Android Activity的生命周期

1. 启动Activity：onCreate()->onStart()->onResume()->Activity is running

2. 按back键返回：onPause()->onStop()->onDestroy() 再次启动时:onCreate()->onStart()->onResume()->Activity is running

3.按home键返回：onPause()->onStop() 再次启动时：onRestart()->onStart()->onResume()->Activity is running

4.切换到别的Activity（当前Activity不finish）： onPause()->onStop() 再次启动时:onCreate()->onStart()->onResume()->Activity is running


5.切换到别的Activity（当前Activity finish）： onPause()->onStop()->onDestroy() 再次启动时:onCreate()->onStart()->onResume()->Activity is running

package com.Aina.Android;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class Test_CeShi extends Activity {
    /** Called when the activity is first created. */
    private int i = 1;
    private Button btn;
    /**
     * 创建
     */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        Log.i("TAG-onCreate", "onCreate()------------" + (i++));
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        btn = (Button) this.findViewById(R.id.Button01);
        btn.setOnClickListener(new Button.OnClickListener(){

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(Test_CeShi.this,fg.class);
                Test_CeShi.this.startActivity(intent);
//              Test_CeShi.this.finish();
            }

        });
    }

    /**
     * 重新开始
     */
    @Override
    protected void onRestart() {
        Log.i("TAG-onRestart", "onRestart()------------" + (i++));
        super.onRestart();
    }

    /**
     * 启动
     */
    @Override
    protected void onStart() {
        Log.i("TAG-onStart", "onStart()------------" + (i++));

        super.onStart();
    }

    /**
     * 重新启动
     */
    @Override
    protected void onResume() {
        Log.i("TAG-onResume", "onResume()------------" + (i++));
        super.onResume();
    }

    /**
     * 暂停
     */
    @Override
    protected void onPause() {
        Log.i("TAG-onPause", "onPause()------------" + (i++));

        super.onPause();
    }

    /**
     * 停止
     */
    @Override
    protected void onStop() {
        Log.i("TAG-onStop", "onStop()------------" + (i++));
        super.onStop();
    }

    /**
     * 销毁
     */
    @Override
    protected void onDestroy() {
        Log.i("TAG-onDestroy", "onDestroy()------------" + (i++));
        super.onDestroy();
    }

}