How to read write a boolean when implementing the Parcelable interface

Question

I m trying to make an ArrayList Parcelable in order to pass to an activity a list of custom object  I start writing a myObjectList class which extends ArrayList lt myObject gt  and implement Parcelable   Some attributes of MyObject are boolean but Parcel don t have  any method read writeBoolean   What is the best way to handle this

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out writeInt mBool   1   0     Write this mBool  in readInt    1    Read

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Short and simple implementation in Kotlin  with nullable support   Add methods to Parcel  fun Parcel writeBoolean flag  Boolean         when flag            true - gt  writeInt 1          false - gt  writeInt 0          else - gt  writeInt -1           fun Parcel readBoolean    Boolean        return when readInt              1 - gt  true         0 - gt  false         else - gt  null           And use it   parcel writeBoolean isUserActive   parcel readBoolean             For true  false  null parcel readBoolean             For only true and false

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You could also make use of the writeValue method  In my opinion that s the most straightforward solution   dst writeValue  myBool      Afterwards you can easily retrieve it with a simple cast to Boolean   boolean myBool    Boolean  source readValue  null      Under the hood the Android Framework will handle it as an integer   writeInt   Boolean  v   1   0

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It is hard to identify the real question here  I guess it is how to deal with booleans when implementing the Parcelable interface      Some attributes of MyObject are boolean but Parcel don t have any method read writeBoolean    You will have to either store the value as a string or as a byte  If you go for a string then you ll have to use the static method of the String class called valueOf   to parse the boolean value  It isn t as effective as saving it in a byte tough   String valueOf theBoolean     If you go for a byte you ll have to implement a conversion logic yourself   byte convBool   -1  if  theBoolean        convBool   1    else       convBool   0      When unmarshalling the Parcel object you have to take care of the conversion to the original type

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This question has already been answered perfectly by other people  if you want to do it on your own   If you prefer to encapsulate or hide away most of the low-level parceling code  you might consider using some of the code I wrote some time ago for simplifying handling of parcelables   Writing to a parcel is as easy as   parcelValues dest  name  maxSpeed  weight  wheels  color  isDriving     where color is an enum and isDriving is a boolean  for example   Reading from a parcel is also not much harder   color    CarColor unparcelValue CarColor class getClassLoader     isDriving    Boolean unparcelValue      Just take a look at the  ParceldroidExample  I added to the project   Finally  it also keeps the CREATOR initializer short   public static final Parcelable Creator lt Car gt  CREATOR       Parceldroid getCreatorForClass Car class

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Here s how I d do it     writeToParcel   dest writeByte  byte   myBoolean   1   0          if myBoolean    true  byte    1   readFromParcel   myBoolean   in readByte      0        myBoolean    true if byte    0

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You could pack your boolean values into a byte using masking and shifting  That would be the most efficient way to do it and is probably what they would expect you to do

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you declare like this  private boolean isSelectionRight   write  out writeInt isSelectionRight   1   0    read isSelectionRight    in readInt      0   boolean type needs to be converted to something that Parcel supports and so we can convert it to int

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I normally have them in an array and call writeBooleanArray and readBooleanArray  If it s a single boolean you need to pack  you could do this   parcel writeBooleanArray new boolean    myBool

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AndroidStudio  using 2 3 atm   after implementing Parcelable on your class  you can simply hold your mouse pointer over your class name and it asks you to add the parcelable implementation     From the four fields  it generates the following   public class YourClass implements Parcelable   String someString  int someInt  boolean someBoolean  List lt String gt  someList   protected YourClass Parcel in        someString   in readString        someInt   in readInt        someBoolean   in readByte      0      someList   in createStringArrayList        Override public void writeToParcel Parcel dest  int flags        dest writeString someString       dest writeInt someInt       dest writeByte  byte   someBoolean   1   0        dest writeStringList someList

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There are many examples in the Android  AOSP  sources  For example  PackageInfo class has a boolean member requiredForAllUsers and it is serialized as follows   public void writeToParcel Parcel dest  int parcelableFlags                dest writeInt requiredForAllUsers   1   0              private PackageInfo Parcel source                requiredForAllUsers   source readInt      0

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I suggested you the easiest way to implement Parcelable if you are using Android Studio     Simply go to File- Settings- Plugins- Browse Repository and search for parcelable  See image   It will automatically create Parcelable   And there is a webiste also for doing this  http   www parcelabler com

[android] How to read/write a boolean when implementing the Parcelable interface?

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