputStream in) {
        super(new BufferedInputStream(in, FRAME_MAX_LENGTH));
    }

    private int getEndOfSeqeunce(DataInputStream in, byte[] sequence) throws IOException {
        int seqIndex = 0;
        byte c;
        for(int i=0; i < FRAME_MAX_LENGTH; i++) {
            c = (byte) in.readUnsignedByte();
            if(c == sequence[seqIndex]) {
                seqIndex++;
                if(seqIndex == sequence.length) {
                    return i + 1;
                }
            } else {
                seqIndex = 0;
            }
        }
        return -1;
    }

    private int getStartOfSequence(DataInputStream in, byte[] sequence) throws IOException {
        int end = getEndOfSeqeunce(in, sequence);
        return (end < 0) ? (-1) : (end - sequence.length);
    }

    private int parseContentLength(byte[] headerBytes) throws IOException, NumberFormatException {
        ByteArrayInputStream headerIn = new ByteArrayInputStream(headerBytes);
        Properties props = new Properties();
        props.load(headerIn);
        return Integer.parseInt(props.getProperty(CONTENT_LENGTH));
    }   

    public Bitmap readMjpegFrame() throws IOException {
        mark(FRAME_MAX_LENGTH);
        int headerLen = getStartOfSequence(this, SOI_MARKER);
        reset();
        byte[] header = new byte[headerLen];
        readFully(header);
        try {
            mContentLength = parseContentLength(header);
        } catch (NumberFormatException nfe) { 
            nfe.getStackTrace();
            Log.d(TAG, "catch NumberFormatException hit", nfe);
            mContentLength = getEndOfSeqeunce(this, EOF_MARKER); 
        }
        reset();
        byte[] frameData = new byte[mContentLength];
        skipBytes(headerLen);
        readFully(frameData);
        return BitmapFactory.decodeStream(new ByteArrayInputStream(frameData));
    }
}
</code>

MjpegView.java:

<code>package com.demo.mjpeg.MjpegView;

import java.io.IOException;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.util.AttributeSet;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class MjpegView extends SurfaceView implements SurfaceHolder.Callback {
    private static final String TAG = "MjpegView";

    public final static int POSITION_UPPER_LEFT  = 9;
    public final static int POSITION_UPPER_RIGHT = 3;
    public final static int POSITION_LOWER_LEFT  = 12;
    public final static int POSITION_LOWER_RIGHT = 6;

    public final static int SIZE_STANDARD   = 1; 
    public final static int SIZE_BEST_FIT   = 4;
    public final static int SIZE_FULLSCREEN = 8;

    private MjpegViewThread thread;
    private MjpegInputStream mIn = null;    
    private boolean showFps = false;
    private boolean mRun = false;
    private boolean surfaceDone = false;    
    private Paint overlayPaint;
    private int overlayTextColor;
    private int overlayBackgroundColor;
    private int ovlPos;
    private int dispWidth;
    private int dispHeight;
    private int displayMode;

    public class MjpegViewThread extends Thread {
        private SurfaceHolder mSurfaceHolder;
        private int frameCounter = 0;
        private long start;
        private Bitmap ovl;

        public MjpegViewThread(SurfaceHolder surfaceHolder, Context context) {
            mSurfaceHolder = surfaceHolder;
        }

        private Rect destRect(int bmw, int bmh) {
            int tempx;
            int tempy;
            if (displayMode == MjpegView.SIZE_STANDARD) {
                tempx = (dispWidth / 2) - (bmw / 2);
                tempy = (dispHeight / 2) - (bmh / 2);
                return new Rect(tempx, tempy, bmw + tempx, bmh + tempy);
            }
            if (displayMode == MjpegView.SIZE_BEST_FIT) {
                float bmasp = (float) bmw / (float) bmh;
                bmw = dispWidth;
                bmh = (int) (dispWidth / bmasp);
                if (bmh > dispHeight) {
                    bmh = dispHeight;
                    bmw = (int) (dispHeight * bmasp);
                }
                tempx = (dispWidth / 2) - (bmw / 2);
                tempy = (dispHeight / 2) - (bmh / 2);
                return new Rect(tempx, tempy, bmw + tempx, bmh + tempy);
            }
            if (displayMode == MjpegView.SIZE_FULLSCREEN){
                return new Rect(0, 0, dispWidth, dispHeight);
            }
            return null;
        }

        public void setSurfaceSize(int width, int height) {
            synchronized(mSurfaceHolder) {
                dispWidth = width;
                dispHeight = height;
            }
        }

        private Bitmap makeFpsOverlay(Paint p, String text) {
            Rect b = new Rect();
            p.getTextBounds(text, 0, text.length(), b);
            int bwidth  = b.width()+2;
            int bheight = b.height()+2;
            Bitmap bm = Bitmap.createBitmap(bwidth, bheight, Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(bm);
            p.setColor(overlayBackgroundColor);
            c.drawRect(0, 0, bwidth, bheight, p);
            p.setColor(overlayTextColor);
            c.drawText(text, -b.left+1, (bheight/2)-((p.ascent()+p.descent())/2)+1, p);
            return bm;           
        }

        public void run() {
            start = System.currentTimeMillis();
            PorterDuffXfermode mode = new PorterDuffXfermode(PorterDuff.Mode.DST_OVER);
            Bitmap bm;
            int width;
            int height;
            Rect destRect;
            Canvas c = null;
            Paint p = new Paint();
            String fps;
            while (mRun) {
                if(surfaceDone) {
                    try {
                        c = mSurfaceHolder.lockCanvas();
                        synchronized (mSurfaceHolder) {
                            try {
                                bm = mIn.readMjpegFrame();
                                destRect = destRect(bm.getWidth(),bm.getHeight());
                                c.drawColor(Color.BLACK);
                                c.drawBitmap(bm, null, destRect, p);
                                if(showFps) {
                                    p.setXfermode(mode);
                                    if(ovl != null) {
                                        height = ((ovlPos & 1) == 1) ? destRect.top : destRect.bottom-ovl.getHeight();
                                        width  = ((ovlPos & 8) == 8) ? destRect.left : destRect.right -ovl.getWidth();
                                        c.drawBitmap(ovl, width, height, null);
                                    }
                                    p.setXfermode(null);
                                    frameCounter++;
                                    if((System.currentTimeMillis() - start) >= 1000) {
                                        fps = String.valueOf(frameCounter)+" fps";
                                        frameCounter = 0; 
                                        start = System.currentTimeMillis();
                                        ovl = makeFpsOverlay(overlayPaint, fps);
                                    }
                                }
                            } catch (IOException e) {
                                e.getStackTrace();
                                Log.d(TAG, "catch IOException hit in run", e);
                            }
                        }
                    } finally { 
                        if (c != null) {
                            mSurfaceHolder.unlockCanvasAndPost(c); 
                        }
                    }
                }
            }
        }
    }

    private void init(Context context) {
        SurfaceHolder holder = getHolder();
        holder.addCallback(this);
        thread = new MjpegViewThread(holder, context);
        setFocusable(true);
        overlayPaint = new Paint();
        overlayPaint.setTextAlign(Paint.Align.LEFT);
        overlayPaint.setTextSize(12);
        overlayPaint.setTypeface(Typeface.DEFAULT);
        overlayTextColor = Color.WHITE;
        overlayBackgroundColor = Color.BLACK;
        ovlPos = MjpegView.POSITION_LOWER_RIGHT;
        displayMode = MjpegView.SIZE_STANDARD;
        dispWidth = getWidth();
        dispHeight = getHeight();
    }

    public void startPlayback() { 
        if(mIn != null) {
            mRun = true;
            thread.start();         
        }
    }

    public void stopPlayback() { 
        mRun = false;
        boolean retry = true;
        while(retry) {
            try {
                thread.join();
                retry = false;
            } catch (InterruptedException e) {
                e.getStackTrace();
                Log.d(TAG, "catch IOException hit in stopPlayback", e);
            }
        }
    }

    public MjpegView(Context context, AttributeSet attrs) { 
        super(context, attrs); init(context); 
    }

    public void surfaceChanged(SurfaceHolder holder, int f, int w, int h) { 
        thread.setSurfaceSize(w, h); 
    }

    public void surfaceDestroyed(SurfaceHolder holder) { 
        surfaceDone = false; 
        stopPlayback(); 
    }

    public MjpegView(Context context) { 
        super(context);
        init(context); 
    }

    public void surfaceCreated(SurfaceHolder holder) { 
        surfaceDone = true; 
    }

    public void showFps(boolean b) { 
        showFps = b; 
    }

    public void setSource(MjpegInputStream source) { 
        mIn = source;
        startPlayback();
    }

    public void setOverlayPaint(Paint p) { 
        overlayPaint = p; 
    }

    public void setOverlayTextColor(int c) { 
        overlayTextColor = c; 
    }

    public void setOverlayBackgroundColor(int c) { 
        overlayBackgroundColor = c; 
    }

    public void setOverlayPosition(int p) { 
        ovlPos = p; 
    }

    public void setDisplayMode(int s) { 
        displayMode = s; 
    }
}
</code>