How to use Parcel in Android?
- by Mike
I'm trying to use Parcel to write and then read back a Parcelable. For some reason, when I read the object back from the file, it's coming back as null.
public void testFoo() {
final Foo orig = new Foo("blah blah");
// Wrote orig to a parcel and then byte array
final Parcel p1 = Parcel.obtain();
p1.writeValue(orig);
final byte[] bytes = p1.marshall();
// Check to make sure that the byte array seems to contain a Parcelable
assertEquals(4, bytes[0]); // Parcel.VAL_PARCELABLE
// Unmarshall a Foo from that byte array
final Parcel p2 = Parcel.obtain();
p2.unmarshall(bytes, 0, bytes.length);
final Foo result = (Foo) p2.readValue(Foo.class.getClassLoader());
assertNotNull(result); // FAIL
assertEquals( orig.str, result.str );
}
protected static class Foo implements Parcelable {
protected static final Parcelable.Creator<Foo> CREATOR = new Parcelable.Creator<Foo>() {
public Foo createFromParcel(Parcel source) {
final Foo f = new Foo();
f.str = (String) source.readValue(Foo.class.getClassLoader());
return f;
}
public Foo[] newArray(int size) {
throw new UnsupportedOperationException();
}
};
public String str;
public Foo() {
}
public Foo( String s ) {
str = s;
}
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel dest, int ignored) {
dest.writeValue(str);
}
}
What am I missing?
UPDATE: To simplify the test I've removed the reading and writing of files in my original example.
