\n In the Android platform, Activity<\/strong> is a key component that constitutes the user interface. \n An activity is a screen that displays a specific task to the user. For example, screens where users can click buttons or \n An activity has states such as creation, start, pause, resume, stop, and destruction, and these states are managed through \n Below is a sample code that creates a basic activity and implements lifecycle methods. \n In Android, transitions between activities occur through Intents<\/strong>. \n Let\u2019s look at sample code that creates two activities, where clicking a button in the first activity \n When using intents, you can also pass data along. Let\u2019s examine how to pass data via intents through \n Today we learned about activities and their lifecycle in Android app development, <\/body><\/p>\n","protected":false},"excerpt":{"rendered":"
\n An activity can be viewed as a screen where the user can perform specific tasks and represents the basic building block of an Android application.\n <\/p>\nWhat is an Activity?<\/h2>\n
\n input information are all considered activities. Each activity exists independently and allows users
\n to perform various tasks by switching between multiple activities.\n <\/p>\nActivity Lifecycle<\/h2>\n
\n the activity’s lifecycle. Understanding the activity lifecycle is crucial for app development.\n <\/p>\nLifecycle Methods<\/h3>\n
\n
onCreate()<\/code>: Called when the activity is first created. Initializes UI and performs setup tasks.<\/li>\nonStart()<\/code>: Called when the activity is about to become visible to the user.<\/li>\nonResume()<\/code>: Called when the activity starts interacting with the user.<\/li>\nonPause()<\/code>: Called when another activity is about to start interacting with the user. Used to save important tasks.<\/li>\nonStop()<\/code>: Called when the activity is no longer visible to the user.<\/li>\nonDestroy()<\/code>: Called when the activity is finishing. Used to clean up remaining resources to prevent memory leaks.<\/li>\n<\/ul>\nActivity Example<\/h2>\n
\n In this example, the current state will be displayed in a TextView.\n <\/p>\n\npublic class MainActivity extends AppCompatActivity {\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_main);\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onCreate called\");\n }\n\n @Override\n protected void onStart() {\n super.onStart();\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onStart called\");\n }\n\n @Override\n protected void onResume() {\n super.onResume();\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onResume called\");\n }\n\n @Override\n protected void onPause() {\n super.onPause();\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onPause called\");\n }\n\n @Override\n protected void onStop() {\n super.onStop();\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onStop called\");\n }\n\n @Override\n protected void onDestroy() {\n super.onDestroy();\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"onDestroy called\");\n }\n}\n <\/code><\/pre>\nCommunication Between Intents and Activities<\/h2>\n
\n An intent is an object used to pass information from one activity to another or to call system components.\n <\/p>\nIntent Usage Example<\/h3>\n
\n transitions to the second activity.\n <\/p>\n\n\/\/ MainActivity.java\npublic class MainActivity extends AppCompatActivity {\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_main);\n Button button = findViewById(R.id.button);\n button.setOnClickListener(v -> {\n Intent intent = new Intent(MainActivity.this, SecondActivity.class);\n startActivity(intent);\n });\n }\n}\n\n\/\/ SecondActivity.java\npublic class SecondActivity extends AppCompatActivity {\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_second);\n TextView textView = findViewById(R.id.textView);\n textView.setText(\"This is the second activity.\");\n }\n}\n <\/code><\/pre>\nPassing Data<\/h2>\n
\n the following example.\n <\/p>\n\n\/\/ MainActivity.java (Adding data transfer)\npublic class MainActivity extends AppCompatActivity {\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_main);\n Button button = findViewById(R.id.button);\n button.setOnClickListener(v -> {\n Intent intent = new Intent(MainActivity.this, SecondActivity.class);\n intent.putExtra(\"message\", \"Hello, Second Activity\");\n startActivity(intent);\n });\n }\n}\n\n\/\/ SecondActivity.java (Receiving data)\npublic class SecondActivity extends AppCompatActivity {\n @Override\n protected void onCreate(Bundle savedInstanceState) {\n super.onCreate(savedInstanceState);\n setContentView(R.layout.activity_second);\n TextView textView = findViewById(R.id.textView);\n String message = getIntent().getStringExtra(\"message\");\n textView.setText(message);\n }\n}\n <\/code><\/pre>\nConclusion<\/h2>\n
\n transitions between activities via intents, and how to pass data.
\n These concepts are fundamental to Android app development and will serve as a starting point
\n for creating more complex apps.
\n In future lessons, we will cover more features and UI elements, so please stay tuned.\n <\/p>\n