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
如果有人喜欢，就发布另一种选择。你可以使用EasyPermissions，这是由谷歌本身提供的，如前所述，“简化Android M系统权限”。
然后你不必直接处理shouldShowRequestPermissionRationale。
其他回答
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。
这段代码要求用户在运行时请求权限， 如果用户允许，执行结果方法， 如果用户拒绝，它会用描述和用户拒绝再次询问(它会用说明再次询问)， 但如果用户选择永远不会再问。 它处理永不再问，显示打开设置选项与说明。
public String storagePermissions = Manifest.permission.READ_EXTERNAL_STORAGE;
private static final int REQUEST_ACCESS =101;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if(checkSelfPermission(storagePermissions)== PackageManager.PERMISSION_GRANTED){
result(); // result is your block of code
}else {
requestPermissions(new String[]{storagePermissions},REQUEST_ACCESS);
}
}
else{
result(); //so if user is lower than api verison M, no permission is requested
}
}
private void showMessageOKCancel(String message, DialogInterface.OnClickListener okListener) {
new AlertDialog.Builder(MainActivity.this)
.setMessage(message)
.setTitle("Hi User..")
.setPositiveButton("Ok", okListener)
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) { //idea calling showMessage funtion again
Snackbar mySnackbar = Snackbar.make( findViewById(R.id.coordinatorlayout),"You Press Cancel.. ", Snackbar.LENGTH_INDEFINITE);
mySnackbar.setAction("Exit", new cancelButton());
mySnackbar.show();
}
})
.create()
.show();
}
private void result(){
//your code
}
@RequiresApi(api = Build.VERSION_CODES.M)
public class NeverAskAgain implements View.OnClickListener{
@Override
public void onClick(View view)
{
goToSettings();
}
}
@RequiresApi(api = Build.VERSION_CODES.M)
private void goToSettings() {
Intent myAppSettings = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:" + getPackageName()));
finish();
myAppSettings.addCategory(Intent.CATEGORY_DEFAULT);
myAppSettings.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivityForResult(myAppSettings, REQUEST_APP_SETTINGS);
}
public class cancelButton implements View.OnClickListener{
@Override
public void onClick(View view){
Toast.makeText(MainActivity.this,"To use this app , you must grant storage permission",Toast.LENGTH_SHORT);
finish();
}
}
@Override
@RequiresApi(api = Build.VERSION_CODES.M)
public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode,permissions,grantResults);
switch(requestCode) {
case REQUEST_ACCESS:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
// permission is granted
result();
break;
}
else if (!shouldShowRequestPermissionRationale(permissions[0])){
showMessageOKCancel("You choose Never Ask Again,option",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Snackbar mySnackbar = Snackbar.make(findViewById(R.id.coordinatorlayout), "Permission=>Storage=>On", Snackbar.LENGTH_INDEFINITE);
mySnackbar.setAction("Settings", new NeverAskAgain());
mySnackbar.show();
}
});
break;
}
else {
showMessageOKCancel("You Denid permission Request..",
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
requestPermissions(new String[]{storagePermissions}, REQUEST_ACCESS);
}
});
break;
}
}
}
public void requestPermission(View view){
if(ContextCompat.checkSelfPermission(this,Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){
if(ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,Manifest.permission.ACCESS_FINE_LOCATION)){
//The Alert Dialog before asking for the second time to help the user understand why he needs to give permission.
AlertDialog alert = new AlertDialog.Builder(this).setMessage("Without the permissions you cannot run the application")
.setCancelable(false)
.setPositiveButton("Okay, I understand", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_FINE_LOCATION);
}
}).setNegativeButton("No, Exit the App", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
System.exit(2);
}
}).create();
alert.setTitle("ALERTY");
alert.show();
//End of the alert Dialog
}
else{
ActivityCompat.requestPermissions(MainActivity.this,
new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, REQUEST_FINE_LOCATION);
}
}
else {
textView.setText("Permission Is Already Granted");
}
}
/*
The shouldShowRequestPermissionRationale() function returns true if the app has requested this permission
previously and the user denied the request.If the user turned down the permission request in the past and chose
the Don't ask again option, this method returns false.
*/
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(requestCode == REQUEST_FINE_LOCATION) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
textView.setText("Hooray! on Request Permissions Granted");
}
else{
//Since the user has chosen the don't ask again option,
if(!ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION)){
//Alert Dialog that will take user to settings where he can manually give the permissions
AlertDialog alert = new AlertDialog.Builder(this).setMessage("You have permanently disabled the permission ")
.setPositiveButton("Go to Settings", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
openSettings();
}
}).setNegativeButton("Don't Go",null).setCancelable(false).create();
alert.setTitle("Give permission manually");
alert.show();
// End of the Alert Dialog
}
else{
textView.setText("Permission has been denied the 1st time");
}
}
}
}
这是openSettings方法。
public void openSettings(){
Intent intent = new Intent();
Uri uri = Uri.fromParts("package",this.getPackageName(),null);
intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).setData(uri);
startActivity(intent);
}
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)
}
}
}
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”?
