Swap broken on Android 6.0 or greater

We are getting ACRA reports such as this:

ANDROID_VERSION=6.0.1
APP_VERSION_NAME=0.100-alpha5
STACK_TRACE=android.view.InflateException: Binary XML file line #240: Attempt to invoke virtual method 'boolean cc.mvdan.accesspoint.WifiApControl.isWifiApEnabled()' on a null object reference
at android.view.LayoutInflater.inflate(LayoutInflater.java:539)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.inflateInnerView(SwapWorkflowActivity.java:336)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showIntro(SwapWorkflowActivity.java:381)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showRelevantView(SwapWorkflowActivity.java:300)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showRelevantView(SwapWorkflowActivity.java:274)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.access$100(SwapWorkflowActivity.java:68)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity$1.onServiceConnected(SwapWorkflowActivity.java:129)
at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1224)
at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1241)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5466)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'boolean cc.mvdan.accesspoint.WifiApControl.isWifiApEnabled()' on a null object reference
at org.fdroid.fdroid.views.swap.StartSwapView.uiUpdateWifiNetwork(StartSwapView.java:439)
at org.fdroid.fdroid.views.swap.StartSwapView.uiInitWifi(StartSwapView.java:356)
at org.fdroid.fdroid.views.swap.StartSwapView.onFinishInflate(StartSwapView.java:180)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:844)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
... 16 more
java.lang.NullPointerException: Attempt to invoke virtual method 'boolean cc.mvdan.accesspoint.WifiApControl.isWifiApEnabled()' on a null object reference
at org.fdroid.fdroid.views.swap.StartSwapView.uiUpdateWifiNetwork(StartSwapView.java:439)
at org.fdroid.fdroid.views.swap.StartSwapView.uiInitWifi(StartSwapView.java:356)
at org.fdroid.fdroid.views.swap.StartSwapView.onFinishInflate(StartSwapView.java:180)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:844)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:798)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.inflateInnerView(SwapWorkflowActivity.java:336)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showIntro(SwapWorkflowActivity.java:381)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showRelevantView(SwapWorkflowActivity.java:300)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.showRelevantView(SwapWorkflowActivity.java:274)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity.access$100(SwapWorkflowActivity.java:68)
at org.fdroid.fdroid.views.swap.SwapWorkflowActivity$1.onServiceConnected(SwapWorkflowActivity.java:129)
at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1224)
at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1241)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5466)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

The isWifiApEnabled() method is failing likely due to this in WifiApManager.getInstance(...):

// getInstance is a standard singleton instance getter, constructing
// the actual class when first called.
public static WifiApControl getInstance(Context context) {
	if (instance == null) {
		if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && !Settings.System.canWrite(context)) {
			Log.e(TAG, "6.0 or later, but haven't been granted WRITE_SETTINGS!");
			return null;
		}
		instance = new WifiApControl(context);
	}
	return instance;
}

And System.Settings.canWrite(...) has the following doc comments:

An app can use this method to check if it is currently allowed to write or modify system settings. In order to gain write access to the system settings, an app must declare the android.Manifest.permission#WRITE_SETTINGS permission in its manifest. If it is currently disallowed, it can prompt the user to grant it this capability through a management UI by sending an Intent with action android.provider.Settings#ACTION_MANAGE_WRITE_SETTINGS.

If I'm not mistaken, then this can either:

• Be logged against the libaccesspoint project, or
• We can ask for the WRITE_SETTINGS permission.

Thoughts @mvdan?

Ideally, it would only request the permissions if the user is going to use the AP setup stuff in swap.

There is nothing to fix in the library- see https://github.com/mvdan/accesspoint/issues/6

The way to fix this is to ask for the permission on 6.0+ upon use.

Milestone changed to 0.100

Reassigned to @eighthave

I stopped the crash, so I"m removing that tag. Here's more on the UX issues that still need to be solved:

• https://stackoverflow.com/a/32083622
• https://stackoverflow.com/a/34249702

Added ~16415 ui and removed bug crash labels

Milestone changed to 1.0

This is the actual way to bring up the perms screen:

Activity activity = getActivity();
Intent intent = new Intent(android.provider.Settings.ACTION_MANAGE_WRITE_SETTINGS);
intent.setData(Uri.parse("package:" + activity.getPackageName()));
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
activity.startActivity(intent);

Closed by the commit above.

Status changed to closed

Wait, this was not closed on purpose.

Status changed to reopened

Removed ui label