원본 : http://code.google.com/android/samples/ApiDemos/src/com/google/android/samples/app/SaveRestoreState.html
/*
* Copyright (C) 2007 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.android.samples.app;
// Need the following import to get access to the app resources, since this
// class is in a sub-package.
import com.google.android.samples.R;
import android.app.Activity;
import android.os.Bundle;
import android.widget.EditText;
import android.widget.TextView;
import java.util.Map;
/**
* <p>Demonstrates required behavior of saving and restoring dynamic activity
* state, so that an activity will restart with the correct state if it is
* stopped by the system.</p>
*
* <p>In general, any activity that has been paused may be stopped by the system
* at any time if it needs more resources for the currently running activity.
* To handle this, before being paused the
* {@link android.app.Activity#onFreeze onFreeze()} method is called before
* an activity is paused, allowing it to supply its current state. If that
* activity then needs to be stopped, upon restarting it will receive its
* last saved state in
* {@link android.app.Activity#onCreate}.</p>
* <p>In this example we are currently saving and restoring the state of the
* top text editor, but not of the bottom text editor. You can see the difference
* by editing the two text fields, then going to a couple different
* applications while the demo is running and then returning back to it.</p>
* <h4>Demo</h4>
* App/Activity/Save & Restore State
* <h4>Source files</h4>
* <table class="LinkTable">
<tr>
<td class="LinkColumn">src/com/google/android/samples/app/SaveRestoreState.java</td>
<td class="DescrColumn">The Save/Restore Screen implementation</td>
</tr>
<tr>
<td class="LinkColumn">/res/any/layout/save_restore_state.xml</td>
<td class="DescrColumn">Defines contents of the screen</td>
</tr>
</table>
*/
public class SaveRestoreState extends Activity
{
/**
* Initialization of the Activity after it is first created. Here we use
* {@link android.app.Activity#setContentView setContentView()} to set up
* the Activity's content, and retrieve the EditText widget whose state we
* will save/restore.
*/
@Override
protected void onCreate(Bundle icicle)
{
// Be sure to call the super class.
super.onCreate(icicle);
// See assets/res/any/layout/save_restore_state.xml for this
// view layout definition, which is being set here as
// the content of our screen.
setContentView(R.layout.save_restore_state);
// Set message to be appropriate for this screen.
((TextView)findViewById(R.id.msg)).setText(R.string.save_restore_msg);
// Retrieve the EditText widget whose state we will save.
mSaved = (EditText)findViewById(R.id.saved);
// Look for any previously saved state of the EditText.
Bundle textState = icicle != null ? icicle.getBundle("text") : null;
if (textState != null) {
// Have the widget restore its previously save state. If we
// didn't find any state, we will skip this and thus use the
// default string in the EditText.
mSaved.restoreState(textState);
}
}
/**
* This is where you can save your current state. It is called
* immediately before onStop().
*
* @param outState Map in which to place your state.
*/
@Override
protected void onFreeze(Bundle outState)
{
super.onFreeze(outState);
// Save the current text editor state.
outState.putBundle("text", mSaved.saveStateAndText());
}
/**
* Retrieve the text that is currently in the "saved" editor.
*/
CharSequence getSavedText()
{
return ((EditText)findViewById(R.id.saved)).getText();
}
/**
* Change the text that is currently in the "saved" editor.
*/
void setSavedText(CharSequence text)
{
((EditText)findViewById(R.id.saved)).setText(text);
}
private EditText mSaved;
}
