我正在构建一个应用程序，我希望通过默认的相机活动捕获图像并返回到我的活动并在ImageView中加载该图像。问题是相机活动总是返回null。在我的onActivityResult(int requestCode, int resultCode, Intent data)方法中，我获取的数据为null。这是我的代码：
public class CameraCapture extends Activity {
protected boolean _taken = true;
File sdImageMainDirectory;
Uri outputFileUri;
protected static final String PHOTO_TAKEN = "photo_taken";
private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 0;
@Override
public void onCreate(Bundle savedInstanceState) {
try {
super.onCreate(savedInstanceState);
setContentView(R.layout.cameracapturedimage);
File root = new File(Environment
.getExternalStorageDirectory()
+ File.separator + "myDir" + File.separator);
root.mkdirs();
sdImageMainDirectory = new File(root, "myPicName");
startCameraActivity();
} catch (Exception e) {
finish();
Toast.makeText(this, "Error occured. Please try again later.",
Toast.LENGTH_SHORT).show();
}
}
protected void startCameraActivity() {
outputFileUri = Uri.fromFile(sdImageMainDirectory);
Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
intent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE:
{
if(resultCode==Activity.RESULT_OK)
{
try{
ImageView imageView=(ImageView)findViewById(R.id.cameraImage);
imageView.setImageBitmap((Bitmap) data.getExtras().get("data"));
}
catch (Exception e) {
// TODO: handle exception
}
}
break;
}
default:
break;
}
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
if (savedInstanceState.getBoolean(CameraCapture.PHOTO_TAKEN)) {
_taken = true;
}
}
@Override
protected void onSaveInstanceState(Bundle outState) {
outState.putBoolean(CameraCapture.PHOTO_TAKEN, _taken);
}
}
我做错了吗？
答案 0 :(得分：102)
你错了，因为你做错了。
如果您使用相机意图传递额外参数MediaStore.EXTRA_OUTPUT，则相机活动会将捕获的图像写入该路径，并且不会以onActivityResult方法返回位图。
如果您要检查通过的路径，那么您将知道实际上相机已在该路径中写入捕获的文件。
答案 1 :(得分：18)
我是以另一种方式做的。 data.getData（）字段不保证返回一个Uri，所以我检查它是否为null，如果是，那么图像是额外的。所以代码是 -
if(data.getData()==null){
bitmap = (Bitmap)data.getExtras().get("data");
}else{
bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), data.getData());
}
我在生产应用程序中使用此代码，它正在运行。
答案 2 :(得分：6)
我有类似的问题。我在清单文件中注释掉了一些行，导致缩略图数据返回为空。
您需要以下内容才能使其正常工作：
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
我希望这可以解决您的问题
如果您的手机是三星，则可能与此http://kevinpotgieter.wordpress.com/2011/03/30/null-intent-passed-back-on-samsung-galaxy-tab/
有关还有另一个open question可能会提供更多信息
答案 3 :(得分：4)
如果您使用ImageView显示Camera Intent返回的位图 你需要在onSaveInstanceState中保存imageview引用，并在稍后的onRestoreInstanceState内部恢复它。查看下面的onSaveInstanceState和onRestoreInstanceState的代码。
public class MainActivity extends Activity {
private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 1;
String mCurrentPhotoPath;
ImageView imageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
imageView = (ImageView) findViewById(R.id.imageView1);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.activity_main);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
public void startCamera(View v) throws IOException {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
File photoFile = null;
photoFile = createImageFile();
//intent.putExtra(MediaStore.EXTRA_OUTPUT,Uri.fromFile(photoFile));
if (intent.resolveActivity(getPackageManager()) != null) {
startActivityForResult(intent, CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE);
}
}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE
&& resultCode == RESULT_OK) {
Bundle extras = data.getExtras();
Bitmap imageBitmap = (Bitmap) extras.get("data");
System.out.println(imageBitmap);
imageView.setImageBitmap(imageBitmap);
}
}
private File createImageFile() throws IOException {
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss")
.format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = "file:" + image.getAbsolutePath();
System.out.println(mCurrentPhotoPath);
return image;
}
private void setPic() {
// Get the dimensions of the View
int targetW = imageView.getWidth();
int targetH = imageView.getHeight();
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(mCurrentPhotoPath, bmOptions);
imageView.setImageBitmap(bitmap);
}
@Override
protected void onSaveInstanceState(Bundle outState) {
// TODO Auto-generated method stub
super.onSaveInstanceState(outState);
System.out.println(mCurrentPhotoPath);
imageView = (ImageView) findViewById(R.id.imageView1);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onRestoreInstanceState(savedInstanceState);
System.out.println(mCurrentPhotoPath);
imageView = (ImageView) findViewById(R.id.imageView1);
}
}
答案 4 :(得分：2)
经过多次搜索后：
private static final int TAKE_PHOTO_REQUEST = 1;
private ImageView mImageView;
String mCurrentPhotoPath;
private File photoFile;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_saisir_frais);
mImageView = (ImageView) findViewById(R.id.imageViewPhoto);
dispatchTakePictureIntent();
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == TAKE_PHOTO_REQUEST && resultCode == RESULT_OK) {
// set the dimensions of the image
int targetW =100;
int targetH = 100;
// Get the dimensions of the bitmap
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(photoFile.getAbsolutePath(), bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
// Determine how much to scale down the image
int scaleFactor = Math.min(photoW/targetW, photoH/targetH);
// Decode the image file into a Bitmap sized to fill the View
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
// stream = getContentResolver().openInputStream(data.getData());
Bitmap bitmap = BitmapFactory.decodeFile(photoFile.getAbsolutePath(),bmOptions);
mImageView.setImageBitmap(bitmap);
}
}
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(
imageFileName, /* prefix */
".jpg", /* suffix */
storageDir /* directory */
);
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = "file:" + image.getAbsolutePath();
return image;
}
private void dispatchTakePictureIntent() {
Intent takePhotoIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
try {
photoFile = createImageFile();
takePhotoIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(photoFile));
startActivityForResult(takePhotoIntent, TAKE_PHOTO_REQUEST);
} catch (IOException e) {
e.printStackTrace();
}
}
答案 5 :(得分：1)
请尝试以下代码
{
final String[] imageColumns = { MediaStore.Images.Media._ID,MediaStore.Images.Media.DATA };
final String imageOrderBy = MediaStore.Images.Media._ID + " DESC";
Cursor imageCursor = managedQuery(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, imageColumns, null, null, imageOrderBy);
imageCursor.moveToFirst();
do {
String fullPath = imageCursor.getString(imageCursor.getColumnIndex(MediaStore.Images.Media.DATA));
if (fullPath.contains("DCIM")) {
//get bitmap from fullpath here.
return;
}
}
while (imageCursor.moveToNext());
答案 6 :(得分：0)
您可以从发送到相机意图的文件生成位图。请使用此代码...
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
switch (requestCode) {
case CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE:
{
if(resultCode==Activity.RESULT_OK)
{
int orientation = getOrientationFromExif(sdImageMainDirectory);// get orientation that image taken
BitmapFactory.Options options = new BitmapFactory.Options();
InputStream is = null;
Matrix m = new Matrix();
m.postRotate(orientation);//rotate image
is = new FileInputStream(sdImageMainDirectory);
options.inSampleSize = 4 //(original_image_size/4);
Bitmap bitmap = BitmapFactory.decodeStream(is,null,options);
bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(),
bitmap.getHeight(), m, true);
// set bitmap to image view
//bitmap.recycle();
}
break;
}
default:
break;
}
}
private int getOrientationFromExif(String imagePath) {
int orientation = -1;
try {
ExifInterface exif = new ExifInterface(imagePath);
int exifOrientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (exifOrientation) {
case ExifInterface.ORIENTATION_ROTATE_270:
orientation = 270;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
orientation = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_90:
orientation = 90;
break;
case ExifInterface.ORIENTATION_NORMAL:
orientation = 0;
break;
default:
break;
}
} catch (IOException e) {
//Log.e(LOG_TAG, "Unable to get image exif orientation", e);
}
return orientation;
}
答案 7 :(得分：0)
File cameraFile = null;
public void openChooser() {
Intent pickIntent = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
Intent takePhotoIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
cameraFile = new File(android.os.Environment.getExternalStorageDirectory(), "temp.jpg");
takePhotoIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(cameraFile));
String pickTitle = "Select or take a new Picture"; // Or get from strings.xml
Intent chooserIntent = Intent.createChooser(pickIntent, pickTitle);
chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS,new Intent[]{takePhotoIntent});
startActivityForResult(chooserIntent, SELECT_PHOTO);
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case SELECT_PHOTO:
if (resultCode == Activity.RESULT_OK) {
Uri selectedImage = data.getData();
if (selectedImage != null) {
//from gallery
} else if (cameraFile != null) {
//from camera
Uri cameraPictureUri = Uri.fromFile(cameraFile);
}
}
break;
}
}
答案 8 :(得分：0)
试试本教程。它适用于我，并在宣言和照片中使用许可。也 检查权限
答案 9 :(得分：0)
经过大量的研究，我终于得出了结论。 为此，您应该将捕获的图像保存到外部存储器。 然后，在上传时检索。 这样，图像分辨率不会降低，您也不会得到NullPointerException！ 我使用时间戳来命名文件，因此每次都获得唯一的文件名。
<string name="DetailsOfWiFiDef">The WiFi status is ${myObject.status},
the name of WiFi is ${myObject.name}\n\n
</string>
val myObject=getIt()
val s=mContext.getString(R.string.DetailsOfWiFiDef)
val sb = StringBuilder()
sb.append(s) //The string keep original
创建文件名的功能：
val myObject=getIt()
val k="The WiFi status is ${myObject.status},the name of WiFi is ${myObject.name} \n"
val sb = StringBuilder()
sb.append(k) //It has been replaced
和onActivityResult：
private void fileChooser2() {
StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
StrictMode.setVmPolicy(builder.build());
Intent intent=new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
File pictureDirectory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
String pictureName=getPictureName();
fi=pictureName;
File imageFile=new File(pictureDirectory,pictureName);
Uri pictureUri = Uri.fromFile(imageFile);
intent.putExtra(MediaStore.EXTRA_OUTPUT,pictureUri);
startActivityForResult(intent,PICK_IMAGE_REQUEST2);
}
希望这会有所帮助：）
编辑：授予摄像机权限以及清单中存储的写入和读取权限。
答案 10 :(得分：0)
从相机取景时，很少有手机返回null。下面的解决方法将解决。确保检查数据是否为空。
private int CAMERA_NEW = 2;
private String imgPath;
private void takePhotoFromCamera() {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, setImageUri());
startActivityForResult(intent, CAMERA_NEW);
}
// to get the file path
private Uri setImageUri() {
// Store image in dcim
File file = new File(Environment.getExternalStorageDirectory() + "/DCIM/", "image" + new Date().getTime() + ".png");
Uri imgUri = Uri.fromFile(file);
this.imgPath = file.getAbsolutePath();
return imgUri;
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == CAMERA_NEW) {
try {
Log.i("Crash","CAMERA_NEW");
if(data!=null &&(Bitmap) data.getExtras().get("data")!=null){
bitmap = (Bitmap) data.getExtras().get("data");
personImage.setImageBitmap(bitmap);
Utils.saveImage(bitmap, getActivity());
}else{
File f= new File(imgPath);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_8888;
options.inSampleSize= 4;
bitmap = BitmapFactory.decodeStream(new FileInputStream(f), null, options);
personImage.setImageBitmap(bitmap);
}
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(getActivity(), "Failed!", Toast.LENGTH_SHORT).show();
}
}