原理

通过向当前Activity添加一个不可见的Fragment，从而实现权限申请流程的封装。

实现

不可见的Fragment

internal class EPermissionFragment : Fragment() {
    private var mCallback: EPermissionCallback? = null

    fun requestPermission(callback: EPermissionCallback, vararg permissions: String) {
        mCallback = callback
        // 申请权限
        requestPermissions(permissions, CODE_REQUEST_PERMISSION)
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        if (requestCode == CODE_REQUEST_PERMISSION) {
            val deniedList = ArrayList<String>()
            val deniedForeverList = ArrayList<String>()
            grantResults.forEachIndexed { index, result ->
                // 提取权限申请结果
                if (result != PackageManager.PERMISSION_GRANTED) {
                    val permission = permissions[index]
                    deniedList.add(permission)
                    // 是否拒绝且不再显示
                    if (!shouldShowRequestPermissionRationale(permission)) {
                        deniedForeverList.add(permission)
                    }
                }
            }
            if (deniedList.isEmpty()) mCallback?.onAllGranted()
            if (deniedList.isNotEmpty()) mCallback?.onDenied(deniedList)
            if (deniedForeverList.isNotEmpty()) mCallback?.onDeniedForever(deniedForeverList)
        }
    }

    override fun onDestroy() {
        mCallback = null
        super.onDestroy()
    }
}
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封装权限申请

// 扩展FragmentActivity
fun FragmentActivity.runWithPermissions(
    vararg permissions: String,
    onDenied: (ArrayList<String>) -> Unit = { _ -> },
    onDeniedForever: (ArrayList<String>) -> Unit = { _ -> },
    onAllGranted: () -> Unit = {}
) {
    if (checkPermissions(*permissions)) {
        onAllGranted()
        return
    }
    // 添加一个不可见的Fragment
    val isFragmentExist = supportFragmentManager.findFragmentByTag(EPermissionFragment.TAG)
    val fragment = if (isFragmentExist != null) {
        isFragmentExist as EPermissionFragment
    } else {
        val invisibleFragment = EPermissionFragment()
        supportFragmentManager.beginTransaction().add(invisibleFragment, EPermissionFragment.TAG).commitNowAllowingStateLoss()
        invisibleFragment
    }
    val callback = object : EPermissionCallback {
        override fun onAllGranted() {
            onAllGranted()
        }

        override fun onDenied(deniedList: ArrayList<String>) {
            onDenied(deniedList)
        }

        override fun onDeniedForever(deniedForeverList: ArrayList<String>) {
            onDeniedForever(deniedForeverList)
        }
    }
    // 申请权限
    fragment.requestPermission(callback, *permissions)
}
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使用方法

项目build.gradle添加

allprojects {
    repositories {
        ...
        maven { url 'https://www.jitpack.io' }
        }
}
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模块build.gradle添加

dependencies {
    implementation 'com.github.RickyHal:EPermission:$latest_version'
}
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在Activity或者Fragment中直接调用

// 申请存储权限
runWithPermissions(
    *EPermissions.STORAGE,
    onDenied = {
        Toast.makeText(this, "STORAGE permission denied", Toast.LENGTH_SHORT).show()
    },
    onDeniedForever = {
        Toast.makeText(this, "STORAGE permission denied forever", Toast.LENGTH_SHORT).show()
    },
    onAllGranted = {
        Toast.makeText(this, "STORAGE permission granted", Toast.LENGTH_SHORT).show()
    }
)
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也可以用下面这个简单的方法

runWithStoragePermission(onFailed = {
    Toast.makeText(this, "SMS permission denied", Toast.LENGTH_SHORT).show()
}) {
    Toast.makeText(this, "SMS permission granted", Toast.LENGTH_SHORT).show()
}
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一次申请多个权限

runWithPermissions(*EPermissions.CAMERA, *EPermissions.STORAGE,
    onDenied = { deniedList ->
        Toast.makeText(this, "permission denied $deniedList", Toast.LENGTH_SHORT).show()
    },
    onDeniedForever = { deniedForeverList ->
        Toast.makeText(this, "permission denied forever $deniedForeverList", Toast.LENGTH_SHORT).show()
    },
    onAllGranted = {
        Toast.makeText(this, "Permission all granted", Toast.LENGTH_SHORT).show()
    })
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如果不需要处理失申请权限败的情况，也可以直接这样写

runWithStoragePermission {
    Toast.makeText(this, "SMS permission granted", Toast.LENGTH_SHORT).show()
}
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如果某些操作执行的时候，只能有权限才去执行，则可以使用下面的方法

doWhenPermissionGranted(*EPermissions.CAMERA){
    Toast.makeText(this, "Do this when camera Permission is granted", Toast.LENGTH_SHORT).show()
}
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检查权限

if (checkPermissions(*EPermissions.CAMERA)) {
    Toast.makeText(this, "Camera Permission is granted", Toast.LENGTH_SHORT).show()
} else {
    Toast.makeText(this, "Camera Permission is not granted", Toast.LENGTH_SHORT).show()
}
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