你好我想拍一张照片并将照片保存在片段中。 我的用户应该按一个按钮并拍照并保存，我的相机预览在我的片段中，所以我认为这些事情也应该在片段中发生，所以我试着把片段中的按钮带来但我得到了NullPointerException所以我试图得到位图并使用[this]将其发送到活动：Passing data between a fragment and its container activity但是它给了我阶级演员异常，我不知道该怎么做。 记住，我想拍摄并保存图片，任何帮助都会很精彩。谢谢 这是我在相机片段中的代码：
public class CameraFragment extends Fragment {
private Preview mPreview;
Camera mCamera;
int mNumberOfCameras;
// The first rear facing camera
int mDefaultCameraId;
@Override
public void onCreate(Bundle savedInstanceState) {
Log.d("aron", "we are in oncreate");
super.onCreate(savedInstanceState);
// Create a container that will hold a SurfaceView for camera previews
mPreview = new Preview(this.getActivity());
Log.d("aron", "we are in oncreate and we made preview successfuly");
}
public interface OnDataPass {
public void onDataPass(Bitmap data);
}
OnDataPass dataPasser;
@Override
public void onAttach(Activity a) {
super.onAttach(a);
Log.d("aron", "we are in onattach");
dataPasser = (OnDataPass) a;
}
public void passData() {
Bitmap data=mPreview.getBitmap();
Log.d("aron", "we are in passdata");
dataPasser.onDataPass(data);
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
// Add an up arrow to the "home" button, indicating that the button will go "up"
// one activity in the app's Activity heirarchy.
// Calls to getActionBar() aren't guaranteed to return the ActionBar when called
// from within the Fragment's onCreate method, because the Window's decor hasn't been
// initialized yet. Either call for the ActionBar reference in Activity.onCreate()
// (after the setContentView(...) call), or in the Fragment's onActivityCreated method.
/* Activity activity = this.getActivity();
ActionBar actionBar = activity.getActionBar();
actionBar.setDisplayHomeAsUpEnabled(true);*/
Log.d("aron", "we are in onactivitycreated and we are done with it");
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.d("aron", "we are in oncreateview");
return mPreview;
}
@Override
public void onResume() {
super.onResume();
// Use mCurrentCamera to select the camera desired to safely restore
// the fragment after the camera has been changed
mCamera = Camera.open();
mPreview.setCamera(mCamera);
Log.d("aron", "we are in onresume");
}
@Override
public void onPause() {
super.onPause();
// Because the Camera object is a shared resource, it's very
// important to release it when the activity is paused.
if (mCamera != null) {
mPreview.setCamera(null);
mCamera.release();
mCamera = null;
}
Log.d("aron", "we are in onpause");
}
/* @Override
public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
if (mNumberOfCameras > 1) {
// Inflate our menu which can gather user input for switching camera
inflater.inflate(R.menu.main, menu);
} else {
super.onCreateOptionsMenu(menu, inflater);
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
switch (item.getItemId()) {
case R.id.menu_switch_cam:
// Release this camera -> mCameraCurrentlyLocked
if (mCamera != null) {
mCamera.stopPreview();
mPreview.setCamera(null);
mCamera.release();
mCamera = null;
}
// Acquire the next camera and request Preview to reconfigure
// parameters.
mCurrentCamera = (mCameraCurrentlyLocked + 1) % mNumberOfCameras;
mCamera = Camera.open(mCurrentCamera);
mCameraCurrentlyLocked = mCurrentCamera;
mPreview.switchCamera(mCamera);
// Start the preview
mCamera.startPreview();
return true;
case android.R.id.home:
Intent intent = new Intent(this.getActivity(), MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}*/
}
// ----------------------------------------------------------------------
/**
* A simple wrapper around a Camera and a SurfaceView that renders a centered
* preview of the Camera to the surface. We need to center the SurfaceView
* because not all devices have cameras that support preview sizes at the same
* aspect ratio as the device's display.
*/
class Preview extends ViewGroup implements SurfaceHolder.Callback {
private final String TAG = "Preview";
SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Bitmap cameraBitmap;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
boolean mSurfaceCreated = false;
Preview(Context context) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
}
public void setCamera(Camera camera) {
mCamera = camera;
if (mCamera != null) {
mSupportedPreviewSizes = mCamera.getParameters()
.getSupportedPreviewSizes();
if (mSurfaceCreated) requestLayout();
}
}
public void switchCamera(Camera camera) {
setCamera(camera);
try {
camera.setPreviewDisplay(mHolder);
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// We purposely disregard child measurements because act as a
// wrapper to a SurfaceView that centers the camera preview instead
// of stretching it.
final int width = resolveSize(getSuggestedMinimumWidth(),
widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(),
heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width,
height);
}
if (mCamera != null) {
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
mCamera.setParameters(parameters);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (getChildCount() > 0) {
final View child = getChildAt(0);
final int width = r - l;
final int height = b - t;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null) {
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
}
// Center the child SurfaceView within the parent.
if (width * previewHeight > height * previewWidth) {
final int scaledChildWidth = previewWidth * height
/ previewHeight;
child.layout((width - scaledChildWidth) / 2, 0,
(width + scaledChildWidth) / 2, height);
} else {
final int scaledChildHeight = previewHeight * width
/ previewWidth;
child.layout(0, (height - scaledChildHeight) / 2, width,
(height + scaledChildHeight) / 2);
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
try {
if (mCamera != null) {
mCamera.setPreviewDisplay(holder);
}
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
if (mPreviewSize == null) requestLayout();
mSurfaceCreated = true;
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
if (mCamera != null) {
mCamera.stopPreview();
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null)
return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE)
continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
Log.d("aron", "we are in surface changed");
mCamera.setParameters(parameters);
mCamera.startPreview();
}
public Bitmap getBitmap(){
@SuppressWarnings("unused")
PictureCallback pic=new PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera arg1) {
Log.d("aron", "onPicturetaken");
cameraBitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
}
};
return cameraBitmap;
}
}
在
中表示ClassCastExceptiondataPasser =（OnDataPass）a;
请注意，由于项目的其他部分，我不想使用意图。 请帮帮我!!!
这是我的主持人活动：
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ImageButton capturebtn=(ImageButton)findViewById(R.id.capturebtn);
Log.d("aron", "Image button is created");
capturebtn.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View view) {
@SuppressWarnings("unused")
OnDataPass bitmapPasser=new OnDataPass() {
@Override
public void onDataPass(Bitmap cameraBitmap) {
Log.d("aron","we are in act on click and in datapass got bitmap");
int wid = cameraBitmap.getWidth();
int hgt = cameraBitmap.getHeight();
Bitmap newImage = Bitmap.createBitmap(wid, hgt, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(newImage);
canvas.drawBitmap(cameraBitmap, 0f, 0f, null);
Log.d("aron","bitmap and canvas are made");
FrameLayout frm = (FrameLayout)findViewById(R.id.frameLayout1);
frm.setDrawingCacheEnabled(true);
frm.buildDrawingCache();
Bitmap bitmap = frm.getDrawingCache();
canvas.drawBitmap(bitmap, 0f, 0f, null);
Log.d("aron","framelayout dorost shod");
}
};
}
});
}
}
你可以看到我实现了OnDataPass。
答案 0 :(得分：0)
所以一段时间后我自己解决了问题，可以使用
Camera.PictureCallback
我现在这样做。就像这样：
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
View myActivityView=(RelativeLayout)getActivity().findViewById(R.id.parentContainer);
ImageButton capturebtn=(ImageButton)myActivityView.findViewById(R.id.capturebtn);
capturebtn.setOnClickListener(new View.OnClickListener() {
@SuppressWarnings("UnusedDeclaration")
@Override
public void onClick(View v) {
Log.d("aron", "this is in fragment and this is a damned button say halelooya");
mPreview.TakePicture();
}
});
}
你可以在onActivity的片段中看到我调用了片段父活动并调用了拍照的方法。