要拍摄照片，首先我们需要在中声明所需的权限AndroidManifest.xml。我们需要两个权限：
Camera-打开相机应用。如果属性required设置为true，则如果您没有硬件摄像头，则将无法安装此应用程序。
WRITE_EXTERNAL_STORAGE -创建新文件需要此权限，该文件将保存捕获的照片。
<uses-feature android:name="android.hardware.camera" android:required="true" /> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
从相机拍摄全尺寸照片的主要想法是，在打开相机应用程序并捕获照片之前，我们需要为照片创建新文件。
private void dispatchTakePictureIntent() {
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// 确保有摄影机活动来处理意图
if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
// 创建文件应放在照片所在的位置
File photoFile = null;
try {
photoFile = createImageFile();
} catch (IOException ex) {
Log.e("DEBUG_TAG", "createFile", ex);
}
// 仅在成功创建文件后继续
if (photoFile != null) {
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
}
}
}
private File createImageFile() throws IOException {
// 创建图像文件名
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = getAlbumDir();
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// 保存文件：用于ACTION_VIEW意向的路径
mCurrentPhotoPath = image.getAbsolutePath();
return image;
}
private File getAlbumDir() {
File storageDir = null;
if (Environment.MEDIA_MOUNTED.equals(Environment.getExternalStorageState())) {
storageDir = new File(Environment.getExternalStorageDirectory()
+ "/dcim/"
+ "MyRecipes");
if (!storageDir.mkdirs()) {
if (!storageDir.exists()) {
Log.d("CameraSample", "failed to create directory");
return null;
}
}
} else {
Log.v(getString(R.string.app_name), "External storage is not mounted READ/WRITE.");
}
return storageDir;
}
private void setPic() {
/* There isn't enough memory to open up more than a couple camera photos */
/* So pre-scale the target bitmap into which the file is decoded */
/* Get the size of the ImageView */
int targetW = recipeImage.getWidth();
int targetH = recipeImage.getHeight();
/* Get the size of the image */
BitmapFactory.OptionsbmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds= true;
BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
/* Figure out which way needs to be reduced less */
int scaleFactor = 2;
if ((targetW > 0) && (targetH > 0)) {
scaleFactor = Math.max(photoW / targetW, photoH / targetH);
}
/* Set bitmap options to scale the image decode target */
bmOptions.inJustDecodeBounds= false;
bmOptions.inSampleSize= scaleFactor;
bmOptions.inPurgeable= true;
Matrix matrix = new Matrix();
matrix.postRotate(getRotation());
/* Decode the JPEG file into a Bitmap */
Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);
/* Associate the Bitmap to the ImageView */
recipeImage.setImageBitmap(bitmap);
}
private float getRotation() {
try {
ExifInterface ei = new ExifInterface(mCurrentPhotoPath);
int orientation = ei.getAttributeInt(ExifInterface.TAG_ORIENTATION, ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
return 90f;
case ExifInterface.ORIENTATION_ROTATE_180:
return 180f;
case ExifInterface.ORIENTATION_ROTATE_270:
return 270f;
default:
return 0f;
}
} catch (Exception e) {
Log.e("Add Recipe", "getRotation", e);
return 0f;
}
}
private void galleryAddPic() {
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
File f = new File(mCurrentPhotoPath);
Uri contentUri = Uri.fromFile(f);
mediaScanIntent.setData(contentUri);
sendBroadcast(mediaScanIntent);
}
private void handleBigCameraPhoto() {
if (mCurrentPhotoPath != null) {
setPic();
galleryAddPic();
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == Activity.RESULT_OK) {
handleBigCameraPhoto();
}
}