android连接otg摄像头,Android系统OTG_usb链接摄像头的驱动和使用
這段時間做一個Android項目，需要在一臺Android 4.4.4系統(tǒng)設(shè)備上鏈接usb攝像頭，用作人臉識別，
于是作為Android項目組“骨干”(哈哈臭屁一下^-^)的我開始了usb攝像頭攻堅戰(zhàn)，爬帖子，找博客，
最后眼睛瞅準(zhǔn)了一篇博客(感謝)
http://blog.csdn.net/sukhoi27smk/article/details/18269097
然后下載源碼開始了我的usb攝像頭驅(qū)動之旅
我整理的庫文件下載點擊查看
首先是在Linux Ubuntu系統(tǒng)下面配置環(huán)境，AS，NDK，如果想寫C代碼方便可以安裝QT(個人推薦，其他都行，比如gedit就很好使)
軟件安裝，環(huán)境配置，這些自當(dāng)不必多說。。。網(wǎng)上有N多種方式可以搞定
接下來就開始代碼改造
找到j(luò)ni文件夾下的ImageProc.c文件修改其中的jni接口方法名，使之指向CameraPreview.java
我修改后如下所示，找到其他的jni方法用同樣方式修改方法名(不要忘了同步.h文件中的方法名哦。。。)：
1void Java_com_mojsoft_usbcamera_view_CameraPreview_pixeltobmp( JNIEnv* env,jobject thiz,jobject bitmap)
Ctrl+Alt+T打開終端，cd到你的jni目錄下，運行ndk-build,編譯成功
cd .. 回到j(luò)ni目錄外面，運行l(wèi)s就可以看到libs,obj兩個目錄，將libs中的libImageProc.so文件拷貝到你項目中的jniLibs目錄下(AS)
接下來是java調(diào)用 [注意：java包名和C文件方法格式一致]
將CameraPreview文件放到布局中，編譯運行。。。
接下來就是盯著屏幕。。。
滿滿的驚喜，問題就這么解決了，哈哈
下面是主要的CameraSurfaView類：
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163class CameraPreview extends SurfaceView implements SurfaceHolder.Callback, Runnable{
private static final boolean DEBUG = true;
private static final String TAG = "WebCam";
protected Context context;
private SurfaceHolder holder;
Thread mainLoop = null;
private Bitmap bmp = null;
private byte[] byteArrary;
private boolean cameraExists = false;
private boolean shouldStop = false;
// /dev/videox (x=cameraId+cameraBase) is used.
// In some omap devices, system uses /dev/video[0-3],
// so users must use /dev/video[4-].
// In such a case, try cameraId=0 and cameraBase=4
private int cameraId = 0;
private int cameraBase = 0;
// This definition also exists in ImageProc.h.
// Webcam must support the resolution 640x480 with YUYV format.
static final int IMG_WIDTH = 640;
static final int IMG_HEIGHT = 480;
// The following variables are used to draw camera images.
private int winWidth = 0;
private int winHeight = 0;
private Rect rect;
private int dw, dh;
private float rate;
private boolean isFramAready = false;
private AlreadyRGBListener listener;
// JNI functions
public native int prepareCamera(int videoid);
public native int prepareCameraWithBase(int videoid, int camerabase);
public native void processCamera();
public native void stopCamera();
public native void pixeltobmp(Bitmap bitmap);
public native byte[] getRgb();
static {
System.loadLibrary("ImageProc");
}
public CameraPreview(Context context){
super(context);
this.context = context;
if (DEBUG) Log.d(TAG, "CameraPreview constructed");
setFocusable(true);
holder = getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL);
}
public CameraPreview(Context context, AttributeSet attrs){
super(context, attrs);
this.context = context;
if (DEBUG) Log.d(TAG, "CameraPreview constructed");
setFocusable(true);
holder = getHolder();
holder.addCallback(this);
holder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL);
}
@Override
public void run(){
while (true && cameraExists) {
//obtaining display area to draw a large image
if (winWidth == 0) {
winWidth = this.getWidth();
winHeight = this.getHeight();
if (winWidth * 3 / 4 <= winHeight) {
dw = 0;
dh = (winHeight - winWidth * 3 / 4) / 2;
rate = ((float) winWidth) / IMG_WIDTH;
rect = new Rect(dw, dh, dw + winWidth - 1, dh + winWidth * 3 / 4 - 1);
} else {
dw = (winWidth - winHeight * 4 / 3) / 2;
dh = 0;
rate = ((float) winHeight) / IMG_HEIGHT;
rect = new Rect(dw, dh, dw + winHeight * 4 / 3 - 1, dh + winHeight - 1);
}
}
// obtaining a camera image (pixel data are stored in an array in JNI).
processCamera();
// camera image to bmp
pixeltobmp(bmp);
byte[] arr = getRgb();
isFramAready = true;
Canvas canvas = getHolder().lockCanvas();
if (canvas != null) {
// draw camera bmp on canvas
canvas.drawBitmap(bmp, null, rect, null);
getHolder().unlockCanvasAndPost(canvas);
}
listener.alreadyRGB(arr);
if (shouldStop) {
shouldStop = false;
break;
}
}
}
@Override
public void surfaceCreated(SurfaceHolder holder){
if (DEBUG) Log.d(TAG, "surfaceCreated");
if (bmp == null) {
bmp = Bitmap.createBitmap(IMG_WIDTH, IMG_HEIGHT, Bitmap.Config.ARGB_8888);
}
if (byteArrary == null) {
byteArrary = new byte[IMG_WIDTH * IMG_HEIGHT];
}
// /dev/videox (x=cameraId + cameraBase) is used
//下面一句是原代碼，我嘗試失敗，于是我將其修改為 int ret = prepareCamera(0);后成功調(diào)用
// int ret = prepareCameraWithBase(cameraId, cameraBase);
int ret = prepareCamera(0);
if (ret != -1) cameraExists = true;
mainLoop = new Thread(this);
mainLoop.start();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height){
if (DEBUG) Log.d(TAG, "surfaceChanged");
}
@Override
public void surfaceDestroyed(SurfaceHolder holder){
if (DEBUG) Log.d(TAG, "surfaceDestroyed");
if (cameraExists) {
shouldStop = true;
while (shouldStop) {
try {
Thread.sleep(50); // wait for thread stopping
} catch (Exception e) {
}
}
}
stopCamera();
}
public void setGetBitmapListener(AlreadyRGBListener listener){
this.listener = listener;
}
}
總結(jié)
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