原文:

最近做的APP接近尾声了，就是些优化工作了，

我们都知道现在的APP都会有引导页，就是安装之后第一次打开才显示的引导页面（介绍这个软件的几张可以切换的图）

自己做了一下，结合之前学过的

 

思路很简单，APP的主界面还是作为主Activity，只要新添加一个类来判断是不是第一次打开APP

设主activity 名字为：MainActivity.java   判断是不是第一次打开APP且实现引导页面的类 LoginActivity ，另外还需要一个类 这是中用到的 ZoomOutPageTransformer.java

1.在主activity中,在一开始 先跳转到LoginActivity类中

1  protected void onCreate(Bundle savedInstanceState) { 2         super.onCreate(savedInstanceState); 3         requestWindowFeature(Window.FEATURE_NO_TITLE); 4         setContentView(R.layout.activity_main); 5         startActivity(new Intent(MainActivity.this, LoginActivity.class)); //跳转到LoginActivity类中 6       //初始化 7         init(); 8         initEvent(); 9         //默认显示第一个功能的界面(微信界面)10         setSelect(0);11     }

2.在LoginActivity类中判断是不是第一次打开，如果是，则显示ViewPager切换动画效果

如果不是，则执行finish();语句，直接结束这个Activity  自然的就回到了主Activity中了

 

LoginActivity代码

1 package com.example.qunxiong; 2  3 import java.io.OutputStream; 4 import java.util.ArrayList; 5 import java.util.List; 6  7  8  9 import android.app.Activity;10 import android.content.Context;11 import android.content.Intent;12 import android.content.SharedPreferences;13 import android.content.SharedPreferences.Editor;14 import android.os.Bundle;15 import android.support.v4.view.PagerAdapter;16 import android.support.v4.view.ViewPager;17 import android.view.View;18 import android.view.ViewGroup;19 import android.view.View.OnClickListener;20 import android.widget.Button;21 import android.widget.ImageView;22 import android.widget.ImageView.ScaleType;23 24 public class LoginActivity extends Activity {25     private ViewPager mviewpager; //控件26     private int[] mImgIds = new int[]{R.drawable.bg_rank_shenqi_0,R.drawable.bg_rank_shenqi_1,R.drawable.bg_rank_shenqi_10};//初始化图片27     private List
     
       mImages = new ArrayList
      
       ();28     private Button jump;29      private SharedPreferences preferences;30       private Editor editor;31       private OutputStream os;32       @Override33       protected void onCreate(Bundle savedInstanceState) {34        super.onCreate(savedInstanceState);35        setContentView(R.layout.login);36        preferences = getSharedPreferences("phone", Context.MODE_PRIVATE);37        jump = (Button) findViewById(R.id.jump);38        jump.setOnClickListener(new OnClickListener() {    39             @Override40             public void onClick(View v) {41                 // TODO Auto-generated method stub42                 finish();43             }44         });45        //判断是不是首次登录，46        if (preferences.getBoolean("firststart", true)) {47         editor = preferences.edit();48         //将登录标志位设置为false，下次登录时不在显示首次登录界面49         editor.putBoolean("firststart", false);50         editor.commit();51         mviewpager = (ViewPager) findViewById(R.id.id_viewpager);52         //为ViewPage切换添加动画效果(3.0以上版本才可以有效果)53         mviewpager.setPageTransformer(true, new ZoomOutPageTransformer());54         55         mviewpager.setAdapter(new PagerAdapter() {56             57             @Override58             public Object instantiateItem(View container, int position) {59                 ImageView imageview = new ImageView(LoginActivity.this);60                 imageview.setImageResource(mImgIds[position]);61                 imageview.setScaleType(ScaleType.CENTER_CROP); //设置图片不变形62                 ((ViewGroup) container).addView(imageview);63                 mImages.add(imageview);64                 return imageview;65             };66             @Override67             public void destroyItem(View container, int position, Object object) {68                 // TODO Auto-generated method stub69                 70                 ((ViewPager) container).removeView(mImages.get(position));71             }72             public boolean isViewFromObject(View view, Object object) {73                 // TODO Auto-generated method stub74                 return view == object;75             }76             77             @Override78             public int getCount() {                   //返回图片个数79                 // TODO Auto-generated method stub80                 return mImgIds.length;81             }82         });83        }84        else 85        {86            finish();87        }88        89       }90 }91
      
     

 切换动画效果代码 

ZoomOutPageTransformer.java

1 package com.example.qunxiong; 2  3 import android.annotation.SuppressLint; 4 import android.support.v4.view.ViewPager; 5 import android.view.View; 6  7 public class ZoomOutPageTransformer implements ViewPager.PageTransformer { 8     private static final float MIN_SCALE = 0.85f; 9     private static final float MIN_ALPHA = 0.5f;10     11     @SuppressLint("NewApi") public void transformPage(View view, float position) {12         int pageWidth = view.getWidth();13         int pageHeight = view.getHeight();14 15         if (position < -1) { // [-Infinity,-1)16             // This page is way off-screen to the left.17             view.setAlpha(0);18 19         } else if (position <= 1) { // [-1,1]20             // Modify the default slide transition to shrink the page as well21             float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));22             float vertMargin = pageHeight * (1 - scaleFactor) / 2;23             float horzMargin = pageWidth * (1 - scaleFactor) / 2;24             if (position < 0) {25                 view.setTranslationX(horzMargin - vertMargin / 2);26             } else {27                 view.setTranslationX(-horzMargin + vertMargin / 2);28             }29 30             // Scale the page down (between MIN_SCALE and 1)31             view.setScaleX(scaleFactor);32             view.setScaleY(scaleFactor);33 34             // Fade the page relative to its size.35             view.setAlpha(MIN_ALPHA +36                     (scaleFactor - MIN_SCALE) /37                     (1 - MIN_SCALE) * (1 - MIN_ALPHA));38 39         } else { // (1,+Infinity]40             // This page is way off-screen to the right.41             view.setAlpha(0);42         }43     }44 }