activeity 生命週期

package com.ActivityLifeCycle;

import android.app.Activity;

import android.content.SharedPreferences;

import android.os.Bundle;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.TextView;

import android.widget.Toast;

public class ActivityLifeCycle extends Activity {

public static final String MYPREFSID = "MyPrefs001";

public static final int actMode = Activity.MODE_PRIVATE;

EditText txtMsg;

Button btnFinish;

TextView txtToDo;

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

txtMsg = (EditText) findViewById(R.id.txtMsg);

//updateFromSavedState_IfNeeded();

txtToDo = (TextView) findViewById(R.id.txtToDo);

String msg = "Instructions:                                 \n "

+ "0. New instance (onCreate, onStart, onResume)   \n "

+ "1. Back Arrow   (onPause, onStop, onDestroy)    \n "

+ "2. Finish       (onPause, onStop, onDestroy)    \n "

+ "3. Home (onPause, onStop) \n "

+ "4. After 3> App Tab> re-execute current app     \n "

+ "  (onRestart, onStart, onResume) \n "

+ "5. Run DDMS> Receive a phone call or SMS \n "

+ "  (onRestart, onStart, onResume) \n "

+ "6. Enter some data - repeat steps 1-5    \n ";

txtToDo.setText(msg);

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

btnFinish.setOnClickListener(new Button.OnClickListener() {

@Override

public void onClick(View v) {

finish();

}

});

Toast.makeText(getBaseContext(), "onCreate ...", Toast.LENGTH_LONG)

.show();

}//onCreate

@Override

protected void onDestroy() {   //破壞

super.onDestroy();

clearMyPrefs();    //清除

Toast.makeText(getBaseContext(), "onDestroy ...", Toast.LENGTH_LONG)

.show();                   //跳出toast視窗說明

}

@Override

protected void onPause() {   //暫停

super.onPause();

saveDataFromCurrentState();    //儲存

Toast.makeText(getBaseContext(), "onPause ...", Toast.LENGTH_LONG)

.show();

}

@Override

protected void onRestart() {//重新開始

super.onRestart();

Toast.makeText(getBaseContext(), "onRestart ...", Toast.LENGTH_LONG)

.show();

}

@Override

protected void onResume() { //重新開始，再繼續

super.onResume();

Toast.makeText(getBaseContext(), "onResume...", Toast.LENGTH_LONG)

.show();

}

@Override

protected void onStart() {  //開始

super.onStart();

Toast.makeText(getBaseContext(), "onStart ...", Toast.LENGTH_LONG)

.show();

}

@Override

protected void onStop() {  //停止

super.onStop();

Toast.makeText(getBaseContext(), "onStop ...", Toast.LENGTH_LONG)

.show();

}

protected void updateFromSavedState_IfNeeded() {

SharedPreferences myPrefs = getSharedPreferences(MYPREFSID, actMode);

if ((myPrefs != null) && (myPrefs.contains("txtMsg"))) {

String myData = myPrefs.getString("txtMsg", "");

txtMsg.setText(myData);

}

}// UpdateFromSavedState_IfNeeded

protected void saveDataFromCurrentState() {    //儲存到暫存區

SharedPreferences myPrefs = getSharedPreferences(MYPREFSID, actMode);

SharedPreferences.Editor myEditor = myPrefs.edit();

myEditor.putString("txtMsg", txtMsg.getText().toString());

myEditor.commit();

}// saveDataFromCurrentState

protected void clearMyPrefs() {                       //清除暫存區

SharedPreferences myPrefs = getSharedPreferences(MYPREFSID, actMode);

SharedPreferences.Editor myEditor = myPrefs.edit();

myEditor.clear();

myEditor.commit();

}

/*

* protected void onRestoreInstanceState(Bundle savedInstanceState) This

* method is called after onStart() when the activity is being

* re-initialized from a previously saved state. The default implementation

* of this method performs a restore of any view state that had previously

* been frozen by onSaveInstanceState(Bundle).

*/

@Override

protected void onRestoreInstanceState(Bundle savedInstanceState) {

super.onRestoreInstanceState(savedInstanceState);

Toast.makeText(getBaseContext(), "onRestoreInstanceState ...BUNDLING",

Toast.LENGTH_LONG).show();

}

/*

* protected void onSaveInstanceState(Bundle outState)

* 

* Called to retrieve per-instance state from an activity before being

* killed so that the state can be restored in onCreate(Bundle) or

* onRestoreInstanceState(Bundle) (the Bundle populated by this method will

* be passed to both). This method is called before an activity may be

* killed so that when it comes back some time in the future it can restore

* its state. For example, if activity B is launched in front of activity A,

* and at some point activity A is killed to reclaim resources, activity A

* will have a chance to save the current state of its user interface via

* this method so that when the user returns to activity A, the state of the

* user interface can be restored via: onCreate(Bundle) or

* onRestoreInstanceState(Bundle).

*/

@Override

protected void onSaveInstanceState(Bundle outState) {

super.onSaveInstanceState(outState);

Toast.makeText(getBaseContext(), "onSaveInstanceState ...BUNDLING",

Toast.LENGTH_LONG).show();

} // onSaveInstanceState

}//LyfeCicleDemo