Easypermissions简化了Android M的运行时权限的申请、结果处理、判断等步骤。

1 相关文档

官方文档：

https://github.com/googlesamples/easypermissions

运行时权限官方文档解释：

https://developer.android.com/training/permissions/requesting.html

2 为什么使用Easypermissions

Android M对权限系统进行了改变。Android M之前所需权限只需要在AndroidManifest中申请即可。但更新Android M系统后，部分“Dangerous Permission”需要在运行时询问申请。

Normal and Dangerous Permissions解释：
https://developer.android.com/guide/topics/security/permissions.html#normal-dangerous

如下图所示：

运行时权限申请

代码中如果需要申请运行时权限步骤：

1 检查运行时权限

ContextCompat.checkSelfPermission(thisActivity,

                Manifest.permission.READ_CONTACTS)

        != PackageManager.PERMISSION_GRANTED

2 申请权限

ActivityCompat.requestPermissions(thisActivity,

                new String[]{Manifest.permission.READ_CONTACTS},

                MY_PERMISSIONS_REQUEST_READ_CONTACTS);

3 接收权限处理结果

@Override

public void onRequestPermissionsResult(int requestCode,

        String permissions[], int[] grantResults) {

    switch (requestCode) {

        case MY_PERMISSIONS_REQUEST_READ_CONTACTS: {

            // If request is cancelled, the result arrays are empty.

            if (grantResults.length > 0

                && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay! Do the

                // contacts-related task you need to do.

            } else {

                // permission denied, boo! Disable the

                // functionality that depends on this permission.

            }

            return;

        }

        // other 'case' lines to check for other

        // permissions this app might request

    }

}

以上即是google建议的运行时权限处理过程。代码量和处理地方还是比较繁琐的。so，Easypermissions应运而生。

3 如何使用

首先，引用库

dependencies {

  compile 'pub.devrel:easypermissions:0.1.9'

}

同样，easypermissions处理权限分为3步。

1 检查权限

String[] perms = {Manifest.permission.CAMERA, Manifest.permission.CHANGE_WIFI_STATE};

if (EasyPermissions.hasPermissions(this, perms)) {

   //...

} else {

    //...

}

2 申请权限

EasyPermissions.requestPermissions(this, "拍照需要摄像头权限",

                    RC_CAMERA_AND_WIFI, perms);

3 实现EasyPermissions.PermissionCallbacks接口，直接处理权限是否成功申请

    @Override

    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {

        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        // Forward results to EasyPermissions

        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);

    }

    //成功

    @Override

    public void onPermissionsGranted(int requestCode, List<String> list) {

        // Some permissions have been granted

        // ...

    }

    //失败

    @Override

    public void onPermissionsDenied(int requestCode, List<String> list) {

        // Some permissions have been denied

        // ...

    }

4 总结

Easypermissions主要简化了对权限申请结果的处理和判断，直接以接口的方式回调处理结果。不需要再自行进行处理。