06 bundle 对象

package com.szy.activity;

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;
import android.widget.EditText;

public class MainActivity extends Activity
{
private final static String TAG="MainActivity";
private static final String CONTENT = "content";
private Button secondBtn=null;
private EditText txt = null;

@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
txt=(EditText)findViewById(R.id.txt);
if (null!=savedInstanceState&&savedInstanceState.containsKey(CONTENT))
{
txt.setText(savedInstanceState.getString(CONTENT));
}
secondBtn=(Button)findViewById(R.id.secondBtn);
secondBtn.setOnClickListener(listener);
Log.i(TAG, "MainActivity-->onCreate");
}

@Override
protected void onDestroy()
{
super.onDestroy();
Log.i(TAG, "MainActivity-->onDestroy");
}

@Override
protected void onPause()
{
super.onPause();
Log.i(TAG, "MainActivity-->onPause");
}

@Override
protected void onRestart()
{
super.onRestart();
Log.i(TAG, "MainActivity-->onRestart");
}

@Override
protected void onResume()
{
super.onResume();
Log.i(TAG, "MainActivity-->onResume");
}

@Override
protected void onStart()
{
super.onStart();
Log.i(TAG, "MainActivity-->onStart");
}

@Override
protected void onStop()
{
super.onStop();
Log.i(TAG, "MainActivity-->onStop");
}

@Override
protected void onSaveInstanceState(Bundle outState)
{
super.onSaveInstanceState(outState);
Log.i(TAG, "MainActivity-->onSaveInstanceState");
String content=txt.getText().toString();
outState.putString(CONTENT, content);
}

private OnClickListener listener=new OnClickListener()
{
@Override
public void onClick(View v)
{
Button btn=(Button)v;
Intent intent=new Intent();
switch (btn.getId())
{
case R.id.secondBtn:
intent.setClass(MainActivity.this, SecondActivity.class);
break;
}
startActivity(intent);
}

};

}

protected void onSaveInstanceState(Bundle outState) 中的bundle对象由系统保存，下次执行时候 会将bundle传进来。