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 cl

Answer 1

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.

Answer 2

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 );

Answer 3

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.

Answer 4

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;
    ...
}

Answer 5

you declare like this

 private boolean isSelectionRight;

write

 out.writeInt(isSelectionRight ? 1 : 0);

read

isSelectionRight  = (in.readInt() == 0) ? false : true;

boolean type needs to be converted to something that Parcel supports and so we can convert it to int.

Answer 6

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});