[android基础]Activity生命周期全解

说道Activity生命周期有张图肯定要挂一下的:

onCreate>>>onStart>>>onResume>>>onPause>>>onStop>>>onDestroy | onRestart

下面写了一个activity来测试这些内容:

package com.hebo.studytest.activitys;

import com.hebo.studytest.R;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.ServiceConnection;
import android.os.Bundle;
import android.os.IBinder;
import android.util.Log;
import android.view.Menu;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;

/**
 * Activity生命周期 and instanceState保存和恢复数据
 * @author HeBo
 * @Version V1.0
 */

public class MainActivity extends Activity {
	
	private final String TAG = "myActivity=====";

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		Log.i(TAG,"onCreate====");
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
	}
	
	@Override
	protected void onStart() {
		Log.i(TAG,"onStart====");
		super.onStart();
	}
	
	@Override
	protected void onResume() {
		Log.i(TAG,"onResume====");
		super.onResume();
	}
	
	@Override
	protected void onPause() {
		Log.i(TAG,"onPause====");
		super.onPause();
	}
	
	@Override
	protected void onStop() {
		Log.i(TAG,"onStop====");
		super.onStop();
	}
	
	@Override
	protected void onDestroy() {
		Log.i(TAG,"onDestroy====");
		super.onDestroy();
	}
	
	@Override
	protected void onRestart() {
		Log.i(TAG,"onRestart====");
		super.onRestart();
	}
	
	@Override
	protected void onSaveInstanceState(Bundle outState) {
		Log.i(TAG,"onSaveInstanceState====");
		super.onSaveInstanceState(outState);
	}
	
	@Override
	protected void onRestoreInstanceState(Bundle savedInstanceState) {
		Log.i(TAG,"onRestoreInstanceState====");
		super.onRestoreInstanceState(savedInstanceState);
	}

}

第一次运行效果如图:                         onCreate>>>onStart>>>onResume

此时按下手机home键:                    onPause>>>onSaveInstanceState>>>onStop

再次返回APP:                                  onRestart>>>onStart>>>onResume

按返回键,让程序退出:               onPause>>>onStop>>>onDestroy

activity在横竖屏切换的时候,周期也会发生一些变化,我们从头开始看:
1.首先第一次启动APP,默认竖屏,周期情况如图:

2.旋转屏幕为横屏:
onPause>>>onSaveInstanceState>>>onStop>>>onDestory>>>onCreate>>>onStart>>>onRestoreInstanceState>>>onResume

3.再次旋转为竖屏:
onPause>>>onSaveInstanceState>>>onStop>>>onDestory>>>onCreate>>>onStart>>>onRestoreInstanceState>>>onResume