QuickNote | 一款简约好用的笔记App。万水千山总是情，来个star行不行！

test is never null, since you have assigned an object to this variable before: ArrayList test = new ArrayList();

Try this instead: if(test.isEmpty())

Try this:-

Is your Activity in your AndroidManifest.xml?

If it is, you have to retrieve the title from your extras from onCreate() of MainActivity instead from the constructor.

Something like that:

how to dynamically change heights of the note cards based on their text length - you can just set the layout height to wrap_content like this:

android:layout_height="wrap_content"

You can put your items in scrollView like this:

instead of

I suppose you are loading items in your loadCategory function (cannot tell for sure, since you left out the definition of that function).

You need to call tableView.reloadData() after you retrieve the data into the data source structures (items in your case) and not before that.

You can skip the masking step and go straight to the mapping.

Actually, by introducing the following line, I feel that you create your own problem.

One option is mentioned in the comments: force a migration of data to XML and then get rid of the old class.

Another option is to try to parse it without the usage of Java Serialization machinery. There are some tools that parse java serialized data like https://github.com/gagern/nodeJavaDeserialization I could not find any library in java though, but, if you only have one class data to parse, the task to parse it does not seem so scary. The documentation on the format is available: http://docs.oracle.com/javase/6/docs/platform/serialization/spec/serialTOC.html , and ObjectOutputStream/ObjectInputStream source too.

And one more option would be to play with the serialized data before deserializing. Imagine that you rename your existing QuickNote to QuickNot2 (ugly, but will be useful later) and create your new class as QuickNote. Then, before deserializing the QuickNot2, you change that e to 2 in the serialized bytes representation. Here is a proof of concept:

1) it is not available from the repository, why? I don't know, but it is not the latest one for version 23, try com.android.support:recyclerview-v7:23.2.1 instead

2) you don't install the libraries with the SDK manager, that only install the source where gradle get the library from, the library itself gets downloaded when you build

I tried with 23.0.4 and could not get it, with 23.2.1 yes. If you can get version 25.0.0 it means that the repository is installed, maybe the gradle project is messed up somehow. Try to delete the project iml file and .idea folder and recreate it.