用开源项目JazzyViewPager实现ViewPager切换动画

　　JazzyViewPager这个项目可以让viewpager有各种绚丽的动画，而且还可以自由扩展。但从官网下载的lib导入时会出现找不到视图的问题，不知道是不是我人品不行，所以我就自己写了lib。总之，本篇就是来讲这些可以有华丽动画的viewpager。

JazzyViewPager项目地址：https://github.com/jfeinstein10/JazzyViewPager

  

一、布局文件

像viewpager一样，直接写一个控件即可。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:background="#00ff00">

    <com.jfeinstein.jazzyviewpager.JazzyViewPager
        xmlns:app="http://schemas.android.com/apk/res-auto"
        android:id="@+id/jazzyViewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent" >
    </com.jfeinstein.jazzyviewpager.JazzyViewPager>

</LinearLayout>

它里面还有很多属性可以定义的，像上面的可以用app这个命名空间来定义属性。下面是各种属性，基本就是各种动画，和淡入淡出效果

fadeEnable:是否有淡入淡出效果

outLineEnable:viewpager一个视图周边是否有边框

outLineColor:边框颜色

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

    <declare-styleable name="JazzyViewPager">
        <attr name="style">
            <enum name="standard" value="0" />
            <enum name="tablet" value="1" />
            <enum name="cubein" value="2" />
            <enum name="cubeout" value="3" />
            <enum name="flipvertical" value="4" />
            <enum name="fliphorizontal" value="5" />
            <enum name="stack" value="6" />
            <enum name="zoomin" value="7" />
            <enum name="zoomout" value="8" />
            <enum name="rotateup" value="9" />
            <enum name="rotatedown" value="10" />
            <enum name="accordion" value="11" />
        </attr>
        <attr name="fadeEnabled" format="boolean" />
        <attr name="outlineEnabled" format="boolean" />
        <attr name="outlineColor" format="color|reference" />
    </declare-styleable>

</resources> 

二、java代码实现

2.1首先看看它有什么动画效果，至于各种动画是什么样的，自己去试试吧~

* Standard
* Tablet
* CubeIn
* CubeOut
* FlipVertical
* FlipHorizontal
* Stack
* ZoomIn
* ZoomOut
* RotateUp
* RotateDown
* Accordion

2.2设置动画的方法

viewPager.setTransitionEffect(TransitionEffect.Tablet);

or

TransitionEffect effect = TransitionEffect.valueOf("Tablet");
setupJazziness(effect);

2.3简单设置

viewPager.setPageMargin(100);//两个页面之间的间距
viewPager.setFadeEnabled(true);//有淡入淡出效果
viewPager.setOutlineEnabled(true);//有边框
viewPager.setOutlineColor(0xff0000ff);//边框颜色

2.4适配器的写法

这里已经写的很简单了，以后照猫画虎就行。主要就是里面需要用这个viewpager做一些事情。

官方文档中说：Due to the limitations of the ViewPager class (which JazzyViewPager is built upon) in order to get the animations to work correctly for more than 3 Views, you'll have to add the following to theinstantiateItem method of your PagerAdapter.

private JazzyViewPager mJazzy;
/* ... */
@Override
public Object instantiateItem(ViewGroup container, final int position) {
    Object obj = super.instantiateItem(container, position);
    mJazzy.setObjectForPosition(obj, position);
    return obj;
}

大概意思就是如果viewpager中的view超过3个了，就需要添加上面这个方法。这里面的obj就是一个view对象，具体参照下面的例子。

例子：

    /**
     * @author:Jack Tony
     * @tips  :下面的方法需要注意，尽量按照这种写法。
     * @date  :2014-10-22
     */
    class MyAdapter extends PagerAdapter{

        @Override
        public int getCount() {
            // TODO 自动生成的方法存根
            return 10;
        }

        @Override
        public boolean isViewFromObject(View view, Object obj) {
            if (view instanceof OutlineContainer) {
                return ((OutlineContainer) view).getChildAt(0) == obj;
            } else {
                return view == obj;
            }
        }

        /* 如果viewpager中的view超过3个就需要重写这个方法*/
        @Override
        public Object instantiateItem(ViewGroup container, final int position) {
            TextView tv = new TextView(getApplicationContext());
            tv.setText("Page " + (position + 1));
            tv.setTextColor(Color.parseColor("#000000"));
            tv.setTextSize(30);
            tv.setGravity(Gravity.CENTER);
            tv.setBackground(getWallpaper());
            container.addView(tv, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);

            //这句话必须要写，按不同的位置添加视图
            viewPager.setObjectForPosition(tv, position);
            return tv;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object obj) {
            container.removeView(viewPager.findViewFromObject(position));
        }

    }

ok，这样就基本搞定了。贴上全部代码：

MainActivity.java

package com.kale.jazzviewpagertest;

import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.graphics.Color;
import android.os.Bundle;
import android.support.v4.view.PagerAdapter;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.jfeinstein.jazzyviewpager.JazzyViewPager;
import com.jfeinstein.jazzyviewpager.JazzyViewPager.TransitionEffect;
import com.jfeinstein.jazzyviewpager.OutlineContainer;

public class MainActivity extends Activity {

    private JazzyViewPager viewPager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        viewPager = (JazzyViewPager)findViewById(R.id.jazzyViewPager);
        /**
         * 添加动画效果，可以设置很多动画效果。如：
         * Standard
         * Tablet
         * CubeIn
         * CubeOut
         * FlipVertical
         * FlipHorizontal
         * Stack
         * ZoomIn
         * ZoomOut
         * RotateUp
         * RotateDown
         * Accordion
         *
         * 下面是可以通过字符串来产生动画对象的例子：
         * TransitionEffect effect = TransitionEffect.valueOf("Tablet");
         * setupJazziness(effect);
         */
        viewPager.setTransitionEffect(TransitionEffect.Tablet);
        viewPager.setPageMargin(100);//两个页面之间的间距
        viewPager.setFadeEnabled(true);//有淡入淡出效果
        viewPager.setOutlineEnabled(true);//有边框
        viewPager.setOutlineColor(0xff0000ff);//边框颜色
        /**
         * 设置适配器
         * 但当ViewPager中的子View超过三个的时候，我们需要对PagerAdapter修改，
         * 重写InstantiateItem()方法
         */
        viewPager.setAdapter(new MyAdapter());

        viewPager.setOnPageChangeListener(null);//可以监听page的改变
    }

    /**
     * @author:Jack Tony
     * @tips  :下面的方法需要注意，尽量按照这种写法。
     * @date  :2014-10-22
     */
    class MyAdapter extends PagerAdapter{

        @Override
        public int getCount() {
            // TODO 自动生成的方法存根
            return 10;
        }

        @Override
        public boolean isViewFromObject(View view, Object obj) {
            if (view instanceof OutlineContainer) {
                return ((OutlineContainer) view).getChildAt(0) == obj;
            } else {
                return view == obj;
            }
        }

        /* 如果viewpager中的view超过3个就需要重写这个方法*/
        @Override
        public Object instantiateItem(ViewGroup container, final int position) {
            TextView tv = new TextView(getApplicationContext());
            tv.setText("Page " + (position + 1));
            tv.setTextColor(Color.parseColor("#000000"));
            tv.setTextSize(30);
            tv.setGravity(Gravity.CENTER);
            tv.setBackground(getWallpaper());
            container.addView(tv, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);

            //这句话必须要写，按不同的位置添加视图
            viewPager.setObjectForPosition(tv, position);
            return tv;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object obj) {
            container.removeView(viewPager.findViewFromObject(position));
        }

    }
}

最终效果：

扩展：

我们当然可以继续扩展动画，下面就扩展一个动画。

一、先定义一个动画名字，这里叫test

public enum TransitionEffect {
        Standard,
        Tablet,
        CubeIn,
        CubeOut,
        FlipVertical,
        FlipHorizontal,
        Stack,
        ZoomIn,
        ZoomOut,
        RotateUp,
        RotateDown,
        Accordion,
        Test;}

二、写实现方式

protected void animateTest(View left, View right, float positionOffset) {
 if (mState != State.IDLE) {
  if (left != null) {
   //此处增加具体动画
 }
  if (right != null) {
   //此处增加具体动画实现
 }
 }
}

这里举一个源码中table的例子

    protected void animateTablet(View left, View right, float positionOffset) {
        if (mState != State.IDLE) {
            if (left != null) {
                manageLayer(left, true);
                mRot = 30.0f * positionOffset;
                mTrans = getOffsetXForRotation(mRot, left.getMeasuredWidth(),
                        left.getMeasuredHeight());
                ViewHelper.setPivotX(left, left.getMeasuredWidth()/2);
                ViewHelper.setPivotY(left, left.getMeasuredHeight()/2);
                ViewHelper.setTranslationX(left, mTrans);
                ViewHelper.setRotationY(left, mRot);
                logState(left, "Left");
            }
            if (right != null) {
                manageLayer(right, true);
                mRot = -30.0f * (1-positionOffset);
                mTrans = getOffsetXForRotation(mRot, right.getMeasuredWidth(),
                        right.getMeasuredHeight());
                ViewHelper.setPivotX(right, right.getMeasuredWidth()*0.5f);
                ViewHelper.setPivotY(right, right.getMeasuredHeight()*0.5f);
                ViewHelper.setTranslationX(right, mTrans);
                ViewHelper.setRotationY(right, mRot);
                logState(right, "Right");
            }
        }
    }

三、添加实现代码到设置项中

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
  if (mState == State.IDLE && positionOffset > 0) {
  oldPage = getCurrentItem();
  mState = position == oldPage ? State.GOING_RIGHT : State.GOING_LEFT;
}
boolean goingRight = position == oldPage;
if (mState == State.GOING_RIGHT && !goingRight)
  mState = State.GOING_LEFT;
  else if (mState == State.GOING_LEFT && goingRight)
  mState = State.GOING_RIGHT;

  float effectOffset = isSmall(positionOffset) ? 0 : positionOffset;

  // mLeft = getChildAt(position);
  // mRight = getChildAt(position+1);
  mLeft = findViewFromObject(position);
  mRight = findViewFromObject(position+1);

  if (mFadeEnabled)
  animateFade(mLeft, mRight, effectOffset);
  if (mOutlineEnabled)
  animateOutline(mLeft, mRight);

  switch (mEffect) {
  case Standard:
  break;
  case Tablet:
  animateTablet(mLeft, mRight, effectOffset);
  break;
  case CubeIn:
  animateCube(mLeft, mRight, effectOffset, true);
  break;
  case CubeOut:
  animateCube(mLeft, mRight, effectOffset, false);
  break;
  case FlipVertical:
  animateFlipVertical(mLeft, mRight, positionOffset, positionOffsetPixels);
  break;
  case FlipHorizontal:
  animateFlipHorizontal(mLeft, mRight, effectOffset, positionOffsetPixels);
  case Stack:
  animateStack(mLeft, mRight, effectOffset, positionOffsetPixels);
  break;
  case ZoomIn:
  animateZoom(mLeft, mRight, effectOffset, true);
  break;
  case ZoomOut:
  animateZoom(mLeft, mRight, effectOffset, false);
  break;
  case RotateUp:
  animateRotate(mLeft, mRight, effectOffset, true);
  break;
  case RotateDown:
  animateRotate(mLeft, mRight, effectOffset, false);
  break;
  case Accordion:
  animateAccordion(mLeft, mRight, effectOffset);
  break;
  case Test:  
　　animateTest(mLeft, mRight, effectOffset);
  break;
}

super.onPageScrolled(position, positionOffset, positionOffsetPixels);

if (effectOffset == 0) {
disableHardwareLayer();
mState = State.IDLE;
}

}

原理和思路讲解：http://blog.csdn.net/lmj623565791/article/details/38026503

源码下载：http://download.csdn.net/detail/shark0017/8070139

参考自：http://blog.csdn.net/t12x3456/article/details/13290349