Implement Parcelable for a List>

Question

I want to pass a List<Map<String, String>> to another Activity. How to implement Parcelable for it?

http://stackoverflow.com/questions/4141944/android-pass-listgeopoint-to-another-activity — Kazekage Gaara, Jun 04 '12 at 06:44
Wouldn't you just add your List to the intent (with putExtra()) when you call your activity — gideon, Jun 04 '12 at 06:45
http://stackoverflow.com/questions/7400564/android-parcelable-retailerorderactivity-java-return-null/7400675#7400675 — Lalit Poptani, Jun 04 '12 at 06:47
Can anybody give me some code? It's too hard to implement. It is absolutely not like to the GeoPoint sample above. — emeraldhieu, Jun 04 '12 at 07:04
Can't you use `putExtra (String name, Serializable value)` ? — Gubbel, Jun 04 '12 at 07:08
@Gubbel: Is List> serialized? I can't find out any sample on SO. — emeraldhieu, Jun 04 '12 at 07:09
do you think you can store it in database and retuen a list? — Tai Tran, Jun 04 '12 at 07:11

score 2 · Answer 1 · answered Dec 21 '12 at 19:50

2

When possible, try to use Bundle instead Map. In your case, List<Map<String, String>> a Bundle can replace very well.

More info: http://developer.android.com/reference/android/os/Bundle.html

answered Dec 21 '12 at 19:50

Felipe

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Alex Orlov · Accepted Answer · 2012-06-04T07:25:15.610

You could extend Map and implement Parcelable for it. When writing to parcel, you could write elements count as a first int, then iterate over entries and add them one after another like:

destParcelable.writeInt(size());
for (final Entry<String, String> entry : getEntries()) {
  destParcelable.writeString(entry.getKey());
  destParcelable.writeString(entry.getValue());
}

When reading from parcel just read the first int (that will be your entries count) and start a loop reading key and values one by one:

final int size = srcParcelable.readInt();
for (int i=0; i<size; i++) {
  put(srcParcelable.readString(), srcParcelable.readString());
}

And I believe there is a method to add list of parcelables to bundle, and since your map is a parcelable now it won't be any problems.

score 1 · Answer 3 · edited May 23 '17 at 10:34

You can do it like this: 1. Make a constructor of activity where you want to pass this list.

public Class CalledActivity extends Activity{

List<Map<String, String>> list;
public calledActivity(List<Map<String, String>> list){
this.list=list;
}
}

2. Call this constructor from the activity, you want to pass the list from.

See this question for reference. android activity class constructor working

Implement Parcelable for a List>

3 Answers3