一、在Android应用开发中，使用系统桌面背景作为应用的背景，需要把应用的背景设置为透明背景，然后设置窗口的属性为FLAG_SHOW_WALLPAPER即可显示背景。
1>.修改AndroidManifest.xml文件里面activity属性：
<activity android:name=".WallPaperTest"
android:label="@string/app_name"
android:theme="@android:style/Theme.Translucent">
2>.然后在使用的时候，在onCreate里面添加一个窗口属性
getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WALLPAPER);
二、背景拖动主要是使用了WallpaperManager这个类的两个方法
public voidsetWallpaperOffsetSteps(float xStep, float yStep)
1>.修改ScrollLayout的类，让它支持显示系统背景，并且拖动的时候背景也跟着拖动.基本类文件ScrollLayout.java
[java] view plain copy
packagecom.yao_guet;
importandroid.app.WallpaperManager;
importandroid.content.Context;
importandroid.os.IBinder;
importandroid.util.AttributeSet;
importandroid.util.Log;
importandroid.view.MotionEvent;
importandroid.view.VelocityTracker;
importandroid.view.View;
importandroid.view.ViewConfiguration;
importandroid.view.ViewGroup;
importandroid.widget.Scroller;
/**
* 仿Launcher中的WorkSapce，可以左右滑动切换屏幕的类，支持显示系统背景和滑动
* @author Hekang
* blog: 6600s.diandian.com
* date: 2012-04-22
*/
publicclassScrollLayoutextendsViewGroup {
privatestaticfinalString TAG ="ScrollLayout";
privateScroller mScroller;
privateVelocityTracker mVelocityTracker;
privateintmCurScreen;
privateintmDefaultScreen =0;
privatestaticfinalintTOUCH_STATE_REST =0;
privatestaticfinalintTOUCH_STATE_SCROLLING =1;
privatestaticfinalintSNAP_VELOCITY =600;
privateintmTouchState = TOUCH_STATE_REST;
privateintmTouchSlop;
privatefloatmLastMotionX;
privatefloatmLastMotionY;
privateWallpaperManager mWallpaperManager;
privateintmScrollX;
publicScrollLayout(Context context, AttributeSet attrs) {
this(context, attrs,0);
// TODO Auto-generated constructor stub
}
publicScrollLayout(Context context, AttributeSet attrs,intdefStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
mWallpaperManager = WallpaperManager.getInstance(context);
mScroller =newScroller(context);
mCurScreen = mDefaultScreen;
mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
}
@Override
protectedvoidonLayout(booleanchanged,intl,intt,intr,intb) {
// TODO Auto-generated method stub
Log.e(TAG,"onLayout");
intchildLeft =0;
finalintchildCount = getChildCount();
for(inti=0; i<childCount; i++) {
finalView childView = getChildAt(i);
if(childView.getVisibility() != View.GONE) {
finalintchildWidth = childView.getMeasuredWidth();
childView.layout(childLeft,0,
childLeft+childWidth, childView.getMeasuredHeight());
childLeft += childWidth;
}
}
updateWallpaperOffset();
}
@Override
protectedvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec) {
Log.e(TAG,"onMeasure");
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
finalintwidth = MeasureSpec.getSize(widthMeasureSpec);
finalintwidthMode = MeasureSpec.getMode(widthMeasureSpec);
if(widthMode != MeasureSpec.EXACTLY) {
thrownewIllegalStateException("ScrollLayout only canmCurScreen run at EXACTLY mode!");
}
finalintheightMode = MeasureSpec.getMode(heightMeasureSpec);
if(heightMode != MeasureSpec.EXACTLY) {
thrownewIllegalStateException("ScrollLayout only can run at EXACTLY mode!");
}
// The children are given the same width and height as the scrollLayout
finalintcount = getChildCount();
for(inti =0; i < count; i++) {
getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
}
// Log.e(TAG, "moving to screen "+mCurScreen);
scrollTo(mCurScreen * width,0);
}
/**
* According to the position of current layout
* scroll to the destination page.
*/
publicvoidsnapToDestination() {
finalintscreenWidth = getWidth();
finalintdestScreen = (getScrollX()+ screenWidth/2)/screenWidth;
snapToScreen(destScreen);
}
publicvoidsnapToScreen(intwhichScreen) {
// get the valid layout page
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));
if(getScrollX() != (whichScreen*getWidth())) {
finalintdelta = whichScreen*getWidth()-getScrollX();
mScroller.startScroll(getScrollX(),0,
delta,0, Math.abs(delta)*2);
mCurScreen = whichScreen;
invalidate();// Redraw the layout
}
}
publicvoidsetToScreen(intwhichScreen) {
whichScreen = Math.max(0, Math.min(whichScreen, getChildCount()-1));
mCurScreen = whichScreen;
scrollTo(whichScreen*getWidth(),0);
}
publicintgetCurScreen() {
returnmCurScreen;
}
@Override
publicvoidcomputeScroll() {
// TODO Auto-generated method stub
mScrollX = mScroller.getCurrX();
if(mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
updateWallpaperOffset();
postInvalidate();
}
}
@Override
publicbooleanonTouchEvent(MotionEvent event) {
// TODO Auto-generated method stub
if(mVelocityTracker ==null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(event);
finalintaction = event.getAction();
finalfloatx = event.getX();
finalfloaty = event.getY();
switch(action) {
caseMotionEvent.ACTION_DOWN:
Log.e(TAG,"event down!");
if(!mScroller.isFinished()){
mScroller.abortAnimation();
}
mLastMotionX = x;
break;
caseMotionEvent.ACTION_MOVE:
intdeltaX = (int)(mLastMotionX - x);
mLastMotionX = x;
scrollBy(deltaX,0);
updateWallpaperOffset();
break;
caseMotionEvent.ACTION_UP:
Log.e(TAG,"event : up");
// if (mTouchState == TOUCH_STATE_SCROLLING) {
finalVelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000);
intvelocityX = (int) velocityTracker.getXVelocity();
Log.e(TAG,"velocityX:"+velocityX);
if(velocityX > SNAP_VELOCITY && mCurScreen >0) {
// Fling enough to move left
Log.e(TAG,"snap left");
snapToScreen(mCurScreen -1);
}elseif(velocityX < -SNAP_VELOCITY
&& mCurScreen < getChildCount() -1) {
// Fling enough to move right
Log.e(TAG,"snap right");
snapToScreen(mCurScreen +1);
}else{
snapToDestination();
}
if(mVelocityTracker !=null) {
mVelocityTracker.recycle();
mVelocityTracker =null;
}
// }
mTouchState = TOUCH_STATE_REST;
break;
caseMotionEvent.ACTION_CANCEL:
mTouchState = TOUCH_STATE_REST;
break;
}
returntrue;
}
@Override
publicbooleanonInterceptTouchEvent(MotionEvent ev) {
// TODO Auto-generated method stub
Log.e(TAG,"onInterceptTouchEvent-slop:"+mTouchSlop);
finalintaction = ev.getAction();
if((action == MotionEvent.ACTION_MOVE) &&
(mTouchState != TOUCH_STATE_REST)) {
returntrue;
}
finalfloatx = ev.getX();
finalfloaty = ev.getY();
switch(action) {
caseMotionEvent.ACTION_MOVE:
finalintxDiff = (int)Math.abs(mLastMotionX-x);
if(xDiff>mTouchSlop) {
mTouchState = TOUCH_STATE_SCROLLING;
}
break;
caseMotionEvent.ACTION_DOWN:
mLastMotionX = x;
mLastMotionY = y;
mTouchState = mScroller.isFinished()? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING;
break;
caseMotionEvent.ACTION_CANCEL:
caseMotionEvent.ACTION_UP:
mTouchState = TOUCH_STATE_REST;
break;
}
returnmTouchState != TOUCH_STATE_REST;
}
privatevoidupdateWallpaperOffset() {
intscrollRange = getChildAt(getChildCount() -1).getRight() - getWidth();
IBinder token = getWindowToken();
if(token !=null) {
mWallpaperManager.setWallpaperOffsetSteps(1.0f / (getChildCount() -1),0);
mWallpaperManager.setWallpaperOffsets(getWindowToken(),
Math.max(0.f, Math.min(getScrollX()/(float)scrollRange,1.f)),0);
}
}
}
2>.测试代码WallPaperTest.java：
[java] view plain copy
packagecom.yao_guet;
importandroid.app.Activity;
importandroid.app.WallpaperManager;
importandroid.content.Context;
importandroid.os.Bundle;
importandroid.view.KeyEvent;
importandroid.view.Window;
importandroid.view.WindowManager;
publicclassWallPaperTestextendsActivity {
@Override
protectedvoidonCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.wallpaper_test);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_SHOW_WALLPAPER);
}
@Override
protectedvoidonDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
}
@Override
publicbooleanonKeyDown(intkeyCode, KeyEvent event) {
// TODO Auto-generated method stub
returnsuper.onKeyDown(keyCode, event);
}
}
3>.layout布局文件wallpaper_test.xml：
[html] view plain copy
<?xmlversion="1.0"encoding="utf-8"?>
<com.sf.test.ScrollLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/WallPaperTest"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 1"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 2"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 3"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 4"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 5"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 6"/>
</LinearLayout>
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="This is page 7"/>
</LinearLayout>
</com.sf.test.ScrollLayout>
4>.最后记得修改AndroidManifest.xml文件
<activity android:name=".WallPaperTest"
android:label="@string/app_name"
android:theme="@android:style/Theme.Translucent">