android 6.0 7.0动态获取权限

public class PermissionsManager {

private static final String TAG = PermissionsManager.class.getSimpleName();

private final Set<String> mPendingRequests = new HashSet<String>(1);
private final Set<String> mPermissions = new HashSet<String>(1);
private final List<WeakReference<PermissionsResultAction>> mPendingActions = new ArrayList<WeakReference<PermissionsResultAction>>(1);

private static PermissionsManager mInstance = null;

public static PermissionsManager getInstance() {
if (mInstance == null) {
mInstance = new PermissionsManager();
}
return mInstance;
}

private PermissionsManager() {
initializePermissionsMap();
}

/**
* This method uses reflection to read all the permissions in the Manifest class.
* This is necessary because some permissions do not exist on older versions of Android,
* since they do not exist, they will be denied when you check whether you have permission
* which is problematic since a new permission is often added where there was no previous
* permission required. We initialize a Set of available permissions and check the set
* when checking if we have permission since we want to know when we are denied a permission
<
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/span>     * because it doesn't exist yet.
*/
private synchronized void initializePermissionsMap() {
Field[] fields = Manifest.permission.class.getFields();
for (Field field : fields) {
String name = null;
try {
name = (String) field.get("");
} catch (IllegalAccessException e) {
Log.e(TAG, "Could not access field", e);
}
mPermissions.add(name);
}
}

/**
* This method retrieves all the permissions declared in the application's manifest.
* It returns a non null array of permisions that can be declared.
*
* @param activity the Activity necessary to check what permissions we have.
* @return a non null array of permissions that are declared in the application manifest.
*/
@NonNull
private synchronized String[] getManifestPermissions(@NonNull final Activity activity) {
PackageInfo packageInfo = null;
List<String> list = new ArrayList<String>(1);
try {
Log.d(TAG, activity.getPackageName());
packageInfo = activity.getPackageManager().getPackageInfo(activity.getPackageName(), PackageManager.GET_PERMISSIONS);
} catch (PackageManager.NameNotFoundException e) {
Log.e(TAG, "A problem occurred when retrieving permissions", e);
}
if (packageInfo != null) {
String[] permissions = packageInfo.requestedPermissions;
if (permissions != null) {
for (String perm : permissions) {
Log.d(TAG, "Manifest contained permission: " + perm);
list.add(perm);
}
}
}
return list.toArray(new String[list.size()]);
}

/**
* This method adds the {@link PermissionsResultAction} to the current list
* of pending actions that will be completed when the permissions are
* received. The list of permissions passed to this method are registered
* in the PermissionsResultAction object so that it will be notified of changes
* made to these permissions.
*
* @param permissions the required permissions for the action to be executed.
* @param action      the action to add to the current list of pending actions.
*/
private synchronized void addPendingAction(@NonNull String[] permissions,
@Nullable PermissionsResultAction action) {
if (action == null) {
return;
}
action.registerPermissions(permissions);
mPendingActions.add(new WeakReference<PermissionsResultAction>(action));
}

/**
* This method removes a pending action from the list of pending actions.
* It is used for cases where the permission has already been granted, so
* you immediately wish to remove the pending action from the queue and
* execute the action.
*
* @param action the action to remove
*/
private synchronized void removePendingAction(@Nullable PermissionsResultAction action) {
for (Iterator<WeakReference<PermissionsResultAction>> iterator = mPendingActions.iterator();
iterator.hasNext(); ) {
WeakReference<PermissionsResultAction> weakRef = iterator.next();
if (weakRef.get() == action || weakRef.get() == null) {
iterator.remove();
}
}
}

/**
* This static method can be used to check whether or not you have a specific permission.
* It is basically a less verbose method of using {@link ActivityCompat#checkSelfPermission(Context, String)}
* and will simply return a boolean whether or not you have the permission. If you pass
* in a null Context object, it will return false as otherwise it cannot check the permission.
* However, the Activity parameter is nullable so that you can pass in a reference that you
* are not always sure will be valid or not (e.g. getActivity() from Fragment).
*
* @param context    the Context necessary to check the permission
* @param permission the permission to check
* @return true if you have been granted the permission, false otherwise
*/
@SuppressWarnings("unused")
public synchronized boolean hasPermission(@Nullable Context context, @NonNull String permission) {
return context != null && (ActivityCompat.checkSelfPermission(context, permission)
== PackageManager.PERMISSION_GRANTED || !mPermissions.contains(permission));
}

/**
* This static method can be used to check whether or not you have several specific permissions.
* It is simpler than checking using {@link ActivityCompat#checkSelfPermission(Context, String)}
* for each permission and will simply return a boolean whether or not you have all the permissions.
* If you pass in a null Context object, it will return false as otherwise it cannot check the
* permission. However, the Activity parameter is nullable so that you can pass in a reference
* that you are not always sure will be valid or not (e.g. getActivity() from Fragment).
*
* @param context     the Context necessary to check the permission
* @param permissions the permissions to check
* @return true if you have been granted all the permissions, false otherwise
*/
@SuppressWarnings("unused")
public synchronized boolean hasAllPermissions(@Nullable Context context, @NonNull String[] permissions) {
if (context == null) {
return false;
}
boolean hasAllPermissions = true;
for (String perm : permissions) {
hasAllPermissions &= hasPermission(context, perm);
}
return hasAllPermissions;
}

/**

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* This method will request all the permissions declared in your application manifest
* for the specified {@link PermissionsResultAction}. The purpose of this method is to enable
* all permissions to be requested at one shot. The PermissionsResultAction is used to notify
* you of the user allowing or denying each permission. The Activity and PermissionsResultAction
* parameters are both annotated Nullable, but this method will not work if the Activity
* is null. It is only annotated Nullable as a courtesy to prevent crashes in the case
* that you call this from a Fragment where {@link Fragment#getActivity()} could yield
* null. Additionally, you will not receive any notification of permissions being granted
* if you provide a null PermissionsResultAction.
*
* @param activity the Activity necessary to request and check permissions.
* @param action   the PermissionsResultAction used to notify you of permissions being accepted.
*/
@SuppressWarnings("unused")
public synchronized void requestAllManifestPermissionsIfNecessary(final @Nullable Activity activity,
final @Nullable PermissionsResultAction action) {
if (activity == null) {
return;
}
String[] perms = getManifestPermissions(activity);
requestPermissionsIfNecessaryForResult(activity, perms, action);
}

/**
* This method should be used to execute a {@link PermissionsResultAction} for the array
* of permissions passed to this method. This method will request the permissions if
* they need to be requested (i.e. we don't have permission yet) and will add the
* PermissionsResultAction to the queue to be notified of permissions being granted or
* denied. In the case of pre-Android Marshmallow, permissions will be granted immediately.
* The Activity variable is nullable, but if it is null, the method will fail to execute.
* This is only nullable as a courtesy for Fragments where getActivity() may yeild null
* if the Fragment is not currently added to its parent Activity.
*
* @param activity    the activity necessary to request the permissions.
* @param permissions the list of permissions to request for the {@link PermissionsResultAction}.
* @param action      the PermissionsResultAction to notify when the permissions are granted or denied.
*/
@SuppressWarnings("unused")
public synchronized void requestPermissionsIfNecessaryForResult(@Nullable Activity activity,
@NonNull String[] permissions,
@Nullable PermissionsResultAction action) {
if (activity == null) {
return;
}
addPendingAction(permissions, action);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
doPermissionWorkBeforeAndroidM(activity, permissions, action);
} else {
List<String> permList = getPermissionsListToRequest(activity, permissions, action);
if (permList.isEmpty()) {
//if there is no permission to request, there is no reason to keep the action int the list
removePendingAction(action);
} else {
String[] permsToRequest = permList.toArray(new String[permList.size()]);
mPendingRequests.addAll(permList);
ActivityCompat.requestPermissions(activity, permsToRequest, 1);
}
}
}

/**
* This method should be used to execute a {@link PermissionsResultAction} for the array
* of permissions passed to this method. This method will request the permissions if
* they need to be requested (i.e. we don't have permission yet) and will add the
* PermissionsResultAction to the queue to be notified of permissions being granted or
* denied. In the case of pre-Android Marshmallow, permissions will be granted immediately.
* The Fragment variable is used, but if {@link Fragment#getActivity()} returns null, this method
* will fail to work as the activity reference is necessary to check for permissions.
*
* @param fragment    the fragment necessary to request the permissions.
* @param permissions the list of permissions to request for the {@link PermissionsResultAction}.
* @param action      the PermissionsResultAction to notify when the permissions are granted or denied.
*/
@SuppressWarnings("unused")
public synchronized void requestPermissionsIfNecessaryForResult(@NonNull Fragment fragment,
@NonNull String[] permissions,
@Nullable PermissionsResultAction action) {
Activity activity = fragment.getActivity();
if (activity == null) {
return;
}
addPendingAction(permissions, action);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
doPermissionWorkBeforeAndroidM(activity, permissions, action);
} else {
List<String> permList = getPermissionsListToRequest(activity, permissions, action);
if (permList.isEmpty()) {
//if there is no permission to request, there is no reason to keep the action int the list
removePendingAction(action);
} else {
String[] permsToRequest = permList.toArray(new String[permList.size()]);
mPendingRequests.addAll(permList);
fragment.requestPermissions(permsToRequest, 1);
}
}
}

/**
* This method notifies the PermissionsManager that the permissions have change. If you are making
* the permissions requests using an Activity, then this method should be called from the
* Activity callback onRequestPermissionsResult() with the variables passed to that method. If
* you are passing a Fragment to make the permissions request, then you should call this in
* the {@link Fragment#onRequestPermissionsResult(int, String[], int[])} method.
* It will notify all the pending PermissionsResultAction objects currently
* in the queue, and will remove the permissions request from the list of pending requests.
*
* @param permissions the permissions that have changed.
* @param results     the values for each permission.
*/
@SuppressWarnings("unused")
public synchronized void notifyPermissionsChange(@NonNull String[] permissions, @NonNull int[] results) {
int size = permissions.length;
if (results.length < size) {
size = results.length;
}
Iterator<WeakReference<PermissionsResultAction>> iterator = mPendingActions.iterator();
while (iterator.hasNext()) {
PermissionsResultAction action = iterator.next().get();
for (int n = 0; n < size; n++) {
if (action == null || action.onResult(permissions[n], results[n])) {
iterator.remove();
break;
}
}
}
for (int n = 0; n < size; n++) {
mPendingRequests.remove(permissions[n]);
}
}

/**
* When request permissions on devices before Android M (Android 6.0, API Level 23)
* Do the granted or denied work directly according to the permission status
*
* @param activity    the activity to check permissions
* @param permissions the permissions names
* @param action      the callback work object, containing what we what to do after
*                    permission check
*/
private void doPermissionWorkBeforeAndroidM(@NonNull Activity activity,
@NonNull String[] permissions,
@Nullable PermissionsResultAction action) {
for (String perm : permissions) {
if (action != null) {
if (!mPermissions.contains(perm)) {
action.onResult(perm, Permissions.NOT_FOUND);
} else if (ActivityCompat.checkSelfPermission(activity, perm)
!= PackageManager.PERMISSION_GRANTED) {
action.onResult(perm, Permissions.DENIED);
} else {
action.onResult(perm, Permissions.GRANTED);
}
}
}
}

/**
* Filter the permissions list:
* If a permission is not granted, add it to the result list
* if a permission is granted, do the granted work, do not add it to the result list
*
* @param activity    the activity to check permissions
* @param permissions all the permissions names
* @param action      the callback work object, containing what we what to do after
*                    permission check
* @return a list of permissions names that are not granted yet
*/
@NonNull
private List<String> getPermissionsListToRequest(@NonNull Activity activity,
@NonNull String[] permissions,
@Nullable PermissionsResultAction action) {
List<String> permList = new ArrayList<String>(permissions.length);
for (String perm : permissions) {
if (!mPermissions.contains(perm)) {
if (action != null) {
action.onResult(perm, Permissions.NOT_FOUND);
}
} else if (ActivityCompat.checkSelfPermission(activity, perm) != PackageManager.PERMISSION_GRANTED) {
if (!mPendingRequests.contains(perm)) {
permList.add(perm);
}
} else {
if (action != null) {
action.onResult(perm, Permissions.GRANTED);
}
}
}
return permList;
}

}

PermissionsManager.getInstance().requestAllManifestPermissionsIfNecessary(this, new PermissionsResultAction() {
@Override
public void onGranted() {
//          Toast.makeText(MainActivity.this, "All permissions have been granted", Toast.LENGTH_SHORT).show();
}

@Override
public void onDenied(String permission) {
//Toast.makeText(MainActivity.this, "Permission " + permission + " has been denied", Toast.LENGTH_SHORT).show();
}
});