尝试使用FileProvider（Android）获取URI时出现NullPointerException

我想在点击按钮后拍照。但是当我试图用

FileProvider

获取

URI

时，我得到了

NullPointerException

这是我的错误代码：

Caused by: 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 ibas.orosol.BildActivity.takePicture(BildActivity.java:86)
    at java.lang.reflect.Method.invoke(Native Method) 
    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
    at android.view.View.performClick(View.java:5637) 
    at android.view.View$PerformClick.run(View.java:22429) 
    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:6119) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

问题似乎是：

Caused by: 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 ibas.orosol.BildActivity.takePicture(BildActivity.java:86)
    at java.lang.reflect.Method.invoke(Native Method) 
    at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288) 
    at android.view.View.performClick(View.java:5637) 
    at android.view.View$PerformClick.run(View.java:22429) 
    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:6119) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

这是我的代码：

public void takePicture(View view) throws IOException {

    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    try{
        File file =  createImageFile();

        mUri = FileProvider.getUriForFile(getApplication().getApplicationContext(),
                "ibas.provider", file);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, mUri);
        startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
    } catch (IOException e){
        e.printStackTrace();
    }

}


private File createImageFile() throws IOException {

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String imageFileName = "JPEG_" + timeStamp + "_";
    File storageDir = getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM);
    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;
}

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

    String path = "sdcard/orosol/captured_image.jpg";
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == Activity.RESULT_OK) {
        Log.i("uri-data", "Uri: " + mUri.toString());


        mBitmap = getBitmapFromUri(mImageView,BildActivity.this,mUri);


        mImageView.setImageBitmap(mBitmap);
        mImageView.setScaleType(ImageView.ScaleType.CENTER_CROP);

    }

}

我的舱单：

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="ibas.orosol">

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

<uses-feature
    android:name="android.hardware.camera"
    android:required="false" />

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="ibas.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths" />
</provider>

<!--
     The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
     Google Maps Android API v2, but you must specify either coarse or fine
     location permissions for the 'MyLocation' functionality. 
-->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.AppCompat.NoActionBar">
    <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=".MenuActivity" />
    <activity
        android:name=".HeizoelActivity"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MenuActivity" />
    </activity>
    <activity
        android:name=".BildActivity"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MenuActivity" />
        >
    </activity>
    <activity
        android:name=".FacebookActivity"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MenuActivity" />
    </activity>
    <!--
         The API key for Google Maps-based APIs is defined as a string resource.
         (See the file "res/values/google_maps_api.xml").
         Note that the API key is linked to the encryption key used to sign the APK.
         You need a different API key for each encryption key, including the release key that is used to
         sign the APK for publishing.
         You can define the keys for the debug and release targets in src/debug/ and src/release/. 
    -->
    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="@string/google_maps_key" />

    <activity
        android:name=".KontakteActivity"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MenuActivity" />
    </activity>
    <activity android:name=".UeberUnsActivity"
        android:theme="@style/AppTheme">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".MenuActivity" />
    </activity>
</application>

>

以res/xml格式提供程序

---

知道问题发生在哪里吗？

提供者标记在清单文件中的应用程序标记之外

您应该将其添加到

标记中

 <provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="ibas.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths" />
</provider>

您是否在res/xml文件夹中添加了xml文件？是的，我添加了。仍然是相同的问题。发布…。发布您的完整清单它将是helpfulgetApplication（）。getApplicationContext（）==null？或文件==null？使用前检查。我已经在res下创建了xml文件夹，并添加了provider_paths.xml文件。然后我在应用程序中包含了provide，但“@xml/provider_path”上显示了错误。您是赢家，谢谢。Android上的示例显示了点点滴滴，缺少完整的代码，除非你进入示例代码，否则你无法发现这些问题。你是我的救星，先生！我已经这样做了，但我仍然得到错误。@卫斯理·弗兰克斯检查您传递给getUriForFile的权限是否与清单中声明的权限相同；如果不同，您也会得到相同的错误

 <provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="ibas.provider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths" />
</provider>