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我已經設置了一個Android相機應用程序，該應用程序允許我在主要活動的框架佈局中預覽相機。我想做什麼（不使用攝像機特定的功能;我希望它完全獨立於硬件）在預覽的中心顯示150×150像素的線，可以通過在像素周圍顯示一個框或模糊所有的像素除150 x 150外。此外，如果不拍照，我想閱讀這些像素。最終我要做的效果是，當相機移動時，我會在150 x 150區域內顯示紅色，綠色和藍色濃度的變化。我知道如何做嵌套for循環，並獲得像素的顏色，但我需要知道如何獲得高度和重量的偏移量以開始讀取像素。 在此先感謝您的幫助！ 邁克從相機預覽中主動讀取150 x 150像素
public class MyActivity extends Activity {
final public String TAG = "MyActivity";
static private Camera mCamera = null;
static public Camera getCamera() { return mCamera; }
private static boolean mBPreviewingCamera = false;
private PreviewSurface mPS;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
String lMTH = "onCreate ";
Log.i(TAG, lMTH + "Start");
setContentView(R.layout.activity_color_temperature_estimator);
if (isThereACamera()) {
mPreviewCamera(true);
TextView lTVTemp = (TextView) findViewById(R.id.TV_TEMP);
lTVTemp.setText("Camera exists able to proceed");
lTVTemp = null;
} else {
Toast.makeText(this, "No camera! Uunable to proceed", Toast.LENGTH_LONG).show();
TextView lTVTemp = (TextView) findViewById(R.id.TV_TEMP);
lTVTemp.setText("No camera! Uunable to proceed");
lTVTemp = null;
}
}
public void mPreviewCamera(boolean pBPreviewingCamera) {
String lMTH = "mPreviewCamera ";
try {
if (pBPreviewingCamera) {
Log.i(TAG, lMTH + "Open Camera");
mCamera = Camera.open();
mPS = new PreviewSurface(this);
FrameLayout lFVPreview = (FrameLayout) findViewById(R.id.FL_Preview);
lFVPreview.addView(mPS);
lFVPreview = null;
mBPreviewingCamera = true;
Button lBTNTemp = (Button) findViewById(R.id.BTN_CLOSE);
lBTNTemp.setText(R.string.BTN_CLOSE);
lBTNTemp = null;
} else {
Log.i(TAG, lMTH + "Open Camera");
mCloseCamera();
Button lBTNTemp = (Button) findViewById(R.id.BTN_CLOSE);
lBTNTemp.setText(R.string.BTN_OPEN);
lBTNTemp = null;
}
} catch (Exception e) {
Log.i(TAG, lMTH + e.getMessage());
mCloseCamera();
e.printStackTrace();
}
}
public void mCloseCamera() {
String lMTH = "mCloseCamera ";
Log.i(TAG, lMTH + "Turn Camera Off");
if (mCamera != null) {
mCamera.stopPreview();
mCamera.release();
}
mCamera = null;
mBPreviewingCamera = false;
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
String lMTH = "onPause ";
Log.i(TAG, lMTH + "Turn Camera Off");
mPreviewCamera(false);
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
String lMTH = "onDestroy ";
Log.i(TAG, lMTH + "Turn Camera Off");
mPreviewCamera(false);
}
/** Check if this phone has a camera */
private boolean isThereACamera() {
if (getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
// There is a camera
return true;
} else {
// There isn't a camera
return false;
}
}
public void mBTN(View view) {
mPreviewCamera(!mBPreviewingCamera);
}
}
public class PreviewSurface extends SurfaceView implements SurfaceHolder.Callback {
final static public String TAG = "PreviewSurface";
private SurfaceHolder mSH;
/**
* @param context
*/
public PreviewSurface(Context pContext) {
super(pContext);
// TODO Auto-generated constructor stub
String lMTH = "PreviewSurface(Context pContext) ";
Log.i(TAG, lMTH + "Constructor");
pContext = null;
mSH = getHolder();
mSH.addCallback(this);
mSH.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
/* (non-Javadoc)
* @see android.view.SurfaceHolder.Callback#surfaceChanged(android.view.SurfaceHolder, int, int, int)
*/
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
String lMTH = "surfaceChanged ";
// TODO Auto-generated method stub
Log.i(TAG, lMTH + "arg1 = " + arg1 + " arg2 " + arg2 + " arg3 " + arg3);
if (arg0.getSurface() != null) {
// stop old preview if it exists
try {
Log.i(TAG, lMTH + "Stop Preview ");
MyActivity.getCamera().stopPreview();
} catch (Exception e) {
Log.i(TAG, lMTH + "Stoping preview exception " + e.getMessage());
}
// start new preview
try {
Log.i(TAG, lMTH + "Set Preview ");
MyActivity.getCamera().setPreviewDisplay(arg0);
Log.i(TAG, lMTH + "Start Preview ");
MyActivity.getCamera().startPreview();
} catch (Exception e){
Log.i(TAG, lMTH + "Starting camera preview exception " + e.getMessage());
}
}
// stop preview before making changes
}
/* (non-Javadoc)
* @see android.view.SurfaceHolder.Callback#surfaceCreated(android.view.SurfaceHolder)
*/
public void surfaceCreated(SurfaceHolder arg0) {
String lMTH = "surfaceCreated ";
// TODO Auto-generated method stub
try {
Log.i(TAG, lMTH + "Set Preview ");
MyActivity.getCamera().setPreviewDisplay(arg0);
Log.i(TAG, lMTH + "Start Preview ");
MyActivity.getCamera().startPreview();
} catch (Exception e) {
Log.i(TAG, lMTH + "Exception " + e.getMessage());
e.printStackTrace();
}
}
/* (non-Javadoc)
* @see android.view.SurfaceHolder.Callback#surfaceDestroyed(android.view.SurfaceHolder)
*/
public void surfaceDestroyed(SurfaceHolder arg0) {
String lMTH = "surfaceDestroyed ";
// TODO Auto-generated method stub
Log.i(TAG, lMTH + "Activity will handle destroy");
}