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RxPermissions 源码解析

简介

RxPermissions 是基于 RxJava 开发的用于帮助在Android 6.0 中处理运行时权限检测的框架。在 Android 6.0 中增加了对危险权限的动态申请，而不是像 Android 6.0 之前的默认全部获取的方式。

原始动态权限的获取

如果按照以往的获取权限方式的话，那么我们获取权限一般需要有 3 个步骤，第一步是先判断当前是否已经获取到该权限了；第 2 步申请对应的权限；第 3 步在 Activity 或者 Fragment 中处理获取权限的结果。具体的实现步骤如下：

step 1：判断权限是否已经获取。

if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.CAMERA)) {
            //用于开发者提示用户权限的用途
        } else {
            //申请权限
        }

step 2:申请权限

ActivityCompat.requestPermissions(MainActivity.this,
                                    new String[]{Manifest.permission.CAMERA},
                                    REQUEST_CAMERA);

step 3:结果处理

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
        @NonNull int[] grantResults) {
    // 判断请求码，确定当前申请的权限
    if (requestCode == REQUEST_CAMERA) {
        //判断权限是否申请通过
        if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            //授权成功
        } else {
               //授权失败
        }
    } else {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

RxPermissions 的简单使用

其实 RxPermissions 的使用方式有两种

方式 1：

RxPermissions rxPermissions = new RxPermissions(MainActivity.this);
        rxPermissions
                .request(Manifest.permission.READ_EXTERNAL_STORAGE,
                        Manifest.permission.WRITE_EXTERNAL_STORAGE)//这里填写所需要的权限
                .subscribe(new Consumer<Boolean>() {
                    @Override
                    public void accept(Boolean aBoolean) throws Exception {
                        if (aBoolean) {
                            // 通过
                        }else{
                            // 拒绝
                        }
                    }
                });

方式 2：结合 RxBinding 来使用

RxPermissions rxPermissions = new RxPermissions(MainActivity.this);
// Must be done during an initialization phase like onCreate
RxView.clicks(findViewById(R.id.enableCamera))
    .compose(rxPermissions.ensure(Manifest.permission.CAMERA))
    .subscribe(granted -> {
        // R.id.enableCamera has been clicked
    });

源码分析

整体介绍

接着我们来对这个 RxPermissions 进行一个源码的解析，但是打开源码的时候，我们可以发现，这个库里面，其实就只有 3 个类：RxPermissions、RxPermissionsFragment、Permission

RxPermissions
- 最主要的实现类，利用 rxjava，为我们提供了方便权限申请的类
RxPermissionsFragment
- 是一个 fragment，主要的动态权限获取类
Permission
- 定义的权限的 model 类

源码分析

RxPermissions 实例创建

对于源码的分析，我们应该先从简单的使用入手。下面我们可以先看看实例化 RxPermissionsFragment 的时候是做了什么？

    RxPermissionsFragment mRxPermissionsFragment;

    public RxPermissions(@NonNull Activity activity) {
        mRxPermissionsFragment = getRxPermissionsFragment(activity);
    }

我们可以看到，上面的代码中，实例化 RxPermissionsFragment 的时候，里面先创建了一个 RxPermissionsFragment 的实例。我们再接着看 getRxPermissionsFragment 这个方法的实现。

    private RxPermissionsFragment getRxPermissionsFragment(Activity activity) {
        //  查找 RxPermissionsFragment 是否已经被添加了
        RxPermissionsFragment rxPermissionsFragment = findRxPermissionsFragment(activity);
        boolean isNewInstance = rxPermissionsFragment == null;
        if (isNewInstance) {
            rxPermissionsFragment = new RxPermissionsFragment();
            FragmentManager fragmentManager = activity.getFragmentManager();
            fragmentManager
                    .beginTransaction()
                    .add(rxPermissionsFragment, TAG)
                    .commitAllowingStateLoss();
            fragmentManager.executePendingTransactions();
        }
        return rxPermissionsFragment;
    }

在 getRxPermissionsFragment() 这个方法中，首先是先查找当前是否已经添加了这个 rxPermissionsFragment 的实例，如果已经添加，那么直接返回已经添加的实例，如果没有添加过的话，那么就重新再创建一个 RxPermissionsFragment 实例并提交；

    private RxPermissionsFragment findRxPermissionsFragment(Activity activity) {
        return (RxPermissionsFragment) activity.getFragmentManager().findFragmentByTag(TAG);
    }

到此，rxPermissionsFragment 的实例化已经完成，接着我们需要看看 request 这个方法中实现了什么。

request 方法

    public Observable<Boolean> request(final String... permissions) {
        return Observable.just(TRIGGER).compose(ensure(permissions));
    }

    static final Object TRIGGER = new Object();

从上面的代码中，我们可以看到，request 方法中需要传入的参数是一个权限的数组，返回值是 Observable 对象。Observable.just(TRIGGER) 是快捷创建一个 Observable 的方式，由于 TRIGGER 是一个空的 Object 对象，所以 TRIGGER 就是一个占位符而已，Observable.just(TRIGGER) 创建的是一个 Observable,之后通过 compose 将 Observable 转化为 Observable 并返回。在 compose 中需要的参数是一个 ObservableTransformer，那么我们接着看 ensure() 这个方法。

ensure(permissions);

public <T> ObservableTransformer<T, Boolean> ensure(final String... permissions) {
        // 创建一个Transformer对象返回
        return new ObservableTransformer<T, Boolean>() {
            @Override
            public ObservableSource<Boolean> apply(Observable<T> o) {
                //request(o, permissions) 方法返回 Observable<Permission> 对象
                return request(o, permissions)
                        // 将 Observable<Permission> 转换为 Observable<Boolean>，在这里会等待所有的权限都返回了一次性发射数据。
                        .buffer(permissions.length)
                        .flatMap(new Function<List<Permission>, ObservableSource<Boolean>>() {
                            @Override
                            public ObservableSource<Boolean> apply(List<Permission> permissions) throws Exception {
                                // 如果permissions为空那么直接返回Observable.empty();
                                if (permissions.isEmpty()) {
                                    // Occurs during orientation change, when the subject receives onComplete.
                                    // In that case we don't want to propagate that empty list to the
                                    // subscriber, only the onComplete.
                                    return Observable.empty();
                                }
                                // Return true if all permissions are granted.
                                for (Permission p : permissions) {
                                    if (!p.granted) {
                                        return Observable.just(false);
                                    }
                                }
                                return Observable.just(true);
                            }
                        });
            }
        };
    }

在 ensure 的这个方法中，最终会返回的是 ObservableTransformer<T, Boolean> 对象。接着我们看看 ObservableTransformer 的匿名实现类里面的 apply 方法，这里实现的就是将 Observable 转换为 Observable 的操作。我们对 apply 这个方法里面的代码进行简化一下。

return request(o,permissions)
    .buffer(permissions.length)
    .flatMap(new Function<List<Permission>, ObservableSource<Boolean>>{});

request() 方法返回 Observable 对象
buffer(len) 操作符将一个 Observable 变换为 Observable<List>，原来的 Observable 正常发射数据，变换产生的 Observable 发射这些数据的缓存集合。buffer 将数据缓存到一个集合当中，然后在适当(比如：所有请求的权限结果都返回了）的时机一起发送。
flatMap() 方法将 Observable<List> 转化为 Observable

request(o, permissions);

    private Observable<Permission> request(final Observable<?> trigger, final String... permissions) {
        if (permissions == null || permissions.length == 0) {
            throw new IllegalArgumentException("RxPermissions.request/requestEach requires at least one input permission");
        }
        return oneOf(trigger, pending(permissions))
                .flatMap(new Function<Object, Observable<Permission>>() {
                    @Override
                    public Observable<Permission> apply(Object o) throws Exception {
                        return requestImplementation(permissions);
                    }
                });
    }

在 request 这个方法里面，其实 oneOf() 和 pending() 方法我们可以忽略的，主要的话，我们应该关注 requestImplementation(final String... permissions) 这个方法，在这个方法里面，主要实现了权限的请求。

requestImplementation


    @TargetApi(Build.VERSION_CODES.M)
    private Observable<Permission> requestImplementation(final String... permissions) {
        List<Observable<Permission>> list = new ArrayList<>(permissions.length);
        List<String> unrequestedPermissions = new ArrayList<>();

        // In case of multiple permissions, we create an Observable for each of them.
        // At the end, the observables are combined to have a unique response.
        for (String permission : permissions) {
            mRxPermissionsFragment.log("Requesting permission " + permission);
            if (isGranted(permission)) {
                // Already granted, or not Android M
                // Return a granted Permission object.
                // 权限已经被同意或者不是 Android 6.0 以上版本，创建一个 同意的 Permission 对象。
                list.add(Observable.just(new Permission(permission, true, false)));
                continue;
            }

            if (isRevoked(permission)) {
                // 权限被拒绝，返回一个 拒绝的 Permission 对象。
                list.add(Observable.just(new Permission(permission, false, false)));
                continue;
            }

            PublishSubject<Permission> subject = mRxPermissionsFragment.getSubjectByPermission(permission);
            // 如果 subject 不存在，那么创建一个 subject。
            if (subject == null) {
                unrequestedPermissions.add(permission);
                subject = PublishSubject.create();
                mRxPermissionsFragment.setSubjectForPermission(permission, subject);
            }

            list.add(subject);
        }
        
        // 还未提起申请的权限进行申请
        if (!unrequestedPermissions.isEmpty()) {
            String[] unrequestedPermissionsArray = unrequestedPermissions.toArray(new String[unrequestedPermissions.size()]);
            requestPermissionsFromFragment(unrequestedPermissionsArray);
        }
        
        // 严格按照顺序发射数据
        return Observable.concat(Observable.fromIterable(list));
    }

onRequestPermissionsResult()


    @TargetApi(Build.VERSION_CODES.M)
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        if (requestCode != PERMISSIONS_REQUEST_CODE) return;

        boolean[] shouldShowRequestPermissionRationale = new boolean[permissions.length];

        for (int i = 0; i < permissions.length; i++) {
            shouldShowRequestPermissionRationale[i] = shouldShowRequestPermissionRationale(permissions[i]);
        }

        onRequestPermissionsResult(permissions, grantResults, shouldShowRequestPermissionRationale);
    }

    void onRequestPermissionsResult(String permissions[], int[] grantResults, boolean[] shouldShowRequestPermissionRationale) {
        for (int i = 0, size = permissions.length; i < size; i++) {
            log("onRequestPermissionsResult  " + permissions[i]);
            // Find the corresponding subject
            PublishSubject<Permission> subject = mSubjects.get(permissions[i]);
            if (subject == null) {
                // No subject found
                Log.e(RxPermissions.TAG, "RxPermissions.onRequestPermissionsResult invoked but didn't find the corresponding permission request.");
                return;
            }
            // 发射权限申请结果
            mSubjects.remove(permissions[i]);
            boolean granted = grantResults[i] == PackageManager.PERMISSION_GRANTED;
            subject.onNext(new Permission(permissions[i], granted, shouldShowRequestPermissionRationale[i]));
            subject.onComplete();
        }
    }

RxJava 操作符

Observable.just()

just 操作符是将一个对象转化为 Observable 的操作符。这个对象可以是一个数字、字符串或者是数组对象等，是 RxJava 中快速创建一个 Observable 对象的操作符。如果有 subscriber 订阅的话，那么会依次调用 onNext() 和 OnComplete() 方法。所以这里只是创建了一个 Observable 对象，方便后续的调用。

compose(Transformer)操作符

compose 操作符是对 Observable 对象的整体转化。例如：通过 Transformer，我们可以将 Observable 对象转换成 Observable 对象了。

    public static ObservableTransformer<String,Boolean> getTransformer(){
        return new ObservableTransformer<String, Boolean>() {
            @Override
            public ObservableSource<Boolean> apply(Observable<String> upstream) {
                return upstream.flatMap(new Function<String, ObservableSource<Boolean>>() {
                    @Override
                    public ObservableSource<Boolean> apply(String s) throws Exception {
                        return Observable.just(true);
                    }
                });
            }
        };
    }


    /**
     * 线程切换
     * @return
     */
    public static <T> ObservableTransformer<T,T> getScheduler(){
        return new ObservableTransformer<T, T>() {
            @Override
            public ObservableSource<T> apply(Observable<T> upstream) {
                return upstream.subscribeOn(Schedulers.io())
                        .observeOn(AndroidSchedulers.mainThread());
            }
        };
    }

buffer 操作符

buffer 操作符将一个 Observable 变换为另一个，原来的 Observable 正常发射数据，变换产生的 Observable 发射这些数据的缓存集合。buffer将数据缓存到一个集合当中，然后在适当的时机一起发送。 buffer(count) 以列表(List)的形式发射非重叠的缓存，每一个缓存至多包含来自原始Observable的count项数据（最后发射的列表数据可能少于count项）

例如：缓存 2 个数据之后，再发送数据（调用 buffer(count) 函数）

                Observable.just(1,2,3,4,5,6)
                        .buffer(2)
                        .subscribe(integers -> {
                            Log.i(TAG, "accept size: "+integers.size());
                            for (Integer integer : integers) {
                                Log.i(TAG, "accept: "+integer);
                            }
                        });

输出结果

2018-12-14 11:16:28.452 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept size: 2
2018-12-14 11:16:28.452 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 1
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 2
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept size: 2
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 3
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 4
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept size: 2
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 5
2018-12-14 11:16:28.453 28126-28126/com.luwei.lwbaselib I/LwBaseActivity: accept: 6

例如：缓存 3 个数据，再发送数据，每次移动 1 步

                Observable.just(1,2,3,4)
                        .buffer(3,1)
                        .subscribe(integers -> {
                            Log.i(TAG, "accept size: "+integers.size());
                            for (Integer integer : integers) {
                                Log.i(TAG, "accept: "+integer);
                            }
                        });

输出结果

2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept size: 3
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 1
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 2
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 3
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept size: 3
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 2
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 3
2018-12-14 11:24:31.455 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 4
2018-12-14 11:24:31.456 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept size: 2
2018-12-14 11:24:31.456 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 3
2018-12-14 11:24:31.456 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 4
2018-12-14 11:24:31.456 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept size: 1
2018-12-14 11:24:31.456 29164-29164/com.luwei.lwbaselib I/LwBaseActivity: accept: 4

concat 操作符

是接收若干个Observables，发射数据是有序的，不会交叉。

Subject

作为 Observable 和 Observer 之间的桥梁
可以当做 Observable
可以当做 Observer

PublishSubject

继承至 Subject，它的 Observer 只会接收到 PublishSubject 被订阅之后发送的数据。示例代码如下；我们只会接收到 publishSubject3 和 publishSubject4；

                PublishSubject<String> publishSubject = PublishSubject.create();
                publishSubject.onNext("publishSubject1");
                publishSubject.onNext("publishSubject2");
                publishSubject.subscribe(new Consumer<String>() {
                    @Override
                    public void accept(String s) throws Exception {
                        Log.i(TAG, "accept: "+s);
                    }
                });
                publishSubject.onNext("publishSubject3");
                publishSubject.onNext("publishSubject4");

执行结果

2018-12-14 11:33:18.168 29916-29916/com.luwei.lwbaselib I/LwBaseActivity: accept: publishSubject3
2018-12-14 11:33:18.168 29916-29916/com.luwei.lwbaselib I/LwBaseActivity: accept: publishSubject4

举一反三

可以看到，在 RxPermissions 这个获取权限的开源框架中，往 Activity 中添加了一个空的 Fragment，这个 fragment 才是用来发起申请权限和处理权限的请求，最后再将结果返回，这样子就避免了我们发送请求之后，还需要在 onRequestPermissionsResult 中进行处理，并判断 requestCode 等繁琐操作。想到这里，我们平时使用 startActivityForResult 时，我们也可以同样采用这样的思路来简化我们的请求。

同样的，我们采用添加空白的 fragment，来做 startActivityForResult 请求，主要的实现类有 SimpleForResult 和 SimpleOnResultFragment，ActivityResultInfo 是请求 model，接下我们先看代码。

SimpleForResult


/**
 * @Author: chenjianrun
 * @Time: 2018/12/7
 * @Description:   避免调用 startActivity 时，需要 onActivityResult 处理的类
 */
public class SimpleForResult {
    private static final String TAG = "SimpleForResult";
    private SimpleOnResultFragment mSimpleOnResultFragment;

    public SimpleForResult(AppCompatActivity activity) {
        mSimpleOnResultFragment = getOnResultFragment(activity.getSupportFragmentManager());
    }

    public SimpleForResult(Fragment fragment){
        mSimpleOnResultFragment = getOnResultFragment(fragment.getChildFragmentManager());
    }

    private SimpleOnResultFragment getOnResultFragment(FragmentManager fragmentManager) {
        SimpleOnResultFragment simpleOnResultFragment = findSimpleOnResultFragment(fragmentManager);
        if (simpleOnResultFragment == null) {
            simpleOnResultFragment = new SimpleOnResultFragment();
            fragmentManager
                    .beginTransaction()
                    .add(simpleOnResultFragment, TAG)
                    .commitAllowingStateLoss();
            fragmentManager.executePendingTransactions();
        }
        return simpleOnResultFragment;
    }

    private SimpleOnResultFragment findSimpleOnResultFragment(FragmentManager fragmentManager) {
        return (SimpleOnResultFragment) fragmentManager.findFragmentByTag(TAG);
    }

    public Observable<ActivityResultInfo> startForResult(Intent intent) {
        return mSimpleOnResultFragment.startForResult(intent);
    }

    public Observable<ActivityResultInfo> startForResult(Class<?> clazz) {
        Intent intent = new Intent(mSimpleOnResultFragment.getActivity(), clazz);
        return startForResult(intent);
    }

    public void startForResult(Intent intent, Callback callback) {
        mSimpleOnResultFragment.startForResult(intent, callback);
    }

    public void startForResult(Class<?> clazz, Callback callback) {
        Intent intent = new Intent(mSimpleOnResultFragment.getActivity(), clazz);
        startForResult(intent, callback);
    }

    public interface Callback {
        void onActivityResult(int requestCode, int resultCode, Intent data);
    }
}

SimpleOnResultFragment


/**
 * @Author: chenjianrun
 * @Time: 2018/12/7
 * @Description:    真正调用 startActivity 和处理 onActivityResult 的类。
 */
public class SimpleOnResultFragment extends Fragment {
    private static Map<Integer, PublishSubject<ActivityResultInfo>> mSubjects = new HashMap<>();
    private static Map<Integer, SimpleForResult.Callback> mCallbacks = new HashMap<>();

    public SimpleOnResultFragment() {
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRetainInstance(true);
    }

    public Observable<ActivityResultInfo> startForResult(final Intent intent) {
        int requestCode = generateRequestCode();
        PublishSubject<ActivityResultInfo> subject = PublishSubject.create();
        mSubjects.put(requestCode, subject);
        startActivityForResult(intent, requestCode);
        return subject;
    }

    public void startForResult(Intent intent, SimpleForResult.Callback callback) {
        int requestCode = generateRequestCode();
        mCallbacks.put(requestCode, callback);
        startActivityForResult(intent, requestCode);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        //rxjava方式的处理
        PublishSubject<ActivityResultInfo> subject = mSubjects.remove(requestCode);
        if (subject != null) {
            subject.onNext(new ActivityResultInfo(requestCode, resultCode, data));
            subject.onComplete();
        }

        //callback方式的处理
        SimpleForResult.Callback callback = mCallbacks.remove(requestCode);
        if (callback != null) {
            callback.onActivityResult(requestCode, resultCode, data);
        }
    }

    private int generateRequestCode(){
        Random random = new Random();
        for (;;){
            int code = random.nextInt(65536);
            if (!mSubjects.containsKey(code) && !mCallbacks.containsKey(code)){
                return code;
            }
        }
    }
}

ActivityResultInfo

package com.luwei.util.forresult;

import android.content.Intent;

/**
 * @Author: chenjianrun
 * @Time: 2018/12/7
 * @Description:
 */
public class ActivityResultInfo {
    private int requestCode;
    private int resultCode;
    private Intent data;

    public ActivityResultInfo(int requestCode, int resultCode, Intent data) {
        this.requestCode = requestCode;
        this.resultCode = resultCode;
        this.data = data;
    }

    public int getRequestCode() {
        return requestCode;
    }

    public void setRequestCode(int requestCode) {
        this.requestCode = requestCode;
    }

    public ActivityResultInfo(int resultCode, Intent data) {
        this.resultCode = resultCode;
        this.data = data;
    }

    public int getResultCode() {
        return resultCode;
    }

    public void setResultCode(int resultCode) {
        this.resultCode = resultCode;
    }

    public Intent getData() {
        return data;
    }

    public void setData(Intent data) {
        this.data = data;
    }
}

简单使用示例

简单的 Activity 调用

// 简化调用 startActivityForResult 及避免在 onActivityResult 中处理繁琐的结果
                SimpleForResult simpleForResult = new SimpleForResult(this);
                simpleForResult.startForResult(ToastActivity.class)
                        .subscribe((resultInfo) -> {
                            if (resultInfo.getData() != null) {
                                ToastUtils.showLong(resultInfo.getData().getStringExtra("result"));
                            }
                        });

调用摄像头

    /**
     * 打开摄像头
     */
    private void openCamera() {
        try {
            mTmpFile = FileUtils.createTmpFile(this);
        } catch (IOException e) {
            e.printStackTrace();
        }
        simpleForResult.startForResult(getOpenCameraIntent(this, mTmpFile))
                .subscribe((resultInfo -> {
                    if (resultInfo.getResultCode() == RESULT_OK) {
                        mHeadUrl = mTmpFile.getAbsolutePath();
                        ImageLoaderUtils.loadCircleImage(this, ivHeader, mHeadUrl);
                        // 裁剪(如果没有要求可裁剪，也可以不要）
                        startPictureZoom(mTmpFile);
                    }
                }));
    }


    /**
     * 获取打开照相机的 intent，适配 Android 7.0
     * @param activity
     * @param mTmpFile
     * @return
     */
    public static Intent getOpenCameraIntent(Activity activity,File mTmpFile){
        Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (intent.resolveActivity(activity.getPackageManager()) != null) {
            if (mTmpFile != null && mTmpFile.exists()) {
                if (Build.VERSION.SDK_INT >= 24) {
                    // 适配 Android 7.0
                    intent.putExtra(MediaStore.EXTRA_OUTPUT,
                            FileProvider.getUriForFile(activity, activity.getPackageName()+".provider",mTmpFile));
                } else {
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(mTmpFile));
                }
            } else {
                Toast.makeText(activity, me.nereo.image_selector.R.string.error_image_not_exist, Toast.LENGTH_SHORT).show();
            }
        } else {
            Toast.makeText(activity, me.nereo.image_selector.R.string.msg_no_camera, Toast.LENGTH_SHORT).show();
        }
        return intent;
    }