Android中的动画（待续）

Android中的动画分为三种：帧动画（Frame Animation）、补间动画（Tween Animation）和属性动画（Property Animation）。

帧动画

就是通过一系列drawable依次显示来模拟动画效果。

girl.xml

<?xml version="1.0" encoding="utf-8"?>
<animation-list xmlns:android="http://schemas.android.com/apk/res/android"
android:oneshot="false">
<item
android:drawable="@drawable/girl_1"
android:duration="200"/>
<item
android:drawable="@drawable/girl_2"
android:duration="200"/>
<item
android:drawable="@drawable/girl_3"
android:duration="200"/>
<item
android:drawable="@drawable/girl_4"
android:duration="200"/>
<item
android:drawable="@drawable/girl_5"
android:duration="200"/>
<item
android:drawable="@drawable/girl_6"
android:duration="400"/>
<item
android:drawable="@drawable/girl_7"
android:duration="400"/>
<item
android:drawable="@drawable/girl_6"
android:duration="400"/>
<item
android:drawable="@drawable/girl_7"
android:duration="400"/>
<item
android:drawable="@drawable/girl_6"
android:duration="400"/>
<item
android:drawable="@drawable/girl_7"
android:duration="400"/>
<item
android:drawable="@drawable/girl_8"
android:duration="200"/>
<item
android:drawable="@drawable/girl_9"
android:duration="200"/>
<item
android:drawable="@drawable/girl_10"
android:duration="200"/>
<item
android:drawable="@drawable/girl_11"
android:duration="200"/>

</animation-list>

MainActivity.java

public class MainActivity extends Activity {
private ImageView iv;
private AnimationDrawable mAnimationDrawable;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.iv);
// 把xml文件的动画资源设置为iv背景
iv.setBackgroundResource(R.drawable.girl);
// 获取设置的动画资源。 执行可能需要花费一定的时间
mAnimationDrawable = (AnimationDrawable) iv.getBackground();

}

public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mAnimationDrawable.start(); //异步操作
return true;
}
return super.onTouchEvent(event);
}
}

补间动画

Android中共有四种补间动画：透明度alpha、位移translate、缩放scale、旋转rotate。并且，可以使用set来定义以上四种动作的混合效果。我们可以通过逻辑代码来实现补间动画，也可以通过配置xml文件来实现相同效果。

特性：智能应用与View对象，而且只支持一部分属性。它只是改变了View对象绘制的位置，而没有改变View对象本身的范围

方法一、逻辑代码

MainActivity.java

public class MainActivity extends Activity {
private ImageView iv;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.iv);
}
//透明度动画 AlphaAnimation
public void alpha(View view){
AlphaAnimation aa = new AlphaAnimation(0.0f, 1.0f);
aa.setDuration(2000);
aa.setRepeatCount(1); //重复一次，总共两次
//aa.setRepeatCount(Animation.INFINITE); //无限循环播放
aa.setRepeatMode(Animation.REVERSE); //倒序播放
aa.setFillAfter(true); //停留在最后的效果
iv.startAnimation(aa);  //开始动画
}

//位移动画 TranslateAnimation
public void trans(View view){
TranslateAnimation ta = new TranslateAnimation(Animation.RELATIVE_TO_PARENT, -0.5f,
Animation.RELATIVE_TO_PARENT, 0.5f,  //父窗体宽度的50%
Animation.RELATIVE_TO_PARENT, 0.0f,
Animation.RELATIVE_TO_PARENT, 0.0f);
ta.setDuration(2000);
ta.setRepeatCount(1);
ta.setRepeatMode(Animation.REVERSE);
iv.startAnimation(ta);
}

//缩放动画 ScaleAnimation
public void scale(View view){
ScaleAnimation sa = new ScaleAnimation(0.1f, 2.0f, 0.1f, 2.0f, Animation.RELATIVE_TO_SELF,
0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
sa.setDuration(2000<
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sa.setRepeatCount(1);
sa.setRepeatMode(Animation.REVERSE);
sa.setFillAfter(true);
iv.startAnimation(sa);
}

//旋转动画 RotateAnimation
public void rotate(View view){
RotateAnimation ra = new RotateAnimation(0, 360, Animation.RELATIVE_TO_SELF,
0.0f, Animation.RELATIVE_TO_SELF, 0.0f);
ra.setDuration(2000);
ra.setRepeatCount(1);
ra.setRepeatMode(Animation.REVERSE);
iv.startAnimation(ra);
}

//动画组合 AnimationSet
public void set(View view){
AnimationSet set = new AnimationSet(false);

TranslateAnimation ta = new TranslateAnimation(Animation.RELATIVE_TO_PARENT, -0.5f,
Animation.RELATIVE_TO_PARENT, 0.5f,
Animation.RELATIVE_TO_PARENT, -0.5f,
Animation.RELATIVE_TO_PARENT, 0.5f);
ta.setDuration(2000);
ta.setRepeatCount(1);
ta.setRepeatMode(Animation.REVERSE);

ScaleAnimation sa = new ScaleAnimation(0.1f, 2.0f, 0.1f, 2.0f, Animation.RELATIVE_TO_SELF,
0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
sa.setDuration(2000);
sa.setRepeatCount(1);
sa.setRepeatMode(Animation.REVERSE);

RotateAnimation ra = new RotateAnimation(0, 360, Animation.RELATIVE_TO_SELF,
0.0f, Animation.RELATIVE_TO_SELF, 0.0f);
ra.setDuration(2000);
ra.setRepeatCount(1);
ra.setRepeatMode(Animation.REVERSE);

set.addAnimation(ra);
//set.addAnimation(ta);
set.addAnimation(sa);
iv.startAnimation(set);
}
}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal" >

<Button
android:onClick="rotate"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="旋转" />

<Button
android:onClick="scale"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="缩放" />

<Button
android:onClick="trans"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="位移" />

<Button
android:onClick="alpha"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="透明度" />

<Button
android:onClick="set"
android:layout_width="0dip"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="组合动画" />
</LinearLayout>

<ImageView
android:id="@+id/iv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:src="@drawable/ic_launcher" />

</RelativeLayout>

方法二、配置xml文件

在res文件夹中创建anim文件夹进行配置，最后在MainActivity中调用AnimationUtils.loadAnimation方法即可。

<?xml version="1.0" encoding="utf-8"?>
<alpha xmlns:android="http://schemas.android.com/apk/res/android"
android:fromAlpha="0.0"
android:toAlpha="1.0"
android:duration="2000"
android:repeatCount="1"
android:repeatMode="reverse"
android:fillAfter="true"
>
</alpha>

<?xml version="1.0" encoding="utf-8"?>
<translate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromXDelta="-50%p"
android:toXDelta="50%p"
android:fromYDelta="0"
android:toYDelta="0"
android:duration="2000"
android:repeatCount="1"
android:repeatMode="reverse">

</translate>

<?xml version="1.0" encoding="utf-8"?>
<rotate xmlns:android="http://schemas.android.com/apk/res/android"
android:fromDegrees="0"
android:toDegrees="360"
android:pivotX="50%"
android:pivotY="50%"
android:duration="2000"
android:repeatCount="1"
android:repeatMode="reverse" >

</rotate>

<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"
android:fromXScale="0.1"
android:toXScale="2.0"
android:fromYScale="0.1"
android:toYScale="2.0"
android:duration="2000"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="1"
android:repeatMode="reverse" >

</scale>

<?xml version="1.0" encoding="utf-8"?>
<set>

<alpha
xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="2000"
android:fillAfter="true"
android:fromAlpha="0.0"
android:repeatCount="1"
android:repeatMode="reverse"
android:toAlpha="1.0" >
</alpha>

<rotate       xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="2000"
android:fromDegrees="0"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="1"
android:repeatMode="reverse"
android:toDegrees="360" >
</rotate>

<scale       xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="2000"
android:fromXScale="0.1"
android:fromYScale="0.1"
android:pivotX="50%"
android:pivotY="50%"
android:repeatCount="1"
android:repeatMode="reverse"
android:toXScale="2.0"
android:toYScale="2.0" >
</scale>

<translate      xmlns:android="http://schemas.android.com/apk/res/android"
android:duration="2000"
android:fromXDelta="-50%p"
android:fromYDelta="0"
android:repeatCount="1"
android:repeatMode="reverse"
android:toXDelta="50%p"
android:toYDelta="0" >
</translate>

</set>

MainActivity.java

public class MainActivity extends Activity {
private ImageView iv;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
iv = (ImageView) findViewById(R.id.iv);
}
//透明度动画
public void alpha(View view){
Animation aa = AnimationUtils.loadAnimation(this, R.anim.alpha);
iv.startAnimation(aa);
}
//位移动画
public void trans(View view){
Animation ta = AnimationUtils.loadAnimation(this, R.anim.trans);
iv.startAnimation(ta);
}
//缩放动画
public void scale(View view){
Animation sa = AnimationUtils.loadAnimation(this, R.anim.scale);
iv.startAnimation(sa);
}

//旋转动画
public void rotate(View view){
Animation ra = AnimationUtils.loadAnimation(this, R.anim.rotate);
iv.startAnimation(ra);
}
//动画组合
public void set(View view){
Animation set = AnimationUtils.loadAnimation(this, R.anim.set);
iv.startAnimation(set);
}
}

属性动画

特性：可改变空间的属性，如位置、大小等。

（待续）