MainActivity.java

package com.example.activity_lifecycle;

import android.os.Bundle;
import android.app.Activity;
import android.util.Log;

public class MainActivity extends Activity {
	String msg ="Android: ";

	/** Called when the activity is first created. */
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		Log.d(msg, "The onCreate() event");
	}

	/** Called when the activity is about to become visible. */
	@Override
	protected void onStart() {
		super.onStart();
		Log.d(msg, "The onStart() event");
	}

	/**Called after the activity has been stopped, prior to it being started again.*/
	@Override
	protected void onRestart() {
		// TODO Auto-generated method stub
		super.onRestart();
		Log.d(msg, "The onRestart() event");
	}

	/** Called when the activity has become visible. */
	@Override
	protected void onResume() {
		super.onResume();
		Log.d(msg, "The onResume() event");
	}

	/** Called when another activity is taking focus. */
	@Override
	protected void onPause() {
		super.onPause();
		Log.d(msg, "The onPause() event");
	}

	/** Called when the activity is no longer visible. */
	@Override
	protected void onStop() {
		super.onStop();
		Log.d(msg, "The onStop() event");
	}

	/** Called just before the activity is destroyed. */
	@Override
	public void onDestroy() {
		super.onDestroy();
		Log.d(msg, "The onDestroy() event");
	}
	
/**
 * run program->Back key->run program:onCreate()->onStart()->onResume()===================>onPause()->onStop()->onDestroy()===================>onCreate()->onStart()->onResume()
 * run program->Home key->run program:onCreate()->onStart()->onResume()===================>onPause()->onStop()===================>onRestart()->onStart()->onResume()	
 */
}