Android欢迎页面WelcomeActivity实现

欢迎页面有两种情况：1、已经进入过app；2、首次安装或者刚刚更新到最新版本

1、情况1就一个背景图、一个跳过按钮、按钮上有个倒计时
直接上代码：
WelcomeActivity.java

 private void initOtherView() {
        View view = View.inflate(this, R.layout.welcome_activity, null);
        countDownTimer = new StartTimerTask(3000, 1000);//总倒计时3秒，间隔1秒
        passTv = (TextView) view.findViewById(R.id.pass_tv);//跳过按钮
        passTv.setVisibility(View.VISIBLE);
        passTv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {//点击跳过按钮
                if (countDownTimer != null && countDownTimer.getRunStatus()) {
                    countDownTimer.cancel();
                }
                redirectTo();//跳到主页面
            }
        });

        setContentView(view);
        // 渐变展示启动屏
        AlphaAnimation aa = new AlphaAnimation(0.5f, 1.0f);
        aa.setDuration(800);
        view.startAnimation(aa);
        aa.setAnimationListener(new Animation.AnimationListener() {
            @Override
            public void onAnimationEnd(Animation arg0) {
                if (passTv != null) {
                    countDownTimer.start();
                } else {
                    redirectTo();
                }
            }

            @Override
            public void onAnimationRepeat(Animation animation) {
            }

            @Override
            public void onAnimationStart(Animation animation) {
            }
        });
   }

 class StartTimerTask extends CountDownTimer {
        private boolean isRunning = true;

        public StartTimerTask(long millisInFuture, long countDownInterval) {
            super(millisInFuture, countDownInterval);
        }

        public boolean getRunStatus() {
            return isRunning;
        }

        public void onTick(long millisUntilFinished) {
            isRunning = true;
            passTv.setText(millisUntilFinished / 1000 + "s跳过");
        }

        public void onFinish() {//倒计时完成
            isRunning = false;
            passTv.setText("跳过");
            redirectTo();
        }
    }

  private void redirectTo() {
        MainActivity.startActivity(WelcomeActivity.this);
        finish();
    }

welcome_activity.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/welcome"
    android:orientation="vertical">

    <TextView
        android:id="@+id/pass_tv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="right|top"
        android:layout_margin="16dp"
        android:background="@drawable/pass_bg"
        android:gravity="center"
        android:text="3s跳过"
        android:textColor="#e7e7e7"
        android:textSize="@dimen/text_size_12"
        android:visibility="gone" />
LinearLayout>

2、情况2会使用JakeWharton写的ViewPagerIndicator
下载地址：https://github.com/JakeWharton/ViewPagerIndicator
所以我们先来看看ViewPagerIndicator的动态图

这里我们只需要关注SampleCirclesDefault 和 CirclePageIndicator

我们可以把整个library当做一个Moudle导入或者选择复制相关的代码到自己的项目中
我这里直接把library当做一个Moudle导入到项目中

    private void initFirstView() {
        setContentView(R.layout.welcome_guide);
        ViewPager viewPager = (ViewPager) findViewById(R.id.viewPager);
        CirclePageIndicator indicator = (CirclePageIndicator)              findViewById(R.id.indicator);

        GuideAdapter mAdapter = new GuideAdapter(getSupportFragmentManager(), 0);
        viewPager.setAdapter(mAdapter);
        indicator.setViewPager(viewPager);
    }

public class GuideAdapter extends FragmentPagerAdapter {
    private int[] CONTENT = new int[]{R.drawable.welcome1, R.drawable.welcome2, R.drawable.welcome3, R.drawable.welcome4};

    private int mCount = CONTENT.length;

    private int type = 0;

    public GuideAdapter(FragmentManager fm, int type_) {
        super(fm);
        this.type = type_;
    }

    @Override
    public Fragment getItem(int position) {
        return GuideFragment.newInstance(position,type, CONTENT[position % CONTENT.length]);
    }

    @Override
    public int getCount() {
        return mCount;
    }

}

GuideFragment.java仿造ViewPagerIndicator的TestFragment.java即可。
最后一页有个立即体验按钮，实现了心跳的效果，代码如下：

    public void heartbeatAnimation(){
        /**
         * 放大动画
         */
        AnimationSet animationSet = new AnimationSet(true);
        animationSet.addAnimation(new ScaleAnimation(ZOOM_MIN, ZOOM_MAX, ZOOM_MIN, ZOOM_MAX, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,0.5f));
        animationSet.addAnimation(new AlphaAnimation(1.0f, 0.8f));

        animationSet.setDuration(500);
        animationSet.setInterpolator(new AccelerateInterpolator());
        animationSet.setFillAfter(true);

        animationSet.setAnimationListener(new Animation.AnimationListener() {
            @Override
            public void onAnimationStart(Animation animation) {
            }

            @Override
            public void onAnimationRepeat(Animation animation) {
            }

            @Override
            public void onAnimationEnd(Animation animation) {
                /**
                 * 缩小动画
                 */
                AnimationSet animationSet = new AnimationSet(true);
                animationSet.addAnimation(new ScaleAnimation(ZOOM_MAX, ZOOM_MIN, ZOOM_MAX, ZOOM_MIN, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f));
                animationSet.addAnimation(new AlphaAnimation(0.8f, 1.0f));
                animationSet.setDuration(600);
                animationSet.setInterpolator(new DecelerateInterpolator());
                animationSet.setFillAfter(false);
                // 实现心跳的View
                overTv.startAnimation(animationSet);
            }
        });
        // 实现心跳的View
        overTv.startAnimation(animationSet);
    }

最后点击立即体验按钮跳转到主页面，这里使用EventBus来实现

 @OnClick(R.id.over_tv)//点击立即体验按钮
    public void overClick() {
        EventBus.getDefault().post(new FirstStartEvent());
    }

当然需要在WelcomeActivity.java中订阅这个事件

  @Subscribe
    public void onEvent(FirstStartEvent firstStartEvent) {
        redirectTo();//跳转到主页面
    }

别忘了在onCreate和onDestroy

@Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        EventBus.getDefault().register(this);
        if (isFirst) {//说明首次安装或者刚刚更新到最新版本
            initFirstView();
        } else {
            initOtherView();
        }
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        EventBus.getDefault().unregister(this);
    }