Activity 生命周期及启动状态

package com.example.test;

import android.app.Activity;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

//A类

/**

* Activity

* 1、生命周期

* onCreate() -> onStart() -> onResume() -> onPause() -> onStop() ->onDestroy()

* 2、

* 启动：onCreate -> onStart -> onResume

* 按home键 onPause -> onStop ; 回来 onStart -> onResume

* 按返回键 onPause -> onStop -> onDestroy

* 3、

* 跳转

* A->B

* onPause(A) -> onCreate(B) -> onStart(B) -> onResume(B) ->onStop(A)

* 返回 B->A

* onPause(B) -> onStart(A) -> onResume(A) -> onStop(B) -> onDestroy(B)

*

* */

public class ActivityLife extends Activity {

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

p("onCreate");

Button btn = new Button(this);

btn.setText("跳转");

btn.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Intent intent = new Intent(ActivityLife.this, MainActivity.class);

startActivity(intent);

}});

setContentView(btn);

}

@Override

protected void onStart() {

super.onStart();

p("onStart");

}

@Override

protected void onResume() {

super.onResume();

p("onResume");

}

@Override

protected void onPause() {

super.onPause();

p("onPause");

}

@Override

protected void onStop() {

super.onStop();

p("onStop");

}

@Override

protected void onDestroy() {

super.onDestroy();

p("onDestroy");

}

public void p(String str) {

Log.e(this.getClass().getSimpleName(), str);

}

}

//B类

public class MainActivity extends Activity implements OnClickListener {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

print("onCreate");

}

@Override

protected void onStart() {

super.onStart();

print("onStart");

}

@Override

protected void onResume() {

super.onResume();

print("onResume");

}

@Override

protected void onPause() {

super.onPause();

print("onPause");

}

@Override

protected void onStop() {

super.onStop();

print("onStop");

}

@Override

protected void onDestroy() {

super.onDestroy();

print("onDestroy");

}

@Override

public void onConfigurationChanged(Configuration newConfig) {

super.onConfigurationChanged(newConfig);

print("onConfigurationChanged");

}

public void print(String str) {

Log.e(this.getClass().getSimpleName(),str);

}

}