拍照并在另一个活动的ImageView中显示它

Question

我有两个活动：MainActivity和ShowPhotoDescriptionActivity。第一个活动有一个FloatingActionButton，当按下时，它启动相机，拍摄照片，并将其保存到该应用程序的文件夹中。之后，第二个Activity被调用。此活动应显示在ImageView中拍摄的最后一张照片。它看起来很简单，但没有用。 我已经尝试了一些解决方案，但其中大多数都没有解决我的任何问题。

在MainActivity我有

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab); 
    fab.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

      //Starts the device's camera 
      dispatchTakePicture(); 

     } 
    }); 

/** 
* Calls an existent camera app to take a picture, then is stores on device in a custom folder 
*/ 
private void dispatchTakePicture() { 

    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE); 
    // Ensure that there's a camera activity to handle the intent 
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) { 
     // Create the File where the photo should go 
     File photoFile = null; 
     try { 
      String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date()); 
      String imageFileName = "photocrowd" + timeStamp + ".jpg"; 
      final String appDirectoryName = "Photocrowd"; 
      photoFile = createImageFile(appDirectoryName, imageFileName); 
     } catch (IOException ex) { 
      // Error occurred while creating the File 
      Toast.makeText(this, "Ocorreu um erro: Não foi posível armazenar a foto", Toast.LENGTH_SHORT).show(); 
      Log.e("Main Activity", "It wasn't possible to catch the photo: "+ex); 
     } 
     // Continue only if the File was successfully created 
     if (photoFile != null) { 

      Uri photoURI = Uri.fromFile(photoFile); 
      takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI); 
      startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO); 
     } 
    } 
} 

/** 
* Creates a folder and a name to the image on the device 
* 
* @return 
* @throws IOException 
*/ 
private File createImageFile(String name_folder, String name_image) throws IOException { 
    // Create an image file name 
    final File imageRoot = new File(Environment.getExternalStoragePublicDirectory(
      Environment.DIRECTORY_PICTURES), name_folder); 
    imageRoot.mkdir(); 
    File image = new File(imageRoot, name_image); 

    // Save a file: path for use with ACTION_VIEW intents 
    mCurrentPhotoPath = image.getAbsolutePath(); 

    return image; 
} 
/** 
* Allows the photo be found for the media scanner and shown in gallery 
*/ 
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); 
    this.sendBroadcast(mediaScanIntent); 
} 

@Override 
protected void onActivityResult(int requestCode, int resultCode, Intent data) { 

    if (requestCode == REQUEST_TAKE_PHOTO && resultCode == RESULT_OK) { 

     galleryAddPic(); 
     //Once the photo is taken and saved, the description activity is called 
     Intent i = new Intent(this, PhotoDescriptionActivity.class); 

     i.putExtra("path", mCurrentPhotoPath); 

     startActivity(i); 
    } 
} 

好吧，这只是允许拍照，保存的文件名为“Photocrowd”文件夹中，其显示在画廊和发送路径其他活动。

在PhotoDescriptionActivity我有

private ImageView mImageView; 
protected void onCreate(@Nullable Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.show_photo_description_activity); 
    Log.v("DESCRIPTION", "Activite PHotoDescription"); 
    mImageView = (ImageView) findViewById(R.id.photo_panel); 

    String imageRoot = getIntent().getStringExtra("path"); 
    Log.v("DESCRIPTION", imageRoot); 

    mImageView.setImageBitmap(BitmapFactory.decodeFile(imageRoot)); 

} 

我已经尝试使用其他方法（使用图书馆，setImageUri及其他）。到imageRoot路径是相同的显示在我的Android（/storage/emulated/0/Pictures/Photocrowd/photocrowd20170419_124851.jpg）

此代码的照片说明是最后一个，我试图和它显示在登录：

E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /storage/emulated/0/Pictures/Photocrowd/photocrowd20170419_130554.jpg: open failed: EACCES (Permission denied) 

我在清单写这些权限：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" /> 
    <uses-permission android:name="android.permission.INTERNET" /> 
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> 

我怎样才能得到这张最后的照片已经拍摄并保存在我的画廊？我知道它看起来很简单，但没什么用。

Answer 1

您未被授予权限“WRITE_EXTERNAL_STORAGE”，如日志中所述： E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /storage/emulated/0/Pictures/Photocrowd/photocrowd20170419_130554.jpg: open failed: EACCES (Permission denied)。

此权限：<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />是危险的许可，并在Android 6.0中，你需要在运行时请求权限：

中的Android 6.0（API级别23）开始，用户权限授予应用程序的应用程序运行时，而不是当他们安装应用程序。此方法简化了应用程序安装过程，因为用户在安装或更新应用程序时无需授予权限。它还使用户可以更好地控制应用程序的功能;

你可以阅读更多的Google Guide

为了方便编码，我建议使用：PermissionsDispatcher，虽然很容易使用，让你的代码干净多了。