动态壁纸LiveWallPaper（字母雨及移动文字到屏幕边缘时会反弹）

上面的字母是从上面掉下来的，那个文字是另外的，会一直移动，碰到屏幕边缘时会几何反弹。。

下落的字母只有一个y速度，移动的字符串有一个x速度和一个Y速度。

下面是代码：

1、继承WallPaper的类

package com.wu.wallpaper;

import java.util.ArrayList;

import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.os.Handler;
import android.service.wallpaper.WallpaperService;
import android.util.Log;
import android.view.SurfaceHolder;

public class MyWallpaper extends WallpaperService implements Contants{

@Override
public Engine onCreateEngine() {
return new MyEngine();
}

class MyEngine extends Engine {
private ArrayList<Word> list;
private Paint mPaint;
private SurfaceHolder holder;
private int width;
private int height;
Word word;
int num = 0;
private int mTextSpeedX = 5;//文字的x速度
private int mTextSpeedY = 2;//文字的y速度
private int mTextX = TEXT_X;
private int mTextY = TEXT_Y;
private int mTextWidth;
private int mTextHeight;
Handler mHandler = new Handler();

private final Runnable ra = new Runnable() {

@Override
public void run() {
draw();
}
};

private void initList() {
list = new ArrayList<Word>();

for (int i = 0; i < WORD_NUMBER; i++) {
addListItem();
}
}

@Override
public void onCreate(SurfaceHolder surfaceHolder) {
super.onCreate(surfaceHolder);
//设置text的字体
Typeface mTypeface = Typeface.createFromAsset(getAssets(), "fanta.ttf");
mPaint = new Paint();
mPaint.setTypeface(mTypeface);
mTextWidth = (int) mPaint.measureText(TEXT);
width = getDesiredMinimumWidth()/2;
height = getDesiredMinimumHeight();
Log.i("test", "textWidth = " + mTextWidth + "   width = " + width);
//mPaint.setShadowLayer(30, 0, 0, WORD_COLOR);
holder = getSurfaceHolder();

initList();
}

@Override
public void onDestroy() {
mHandler.removeCallbacks(ra);
super.onDestroy();
}

@Override
public void onVisibilityChanged(boolean visible) {
if (visible) {
draw();
} else {
mHandler.removeCallbacks(ra);
}
}

@Override
public void onOffsetsChanged(float xOffset, float yOffset,
float xOffsetStep, float yOffsetStep, int xPixelOffset,
int yPixelOffset) {
draw();
}

private void draw() {
num = 0;
//锁定画布
Canvas canvas = holder.lockCanvas();
if (canvas != null) {
//清空画布
mPaint.setColor(BACKGROUND_COLOR);
canvas.drawRect(0, 0, 1024, 600, mPaint);
mPaint.setColor(WORD_COLOR);
mPaint.setTextSize(WORD_SIZE);
//画从上面掉下的字母
for (int i = 0; i < list.size(); i++) {
word = list.get(i);
canvas.drawText(word.getText(), word.getxOffset(), word
.getCurrentY(), mPaint);
}
//画一直移动的文字
mPaint.setTextSize(TEXT_SIZE);
mTextWidth = (int) mPaint.measureText(TEXT);
mTextHeight = (int) mPaint.getFontSpacing();
mTextX += mTextSpeedX;
mTextY += mTextSpeedY;
if (mTextX+mTextWidth > width || mTextX < 0) {
mTextSpeedX = -mTextSpeedX;
}

if (mTextY > height || mTextY < mTextHeight) {
mTextSpeedY = -mTextSpeedY;
}

canvas.drawText(TEXT, mTextX, mTextY, mPaint);
//解锁画布
holder.unlockCanvasAndPost(canvas);
}
//移除回调
mHandler.removeCallbacks(ra);
//调整字母的位置
for (int i = 0; i < list.size(); i++) {
word = list.get(i);
int currentY = word.getCurrentY() + word.getSpeed();
if (currentY > height) {
//如果有字母出了屏幕，则删除
list.remove(i);
num++;
continue;
}

word.setCurrentY(currentY);
}

//如果有字母被删除了，则随机添加新的字母
for (int i = 0; i < num; i++) {
addListItem();
}

//WORD_TIME_UPDATE时间后将线程加入线程队列，即执行线程
mHandler.postDelayed(ra, WORD_TIME_UPDATE);
}

private void addListItem() {
while (!addWord(new Word(width, height)));
}

private boolean addWord(Word word) {
if (list == null) {
return false;
}

//防止两个太近
for (int i = 0; i < list.size(); i++) {
if (Math.abs(word.getxOffset() - list.get(i).getxOffset()) < 20) {
return false;
}
}

list.add(word);
return true;
}
}
}

2、定义了常量的接口

package com.wu.wallpaper;

import android.graphics.Color;

public interface Contants {
static final String[] WORD = {"0", "1", "2", "3", "4", "5", "6", "7", "8", "9",
"a", "b", "C", "d", "e", "f", "g", "h", "i", "j",
"k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
"u", "v", "w", "x", "y", "z", "A", "B", "C", "D",
"E", "F", "G", "H", "I", "J", "K", "L", "M", "N",
"O", "P", "Q", "R", "S", "T", "U", "V", "W", "X",
"Y", "Z"};
//字母的大小
static final int WORD_SIZE = 30;
//字母的颜色
static final int WORD_COLOR = Color.GREEN;
//背景颜色
static final int BACKGROUND_COLOR = Color.BLACK;
//字母的个数,不能太大
static final int WORD_NUMBER = 8;
//刷新的时间间隔ms
static final int WORD_TIME_UPDATE = 10;
//滚动的字符串
static final String TEXT = "吴述军";//
//字符串的起始X、y速度
static final int TEXT_SPEED_X = 5;
static final int TEXT_SPEED_Y = 2;
//字符串的初始显示位置
static final int TEXT_X = 700;
static final int TEXT_Y = 300;
//字符串的字体大小
static final int TEXT_SIZE = 40;
}

3、xml文件夹下的配置文件

<?xml version="1.0" encoding="utf-8"?>
<wallpaper xmlns:android="http://schemas.android.com/apk/res/android"/>

4、manifest文件

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.wu.wallpaper"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk android:minSdkVersion="10" />

<application
android:icon="@drawable/ic_launcher"
android:label="@string/app_name" >
<!-- 配置实时壁纸Service -->
<service android:label="@string/app_name"
android:name=".MyWallpaper"
android:permission="android.permission.BIND_WALLPAPER">
<!-- 为实时壁纸配置intent-filter -->
<intent-filter>
<action	android:name="android.service.wallpaper.WallpaperService" />
</intent-filter>
<!-- 为实时壁纸配置meta-data -->
<meta-data android:name="android.service.wallpaper"
android:resource="@xml/livewallpaper" />
</service>
</application>

</manifest>

要图中的效果，还有一个ttf字体文件