我在使用 Nexus 5 上的相机拍照时遇到问题。我可以毫无问题地从图库中拍摄照片并将其保存到后端。但是，当我尝试使用相机拍照时，在拍照并选择勾号后，应用程序崩溃了...... 我可以看到传递给 onActivityResult() 的 Intent 是空的，但我不知道如何解决这个问题。有人可以帮忙吗？谢谢。
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.Toast;
import com.khackett.runmate.R;
import com.khackett.runmate.utils.FileHelper;
import com.khackett.runmate.utils.ParseConstants;
import com.parse.ParseException;
import com.parse.ParseFile;
import com.parse.ParseUser;
import com.parse.SaveCallback;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
public class MyProfileFragment extends Fragment implements View.OnClickListener {
public static final String TAG = MyProfileFragment.class.getSimpleName();
protected Button mTakePicture;
protected Button mChoosePicture;
/**
* Default constructor
*/
public MyProfileFragment() {
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View rootView = inflater.inflate(R.layout.fragment_my_profile, container, false);
mTakePicture = (Button) rootView.findViewById(R.id.takePictureButton);
mChoosePicture = (Button) rootView.findViewById(R.id.choosePictureButton);
mTakePicture.setOnClickListener(this);
mChoosePicture.setOnClickListener(this);
return rootView;
}
/**
* Called when a view has been clicked.
*
* @param v The view that was clicked.
*/
@Override
public void onClick(View v) {
// Switch statement to select which action to take depending on button/text pressed
switch (v.getId()) {
case R.id.takePictureButton:
takeCameraPicture();
break;
case R.id.choosePictureButton:
chooseGalleryPicture();
break;
default:
System.out.println("Problem with input");
}
}
public static final int TAKE_PHOTO_REQUEST = 1888;
public static final int PICK_PHOTO_REQUEST = 1888;
private static final int CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE = 1888;
// member variable to store the media type as a URI, that can be stored in multiple places
// Uri = uniform resource identifier
protected Uri mMediaUri;
public void takeCameraPicture() {
// Take picture
// use an existing camera app on the phone by starting an intent
// declare intent to capture a photo using whatever camera app is available
Intent takePhotoIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// after invoking the camera,
mMediaUri = getOutputMediaFileUri();
// check that a null value is not returned
if (mMediaUri == null) {
// display an error
Toast.makeText(getActivity(), R.string.error_external_storage, Toast.LENGTH_LONG).show();
} else {
// to add extra data to an intent, use the putExtra() method
takePhotoIntent.putExtra(MediaStore.EXTRA_OUTPUT, mMediaUri);
// start an activity for a result so that the activity exits and returns a result back for us
// ie, the main activity will wait for the result
startActivityForResult(takePhotoIntent, TAKE_PHOTO_REQUEST);
}
}
public void chooseGalleryPicture() {
// Choose picture
Intent choosePhotoIntent = new Intent(Intent.ACTION_GET_CONTENT);
// need to specify which type of action we want to get - an image in this case
choosePhotoIntent.setType("image/*");
startActivityForResult(choosePhotoIntent, PICK_PHOTO_REQUEST);
}
private Uri getOutputMediaFileUri() {
// To be safe, you should check that the SD card / external storage is mounted
// using Environment.getExternalStorageState() before doing this.
// see method below...
if (isExternalStorageAvailable()) {
String appName = MyProfileFragment.this.getString(R.string.app_name);
// get the Uri
// Get the external storage directory - we want to return a file object
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), appName);
// Create our subdirectory
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdir()) {
Log.e(TAG, "Failed to create directory");
return null;
}
}
// Create a file to hold the image
File mediaFile;
// get the current date and time
Date now = new Date();
// convert the date and time into a String datetimestamp
// see http://developer.android.com/guide/topics/media/camera.html#saving-media for the methods used
// need to append a timestamp to make it unique - otherwise it will overwrite the previous photo
String timestamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.ENGLISH).format(now);
String path = mediaStorageDir.getPath() + File.separator;
// create a new file using the constructor that takes a name
mediaFile = new File(path + "IMG_" + timestamp + ".jpg");
Log.d(TAG, "File: " + Uri.fromFile(mediaFile));
// Return the files URI
Log.d(TAG, "Returning the files URI");
return Uri.fromFile(mediaFile);
} else {
return null;
}
}
/**
* check if external storage is available on the users device
*
* @return
*/
private boolean isExternalStorageAvailable() {
// find out what state external storage is in
String state = Environment.getExternalStorageState();
// if external storage is available, return true,
if (state.equals(Environment.MEDIA_MOUNTED)) {
return true;
} else {
return false;
}
}
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (requestCode == CAPTURE_IMAGE_ACTIVITY_REQUEST_CODE) {
if (data == null) {
Log.d(TAG, "Data is null");
Toast.makeText(getActivity(), getString(R.string.general_error), Toast.LENGTH_LONG).show();
} else {
Log.d(TAG, "Data: " + data);
// the intent has data, so set the media uri
Log.d(TAG, "adding the data using the getData() method");
mMediaUri = data.getData();
Log.d(TAG, "Media Uri: " + mMediaUri);
}
// ParseUser.getCurrentUser().put("profilePic", mMediaUri);
saveImageToParse();
}
} else if (resultCode != Activity.RESULT_CANCELED) {
Log.d(TAG, "Problem getting the picture from gallery");
// Toast.makeText(getActivity(), R.string.general_error, Toast.LENGTH_LONG).show();
}
}
public void saveImageToParse() {
Log.d(TAG, "entering saveImageToParse() method");
byte[] fileBytes = FileHelper.getByteArrayFromFile(getActivity(), mMediaUri);
fileBytes = FileHelper.reduceImageForUpload(fileBytes);
String fileName = FileHelper.getFileName(getActivity(), mMediaUri, "file");
ParseFile file = new ParseFile(fileName, fileBytes);
ParseUser.getCurrentUser().put("profilePic", file);
ParseUser.getCurrentUser().saveInBackground(new SaveCallback() {
public void done(ParseException e) {
if (e == null) {
Log.d(TAG, "Image saved successfully");
// myObjectSavedSuccessfully();
} else {
Log.d(TAG, "Image not saved");
// myObjectSaveDidNotSucceed();
}
}
});
}
.
package com.khackett.runmate.utils;
import android.content.Context;
import android.graphics.Bitmap;
import android.net.Uri;
import android.util.Log;
import org.apache.commons.io.IOUtils;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
// https://github.com/treehouse/treehouse_android_utilities
public class FileHelper {
public static final String TAG = FileHelper.class.getSimpleName();
public static final int SHORT_SIDE_TARGET = 1280;
public static byte[] getByteArrayFromFile(Context context, Uri uri) {
byte[] fileBytes = null;
InputStream inStream = null;
ByteArrayOutputStream outStream = null;
Log.d(TAG, "in the getByteArrayFromFile() method");
if (uri.getScheme() != null && uri.getScheme().equals("content")) {
try {
Log.d(TAG, "entering try to set inputstream");
inStream = context.getContentResolver().openInputStream(uri);
outStream = new ByteArrayOutputStream();
byte[] bytesFromFile = new byte[1024 * 1024]; // buffer size (1 MB)
int bytesRead = inStream.read(bytesFromFile);
while (bytesRead != -1) {
outStream.write(bytesFromFile, 0, bytesRead);
bytesRead = inStream.read(bytesFromFile);
}
fileBytes = outStream.toByteArray();
} catch (IOException e) {
Log.e(TAG, e.getMessage());
} finally {
try {
inStream.close();
outStream.close();
} catch (IOException e) { /*( Intentionally blank */ }
}
} else {
try {
File file = new File(uri.getPath());
FileInputStream fileInput = new FileInputStream(file);
fileBytes = IOUtils.toByteArray(fileInput);
} catch (IOException e) {
Log.e(TAG, e.getMessage());
}
}
return fileBytes;
}
public static byte[] reduceImageForUpload(byte[] imageData) {
Bitmap bitmap = ImageResizer.resizeImageMaintainAspectRatio(imageData, SHORT_SIDE_TARGET);
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream);
byte[] reducedData = outputStream.toByteArray();
try {
outputStream.close();
} catch (IOException e) {
// Intentionally blank
}
return reducedData;
}
public static String getFileName(Context context, Uri uri, String fileType) {
String fileName = "uploaded_file.";
if (fileType.equals(ParseConstants.TYPE_IMAGE)) {
fileName += "png";
} else {
// For video, we want to get the actual file extension
if (uri.getScheme().equals("content")) {
// do it using the mime type
String mimeType = context.getContentResolver().getType(uri);
int slashIndex = mimeType.indexOf("/");
String fileExtension = mimeType.substring(slashIndex + 1);
fileName += fileExtension;
} else {
fileName = uri.getLastPathSegment();
}
}
return fileName;
}
}
.
09-01 20:15:49.322 23271-23271/com.khackett.runmate E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.khackett.runmate, PID: 23271
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=67424, result=-1, data=Intent { }} to activity {com.khackett.runmate/com.khackett.runmate.ui.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getScheme()' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:3574)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3617)
at android.app.ActivityThread.access$1300(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1352)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.getScheme()' on a null object reference
at com.khackett.runmate.utils.FileHelper.getByteArrayFromFile(FileHelper.java:29)
at com.khackett.runmate.ui.MyProfileFragment.saveImageToParse(MyProfileFragment.java:233)
at com.khackett.runmate.ui.MyProfileFragment.onActivityResult(MyProfileFragment.java:210)
at android.support.v4.app.FragmentActivity.onActivityResult(FragmentActivity.java:165)
at android.app.Activity.dispatchActivityResult(Activity.java:6192)
at android.app.ActivityThread.deliverResults(ActivityThread.java:3570)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:3617)
at android.app.ActivityThread.access$1300(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1352)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
最佳答案
从日志和您的代码中，您可以跟踪到 mMediaUri 为 null。
这应该是由于屏幕旋转而重新创建 Activity 造成的，例如，如果您的应用通常以纵向运行，而相机强制横向运行，或者您在使用相机时发生旋转。
无论如何要解决这个问题，你必须保存mMediaUrl并在onCreate中恢复它，修改你的Fragment，如下所示:
@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
// Save the user's current state
savedInstanceState.putString("media_url", mMediaUrl.toString());
// Always call the superclass so it can save the view hierarchy state
super.onSaveInstanceState(savedInstanceState);
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (savedInstanceState != null) {
mMediaUrl = Uri.parse(savedInstanceState.getString("media_url"));
}
}
编辑:
注意到另一个问题，更改以下内容:
public static final int TAKE_PHOTO_REQUEST = 1889;
public static final int PICK_PHOTO_REQUEST = 1888;
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode == Activity.RESULT_OK) {
if (requestCode == PICK_PHOTO_REQUEST) {
if (data == null) {
Log.d(TAG, "Data is null");
Toast.makeText(getActivity(), getString(R.string.general_error), Toast.LENGTH_LONG).show();
} else {
Log.d(TAG, "Data: " + data);
// the intent has data, so set the media uri
Log.d(TAG, "adding the data using the getData() method");
mMediaUri = data.getData();
Log.d(TAG, "Media Uri: " + mMediaUri);
}
// ParseUser.getCurrentUser().put("profilePic", mMediaUri);
saveImageToParse();
} else if(requestCode == TAKE_PHOTO_REQUEST) {
saveImageToParse();
}
} else if (resultCode != Activity.RESULT_CANCELED) {
Log.d(TAG, "Problem getting the picture from gallery");
// Toast.makeText(getActivity(), R.string.general_error, Toast.LENGTH_LONG).show();
}
}
关于java - Android 从相机获取 URI，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/32339418/