尝试使用 FileProvider(Android) 获取 URI 时出现 NullPointerException [英] NullPointerException when trying to get URI with FileProvider(Android)

问题描述

我想在点击按钮后拍照.但是我在尝试使用 FileProvider 获取 URI 时得到 NullPointerException.

i want to take a Photo after clicking on a button. But i am getting NullPointerException when trying to get URI with FileProvider.

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)

问题线似乎是:

mUri = FileProvider.getUriForFile(getApplication().getApplicationContext(),
            "ibas.provider", file);

这是我的代码:

Here´s my Code:

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);

    }

}

我的清单:

<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>

res/xml 中的提供者

    <paths xmlns:android="http://schemas.android.com/apk/res/android">
<external-path name="external_files" path="."/> </paths>

知道问题出在哪里吗?

推荐答案

提供者标记在清单文件中的应用程序标记之外.

The provider tag is outside of the application tag in the manifest file .

您应该将它添加到 标签中

You should add it inside the <application></application> tag

 <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>

这篇关于尝试使用 FileProvider(Android) 获取 URI 时出现 NullPointerException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！