Noisli not usable

Summary

Noisli app crashes each time when trying to playback sounds (https://www.noisli.com/).

Steps to reproduce

Run app, click an item to start play back

What is the current behavior?

app force closes once trying to playback sound

What is the expected correct behavior?

App is not crashing and works as intended

Relevant logs and/or screenshots

logcat

2-04 22:25:46.723 10261 10261 E AndroidRuntime: Process: com.noisli.noisli, PID: 10261
12-04 22:25:46.723 10261 10261 E AndroidRuntime: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.media.MediaPlayer.setOnErrorListener(android.media.MediaPlayer$OnErrorListener)' on a null object reference
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.noisli.noisli.PageViewActivity.musicstart(PageViewActivity.java:1217)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.noisli.noisli.MyFragment1.onTouch(MyFragment1.java:699)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.View.dispatchTouchEvent(View.java:11772)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2990)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2968)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2657)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.android.internal.policy.DecorView.superDispatchTouchEvent(DecorView.java:448)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.android.internal.policy.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1829)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.app.Activity.dispatchTouchEvent(Activity.java:3307)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.android.internal.policy.DecorView.dispatchTouchEvent(DecorView.java:410)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.View.dispatchPointerEvent(View.java:12015)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4795)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4609)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4200)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4166)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4293)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4174)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4350)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4200)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4166)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4174)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4147)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6661)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6635)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6596)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6764)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:186)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.os.MessageQueue.nativePollOnce(Native Method)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.os.MessageQueue.next(MessageQueue.java:325)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.os.Looper.loop(Looper.java:142)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at android.app.ActivityThread.main(ActivityThread.java:6494)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at java.lang.reflect.Method.invoke(Native Method)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:440)
12-04 22:25:46.723 10261 10261 E AndroidRuntime: 	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Possible fixes

n/a