我剥离了 MjpegView 并通过更新图像视图来显示流：
主要活动
public class MainActivity extends Activity {
IPCamera cam1, cam2;
ImageView iv1, iv2;
DownloadImageTask task1, task2;
final Handler h = new Handler(new Callback() {
@Override
public boolean handleMessage(Message msg) {
if (msg.what == 1){
Bitmap bmp = (Bitmap) msg.obj;
iv1.setImageBitmap(bmp);
}if(msg.what == 2){
Bitmap bmp = (Bitmap) msg.obj;
iv2.setImageBitmap(bmp);
}
return false;
}
});
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
setContentView(R.layout.activity_main);
iv1 = ((ImageView) findViewById(R.id.imageView1));
iv2 = ((ImageView) findViewById(R.id.imageView2));
cam1 = new IPCamera("http://10.0.0.101/video.cgi", "admin", "admin", this);
cam2 = new IPCamera("http://10.0.0.102/video.cgi", "admin", "admin", this);
task1 = startTask(cam1, 1, false, h);
task2 = startTask(cam2, 2, false, h);
}
private DownloadImageTask startTask(IPCamera cam, int id, boolean useParallelExecution, Handler h) {
DownloadImageTask task = new DownloadImageTask(cam, id);
if (useParallelExecution) {
task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
} else {
task.execute(h);
}
return task;
}
private class DownloadImageTask extends AsyncTask<Handler, Void, Void> {
IPCamera cam;
int id;
DownloadImageTask(IPCamera cam, int id){
this.cam = cam;
this.id = id;
}
protected Void doInBackground(Handler... h) {
cam.startStream(h[0], id);
cam.getFrame();
return null;
}
}
}
IPCamera 类
public class IPCamera{
private static final String TAG = "MjpegActivity";
String url;
String usr;
String pwd;
MjpegInputStream is;
boolean running = false;
Handler h;
Context ctx;
int id;
IPCamera(String url, String usr, String pwd, Context ctx){
this.url = url;
this.usr = usr;
this.pwd = pwd;
this.ctx = ctx;
}
public void startStream(Handler h, int id){
this.h = h;
this.id = id;
is = new MjpegInputStream(httpRequest(url,usr,pwd));
running = true;
}
public void getFrame(){
while (running){
Bitmap b;
try {
b = is.readMjpegFrame();
Message m = h.obtainMessage(id, b);
m.sendToTarget();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public InputStream httpRequest(String url, String usr, String pwd){
HttpResponse res = null;
DefaultHttpClient httpclient = new DefaultHttpClient();
CredentialsProvider credProvider = new BasicCredentialsProvider();
credProvider.setCredentials(new AuthScope(AuthScope.ANY_HOST, AuthScope.ANY_PORT),
new UsernamePasswordCredentials(usr, pwd));
httpclient.setCredentialsProvider(credProvider);
Log.d(TAG, "1. Sending http request");
try {
res = httpclient.execute(new HttpGet(URI.create(url)));
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 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;
}
}
MjpegInputStream
必须将 FRAME_MAX_LENGHT 从 40000 增加到 400000。这样更稳定。
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 = 400000 + 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) {
mContentLength = getEndOfSeqeunce(this, EOF_MARKER);
}
reset();
byte[] frameData = new byte[mContentLength];
skipBytes(headerLen);
readFully(frameData);
return BitmapFactory.decodeStream(new ByteArrayInputStream(frameData));
}
}
不完全干净，但它有效。刚做了24小时稳定性测试，没有错误。如果相机连接断开并在相机弹回时重新连接，仍然必须想出一种方法来停止流线程。