Activity 生命周期

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看图看emo 效果会好的很多

package com.smzq;

import android.app.Activity;

import android.content.Context;

import android.content.Intent;

import android.os.Bundle;

import android.util.Log;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class MainActivity extends Activity {

private static final String TAG=”Mainactivity”;

private Context context=this;

int param=1;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

//activity 创建被调用

Log.i(TAG, “onCreate called.”);

setContentView(R.layout.activity_main);

Button btn=(Button) findViewById(R.id.btn);

btn.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent=new Intent(context,TargetActivity.class);
startActivity(intent);
}
});

}

//ACtivity创建或者后台重新回到前台时被调用

@Override

protected void onStart() {

// TODO Auto-generated method stub

super.onStart();

Log.i(TAG, “OnStart called.”);

}

//Activity 从后台重新回到前台时调用

@Override

protected void onRestart() {

// TODO Auto-generated method stub

super.onRestart();

Log.i(TAG, “OnRestrart called”);

}

//Activity 窗口获得失去焦点时被调用,在OnResume之后或Onpause之后

@Override

public void onWindowFocusChanged(boolean hasFocus) {

// TODO Auto-generated method stub

super.onWindowFocusChanged(hasFocus);

Log.i(TAG, “OnWindowFocusChanged called.”);

}

//Activity 被覆盖到下面或者锁屏被调到

@Override

protected void onPause() {

// TODO Auto-generated method stub

super.onPause();

Log.i(TAG, “Onpause called.”);

//有可能在执行完Onpause或OnStop后,系统资源紧张将Activity杀死,所有必要有必要在保存持久数据

}

//退出Activity 或者跳转到Activity时被调用

@Override

protected void onStop() {

// TODO Auto-generated method stub

super.onStop();

Log.i(TAG, “onDestroy called”);

}

//退出当前ACTIVITY时被调用，调用之后Activit就结束了

@Override

protected void onDestroy() {

// TODO Auto-generated method stub

super.onDestroy();

Log.i(TAG, “Ondestroy”);

}
/*
* Activity被系统杀死杀死时候被调用
* 列如 屏幕方向改变时，Activity被销毁再重建，当前Actity 处于后台，系统资源紧张将其杀死
* 另外 当跳转到其他Activity或者Home回到主屏时也会被调用，系统为了保存当前的view组件状态
* 在Onpause之前被调用
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
// TODO Auto-generated method stub
outState.putInt("param", param);
Log.i(TAG, "onSaveInstanceState .pat param："+param);
super.onSaveInstanceState(outState);
}
/*
* Activity 被系统杀死后重建时被调用
* 例如
*/
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
// TODO Auto-generated method stub
//这两种情况下onRestoreInstanceState都会被调用,在onStart之后.
super.onRestoreInstanceState(savedInstanceState);
Log.i(TAG, "onRestoreInstanceState call。 get param:"+param);

}

}

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