我的相机代码适用于所有Android版本，但在Nougat 7.0中，它会出现以下错误：
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.toString()' on a null object reference
除了在Android 7.0上，它在所有其他版本的android上完美运行。我给了相机的运行时间许可。画廊，但相机仍然无法正常工作。以下是相关代码：
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (resultCode == RESULT_OK) {
if(requestCode == Constants.CROPPED_PIC_REQUEST_CODE){
CropImage.ActivityResult result = (CropImage.ActivityResult) data.getExtras().get(CropImage.CROP_IMAGE_EXTRA_RESULT);
Uri selectedImageUri = result == null ? null : result.getUri();
Bitmap bitmap = null;
Log.d("SetUpProfile","Uri cropped is "+outputFileUri);
bitmap = getBitmap(selectedImageUri);
// bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), selectedImageUri);
circleImageView.setImageBitmap(bitmap);
finalBitmap = bitmap;
}
else if (requestCode == Constants.YOUR_SELECT_PICTURE_REQUEST_CODE) {
final boolean isCamera;
if (data == null) {
isCamera = true;
} else {
final String action = data.getAction();
if (action == null) {
isCamera = false;
} else {
isCamera = action.equals(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
}
}
Uri selectedImageUri;
if (isCamera) {
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
String value = prefs.getString("path", "error");
selectedImageUri = Uri.parse(value);
} else {
selectedImageUri = data == null ? null : data.getData();
}
Intent i = new Intent(Five.this,CropImageActivity.class);
i.putExtra("ImageURI", selectedImageUri.toString());
startActivityForResult(i,Constants.CROPPED_PIC_REQUEST_CODE);
}
}
}
这是我的logcat： -
FATAL EXCEPTION: main
Process: com.sancsvision.wayndr, PID: 31570
java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=11, result=-1, data=Intent { }} to activity {com.sancsvision.wayndr/com.sancsvision.wayndr.Five}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.toString()' on a null object reference
at android.app.ActivityThread.deliverResults(ActivityThread.java:4053)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:4096)
at android.app.ActivityThread.-wrap20(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1516)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String android.net.Uri.toString()' on a null object reference
at com.sancsvision.wayndr.Five.onActivityResult(Five.java:259)
at android.app.Activity.dispatchActivityResult(Activity.java:6917)
at android.app.ActivityThread.deliverResults(ActivityThread.java:4049)
at android.app.ActivityThread.handleSendResult(ActivityThread.java:4096)
at android.app.ActivityThread.-wrap20(ActivityThread.java)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1516)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
答案 0 :(得分：3)
尝试这个不是创建问题的意图，一旦你拍照并保存到SD卡并且在Nougat中获取URI是不同的....
在您的应用程序上实现FileProvider非常容易。首先，您需要在AndroidManifest.xml中的标签下添加一个FileProvider标签，如下所示：AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
...
<application
...
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="${applicationId}.provider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>
</application>
</manifest>
然后在res文件夹下的xml文件夹中创建一个provider_paths.xml文件。如果文件夹不存在，可能需要创建文件夹。
RES / XML / provider_paths.xml
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/>
</paths>
完成！ FileProvider现已声明并可以使用。
最后一步是在MainActivity.java中更改下面的代码行
Uri photoURI = Uri.fromFile(createImageFile());
到
Uri photoURI = FileProvider.getUriForFile(MainActivity.this,
BuildConfig.APPLICATION_ID + ".provider",
createImageFile());
......完成了！您的应用程序现在可以在包括Android Nougat在内的任何Android版本上完美运行。干杯！
答案 1 :(得分：1)
这可能与Nougat的变化有关，而Nougat并不允许＆＃34; file：//＆＃34;计划附加于意图。
查看此博文了解更多详情
答案 2 :(得分：0)
我已使用相机为Android api＆gt; 21
完成图像上传到服务器import android.Manifest;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.MediaStore;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v4.content.FileProvider;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;
import java.io.ByteArrayOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.Random;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private static final int PICK_FILE_REQUEST = 1;
private static final String TAG = MainActivity.class.getSimpleName();
private ArrayList<String> selectedFilePath;
private String SERVER_URL = "http://192.168.1.10:8080/imageUploadWebApi.php";
Button btAttachment;
Button btCamera;
Button bUpload;
TextView tvFileName;
ProgressDialog dialog;
public static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 123;
Uri outputFileUri;
String mCurrentPhotoPath;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (permissionCheck != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
} else {
Init();
}
if ( Build.VERSION.SDK_INT >= 23 && ContextCompat.checkSelfPermission( this, android.Manifest.permission.CAMERA ) != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{android.Manifest.permission.CAMERA},
MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
}
}
@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
switch (requestCode) {
case MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE:
if ((grantResults.length > 0) && (grantResults[0] == PackageManager.PERMISSION_GRANTED)) {
Init();
}
break;
default:
break;
}
}
private void Init() {
btAttachment = (Button)findViewById(R.id.btAttachment);
btCamera=(Button)findViewById(R.id.btCamera);
bUpload = (Button) findViewById(R.id.b_upload);
tvFileName = (TextView) findViewById(R.id.tv_file_name);
btAttachment.setOnClickListener(this);
btCamera.setOnClickListener(this);
bUpload.setOnClickListener(this);
selectedFilePath=new ArrayList<>();
}
@Override
public void onClick(View v) {
switch (v.getId())
{
case R.id.btAttachment:
if(selectedFilePath.size()<5) {
//on attachment icon click
showFileChooser();
}
else
Toast.makeText(this,"You can upload only 5 Images at a time ",Toast.LENGTH_LONG).show();
break;
case R.id.btCamera:
if(selectedFilePath.size()<5) {
try {
Intent cameraIntent= new Intent(
android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
cameraIntent.setFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
outputFileUri = FileProvider.getUriForFile(getApplicationContext(), BuildConfig.APPLICATION_ID + ".provider", createImageFile());
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
} else {
File imagesFolder = new File(Environment.getExternalStorageDirectory(), "Images");
imagesFolder.mkdirs()
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "Img_" + timeStamp;
String fname = imageFileName + ".png";
File file = new File(imagesFolder, fname);
outputFileUri = Uri.fromFile(file);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
}
startActivityForResult(cameraIntent, 100);
}catch(Exception e) {
e.printStackTrace();
}
}
else
Toast.makeText(this,"You can upload only 5 Images at a time ",Toast.LENGTH_LONG).show();
break;
case R.id.b_upload:
selectedFile();
break;
}
}
private File createImageFile() throws IOException {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "Img_" + timeStamp;
File storageDir = new File(Environment.getExternalStorageDirectory(), "Images");
File file=new File(storageDir,imageFileName+".png");
// Save a file: path for use with ACTION_VIEW intents
mCurrentPhotoPath = file.getAbsolutePath();//"file:" + image.getAbsolutePath();
return file;
}
private void selectedFile()
{
if(selectedFilePath.size() != 0){
dialog = ProgressDialog.show(MainActivity.this,"","Uploading File...",true);
for (final String selectedFile:selectedFilePath) {
new Thread(new Runnable() {
@Override
public void run() {
//creating new thread to handle Http Operations
uploadFile(selectedFile);
}
}).start();
}
}else{
Toast.makeText(MainActivity.this,"Please choose a File First", Toast.LENGTH_SHORT).show();
}
}
private void showFileChooser() {
Intent intent = new Intent();
//sets the select file to all types of files
intent.setType("*/*");
//allows to select data and return it
intent.setAction(Intent.ACTION_GET_CONTENT);
//starts new activity to select file and return data
startActivityForResult(Intent.createChooser(intent,"Choose File to Upload.."),PICK_FILE_REQUEST);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if(resultCode == Activity.RESULT_OK){
if(requestCode == PICK_FILE_REQUEST){
if(data == null){
//no data present
return;
}
Uri selectedFileUri =data.getData();
selectedFilePath.add(FilePath.getPath(this,selectedFileUri));
Log.i(TAG,"Selected File Path:" + selectedFilePath);
if(selectedFilePath.size() != 0 ){
String fileName="";
for(int i=0;i<selectedFilePath.size();i++)
{
String[] parts = selectedFilePath.get(i).split("/");
final String RelativefileName = parts[parts.length-1];
fileName=RelativefileName+"\n"+fileName;
}
tvFileName.setText(fileName);
}else{
Toast.makeText(this,"Cannot upload file to server",Toast.LENGTH_SHORT).show();
}
}
else if(requestCode == 100)
{
try {
if(Build.VERSION.SDK_INT <= Build.VERSION_CODES.N) {
// Bitmap bitmap;
File file = null;
FileInputStream fis;
BitmapFactory.Options opts;
int resizeScale;
Bitmap bmp;
file = new File(outputFileUri.getPath());
// This bit determines only the width/height of the
// bitmap
// without loading the contents
opts = new BitmapFactory.Options();
opts.inJustDecodeBounds = true;
fis = new FileInputStream(file);
BitmapFactory.decodeStream(fis, null, opts);
fis.close();
selectedFilePath.add(FilePath.getPath(this,outputFileUri));
}
else
{
selectedFilePath.add(mCurrentPhotoPath);
}
Log.i(TAG,"Selected File Path:" + selectedFilePath);
if(selectedFilePath.size() != 0 ){
String fileName="";
for(int i=0;i<selectedFilePath.size();i++)
{
String[] parts = selectedFilePath.get(i).split("/");
final String RelativefileName = parts[parts.length-1];
fileName=RelativefileName+"\n"+fileName;
}
tvFileName.setText(fileName);
}else{
Toast.makeText(this,"Cannot upload file to server",Toast.LENGTH_SHORT).show();
}
} catch (Exception e) {
e.printStackTrace();
}
}
}
}
public String getPath(Uri uri) {
String[] projection = { MediaStore.Images.Media.DATA };
Cursor cursor = getContentResolver().query(uri, null, null, null, null);
cursor.moveToFirst();
return cursor.getString(0);
}
//android upload file to server
public int uploadFile(final String selectedFilePath){
int serverResponseCode = 0;
HttpURLConnection connection;
DataOutputStream dataOutputStream;
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "*****";
int bytesRead,bytesAvailable,bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
File selectedFile = new File(selectedFilePath);
String[] parts = selectedFilePath.split("/");
final String fileName = parts[parts.length-1];
if (!selectedFile.isFile()){
dialog.dismiss();
runOnUiThread(new Runnable() {
@Override
public void run() {
tvFileName.setText("Source File Doesn't Exist: " + selectedFilePath);
}
});
return 0;
}else{
try{
FileInputStream fileInputStream = new FileInputStream(selectedFile);
URL url = new URL(SERVER_URL);
connection = (HttpURLConnection) url.openConnection();
connection.setDoInput(true);//Allow Inputs
connection.setDoOutput(true);//Allow Outputs
connection.setUseCaches(false);//Don't use a cached Copy
connection.setRequestMethod("POST");
connection.setRequestProperty("Connection", "Keep-Alive");
connection.setRequestProperty("ENCTYPE", "multipart/form-data");
connection.setRequestProperty("Content-Type", "multipart/form-data;boundary=" + boundary);
connection.setRequestProperty("uploaded_file",selectedFilePath);
//creating new dataoutputstream
dataOutputStream = new DataOutputStream(connection.getOutputStream());
//writing bytes to data outputstream
dataOutputStream.writeBytes(twoHyphens + boundary + lineEnd);
dataOutputStream.writeBytes("Content-Disposition: form-data; name=\"uploaded_file\";filename=\""
+ selectedFilePath + "\"" + lineEnd);
dataOutputStream.writeBytes(lineEnd);
//returns no. of bytes present in fileInputStream
bytesAvailable = fileInputStream.available();
//selecting the buffer size as minimum of available bytes or 1 MB
bufferSize = Math.min(bytesAvailable,maxBufferSize);
//setting the buffer as byte array of size of bufferSize
buffer = new byte[bufferSize];
//reads bytes from FileInputStream(from 0th index of buffer to buffersize)
bytesRead = fileInputStream.read(buffer,0,bufferSize);
//loop repeats till bytesRead = -1, i.e., no bytes are left to read
while (bytesRead > 0){
//write the bytes read from inputstream
dataOutputStream.write(buffer,0,bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable,maxBufferSize);
bytesRead = fileInputStream.read(buffer,0,bufferSize);
}
dataOutputStream.writeBytes(lineEnd);
dataOutputStream.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
serverResponseCode = connection.getResponseCode();
String serverResponseMessage = connection.getResponseMessage();
Log.i(TAG, "Server Response is: " + serverResponseMessage + ": " + serverResponseCode);
//response code of 200 indicates the server status OK
if(serverResponseCode == 200){
runOnUiThread(new Runnable() {
@Override
public void run() {
tvFileName.setText("File Upload completed.");
}
});
}
//closing the input and output streams
fileInputStream.close();
dataOutputStream.flush();
dataOutputStream.close();
this.selectedFilePath.clear();
} catch (FileNotFoundException e) {
e.printStackTrace();
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this,"File Not Found",Toast.LENGTH_SHORT).show();
}
});
} catch (MalformedURLException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "URL error!", Toast.LENGTH_SHORT).show();
} catch (IOException e) {
e.printStackTrace();
Toast.makeText(MainActivity.this, "Cannot Read/Write File!", Toast.LENGTH_SHORT).show();
}
dialog.dismiss();
return serverResponseCode;
}
}
}
它正在使用android nougat。
答案 3 :(得分：0)
点击相机按钮或相机图像点击事件
执行此操作Uri fileUri;
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
if (cameraIntent.resolveActivity(getPackageManager()) != null) {
ContentValues values = new ContentValues(1);
values.put(MediaStore.Images.Media.MIME_TYPE, "image/jpg");
fileUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
Log.d("FILEURI",fileUri+"");
editor.putString("Fileurl", fileUri+"");
editor.commit();
cameraIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
startActivityForResult(cameraIntent, CAMERA_REQUEST);
}
在onActivityResult方法中执行此操作
if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {
try {
String utlstr =preferences.getString("Fileurl","");
Log.d("sad",utlstr);
Uri uri = Uri.parse(utlstr);
final File file = inputStreamToFile(getContentResolver().openInputStream(uri), "png");
} catch (FileNotFoundException e) {
e.printStackTrace();
}
}