Android HashMap in Bundle?

Question

The android.os.Message uses a Bundle to send with it\'s sendMessage-method. Therefore, is it possible to put a HashMap inside a

Answer 1

If you want to send all the keys in the bundle, you can try

for(String key: map.keySet()){
    bundle.putStringExtra(key, map.get(key));
}

Answer 2

In Kotlin:

hashMap = savedInstanceState?.getSerializable(ARG_HASH_MAP) as? HashMap<Int, ValueClass>

putSerializable(ARG_HASH_MAP, hashMap)

Answer 3

try as:

Bundle extras = new Bundle();
extras.putSerializable("HashMap",hashMap);
intent.putExtras(extras);

and in second Activity

Bundle bundle = this.getIntent().getExtras();

if(bundle != null) {
   hashMap = bundle.getSerializable("HashMap");
}

because Hashmap by default implements Serializable so you can pass it using putSerializable in Bundle and get in other activity using getSerializable

Answer 4

Please note: If you are using a AppCompatActivity, you will have to call the protected void onSaveInstanceState(Bundle outState) {} (NOT public void onSaveInstanceState(Bundle outState, PersistableBundle outPersistentState) {}) method.

Example code...

Store the map:

@Override
protected void onSaveInstanceState(Bundle outState) {
    super.onSaveInstanceState(outState);
    outState.putSerializable("leftMaxima", leftMaxima);
    outState.putSerializable("rightMaxima", rightMaxima);
}

And receive it in onCreate:

if (savedInstanceState != null) {
    leftMaxima = (HashMap<Long, Float>) savedInstanceState.getSerializable("leftMaxima");
    rightMaxima = (HashMap<Long, Float>) savedInstanceState.getSerializable("rightMaxima");
}

Sorry if it's some kind of a duplicate answer - maybe someone will find it useful. :)

Answer 5

According to the doc, Hashmap implements Serializable, so you can putSerializable I guess. Did you try it ?

Answer 6

  public static Bundle mapToBundle(Map<String, Object> data) throws Exception {
    Bundle bundle = new Bundle();
    for (Map.Entry<String, Object> entry : data.entrySet()) {
        if (entry.getValue() instanceof String)
            bundle.putString(entry.getKey(), (String) entry.getValue());
        else if (entry.getValue() instanceof Double) {
            bundle.putDouble(entry.getKey(), ((Double) entry.getValue()));
        } else if (entry.getValue() instanceof Integer) {
            bundle.putInt(entry.getKey(), (Integer) entry.getValue());
        } else if (entry.getValue() instanceof Float) {
            bundle.putFloat(entry.getKey(), ((Float) entry.getValue()));
        }
    }
    return bundle;
}