我正在制作小型应用，可预览相机，点击屏幕即可保存图像。
我的问题是图像保存后，我想开始不同的活动，它会做预览并有一些工具。但我做什么活动并没有开始。
这是我的代码
public class CameraActivity extends Activity {
private SurfaceView preview = null;
private SurfaceHolder previewHolder = null;
private Camera camera = null;
private boolean inPreview = false;
private boolean cameraConfigured = false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera);
preview = (SurfaceView) findViewById(R.id.preview);
Button button = (Button) findViewById(R.id.button_capture);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (camera != null) {
camera.takePicture(null, null, photoCallback);
onPause();
Intent intent = new Intent(CameraActivity.this, PreviewAndSaveActivity.class);
intent.putExtra("image", "");
CameraActivity.this.startActivity(intent);
}
}
});
previewHolder = preview.getHolder();
previewHolder.addCallback(surfaceCallback);
previewHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
@Override
public void onResume() {
super.onResume();
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.GINGERBREAD) {
Camera.CameraInfo info = new Camera.CameraInfo();
for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
Camera.getCameraInfo(i, info);
if (info.facing == Camera.CameraInfo.CAMERA_FACING_BACK) {
camera = Camera.open(i);
}
}
}
if (camera == null) {
camera = Camera.open();
}
startPreview();
}
@Override
public void onPause() {
if (camera != null) {
if (inPreview) {
camera.stopPreview();
}
camera.release();
camera = null;
}
inPreview = false;
super.onPause();
}
private Camera.Size getBestPreviewSize(int width, int height,
Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPreviewSizes()) {
if (size.width <= width && size.height <= height) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea > resultArea) {
result = size;
}
}
}
}
return (result);
}
private Camera.Size getSmallestPictureSize(Camera.Parameters parameters) {
Camera.Size result = null;
for (Camera.Size size : parameters.getSupportedPictureSizes()) {
if (result == null) {
result = size;
} else {
int resultArea = result.width * result.height;
int newArea = size.width * size.height;
if (newArea < resultArea) {
result = size;
}
}
}
return (result);
}
private void initPreview(int width, int height) {
if (camera != null && previewHolder.getSurface() != null) {
try {
camera.setPreviewDisplay(previewHolder);
} catch (Throwable t) {
Log.e("PreviewDemo-surfaceCallback",
"Exception in setPreviewDisplay()", t);
Toast.makeText(CameraActivity.this, t.getMessage(),
Toast.LENGTH_LONG).show();
}
if (!cameraConfigured) {
Camera.Parameters parameters = camera.getParameters();
Camera.Size size = getBestPreviewSize(width, height, parameters);
Camera.Size pictureSize = getSmallestPictureSize(parameters);
if (size != null && pictureSize != null) {
parameters.setPreviewSize(size.width, size.height);
parameters.setPictureSize(pictureSize.width,
pictureSize.height);
parameters.setPictureFormat(ImageFormat.JPEG);
parameters.setFlashMode(Camera.Parameters.FLASH_MODE_AUTO);
camera.setParameters(parameters);
cameraConfigured = true;
}
}
}
}
private void startPreview() {
if (cameraConfigured && camera != null) {
camera.startPreview();
inPreview = true;
}
}
SurfaceHolder.Callback surfaceCallback = new SurfaceHolder.Callback() {
public void surfaceCreated(SurfaceHolder holder) {
// no-op -- wait until surfaceChanged()
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
initPreview(width, height);
startPreview();
}
public void surfaceDestroyed(SurfaceHolder holder) {
}
};
Camera.PictureCallback photoCallback = new Camera.PictureCallback() {
public void onPictureTaken(byte[] data, Camera camera) {
camera.takePicture(null, null, new PhotoHandler(
getApplicationContext()));
camera.startPreview();
inPreview = true;
}
};
}
在解码和保存图像后的PhotoHandler中我想开始活动
public class PhotoHandler implements PictureCallback {
private final Context context;
public PhotoHandler(Context context) {
this.context = context;
}
@Override
public void onPictureTaken(byte[] data, Camera camera) {
File pictureFileDir = getDir();
if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) {
Log.d("", "Can't create directory to save image.");
Toast.makeText(context, "Can't create directory to save image.",
Toast.LENGTH_LONG).show();
return;
}
SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
String date = dateFormat.format(new Date());
String photoFile = "pic_" + date + ".jpg";
String pictureName = pictureFileDir.getPath() + File.separator
+ photoFile;
File pictureFile = new File(pictureName);
FileOutputStream fos = null;
try {
fos = new FileOutputStream(pictureFile);
fos.write(data);
Intent intent = new Intent(context, PreviewAndSaveActivity.class);
intent.putExtra("image", pictureName);
context.startActivity(intent);
} catch (Exception error) {
Toast.makeText(context, "Image could not be saved.",
Toast.LENGTH_LONG).show();
} finally {
if (fos != null) {
try {
fos.flush();
fos.close();
} catch (IOException e) {
}
}
}
}
private File getDir() {
File sdDir = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
return new File(sdDir, "dir");
}
}
有什么建议我做错了吗？
答案 0 :(得分：0)
试试这段代码：
（替换按钮单击侦听器）
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (camera != null) {
camera.takePicture(null, null, photoCallback);
onPause();
Intent intent = new Intent(CameraActivity.this, PreviewAndSaveActivity.class);
intent.putExtra("image", "");
CameraActivity.this.startActivityForResult(intent, 100);
}
}
});
在您的CameraActivity中，添加此回调方法以在图像保存后重定向另一个活动：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 100) {
// start you new activity from here...
}
super.onActivityResult(requestCode, resultCode, data);
}