Stater

Lightweight library to save state in your Activity/Fragment. Stater also fine works with Kotlin code as it uses bytecode transformation.

Download

In root build.gradle file:

buildscript {
    ext.stater_version = '1.2'
    repositories {
        jcenter()
    }
    dependencies {
        ...
        classpath "ru.alexpanchenko:stater-plugin:$stater_version"
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

In your app build.gradle file add plugin:

apply plugin: 'com.android.application'
...
apply plugin: 'stater-plugin'

Usage

Activity

import ru.alexpanchenko.stater.State;

public class MainActivity extends AppCompatActivity {
  @State
  private int yourVar = 0;
  
  @State
  private Bundle bundleVar;
}

Fragment

import ru.alexpanchenko.stater.State;

public class MainFragment extends Fragment {
  @State
  private int yourVar = 0;
  
  @State
  private Bundle bundleVar;
}

It's all!

If you need to save custom fields just add a setting in your build.gradle file:

apply plugin: 'stater-plugin'

android {
  ...
}

stater {
  customSerializerEnabled = true
}

And then use:

import ru.alexpanchenko.stater.State;

public class MainActivity extends AppCompatActivity {
  @State
  private CustomClass customClass;
  // or
  @State
  private List<CustomClass> customClassList;
  // or
  @State
  private Container<CustomClass> customClassContainer;
}

Supported types

Supported Types
boolean/Boolean/boolean[ ]/Boolean[ ]
byte/Byte/byte[ ]/Byte[ ]
char/Character/char[ ]/Character[ ]
short/Short/short[ ]/Short[ ]
int/Integer/int[ ]/Integer[ ] List/ArrayList<Integer>
float/Float/float[ ]/Float[ ]
long/Long/long[ ]/Long[ ]
double/Double/double[ ]/Double[ ]
String/String[ ] List/ArrayList<String>
CharSequence/CharSequence[ ] List/ArrayList<CharSequence>
Serializable
Parcelable/Parcelable[ ] List/ArrayList<Parcelable>
Bundle
IBinder
Custom types (optional)

How it works

Stater plugin transform classes that inherit Activity/Fragment in compile time (see transformClassesWithStaterTransformFor... task). It save state in onSaveInstanceState and restore it in onCreate.

protected void onCreate(@Nullable Bundle savedInstanceState) {
    if (savedInstanceState != null) {
      this.yourVar = savedInstanceState.getInt("your/class/path_yourVar");
      this.bundleVar = savedInstanceState.bundleVar("your/class/path_bundleVar");
    }
    super.onCreate(savedInstanceState);
}

protected void onSaveInstanceState(@NonNull Bundle outState) {
    outState.putInt("your/class/path_yourVar", this.yourVar);
    outState.putBundle("your/class/path_bundleVar", this.bundleVar);
    super.onSaveInstanceState(outState);
}

Transformed classes you can find in build/intermediates/transforms/StaterTransform/yourPackage.

License

Copyright 2019 Alexey Panchenko

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.