大阪到青岛航班查询:详解Android动画之Tween Animation
来源:百度文库 编辑:偶看新闻 时间:2024/04/30 04:42:20
前面讲了动画中的Frame动画,今天就来详细讲解一下Tween动画的使用。
同样,在开始实例演示之前,先引用官方文档中的一段话:
Tween动画是操作某个控件让其展现出旋转、渐变、移动、缩放的这么一种转换过程,我们成为补间动画。我们可以以XML形式定义动画,也可以编码实现。
如果以XML形式定义一个动画,我们按照动画的定义语法完成XML,并放置于/res/anim目录下,文件名可以作为资源ID被引用;如果由编码实现,我们需要使用到Animation对象。
如果用定义XML方式实现动画,我们需要熟悉一下动画XML语法:
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- android:interpolator="@[package:]anim/interpolator_resource"
- android:shareInterpolator=["true" | "false"] >
- android:fromAlpha="float"
- android:toAlpha="float" />
- android:fromXScale="float"
- android:toXScale="float"
- android:fromYScale="float"
- android:toYScale="float"
- android:pivotX="float"
- android:pivotY="float" />
- android:fromX="float"
- android:toX="float"
- android:fromY="float"
- android:toY="float" />
- android:fromDegrees="float"
- android:toDegrees="float"
- android:pivotX="float"
- android:pivotY="float" />
- ...
XML文件中必须有一个根元素,可以是
另外,在动画中,如果我们添加了android:fillAfter="true"后,这个动画执行完之后保持最后的状态;android:duration="integer"代表动画持续的时间,单位为毫米。
如果要把定义在XML中的动画应用在一个ImageView上,代码是这样的:
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- ImageView image = (ImageView) findViewById(R.id.image);
- Animation testAnim = AnimationUtils.loadAnimation(this, R.anim.test);
- image.startAnimation(testAnim);
下面重点介绍一下插值器的概念:
首先要了解为什么需要插值器,因为在补间动画中,我们一般只定义关键帧(首帧或尾帧),然后由系统自动生成中间帧,生成中间帧的这个过程可以成为“插值”。插值器定义了动画变化的速率,提供不同的函数定义变化值相对于时间的变化规则,可以定义各种各样的非线性变化函数,比如加速、减速等。下面是几种常见的插值器:
然后我们可以这样使用一个插值器:
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- ...
- .../>
如果只简单地引用这些插值器还不能满足需要的话,我们要考虑一下个性化插值器。我们可以创建一个插值器资源修改插值器的属性,比如修改AnticipateInterpolator的加速速率,调整CycleInterpolator的循环次数等。为了完成这种需求,我们需要创建XML资源文件,然后将其放于/res/anim下,然后再动画元素中引用即可。我们先来看一下几种常见的插值器可调整的属性:
下面我们就拿最后一个插值器来举例:
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- android:tension="7.0"/>
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- android:interpolator="@anim/my_overshoot_interpolator"
- .../>
我们可以实现Interpolator接口,因为上面所有的Interpolator都实现了Interpolator接口,这个接口定义了一个方法:float getInterpolation(float input);
此方法由系统调用,input代表动画的时间,在0和1之间,也就是开始和结束之间。
线性(匀速)插值器定义如下:
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- public float getInterpolation(float input) {
- return input;
- }
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- public float getInterpolation(float input) {
- return (float)(Math.cos((input + 1) * Math.PI) / 2.0f) + 0.5f;
- }
讲了这么久的概念,下面我们就结合实例来演示一下几种Tween动画的应用。
先来介绍一下旋转动画的使用,布局文件/res/layout/rotate.xml如下:
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- xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="#FFFFFF">
- android:id="@+id/piechart"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center_horizontal"
- android:src="@drawable/piechart"/>
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- android:interpolator="@android:anim/accelerate_decelerate_interpolator">
- android:fromDegrees="0"
- android:toDegrees="+360"
- android:pivotX="50%"
- android:pivotY="50%"
- android:duration="5000"/>
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- package com.scott.anim;
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.View;
- import android.view.animation.Animation;
- import android.view.animation.AnimationUtils;
- import android.view.animation.LinearInterpolator;
- import android.view.animation.RotateAnimation;
- public class RotateActivity extends Activity {
- private int currAngle;
- private View piechart;
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.rotate);
- piechart = findViewById(R.id.piechart);
- Animation animation = AnimationUtils.loadAnimation(this, R.anim.rotate);
- piechart.startAnimation(animation);
- }
- public void positive(View v) {
- Animation anim = new RotateAnimation(currAngle, currAngle + 180, Animation.RELATIVE_TO_SELF, 0.5f,
- Animation.RELATIVE_TO_SELF, 0.5f);
- /** 匀速插值器 */
- LinearInterpolator lir = new LinearInterpolator();
- anim.setInterpolator(lir);
- anim.setDuration(1000);
- /** 动画完成后不恢复原状 */
- anim.setFillAfter(true);
- currAngle += 180;
- if (currAngle > 360) {
- currAngle = currAngle - 360;
- }
- piechart.startAnimation(anim);
- }
- public void negative(View v) {
- Animation anim = new RotateAnimation(currAngle, currAngle - 180, Animation.RELATIVE_TO_SELF, 0.5f,
- Animation.RELATIVE_TO_SELF, 0.5f);
- /** 匀速插值器 */
- LinearInterpolator lir = new LinearInterpolator();
- anim.setInterpolator(lir);
- anim.setDuration(1000);
- /** 动画完成后不恢复原状 */
- anim.setFillAfter(true);
- currAngle -= 180;
- if (currAngle < -360) {
- currAngle = currAngle + 360;
- }
- piechart.startAnimation(anim);
- }
- }
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- xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:background="#FFFFFF">
- android:id="@+id/splash"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:layout_gravity="center"
- android:src="@drawable/splash"/>
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:layout_gravity="bottom"
- android:text="alpha"
- android:onClick="alpha"/>
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-
- android:fromAlpha="0.0"
- android:toAlpha="1.0"
- android:duration="3000"/>
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- package com.scott.anim;
- import android.app.Activity;
- import android.os.Bundle;
- import android.util.Log;
- import android.view.View;
- import android.view.animation.AlphaAnimation;
- import android.view.animation.Animation;
- import android.view.animation.Animation.AnimationListener;
- import android.view.animation.AnimationUtils;
- import android.widget.ImageView;
- public class AlphaActivity extends Activity implements AnimationListener {
- private ImageView splash;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.alpha);
- splash = (ImageView) findViewById(R.id.splash);
- Animation anim = AnimationUtils.loadAnimation(this, R.anim.alpha);
- anim.setAnimationListener(this);
- splash.startAnimation(anim);
- }
- public void alpha(View view) {
- Animation anim = new AlphaAnimation(1.0f, 0.0f);
- anim.setDuration(3000);
- anim.setFillAfter(true);
- splash.startAnimation(anim);
- }
- @Override
- public void onAnimationStart(Animation animation) {
- Log.i("alpha", "onAnimationStart called.");
- }
- @Override
- public void onAnimationEnd(Animation animation) {
- Log.i("alpha", "onAnimationEnd called");
- }
- @Override
- public void onAnimationRepeat(Animation animation) {
- Log.i("alpha", "onAnimationRepeat called");
- }
- }
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- xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- android:id="@+id/trans_image"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_weight="1"
- android:src="@drawable/person"/>
- android:id="@+id/trans_button"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:layout_gravity="bottom"
- android:text="translate"
- android:onClick="translate"/>
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- android:interpolator="@android:anim/bounce_interpolator">
- android:fromXDelta="0"
- android:fromYDelta="0"
- android:toXDelta="200"
- android:toYDelta="300"
- android:duration="2000"/>
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- package com.scott.anim;
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.View;
- import android.view.animation.Animation;
- import android.view.animation.AnimationUtils;
- import android.view.animation.OvershootInterpolator;
- import android.view.animation.TranslateAnimation;
- import android.widget.ImageView;
- public class TranslateActivity extends Activity {
- private ImageView trans_iamge;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.tanslate);
- trans_iamge = (ImageView) findViewById(R.id.trans_image);
- Animation anim = AnimationUtils.loadAnimation(this, R.anim.translate);
- anim.setFillAfter(true);
- trans_iamge.startAnimation(anim);
- }
- public void translate(View view) {
- Animation anim = new TranslateAnimation(200, 0, 300, 0);
- anim.setDuration(2000);
- anim.setFillAfter(true);
- OvershootInterpolator overshoot = new OvershootInterpolator();
- anim.setInterpolator(overshoot);
- trans_iamge.startAnimation(anim);
- }
- }
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- xmlns:android="http://schemas.android.com/apk/res/android"
- android:orientation="vertical"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent">
- android:id="@+id/scale_image"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:layout_gravity="center"
- android:layout_weight="1"
- android:src="@drawable/person"/>
- android:id="@+id/scale_button"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:layout_gravity="bottom"
- android:text="scale"
- android:onClick="sclae"/>
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- android:interpolator="@android:anim/bounce_interpolator">
- android:fromXScale="1.0"
- android:toXScale="2.0"
- android:fromYScale="1.0"
- android:toYScale="2.0"
- android:pivotX="0.5"
- android:pivotY="50%"
- android:duration="2000"/>
- android:fromAlpha="0.0"
- android:toAlpha="1.0"
- android:duration="3000"/>
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- package com.scott.anim;
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.View;
- import android.view.animation.Animation;
- import android.view.animation.AnimationUtils;
- import android.view.animation.BounceInterpolator;
- import android.view.animation.ScaleAnimation;
- import android.widget.ImageView;
- public class ScaleActivity extends Activity {
- private ImageView scale_iamge;
- @Override
- protected void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.scale);
- scale_iamge = (ImageView) findViewById(R.id.scale_image);
- Animation anim = AnimationUtils.loadAnimation(this, R.anim.scale);
- anim.setFillAfter(true);
- scale_iamge.startAnimation(anim);
- }
- public void sclae(View view) {
- Animation anim = new ScaleAnimation(2.0f, 1.0f, 2.0f, 1.0f,
- Animation.RELATIVE_TO_SELF, 0.5f,
- Animation.RELATIVE_TO_SELF, 0.5f);
- anim.setDuration(2000);
- anim.setFillAfter(true);
- BounceInterpolator bounce = new BounceInterpolator();
- anim.setInterpolator(bounce);
- scale_iamge.startAnimation(anim);
- }
- }