What methods can be used to organize data transfer between Activities in an Android application?

In Android, data transfer between Activities is most commonly done using Intents with additional data (Extras). The main methods are:

• Intent Extras: adding data via putExtra() methods and retrieving via getExtra().
• Serializable or Parcelable objects: for passing complex objects through Intent.
• SharedPreferences: for saving and reading data between Activities, especially if the data needs to persist longer.
• External storage or databases: for large volumes of data.
• Using static fields or singletons: for storing common data in memory (not recommended due to the risk of memory leaks).

Example of passing a string via Intent:

Intent intent = new Intent(CurrentActivity.this, NextActivity.class);
intent.putExtra("key", "value");
startActivity(intent);

// In NextActivity
String value = getIntent().getStringExtra("key");