我正在翻阅关于Android m中的新权限模型的官方文档。它讨论了shouldShowRequestPermissionRationale()函数,如果应用程序之前请求了此权限,并且用户拒绝了请求,该函数将返回true。如果用户在过去拒绝了权限请求并选择Don't ask again选项,则此方法返回false。

但是我们如何区分以下两种情况呢?

案例1:应用程序没有权限,之前也没有向用户请求过权限。在这种情况下,shouldShowRequestPermissionRationale()将返回false,因为这是我们第一次请求用户。

情况2:用户拒绝了权限并选择了“不要再问了”,在这种情况下shouldShowRequestPermissionRationale()将返回false。

我想把用户发送到案例2中的应用设置页面。我怎么微分这两种情况呢?


当前回答

如果有人对Kotlin解决方案感兴趣,我将@muthuraj的答案重构为Kotlin。它也现代化了一点,有一个完成块,而不是监听器。

PermissionUtil

object PermissionUtil {
    private val PREFS_FILE_NAME = "preference"

    fun firstTimeAskingPermission(context: Context, permission: String, isFirstTime: Boolean) {
        val sharedPreference = context.getSharedPreferences(PREFS_FILE_NAME, MODE_PRIVATE)
        sharedPreference.preferences.edit().putBoolean(permission,
                isFirstTime).apply()
    }

    fun isFirstTimeAskingPermission(context: Context, permission: String): Boolean {
        val sharedPreference = context.getSharedPreferences(PREFS_FILE_NAME, MODE_PRIVATE)
        return sharedPreference.preferences.getBoolean(permission,
                true)
    }
}

PermissionHandler

enum class CheckPermissionResult {
    PermissionAsk,
    PermissionPreviouslyDenied,
    PermissionDisabled,
    PermissionGranted
}

typealias PermissionCheckCompletion = (CheckPermissionResult) -> Unit


object PermissionHandler {

    private fun shouldAskPermission(context: Context, permission: String): Boolean {
        return ContextCompat.checkSelfPermission(context,
                permission) != PackageManager.PERMISSION_GRANTED
    }

    fun checkPermission(context: Context, permission: String, completion: PermissionCheckCompletion) {
        // If permission is not granted
        if (shouldAskPermission(context, permission)) {
            //If permission denied previously
            if ((context as Activity).shouldShowRequestPermissionRationale(permission)) {
                completion(CheckPermissionResult.PermissionPreviouslyDenied)
            } else {
                // Permission denied or first time requested
                if (PermissionUtil.isFirstTimeAskingPermission(context,
                                permission)) {
                    PermissionUtil.firstTimeAskingPermission(context,
                            permission,
                            false)
                    completion(CheckPermissionResult.PermissionAsk)
                } else {
                    // Handle the feature without permission or ask user to manually allow permission
                    completion(CheckPermissionResult.PermissionDisabled)
                }
            }
        } else {
            completion(CheckPermissionResult.PermissionGranted)
        }
    }
}

实现

PermissionHandler.checkPermission(activity,
                    Manifest.permission.CAMERA) { result ->
                when (result) {
                    CheckPermissionResult.PermissionGranted -> {
                        // openCamera()
                    }
                    CheckPermissionResult.PermissionDisabled -> {
                        // displayAlert(noPermissionAlert)
                    }
                    CheckPermissionResult.PermissionAsk -> {
                        // requestCameraPermissions()
                    }
                    CheckPermissionResult.PermissionPreviouslyDenied -> {
                        // displayAlert(permissionRequestAlert)
                    }
                }
            }

其他回答

更新

我相信下面CanC的答案是正确的,应该遵循。唯一确定的方法是在onRequestPermissionResult回调中使用shouldShowPermissionRationale来验证这一点。

==

我最初的回答是:

我发现的唯一方法是自己跟踪这是否是第一次(例如使用共享的偏好)。如果不是第一次,则使用shouldShowRequestPermissionRationale()进行区分。

另见:Android M -检查运行时权限-如何确定用户是否勾选了“永不再问”?

正确使用shouldShowRequestPermissionRationale是on onRequestPermissionsResult。

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
    <androidx.appcompat.widget.LinearLayoutCompat
        xmlns:android="http://schemas.android.com/apk/res/android"
        xmlns:app="http://schemas.android.com/apk/res-auto"
        xmlns:tools="http://schemas.android.com/tools"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        tools:context=".MainActivity"
        android:gravity="center">
    
        <androidx.appcompat.widget.AppCompatButton
            android:id="@+id/btn_camera"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Camera"
            android:textAllCaps="false"
            android:background="@color/purple_200"
            android:layout_marginTop="20dp"
            >
        </androidx.appcompat.widget.AppCompatButton>
        <androidx.appcompat.widget.AppCompatButton
            android:id="@+id/btn_storage"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Storage"
            android:textAllCaps="false"
            android:background="@color/purple_200"
            android:layout_marginTop="30dp"
            >
        </androidx.appcompat.widget.AppCompatButton>
    
    </androidx.appcompat.widget.LinearLayoutCompat>
enter code here

MainActivity.kt

package com.example.myapplication
import android.Manifest
import android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.widget.Button
import android.widget.Toast
import androidx.appcompat.app.AlertDialog
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
class MainActivity : AppCompatActivity() {
    private val TAG = "MainActivity"
    lateinit var btnCamera: Button
    private val cameraRequestCode = 100
    lateinit var btnStorage: Button
    private val storageRequestCode = 200
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        btnCamera = findViewById(R.id.btn_camera)
        btnStorage = findViewById(R.id.btn_storage)
        btnCamera.setOnClickListener {
            checkPermission(android.Manifest.permission.CAMERA, cameraRequestCode)
        }
        btnStorage.setOnClickListener {
            checkPermission(android.Manifest.permission.READ_EXTERNAL_STORAGE, storageRequestCode)
        }
    }

    private fun checkPermission(permissionName: String, requestCode: Int) {
        /**
         * if the permission is given means it will give the  permissionNumber = 0
         * if the permission is not  given means it will give the  permissionNumber =-1
         * It s same as we are checking for PackageManager.PERMISSION_DENIED =-1 & PackageManager.GRANTED=0
         */
        val permissionNumber: Int =
            ContextCompat.checkSelfPermission(this@MainActivity, permissionName)
        if (permissionNumber == PackageManager.PERMISSION_GRANTED) {

        } else if (permissionNumber == PackageManager.PERMISSION_DENIED) {
            askpermission(permissionName, requestCode, permissionNumber)

        }

    }

    private fun askpermission(permissionName: String, permissionCode: Int, permissionNumner: Int) {
        ActivityCompat.requestPermissions(
            this@MainActivity,
            arrayOf(permissionName),
            permissionCode
        )
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == cameraRequestCode) {
            if (permissions.size > 0) {
                if (permissions[0].toString().equals(Manifest.permission.CAMERA, ignoreCase = true)) {
                    if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                        Toast.makeText(applicationContext,"Permission Granted",Toast.LENGTH_SHORT).show()

                    }else{
                        if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
                           var permissionDeniedStatus= checkDeniedPermissionStatus(permissions[0]);
                            if(permissionDeniedStatus){
                                /**
                                 * Permission Denied
                                 */
                                Toast.makeText(applicationContext,"Permission Denied",Toast.LENGTH_SHORT).show()
                            }else{
                                /**
                                 * Permission Denied and Selected Don t ask again.
                                 */
                                showDialog("Permission Denied","Permission Denied Permanently\nOpen Setting to allow")
                            }
                        }
                    }
                }
            }
        }else  if (requestCode == storageRequestCode) {
            if(permissions[0].toString().equals(Manifest.permission.READ_EXTERNAL_STORAGE, ignoreCase = true)){
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                        Toast.makeText(applicationContext,"Permission Granted",Toast.LENGTH_SHORT).show()
                    }
                }else{
                    if (grantResults[0] == PackageManager.PERMISSION_DENIED) {
                        var permissionDeniedStatus= checkDeniedPermissionStatus(permissions[0]);
                        if(permissionDeniedStatus){
                            /**
                             * Permission Denied
                             */
                            Toast.makeText(applicationContext,"Permission Denied",Toast.LENGTH_SHORT).show()
                        }else{
                            /**
                             * Permission Denied and Selected Don t ask again.
                             */
                            showDialog("Permission Denied","Permission Denied Permanently\nOpen Setting to allow")
                        }
                    }
                }
            }
        }
    }

    private fun checkDeniedPermissionStatus(permissionName: String) :Boolean{
        val permissionDeniedStatus: Boolean = ActivityCompat.shouldShowRequestPermissionRationale(this@MainActivity, permissionName)
        return permissionDeniedStatus
    }

    private fun showDialog(title: String, message: String) {
        val builder = AlertDialog.Builder(this)
        builder.setTitle(title)
        builder.setMessage(message)
        builder.setPositiveButton(android.R.string.yes) { dialog, which ->

        }

        builder.setNegativeButton(android.R.string.no) { dialog, which ->

        }
        builder.show()
    }
}

我理解它的方式,shouldShowRequestPermissionRationale()在底层运行许多用例,并通知应用程序是否显示正在请求的权限的解释。

运行时权限背后的思想是,大多数情况下,用户将对权限请求说Yes。这样用户就只需要点击一次。当然,这个请求应该在正确的上下文中使用——即在按下“摄像”按钮时请求摄像许可。

If the user denies the request, but after some time comes around and presses the "Camera" button again, shouldShowRequestPermissionRationale() will return true, so the app can show some meaningful explanation why the permission is requested, and why the app won't work properly without it. Normally you would show in that dialog window a button to deny again/decide later, and a button to grant the permissions. The grant permissions button in the rationale dialog, should start the permission request again. This time the user will also have a "Never show again" checkbox. Should he decide to select it, and deny the permission again, it would notify the Android system that the user and the app are not on the same page. That action would have two consequences - shouldShowRequestPermissionRationale() will always return false, and the requestPermissions() method will not show any dialog, but will directly return denied to the onRequestPermissionsResult callback.

但是还有另一种可能的场景,可以使用onRequestPermissionsResult。例如,一些设备可能有禁用摄像头的设备策略(为CIA、DARPA等工作)。在这些设备上,onRequestPermissionsResult将总是返回false,并且requestPermissions()方法将无声地拒绝请求。

这是我从Ben Poiesz (Android框架的产品经理)的播客中了解到的。 http://androidbackstage.blogspot.jp/2015/08/episode-33-permission-mission.html

可能对某人有用:——

我注意到的是,如果我们在onRequestPermissionsResult()回调方法中检查shouldshowrequestpermissionration理()标志,它只显示两种状态。

状态1:-返回true:——任何时候用户单击Deny permissions(包括第一次)。

状态2:-返回false:-如果用户选择“永不再问”。

链接到详细的工作示例。

我们可以这样做吗?

@Retention(RetentionPolicy.SOURCE)
@IntDef({GRANTED, DENIED, NEVER})
public @interface PermissionStatus {
}

public static final int GRANTED = 0;
public static final int DENIED = 1;
public static final int NEVER = 2;

@PermissionStatus
public static int getPermissionStatus(Activity activity, String permission) {
    if (ActivityCompat.shouldShowRequestPermissionRationale(activity, permission)) {
        return DENIED;
    } else {
        if (ActivityCompat.checkSelfPermission(activity, permission) == PackageManager.PERMISSION_GRANTED) {
            return GRANTED;
        } else {
            return NEVER;
        }
    }
}