根据这个:http://developer.android.com/preview/features/runtime-permissions.html#coding一个应用程序可以检查运行时权限和请求权限,如果它还没有被授予。弹出如下对话框:
如果用户拒绝一个重要的权限,在我看来,应用程序应该显示一个解释为什么需要权限和什么影响拒绝。该对话框有两个选项:
重试(再次请求许可)
拒绝(应用程序将工作没有该许可)。
但是,如果用户选中“Never ask again”,则不应该显示带有解释的第二个对话框,特别是如果用户之前已经拒绝了一次。
现在的问题是:我的应用程序如何知道用户是否选中了Never ask again?IMO onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults)没有给我这个信息。
第二个问题是:谷歌是否计划在权限对话框中包含一个自定义消息,以解释为什么应用程序需要权限?这样就不会出现第二个对话框,这肯定会带来更好的用户体验。
您可以通过检查权限原理是否显示在onRequestPermissionsResult()回调方法中来确定它。如果您发现任何权限集永远不会再次请求,您可以请求用户从设置中授予权限。
我的完整实现如下所示。它适用于单个或多个权限请求。使用以下或直接使用我的库。
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(permissions.length == 0){
return;
}
boolean allPermissionsGranted = true;
if(grantResults.length>0){
for(int grantResult: grantResults){
if(grantResult != PackageManager.PERMISSION_GRANTED){
allPermissionsGranted = false;
break;
}
}
}
if(!allPermissionsGranted){
boolean somePermissionsForeverDenied = false;
for(String permission: permissions){
if(ActivityCompat.shouldShowRequestPermissionRationale(this, permission)){
//denied
Log.e("denied", permission);
}else{
if(ActivityCompat.checkSelfPermission(this, permission) == PackageManager.PERMISSION_GRANTED){
//allowed
Log.e("allowed", permission);
} else{
//set to never ask again
Log.e("set to never ask again", permission);
somePermissionsForeverDenied = true;
}
}
}
if(somePermissionsForeverDenied){
final AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
alertDialogBuilder.setTitle("Permissions Required")
.setMessage("You have forcefully denied some of the required permissions " +
"for this action. Please open settings, go to permissions and allow them.")
.setPositiveButton("Settings", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS,
Uri.fromParts("package", getPackageName(), null));
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
})
.setCancelable(false)
.create()
.show();
}
} else {
switch (requestCode) {
//act according to the request code used while requesting the permission(s).
}
}
}
你可以听漂亮。
侦听器
interface PermissionListener {
fun onNeedPermission()
fun onPermissionPreviouslyDenied(numberDenyPermission: Int)
fun onPermissionDisabledPermanently(numberDenyPermission: Int)
fun onPermissionGranted()
}
MainClass的权限
class PermissionUtil {
private val PREFS_FILENAME = "permission"
private val TAG = "PermissionUtil"
private fun shouldAskPermission(context: Context, permission: String): Boolean {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
val permissionResult = ActivityCompat.checkSelfPermission(context, permission)
if (permissionResult != PackageManager.PERMISSION_GRANTED) {
return true
}
}
return false
}
fun checkPermission(context: Context, permission: String, listener: PermissionListener) {
Log.i(TAG, "CheckPermission for $permission")
if (shouldAskPermission(context, permission)) {
// Load history permission
val sharedPreference = context.getSharedPreferences(PREFS_FILENAME, 0)
val numberShowPermissionDialog = sharedPreference.getInt(permission, 0)
if (numberShowPermissionDialog == 0) {
(context as? Activity)?.let {
if (ActivityCompat.shouldShowRequestPermissionRationale(it, permission)) {
Log.e(TAG, "User has denied permission but not permanently")
listener.onPermissionPreviouslyDenied(numberShowPermissionDialog)
} else {
Log.e(TAG, "Permission denied permanently.")
listener.onPermissionDisabledPermanently(numberShowPermissionDialog)
}
} ?: kotlin.run {
listener.onNeedPermission()
}
} else {
// Is FirstTime
listener.onNeedPermission()
}
// Save history permission
sharedPreference.edit().putInt(permission, numberShowPermissionDialog + 1).apply()
} else {
listener.onPermissionGranted()
}
}
}
以这种方式使用
PermissionUtil().checkPermission(this, Manifest.permission.ACCESS_FINE_LOCATION,
object : PermissionListener {
override fun onNeedPermission() {
log("---------------------->onNeedPermission")
// ActivityCompat.requestPermissions(this@SplashActivity,
// Array(1) { Manifest.permission.ACCESS_FINE_LOCATION },
// 118)
}
override fun onPermissionPreviouslyDenied(numberDenyPermission: Int) {
log("---------------------->onPermissionPreviouslyDenied")
}
override fun onPermissionDisabledPermanently(numberDenyPermission: Int) {
log("---------------------->onPermissionDisabled")
}
override fun onPermissionGranted() {
log("---------------------->onPermissionGranted")
}
})
在activity或fragmnet中覆盖onRequestPermissionsResult
override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
if (requestCode == 118) {
if (permissions[0] == Manifest.permission.ACCESS_FINE_LOCATION && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
getLastLocationInMap()
}
}
}
这里有一个很好的和简单的方法来检查当前的权限状态:
@Retention(RetentionPolicy.SOURCE)
@IntDef({GRANTED, DENIED, BLOCKED_OR_NEVER_ASKED })
public @interface PermissionStatus {}
public static final int GRANTED = 0;
public static final int DENIED = 1;
public static final int BLOCKED_OR_NEVER_ASKED = 2;
@PermissionStatus
public static int getPermissionStatus(Activity activity, String androidPermissionName) {
if(ContextCompat.checkSelfPermission(activity, androidPermissionName) != PackageManager.PERMISSION_GRANTED) {
if(!ActivityCompat.shouldShowRequestPermissionRationale(activity, androidPermissionName)){
return BLOCKED_OR_NEVER_ASKED;
}
return DENIED;
}
return GRANTED;
}
警告:在用户通过用户提示接受/拒绝权限之前,在第一个应用程序启动时返回BLOCKED_OR_NEVER_ASKED(在sdk 23+设备上)
更新:
Android支持库现在似乎也有一个非常类似的类Android .support.v4.content。PermissionChecker,包含checkSelfPermission(),返回:
public static final int PERMISSION_GRANTED = 0;
public static final int PERMISSION_DENIED = -1;
public static final int PERMISSION_DENIED_APP_OP = -2;