Android6.0，7.0拍照和相冊異常，運行時權限

關於Android7.0調用系統相機拍照、訪問相冊的一些問題：

在Android6.0中Google提出了動態申請權限的Api,調用相機拍照，訪問SDcard等操作都需要先申請對應的權限如下：

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

Google是反對放寬私有目錄的訪問權限的，所以收起對私有文件的訪問權限是Android將來發展的趨勢。

Android7.0中嘗試傳遞 file:// URI 會觸發 FileUriExposedException，因爲在Android7.0之後Google認爲直接使用本地的根目錄即file:// URI是不安全的操作，直接訪問會拋出FileUriExposedExCeption異常，這就意味着在Android7.0以前我們訪問相機拍照存儲時，如果使用URI的方式直接存儲剪裁圖片就會造成這個異常，那麼如何解決這個問題呢？（文章結尾會附上demo的連接）

Google爲我們提供了FileProvider類，進行一種特殊的內容提供，FileProvider時ContentProvide的子類，它使用了和內容提供器類似的機制來對數據進行保護，可以選擇性地將封裝過的Uri共享給外部，從而提高了應用的安全性。下面就讓我們看一下如何使用這個內容提供者進行數據訪問的：

使用FileProvider獲取Uri就會將以前的file:// URI準換成content:// URI，實現一種安全的應用間數據訪問，內容提供者作爲Android的四大組件之一，使用同樣需要在清單文件AndroidManifest.xml中進行註冊的，註冊方法如下：

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

provider標籤裏的 android:name的值是FileProvider的包名+類名爲固定值。android:authorities的值相當於一個標誌，當我們使用FileProvider的getUriForFile方法時的一個參數需和清單文件註冊時的保持一致，這裏我使用的是:com.zz.fileprovider可自行定義。exported:要求必須爲false，爲true則會報安全異常。grantUriPermissions:true，表示授予 URI 臨時訪問權限。<meta-data />標籤裏面是用來指定共享的路徑。 android:resource="@xml/file_paths"就是我們的共享路徑配置的xml文件。關於xml文件的配置如下：

在res目錄下創建xml文件夾，file_paths.xml文件內容如下：

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <paths>
        <external-path
            name="camera_photos"
            path="" />
    </paths>
</resources>

external-path標籤用來指定Uri共享的，name屬性的值可以自定義，path屬性的值表示共享的具體位置，設置爲空，就表示共享整個SD卡，也可指定對應的SDcard下的文件目錄，根據需求自行定義。接下來就是調用系統相機進行拍照了，代碼如下：

首先獲取相機和訪問SDcard權限：

/**
 * 自動獲取相機權限
 */
private void autoObtainCameraPermission() {

    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED
            || ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
            ToastUtils.showShort(this, "您已經拒絕過一次");
        }
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE}, CAMERA_PERMISSIONS_REQUEST_CODE);
    } else {//有權限直接調用系統相機拍照
        if (hasSdcard()) {
            imageUri = Uri.fromFile(fileUri);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                imageUri = FileProvider.getUriForFile(MainActivity.this, "com.zz.fileprovider", fileUri);//通過FileProvider創建一個content類型的Uri
            PhotoUtils.takePicture(this, imageUri, CODE_CAMERA_REQUEST);
        } else {
            ToastUtils.showShort(this, "設備沒有SD卡！");
        }
    }
}

動態申請權限的回調方法：

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);

    switch (requestCode) {
        case CAMERA_PERMISSIONS_REQUEST_CODE: {//調用系統相機申請拍照權限回調
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                if (hasSdcard()) {
                    imageUri = Uri.fromFile(fileUri);
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                        imageUri = FileProvider.getUriForFile(MainActivity.this, "com.zz.fileprovider", fileUri);//通過FileProvider創建一個content類型的Uri
                    PhotoUtils.takePicture(this, imageUri, CODE_CAMERA_REQUEST);
                } else {
                    ToastUtils.showShort(this, "設備沒有SD卡！");
                }
            } else {

                ToastUtils.showShort(this, "請允許打開相機！！");
            }
            break;


        }
        case STORAGE_PERMISSIONS_REQUEST_CODE://調用系統相冊申請Sdcard權限回調
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                PhotoUtils.openPic(this, CODE_GALLERY_REQUEST);
            } else {

                ToastUtils.showShort(this, "請允許打操作SDCard！！");
            }
            break;
    }
}

*注：PhotoUtils是博主對拍照和相冊獲取照片的封裝下面會給出，PhotoUtils類和完整的MainActivity類

重點看一下imageUri的獲取，代碼中imageUri是用於存儲拍照後照片的Uri，調用相機拍照之前首先判斷一下系統版本，AndroidN也就是Android7.0以上的系統通過FileProvider獲取Uri方法的參數分別爲，上下文對象、清單文件配置的android:authorities和對應的拍照存儲的圖片。之後就是通過PhotoUtils調用系統相機進行拍照。

PhotoUtils相應代碼如下：

/**
 * @param activity    當前activity
 * @param imageUri    拍照後照片存儲路徑
 * @param requestCode 調用系統相機請求碼
 */
public static void takePicture(Activity activity, Uri imageUri, int requestCode) {
    //調用系統相機
    Intent intentCamera = new Intent();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        intentCamera.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); //添加這一句表示對目標應用臨時授權該Uri所代表的文件
    }
    intentCamera.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
    //將拍照結果保存至photo_file的Uri中，不保留在相冊中
    intentCamera.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
    activity.startActivityForResult(intentCamera, requestCode);
}

方法說明：通過Intent調用系統相機拍照，如果本機版本大於等於anroid7.0需要臨時授權Uri的訪問權限如下：

intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
其他部分和以前正常調用系統相機一樣。
接下來就是對拍完的照片進行剪裁：

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

    if (resultCode == RESULT_OK) {
        switch (requestCode) {
            case CODE_CAMERA_REQUEST://拍照完成回調
                cropImageUri = Uri.fromFile(fileCropUri);
                PhotoUtils.cropImageUri(this, imageUri, cropImageUri, 1, 1, output_X, output_Y, CODE_RESULT_REQUEST);
                break;
            case CODE_GALLERY_REQUEST://訪問相冊完成回調
                if (hasSdcard()) {
                    cropImageUri = Uri.fromFile(fileCropUri);
                    Uri newUri = Uri.parse(PhotoUtils.getPath(this, data.getData()));
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                        newUri = FileProvider.getUriForFile(this, "com.zz.fileprovider", new File(newUri.getPath()));
                    PhotoUtils.cropImageUri(this, newUri, cropImageUri, 1, 1, output_X, output_Y, CODE_RESULT_REQUEST);
                } else {
                    ToastUtils.showShort(this, "設備沒有SD卡！");
                }
                break;
            case CODE_RESULT_REQUEST:
                Bitmap bitmap = PhotoUtils.getBitmapFromUri(cropImageUri, this);
                if (bitmap != null) {
                    showImages(bitmap);
                }
                break;
        }
    }
}
剪裁代碼如下：
/**
 * @param activity    當前activity
 * @param orgUri      剪裁原圖的Uri
 * @param desUri      剪裁後的圖片的Uri
 * @param aspectX     X方向的比例
 * @param aspectY     Y方向的比例
 * @param width       剪裁圖片的寬度
 * @param height      剪裁圖片高度
 * @param requestCode 剪裁圖片的請求碼
 */
public static void cropImageUri(Activity activity, Uri orgUri, Uri desUri, int aspectX, int aspectY, int width, int height, int requestCode) {
    Intent intent = new Intent("com.android.camera.action.CROP");
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
    }
    intent.setDataAndType(orgUri, "image/*");
    intent.putExtra("crop", "true");
    intent.putExtra("aspectX", aspectX);
    intent.putExtra("aspectY", aspectY);
    intent.putExtra("outputX", width);
    intent.putExtra("outputY", height);
    intent.putExtra("scale", true);
    //將剪切的圖片保存到目標Uri中
    intent.putExtra(MediaStore.EXTRA_OUTPUT, desUri);
    intent.putExtra("return-data", false);
    intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
    intent.putExtra("noFaceDetection", true);
    activity.startActivityForResult(intent, requestCode);
}
和以前正常剪裁代碼基本相同，和上面意圖打開相機一樣，如果本機版本大於等於anroid7.0需要臨時授權Uri的訪問權限如下：
intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
到此整體調用系統相機拍照、剪裁完成，剪裁後照片存儲到cropImageUri對應路徑。
訪問相冊代碼如下：
/**
 * @param activity    當前activity
 * @param requestCode 打開相冊的請求碼
 */
public static void openPic(Activity activity, int requestCode) {
    Intent photoPickerIntent = new Intent(Intent.ACTION_GET_CONTENT);
    photoPickerIntent.setType("image/*");
    activity.startActivityForResult(photoPickerIntent, requestCode);
}
上文中已貼出訪問相冊後的onActivityResult的回調，主要也是一樣的操作解析Uri調用剪裁圖片：
 if (hasSdcard()) {
                    cropImageUri = Uri.fromFile(fileCropUri);
                    Uri newUri = Uri.parse(PhotoUtils.getPath(this, data.getData()));
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                        newUri = FileProvider.getUriForFile(this, "com.zz.fileprovider", new File(newUri.getPath()));
                    PhotoUtils.cropImageUri(this, newUri, cropImageUri, 1, 1, output_X, output_Y, CODE_RESULT_REQUEST);
                } else {
                    ToastUtils.showShort(this, "設備沒有SD卡！");
                }
                break;
*注：Android4.4之後選取中的圖片不再返回真實的Uri了，而是封裝過的Uri,所以在4.4以上，就要對這個Uri進行解析，即上面的PhotoUtils.getPath()方法，
具體Uri的解析見PhotoUtils類。android4.4以前直接data.getData就可以獲取到真是Uri不用解析。

解析獲取真實的Uri後，判斷系統版本開始通過FileProvider獲取新的Uri之後就可以同樣的圖片剪裁了。 
MainActivity代碼如下：
package choicemmed.com.android60permissionsdemo;

import android.Manifest;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.media.ExifInterface;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.support.annotation.NonNull;
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.util.Log;
import android.view.View;
import android.widget.Button;

import com.google.android.gms.common.api.GoogleApiClient;
import com.lidroid.xutils.ViewUtils;
import com.lidroid.xutils.view.annotation.ViewInject;
import com.lidroid.xutils.view.annotation.event.OnClick;

import java.io.File;

import de.hdodenhof.circleimageview.CircleImageView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    private static final String TAG = "MainActivity";
    @ViewInject(R.id.photo)
    private CircleImageView photo;
    @ViewInject(R.id.takePic)
    private Button takePic;
    @ViewInject(R.id.takeGallery)
    private Button takeGallery;
    @ViewInject(R.id.test)
    private Button test;
    private static final int CODE_GALLERY_REQUEST = 0xa0;
    private static final int CODE_CAMERA_REQUEST = 0xa1;
    private static final int CODE_RESULT_REQUEST = 0xa2;
    private static final int CAMERA_PERMISSIONS_REQUEST_CODE = 0x03;
    private static final int STORAGE_PERMISSIONS_REQUEST_CODE = 0x04;
    private File fileUri = new File(Environment.getExternalStorageDirectory().getPath() + "/photo.jpg");
    private File fileCropUri = new File(Environment.getExternalStorageDirectory().getPath() + "/crop_photo.jpg");
    private Uri imageUri;
    private Uri cropImageUri;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ViewUtils.inject(this);
    }
    

    @OnClick({R.id.takePic, R.id.takeGallery})
    @Override
    public void onClick(View v) {
        switch (v.getId()) {
            case R.id.takePic:
                autoObtainCameraPermission();
                break;
            case R.id.takeGallery:
                autoObtainStoragePermission();
                break;
        }
    }

    /**
     * 自動獲取相機權限
     */
    private void autoObtainCameraPermission() {

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED
                || ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {

            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
                ToastUtils.showShort(this, "您已經拒絕過一次");
            }
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA, Manifest.permission.READ_EXTERNAL_STORAGE}, CAMERA_PERMISSIONS_REQUEST_CODE);
        } else {//有權限直接調用系統相機拍照
            if (hasSdcard()) {
                imageUri = Uri.fromFile(fileUri);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                    imageUri = FileProvider.getUriForFile(MainActivity.this, "com.zz.fileprovider", fileUri);//通過FileProvider創建一個content類型的Uri
                PhotoUtils.takePicture(this, imageUri, CODE_CAMERA_REQUEST);
            } else {
                ToastUtils.showShort(this, "設備沒有SD卡！");
            }
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        switch (requestCode) {
            case CAMERA_PERMISSIONS_REQUEST_CODE: {//調用系統相機申請拍照權限回調
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    if (hasSdcard()) {
                        imageUri = Uri.fromFile(fileUri);
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                            imageUri = FileProvider.getUriForFile(MainActivity.this, "com.zz.fileprovider", fileUri);//通過FileProvider創建一個content類型的Uri
                        PhotoUtils.takePicture(this, imageUri, CODE_CAMERA_REQUEST);
                    } else {
                        ToastUtils.showShort(this, "設備沒有SD卡！");
                    }
                } else {

                    ToastUtils.showShort(this, "請允許打開相機！！");
                }
                break;


            }
            case STORAGE_PERMISSIONS_REQUEST_CODE://調用系統相冊申請Sdcard權限回調
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    PhotoUtils.openPic(this, CODE_GALLERY_REQUEST);
                } else {

                    ToastUtils.showShort(this, "請允許打操作SDCard！！");
                }
                break;
        }
    }

    private int output_X = 480;
    private int output_Y = 480;

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

        if (resultCode == RESULT_OK) {
            switch (requestCode) {
                case CODE_CAMERA_REQUEST://拍照完成回調
                    cropImageUri = Uri.fromFile(fileCropUri);
                    PhotoUtils.cropImageUri(this, imageUri, cropImageUri, 1, 1, output_X, output_Y, CODE_RESULT_REQUEST);
                    break;
                case CODE_GALLERY_REQUEST://訪問相冊完成回調
                    if (hasSdcard()) {
                        cropImageUri = Uri.fromFile(fileCropUri);
                        Uri newUri = Uri.parse(PhotoUtils.getPath(this, data.getData()));
                        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N)
                            newUri = FileProvider.getUriForFile(this, "com.zz.fileprovider", new File(newUri.getPath()));
                        PhotoUtils.cropImageUri(this, newUri, cropImageUri, 1, 1, output_X, output_Y, CODE_RESULT_REQUEST);
                    } else {
                        ToastUtils.showShort(this, "設備沒有SD卡！");
                    }
                    break;
                case CODE_RESULT_REQUEST:
                    Bitmap bitmap = PhotoUtils.getBitmapFromUri(cropImageUri, this);
                    if (bitmap != null) {
                        showImages(bitmap);
                    }
                    break;
            }
        }
    }


    /**
     * 自動獲取sdk權限
     */

    private void autoObtainStoragePermission() {
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, STORAGE_PERMISSIONS_REQUEST_CODE);
        } else {
            PhotoUtils.openPic(this, CODE_GALLERY_REQUEST);
        }

    }

    private void showImages(Bitmap bitmap) {
        photo.setImageBitmap(bitmap);
    }

    /**
     * 檢查設備是否存在SDCard的工具方法
     */
    public static boolean hasSdcard() {
        String state = Environment.getExternalStorageState();
        return state.equals(Environment.MEDIA_MOUNTED);
    }


}
PhotoUtils代碼如下：
package choicemmed.com.android60permissionsdemo;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.ContentUris;
import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;

/**
 * Created by:zheng zhong on 2016/8/6 16:16
 * Email [email protected]
 */
public class PhotoUtils {
    private static final String TAG = "PhotoUtils";

    /**
     * @param activity    當前activity
     * @param imageUri    拍照後照片存儲路徑
     * @param requestCode 調用系統相機請求碼
     */
    public static void takePicture(Activity activity, Uri imageUri, int requestCode) {
        //調用系統相機
        Intent intentCamera = new Intent();
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            intentCamera.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION); //添加這一句表示對目標應用臨時授權該Uri所代表的文件
        }
        intentCamera.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
        //將拍照結果保存至photo_file的Uri中，不保留在相冊中
        intentCamera.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        activity.startActivityForResult(intentCamera, requestCode);
    }

    /**
     * @param activity    當前activity
     * @param requestCode 打開相冊的請求碼
     */
    public static void openPic(Activity activity, int requestCode) {
        Intent photoPickerIntent = new Intent(Intent.ACTION_GET_CONTENT);
        photoPickerIntent.setType("image/*");
        activity.startActivityForResult(photoPickerIntent, requestCode);
    }

    /**
     * @param activity    當前activity
     * @param orgUri      剪裁原圖的Uri
     * @param desUri      剪裁後的圖片的Uri
     * @param aspectX     X方向的比例
     * @param aspectY     Y方向的比例
     * @param width       剪裁圖片的寬度
     * @param height      剪裁圖片高度
     * @param requestCode 剪裁圖片的請求碼
     */
    public static void cropImageUri(Activity activity, Uri orgUri, Uri desUri, int aspectX, int aspectY, int width, int height, int requestCode) {
        Intent intent = new Intent("com.android.camera.action.CROP");
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        }
        intent.setDataAndType(orgUri, "image/*");
        intent.putExtra("crop", "true");
        intent.putExtra("aspectX", aspectX);
        intent.putExtra("aspectY", aspectY);
        intent.putExtra("outputX", width);
        intent.putExtra("outputY", height);
        intent.putExtra("scale", true);
        //將剪切的圖片保存到目標Uri中
        intent.putExtra(MediaStore.EXTRA_OUTPUT, desUri);
        intent.putExtra("return-data", false);
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());
        intent.putExtra("noFaceDetection", true);
        activity.startActivityForResult(intent, requestCode);
    }

    /**
     * 讀取uri所在的圖片
     *
     * @param uri      圖片對應的Uri
     * @param mContext 上下文對象
     * @return 獲取圖像的Bitmap
     */
    public static Bitmap getBitmapFromUri(Uri uri, Context mContext) {
        try {
            Bitmap bitmap = MediaStore.Images.Media.getBitmap(mContext.getContentResolver(), uri);
            return bitmap;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * @param context 上下文對象
     * @param uri     當前相冊照片的Uri
     * @return 解析後的Uri對應的String
     */
    @SuppressLint("NewApi")
    public static String getPath(final Context context, final Uri uri) {

        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
        String pathHead = "file:///";
        // DocumentProvider
        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
            // ExternalStorageProvider
            if (isExternalStorageDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];
                if ("primary".equalsIgnoreCase(type)) {
                    return pathHead + Environment.getExternalStorageDirectory() + "/" + split[1];
                }
            }
            // DownloadsProvider
            else if (isDownloadsDocument(uri)) {

                final String id = DocumentsContract.getDocumentId(uri);

                final Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));

                return pathHead + getDataColumn(context, contentUri, null, null);
            }
            // MediaProvider
            else if (isMediaDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];

                Uri contentUri = null;
                if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
                } else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
                } else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                }

                final String selection = "_id=?";
                final String[] selectionArgs = new String[]{split[1]};

                return pathHead + getDataColumn(context, contentUri, selection, selectionArgs);
            }
        }
        // MediaStore (and general)
        else if ("content".equalsIgnoreCase(uri.getScheme())) {
            return pathHead + getDataColumn(context, uri, null, null);
        }
        // File
        else if ("file".equalsIgnoreCase(uri.getScheme())) {
            return pathHead + uri.getPath();
        }
        return null;
    }

    /**
     * Get the value of the data column for this Uri. This is useful for
     * MediaStore Uris, and other file-based ContentProviders.
     *
     * @param context       The context.
     * @param uri           The Uri to query.
     * @param selection     (Optional) Filter used in the query.
     * @param selectionArgs (Optional) Selection arguments used in the query.
     * @return The value of the _data column, which is typically a file path.
     */
    private static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) {

        Cursor cursor = null;
        final String column = "_data";
        final String[] projection = {column};
        try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null);
            if (cursor != null && cursor.moveToFirst()) {
                final int column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }

    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    private static boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri.getAuthority());
    }

    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is DownloadsProvider.
     */
    private static boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
    }

    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is MediaProvider.
     */
    private static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }

}

最後附上demo的GitHub地址：點擊打開鏈接

關於Android7.0調用系統相機拍照、訪問系統相冊的問題大概就是這樣、如有其它的問題歡迎大家留言、指正Ｏ(≧口≦)Ｏ