API上的XML相机意图上的空对象=> 24 [重复]
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【中文标题】API上的XML相机意图上的空对象=> 24 [重复]【英文标题】：Null Object on XML Camera Intent on API =>24 [duplicate] 【发布时间】：2018-02-24 15:40:17 【问题描述】：我试图让相机意图在更高的 API 上工作，但当我尝试时它崩溃了。我认为某些路径有问题，但我不知道是什么。它在 API 23 上运行良好。
FATAL EXCEPTION: main
Process: ur.mi.android.wgplus05, PID: 22088
java.lang.NullPointerException: Attempt to invoke virtual method 'android.content.res.XmlResourceParser android.content.pm.PackageItemInfo.loadXmlMetaData(android.content.pm.PackageManager, java.lang.String)' on a null object reference
at android.support.v4.content.FileProvider.parsePathStrategy(FileProvider.java:583)
at android.support.v4.content.FileProvider.getPathStrategy(FileProvider.java:557)
at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:399)
at ur.mi.android.wgplus05.Camera.takePicture(Camera.java:50)
at ur.mi.android.wgplus05.PictureActivity.takePicture(PictureActivity.java:148)
at ur.mi.android.wgplus05.PictureActivity.checkPermission(PictureActivity.java:140)
at ur.mi.android.wgplus05.PictureActivity.onOptionsItemSelected(PictureActivity.java:101)
at android.app.Activity.onMenuItemSelected(Activity.java:3204)
at android.support.v4.app.FragmentActivity.onMenuItemSelected(FragmentActivity.java:408)
at android.support.v7.app.AppCompatActivity.onMenuItemSelected(AppCompatActivity.java:195)
at android.support.v7.view.WindowCallbackWrapper.onMenuItemSelected(WindowCallbackWrapper.java:113)
at android.support.v7.app.AppCompatDelegateImplV9.onMenuItemSelected(AppCompatDelegateImplV9.java:679)
at android.support.v7.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:822)
at android.support.v7.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:156)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:969)
at android.support.v7.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:959)
at android.support.v7.widget.ActionMenuView.invokeItem(ActionMenuView.java:623)
at android.support.v7.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:154)
at android.view.View.performClick(View.java:5610)
at android.view.View$PerformClick.run(View.java:22260)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6077)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:865)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:755)
第 50 行：
Uri photoURI = FileProvider.getUriForFile(activityContext,
BuildConfig.APPLICATION_ID + ".genericfileprovider",
photoFile);
public class Camera
PictureActivity activityContext;
private String currentPhotoPath;
public Camera(PictureActivity activityContext)
this.activityContext = activityContext;
public void takePicture(int requestCode)
Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// Ensure that there's a camera activity to handle the intent
if (takePictureIntent.resolveActivity(activityContext.getPackageManager()) != null)
// Create the File where the photo should go
File photoFile = null;
try
photoFile = createImageFile();
catch (IOException ex)
// Error occurred while creating the File
return;
// Continue only if the File was successfully created
if (photoFile != null)
if(Build.VERSION.SDK_INT < 24)
Uri photoURI = Uri.fromFile(photoFile);
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
activityContext.startActivityForResult(takePictureIntent, requestCode);
else
Uri photoURI = FileProvider.getUriForFile(activityContext,
BuildConfig.APPLICATION_ID + ".genericfileprovider",
photoFile);
takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
activityContext.startActivityForResult(takePictureIntent, requestCode);
public String getCurrentPhotoPath()
return currentPhotoPath;
public Bitmap getScaledBitmap(String path, Point targetSize)
BitmapFactory.Options bmOptions = new BitmapFactory.Options();
bmOptions.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, bmOptions);
int photoW = bmOptions.outWidth;
int photoH = bmOptions.outHeight;
int scaleFactor = Math.min(photoW / targetSize.x, photoH / targetSize.y);
bmOptions.inJustDecodeBounds = false;
bmOptions.inSampleSize = scaleFactor;
bmOptions.inPurgeable = true;
Bitmap bitmap = BitmapFactory.decodeFile(path, bmOptions);
return bitmap;
private File createImageFile() throws IOException
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.ENGLISH).format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
File storageDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File image = File.createTempFile(imageFileName, ".jpg", storageDir);
currentPhotoPath = image.getAbsolutePath();
return image;
清单：
<?xml version="1.0" encoding="utf-8"?>
<uses-feature android:name="android.hardware.camera"
android:required="true"/>
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.hardware.camera.autofocus" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_icon_hdx"
android:label="@string/app_name"
android:roundIcon="@drawable/ic_icon_hdx"
android:supportsRtl="true"
android:theme="@style/Theme.AppCompat.Light.DarkActionBar">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name=".Finanzen" />
<activity android:name=".Einkaufsliste" />
<activity android:name=".Einkaufsliste2" />
<activity android:name=".toDoList" />
<activity android:name=".Settings" />
<activity android:name=".PictureActivity" />
<activity
android:name=".Putzplan"
android:windowSoftInputMode="adjustResize" />
<activity android:name=".Kalender" />
<provider
android:name=".GenericFileProvider"
android:authorities="$applicationId.ur.mi.android.wgplus05.genericfileprovider"
android:exported="false"
android:grantUriPermissions="true">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="@xml/provider_paths"/>
</provider>
</application>
</manifest>
那是路径
<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/>
</paths>
【问题讨论】：
我认为它的权限问题使用运行时权限 【参考方案1】：android:authorities="$applicationId.ur.mi.android.wgplus05.genericfileprovider"
BuildConfig.APPLICATION_ID + ".genericfileprovider"
这些不匹配。他们需要匹配。否则，FileProvider 找不到ContentProvider，因为您向getUriForFile() 提供了无效的权限名称。
因此，例如，您可以将第一行更改为：
android:authorities="$applicationId.genericfileprovider"
然后，这两个值将匹配（应用程序 ID 加上 .genericfileprovider）。
【讨论】：
好吧，如果我这样做：android:authorities="$applicationId.genericfileprovider" 它应该可以工作吗？ @boom3x：至少它应该能让你克服这个错误。您还有其他问题（android.hardware.camera.autofocus 不是权限，如果配置更改或当相机应用程序处于前台时您的进程被终止，您不会保留currentPhotoPath）。 This sample app 演示如何将ACTION_IMAGE_CAPTURE 与FileProvider 一起使用。【参考方案2】：
getUriForFile 中的第二个参数应与 xml 中的 authorities 属性匹配。
BuildConfig.APPLICATION_ID + ".ur.mi.android.wgplus05.genericfileprovider"
【讨论】：
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