本讲内容:Android 动画入门指南
1、补间动画
2、逐帧动画
Android中动画的实现分两种方式,一种方式是补间动画 Teen Animation,就是说你定义一个开始和结束,中间的部分由程序运算得到。另一种叫逐帧动画 Frame Animation,就是说一帧一帧的连起来播放就变成了动画。有点Flash基础的同学理解起来会很容易。接下来我们一个一个学习。
一、补间动画 Teen Animation
Android中实现补间动画的思路是这样的,
1、首先用XML定义一个动画效果
2、依据这个XML使用AnimationUtils工具类创建一个Animationd对象
3、调用View组件的startAnimation方法实现动画。
接下来我们用一个例子来看一下。
1、创建一个项目 Lesson24_Animation,主Activity名字叫MainActivity.java
2、在res目录下创建一个anim目录,在目录下创建下面五个动画定义文件,需要注意的是这5个文件在是2.2下调试通过的,网上很多文档的xml是无法通过IDE的检查的,可能是新版本检查更严格了。
alpha_animation.xml
1 | <? xml version = "1.0" encoding = "utf-8" ?> |
3 | < ALPHA xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/accelerate_interpolator" android:repeatcount = "1" android:repeatmode = "restart" android:fromalpha = "0.5" android:toalpha = "1.0" android:duration = "300" /> |
4 | < ALPHA xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/accelerate_interpolator" android:repeatcount = "0" android:repeatmode = "restart" android:fromalpha = "0.5" android:toalpha = "1.0" android:duration = "3000" /> |
composite_animation.xml
2 | < SCALE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/accelerate_decelerate_interpolator" android:duration = "700" android:fromxscale = "1.0" android:toxscale = "1.4" android:fromyscale = "1.0" android:toyscale = "0.6" android:pivotx = "50%" android:pivoty = "50%" android:fillafter = "false" /> |
3 | </ SET >< SET android:interpolator = "@android:anim/decelerate_interpolator" > |
4 | < SCALE xmlns:android = "http://schemas.android.com/apk/res/android" android:duration = "400" android:fromxscale = "1.4" android:toxscale = "0.0" android:fromyscale = "0.6" android:toyscale = "0.0" android:pivotx = "50%" android:pivoty = "50%" android:startoffset = "700" android:fillbefore = "false" /> |
5 | < ROTATE xmlns:android = "http://schemas.android.com/apk/res/android" android:duration = "400" android:toyscale = "0.0" android:pivotx = "50%" android:pivoty = "50%" android:startoffset = "700" android:fromdegrees = "0" android:todegrees = "-45" /> |
rotate_animation.xml
1 | <? xml version = "1.0" encoding = "utf-8" ?> |
3 | < ROTATE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/decelerate_interpolator" android:duration = "4000" android:pivotx = "50%" android:pivoty = "50%" android:fromdegrees = "0" android:todegrees = "-1440" > |
scale_animation.xml
1 | <? xml version = "1.0" encoding = "utf-8" ?> |
3 | < SCALE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/decelerate_interpolator" android:duration = "1000" android:fromxscale = "0.0" android:toxscale = "1.0" android:fromyscale = "0.0" android:toyscale = "1.0" android:pivotx = "0%" android:pivoty = "100%" android:fillafter = "false" > |
5 | < SCALE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/decelerate_interpolator" android:duration = "1000" android:fromxscale = "0.0" android:toxscale = "1.0" android:fromyscale = "0.0" android:toyscale = "1.0" android:pivotx = "50%" android:pivoty = "50%" android:fillafter = "false" > |
translate_animation.xml
1 | <? xml version = "1.0" encoding = "utf-8" ?> |
3 | < TRANSLATE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/decelerate_interpolator" android:duration = "2000" android:fromxdelta = "0" android:toxdelta = "300" android:fromydelta = "0" android:toydelta = "0" > |
5 | < TRANSLATE xmlns:android = "http://schemas.android.com/apk/res/android" android:interpolator = "@android:anim/decelerate_interpolator" android:duration = "2000" android:startoffset = "2000" android:fromxdelta = "0" android:toxdelta = "-300" android:fromydelta = "0" android:toydelta = "0" > |
3、MainActivity.java的内容如下:
01 | package android.basic.lesson24; |
03 | import android.app.Activity; |
04 | import android.os.Bundle; |
05 | import android.view.View; |
06 | import android.view.View.OnClickListener; |
07 | import android.view.animation.Animation; |
08 | import android.view.animation.AnimationUtils; |
09 | import android.widget.ImageButton; |
11 | public class MainAnimation extends Activity { |
12 | /** Called when the activity is first created. */ |
14 | public void onCreate(Bundle savedInstanceState) { |
15 | super .onCreate(savedInstanceState); |
16 | setContentView(R.layout.main); |
19 | final ImageButton ib1 = (ImageButton) findViewById(R.id.ImageButton01); |
20 | final ImageButton ib2 = (ImageButton) findViewById(R.id.ImageButton02); |
21 | final ImageButton ib3 = (ImageButton) findViewById(R.id.ImageButton03); |
22 | final ImageButton ib4 = (ImageButton) findViewById(R.id.ImageButton04); |
23 | final ImageButton ib5 = (ImageButton) findViewById(R.id.ImageButton05); |
26 | OnClickListener ocl = new OnClickListener() { |
29 | public void onClick(View v) { |
31 | case R.id.ImageButton01: |
33 | Animation ani1 = AnimationUtils.loadAnimation( |
34 | getApplicationContext(), R.anim.alpha_animation); |
36 | ib1.startAnimation(ani1); |
38 | case R.id.ImageButton02: |
39 | Animation ani2 = AnimationUtils.loadAnimation( |
40 | getApplicationContext(), R.anim.scale_animation); |
41 | ib2.startAnimation(ani2); |
43 | case R.id.ImageButton03: |
44 | Animation ani3 = AnimationUtils.loadAnimation( |
45 | getApplicationContext(), R.anim.translate_animation); |
46 | ib3.startAnimation(ani3); |
48 | case R.id.ImageButton04: |
49 | Animation ani4 = AnimationUtils.loadAnimation( |
50 | getApplicationContext(), R.anim.rotate_animation); |
51 | ib4.startAnimation(ani4); |
53 | case R.id.ImageButton05: |
54 | Animation ani5 = AnimationUtils.loadAnimation( |
55 | getApplicationContext(), R.anim.composite_animation); |
56 | ib5.startAnimation(ani5); |
65 | ib1.setOnClickListener(ocl); |
66 | ib2.setOnClickListener(ocl); |
67 | ib3.setOnClickListener(ocl); |
68 | ib4.setOnClickListener(ocl); |
69 | ib5.setOnClickListener(ocl); |
4、运行程序,查看结果
原始图
点击第一个按钮的透明度变化效果
点击第二个按钮的缩放效果,这里看到的是两个缩放效果同时作用叠加的效果。也就是说默认情况下效果是同时发生的,而不是先后执行的,除非你使用 startoffset属性指定。同学们看这一讲最重要的还是自己练习来体会。
点击第三个按钮的位移效果,这个例子里我们可以清楚看到android:startOffset="2000"的作用,数独按钮前2秒向右移了300像素,后2秒又回到原处,注意第二个translate中的负值参数,它清晰的告诉我们位移数据是相对自身当时位置的。
点击第四个按钮的旋转效果,负的度数表示逆时针旋转。
点击第五个按钮的复合动画效果,这个效果的代码我是直接粘贴的官方帮助文档里的代码,看着效果还不赖^_^
二、逐帧动画
我们知道,Android是不支持Gif动画的,也不建议使用Gif动画,比较不幸的是到Android 2.2版本为止也不支持APNG这种png动画格式,所以我们制作只能用多张png图片逐帧播放的方式来实现动画效果。下面我们用一个例子来学习一下逐帧动画。
1、新建一个项目 Lesson24_FrameAnimation , 主Acitivy名字叫 MainFrameAnimation.java
2、拷贝下列图片到 res/drawable目录下
2、在res/anim目录下,新建一个文件 firefox_animation.xml 内容如下:
01 | <? xml version = "1.0" encoding = "utf-8" ?> |
03 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_0" /> |
04 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_1" /> |
05 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_2" /> |
06 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_3" /> |
07 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_4" /> |
08 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_5" /> |
09 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_6" /> |
10 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_7" /> |
11 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_8" /> |
12 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_9" /> |
13 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_10" /> |
14 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_11" /> |
15 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_12" /> |
16 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_13" /> |
17 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_14" /> |
18 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_15" /> |
19 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_16" /> |
20 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_17" /> |
21 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_18" /> |
22 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_19" /> |
23 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_20" /> |
24 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_21" /> |
25 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_22" /> |
26 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_23" /> |
27 | < ITEM android:duration = "50" android:drawable = "@drawable/firefox_animation_24" /> |
3、在res/layout/main.xml中写入如下内容:
01 | <? xml version = "1.0" encoding = "utf-8" ?> |
04 | < TEXTVIEW android:layout_height = "wrap_content" android:layout_width = "fill_parent" android:text = "Android逐帧动画示例" android:textsize = "20sp" /> |
06 | < IMAGEVIEW android:layout_height = "wrap_content" android:layout_width = "wrap_content" android:background = "@anim/firefox_animation" android:id = "@+id/ImageView01" android:layout_margin = "10dp" > |
09 | < BUTTON type = submit android:layout_height = "wrap_content" android:layout_width = "wrap_content" android:text = "开始动画" android:textsize = "20sp" android:id = "@+id/Button01" > |
11 | < BUTTON type = submit android:layout_height = "wrap_content" android:layout_width = "wrap_content" android:text = "停止动画" android:textsize = "20sp" android:id = "@+id/Button02" > |
3、在MainFrameAnimation.javaz中的内容如下:
01 | package android.basic.lesson24; |
03 | import android.app.Activity; |
04 | import android.graphics.drawable.AnimationDrawable; |
05 | import android.os.Bundle; |
06 | import android.view.View; |
07 | import android.view.View.OnClickListener; |
08 | import android.widget.Button; |
09 | import android.widget.ImageView; |
11 | public class MainFrameAnimaton extends Activity { |
12 | /** Called when the activity is first created. */ |
14 | public void onCreate(Bundle savedInstanceState) { |
15 | super .onCreate(savedInstanceState); |
16 | setContentView(R.layout.main); |
19 | Button b1 = (Button) findViewById(R.id.Button01); |
20 | Button b2 = (Button) findViewById(R.id.Button02); |
21 | final ImageView iv = (ImageView) findViewById(R.id.ImageView01); |
24 | OnClickListener ocl = new OnClickListener() { |
27 | public void onClick(View v) { |
30 | AnimationDrawable ad = (AnimationDrawable) iv.getBackground(); |
46 | b1.setOnClickListener(ocl); |
47 | b2.setOnClickListener(ocl); |
4、运行程序,查看效果:
换个背景再来一张,可以看到png动画的透明就是不一般^_^
顺便提一下,我的这些可爱的小狐狸图标,是在APNG这个项目中找到的,感兴趣的朋友去搜搜APNG吧。
本讲就到这里吧。