一个简单的屏幕保护例子

package com.example.screensaverdemos;

import java.util.Date;
import android.os.Bundle;
import android.os.Handler;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;

/**
* @author Administrator
* ScreenSaveSetting summary:
* 当屏幕或按键没有被触碰的时间超过5s时，会进入屏幕保护模式。屏幕保护模式下，原来的布局文件被隐藏，只显示图片背景，
* 且每1s图片切换一次，图片切换时有淡入、淡出效果。本实例中使用了4个Handler来处理不同的功能模块。
* mMainTask每1s执行一次，
* 手机处于无人触碰状态时：
* 1s后，mCounter1 = 1
* 2s后，mCounter1 = 2；
* ...
* 5s后，mCounter = 5，mTimePeriod  = 5.009s,进入屏幕保护模式。显示屏幕淡出效果
* 6s后，执行mSwitchImageTask切换背景图片，同时又屏幕淡入效果
* 7s后，nothing
* 8s后，nothing
* 9s后，nothing
* 10s后，显示屏幕淡出效果
* 11s后，切换背景图片，显示屏幕淡入效果
* ...
* 注：所有的Handler都在一个Thread中运行
*/
public class ScreenSaveSettingActivity extends Activity {
private static final String TAG = "yxf";

private final static long INTERVAL_SCREENSAVER = 1000;
private final static long INTERVAL_KEYPADESAVER = 1000;
private final static long INTERVAL_FADE = 100;
private final static float HOLD_STILL_SECONDS = (float) 5;

private int mCounter1;// Calculate the count in mMainTask
private int mCounter2;//Calculate the count in mSetImageTask
private int mCounter3;//Calculate the count in mFadeOutTask
private int mCounter4;//Calculate the count in mFadeInTask

private long mTimePeriod;
private Date mLastUpdateTime;
/*每隔5s中更换一张照片*/
private int mSecondsToChange = 5;
private boolean mIsShowingScreenSaver;
/*flag to control whether to show fade out animation*/
private boolean mFadeOutFlag;
/*flag to control whether to show fade in animation*/
private boolean mFadeInFlag;

private TextView mTextView;
private ImageView mImageView;
private EditText mEditText;

private int mDrawablePos;
/* 设定Screen Saver需要用到的背景图 */
private static int[] mScreenDrawable = new int[]{
R.drawable.screen1,
R.drawable.screen2,
R.drawable.screen3,
R.drawable.screen4,
R.drawable.screen5
};
private Handler mMainHandler = new Handler();
private Handler mSwitchImageHandler = new Handler();
private Handler mFadeOutHandler = new Handler();
private Handler mFadeInHandler = new Handler();

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_main);
/* onCreate all Widget */
mTextView = (TextView)findViewById(R.id.textView1);
mImageView = (ImageView)findViewById(R.id.imageView1);
mEditText = (EditText)findViewById(R.id.editText1);

/* get the last time that user touches the screen */
mLastUpdateTime = new Date(System.currentTimeMillis());

/* set the original visibility */
recoverOriginalLayout();
}

@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
mMainHandler.postDelayed(mMainTask, INTERVAL_KEYPADESAVER);
}

/**
* mMainTask是核心代码，当mCounter=5时，timePeriodSecond>5s,第一次进入屏幕保护模式。
* 第6s(5s)期间的工作，：
*     1. 调用mFadeOutHandler推送mSwitchImageTask，1s后执行。
*     2. 设mFadeOutFlag=true，调用mFadeOutHandler推送mShowFadeOutTask，100ms后执行，接下来的1s也就是第6s期间会通过不停执行
*        mFadeOutTask来形成淡出动画。
*     3.设置mIsShowingScreenSaver为true。
* 第7s(6s后)期间的工作，mCounter1=6：
*     1. 上一秒的mSwitchImageTask这时候执行，设置背景为第一张图片。
*     2. 设置mFadeInFlag为true，调用mFadeInHandler推送mShowFadeInTask，0.1s后执行。
*     3. 设置mCountg3=0，mFadeOutFlag = false，这样就停止了mShowFadeOutTask的执行。
*     4. 不断的执行mShowFadeInTask形成淡入动画
* 7s后(第8s)做的工作，mCounter1=7：
*     1. 设置mFadeInFlag和mFadeOuntFlag均为false，mCounter3和mCounter4均为0,即使图片处于静止状态。
* 8s后(第9s)做的工作，mCounter1=8，与第8s一样；第10s也也与他一样；
* 10s后(第11s)时，mCounter1=10:
*     1.设置mFadeOutFlag为true，推送mFadeOutTask，0.1s后执行
*     2.重复调用mFadeOutTask形成淡出动画
*
*/
private Runnable mMainTask = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
mCounter1++;
Date timeNow = new Date(System.currentTimeMillis());
mTimePeriod = timeNow.getTime() - mLastUpdateTime.getTime();
float timePeriodSecond = ((float) mTimePeriod / 1000);
if (timePeriodSecond > HOLD_STILL_SECONDS) {
if (mIsShowingScreenSaver) {
/* ScreenSaver is running already */
if ((mCounter1 % mSecondsToChange) == 0) {
mFadeOutFlag = true;
mFadeOutHandler.postDelayed(mShowFadeOutTask, INTERVAL_FADE);
} else {
if (mFadeOutFlag) {
mFadeInFlag = true;
mFadeInHandler.postDelayed(mShowFadeInTask, INTERVAL_FADE);
} else {
mFadeInFlag = false;
mCounter4 = 0;
mFadeInHandler.removeCallbacks(mShowFadeInTask);
}
mCounter3 = 0;
mFadeOutFlag = false;
}
} else {
/*已经有足够长的时间没有用户触碰屏幕，进入屏幕保护模式*/
mSwitchImageHandler.postDelayed(mSwitchImageTask, INTERVAL_SCREENSAVER);
if ((mCounter1 % mSecondsToChange) == 0) {
mFadeOutFlag = true;
mFadeOutHandler.postDelayed(mShowFadeOutTask, INTERVAL_FADE);
} else {
if (mFadeOutFlag) {
mFadeInFlag = true;
mFadeInHandler.postDelayed(mShowFadeInTask, INTERVAL_FADE);
} else {
mFadeInFlag = false;
mCounter4 = 0;
mFadeInHandler.removeCallbacks(mShowFadeInTask);
}
mCounter3 = 0;
mFadeOutFlag = false;
}
mIsShowingScreenSaver = true;
}
} else {
mIsShowingScreenSaver = false;
/* 恢复原来的Layout Visible */
recoverOriginalLayout();
}
mMainHandler.postDelayed(mMainTask, INTERVAL_KEYPADESAVER);
}
};

private Runnable mSwitchImageTask = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
if (mIsShowingScreenSaver) {
mCounter2++;
hideOriginalLayout();
showScreenSaver();
mSwitchImageHandler.postDelayed(mSwitchImageTask,
INTERVAL_SCREENSAVER);
} else {
mSwitchImageHandler.removeCallbacks(mSwitchImageTask);
}
}
};

private Runnable mShowFadeOutTask = new Runnable() {
@SuppressWarnings("deprecation")
@Override
public void run() {
// TODO Auto-generated method stub
if(mFadeOutFlag && mIsShowingScreenSaver){
mCounter3++;
/* 设定ImageView的透明度渐暗下去 */
mImageView.setAlpha(255 - mCounter3*28);
mFadeOutHandler.postDelayed(mShowFadeOutTask, INTERVAL_FADE);
}else{
mFadeOutHandler.removeCallbacks(mShowFadeOutTask);
}
}
};

private Runnable mShowFadeInTask = new Runnable(){
@Override
public void run() {
// TODO Auto-generated method stub
if(mFadeInFlag && mIsShowingScreenSaver){
mCounter4++;
/* 设定ImageView的透明度渐暗下去 */
mImageView.setAlpha(mCounter4 * 28);
mFadeInHandler.postDelayed(mShowFadeInTask, INTERVAL_FADE);
}else {
mFadeInHandler.removeCallbacks(mShowFadeInTask);
}
}

};
private void hideOriginalLayout(){
mTextView.setVisibility(View.INVISIBLE);
mEditText.setVisibility(View.INVISIBLE);
}

private void showScreenSaver(){
/* 屏幕保护之后要做的事件写在此*/
if (mDrawablePos > 4) {
mDrawablePos = 0;
}
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
final int screenWidth = dm.widthPixels;
final int screenHeight = dm.heightPixels;
Bitmap bmp = BitmapFactory.decodeResource(getResources(),
mScreenDrawable[mDrawablePos]);
/* Matrix比例 */
float scaleWidth = ((float) screenWidth) / bmp.getWidth();
float scaleHeight = ((float) screenHeight) / bmp.getHeight();

Matrix matrix = new Matrix();
/* 使用Matrix.postScale设定维度ReSize */
matrix.postScale(scaleWidth, scaleHeight);

/* ReSize图文件吹屏幕分辨率 */
Bitmap resizedBitmap = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(),
bmp.getHeight(), matrix, true);
BitmapDrawable myNewBitmapDrawable = new BitmapDrawable(resizedBitmap);
mImageView.setImageDrawable(myNewBitmapDrawable);

/* 使ImageView可见 */
mImageView.setVisibility(View.VISIBLE);

/* 每间隔设定秒数置换图片ID，在下一个runnable2才会生效 */
// 在mTask2中将intDrawable加1，以显示下一张图片
if (mCounter2 % mSecondsToChange == 0) {
mDrawablePos++;
}
}

private void recoverOriginalLayout(){
mTextView.setVisibility(View.VISIBLE);
mEditText.setVisibility(View.VISIBLE);
mImageView.setVisibility(View.GONE);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
// TODO Auto-generated method stub
if (mIsShowingScreenSaver && keyCode != 4) {
/* 当屏幕保护程序正在执行中，触动解除屏幕保护程序 */
onUserWakeUpEvent();
} else {
/* 更新User未触动手机的时间戳记 */
updateUserActionTime();
}
return super.onKeyDown(keyCode, event);

}

public void updateUserActionTime() {
/* 取得按键事件时的系统Time millis */
Date timeNow = new Date(System.currentTimeMillis());
mLastUpdateTime.setTime(timeNow.getTime());
}

private void onUserWakeUpEvent(){
if(mIsShowingScreenSaver){
try{
resetScreenSaverListener();
}catch (Exception e){
e.printStackTrace();
}
}
}

private void resetScreenSaverListener(){
mMainHandler.removeCallbacks(mMainTask);
mSwitchImageHandler.removeCallbacks(mSwitchImageTask);
Date timeNow = new Date(System.currentTimeMillis());
mLastUpdateTime.setTime(timeNow.getTime());

mIsShowingScreenSaver = false;
mCounter1 = 0;
mCounter2 = 0;

recoverOriginalLayout();
mMainHandler.postDelayed(mMainTask, INTERVAL_KEYPADESAVER);
}

//当一个touch event事件没有被它下面的任一view处理、或者该事件发生在窗口的边界之外时，会调用该方法。
@Override
public boolean onTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
if(mIsShowingScreenSaver){
/* 当屏幕保护程序正执行中，触动解除屏幕保护程序 */
onUserWakeUpEvent();
}else{
/* 更新User未触动手机的时间戳记 */
updateUserActionTime();
}
return super.onTouchEvent(event);
}
}