利用ViewPager做向导界面

RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v4.view.ViewPager
android:id="@+id/vp_guide"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v4.view.ViewPager>

<Button
android:id="@+id/btn_start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="开始体验"
android:layout_centerHorizontal="true"
android:textColor="#f00"
android:layout_alignParentBottom="true"
android:layout_marginBottom="20dp"
android:visibility="invisible" />
</RelativeLayout>

public class GuideActivity extends AppCompatActivity{
private ViewPager vp_guide;
private List<ImageView> imageViews;
private int[] images={R.drawable.guide_1,
R.drawable.guide_2, R.drawable.guide_3};
private Button btn_start;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_guide);
vp_guide= (ViewPager) findViewById(R.id.vp_guide);
btn_start= (Button) findViewById(R.id.btn_start);

initData();
vp_guide.setAdapter(new VpAdapter());
vp_guide.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

}
@Override
public void onPageSelected(int position) {
if(position==imageViews.size()-1){
btn_start.setVisibility(View.VISIBLE);
}else{
btn_start.setVisibility(View.INVISIBLE);
}
}

@Override
public void onPageScrollStateChanged(int state) {

}
});
btn_start.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
GotoActivity.gotoActivity(GuideActivity.this,MainActivity.class);
}
});
}

public void initData(){
imageViews=new ArrayList<>();
ImageView view;
for (int i = 0; i <images.length ; i++) {
view=new ImageView(this);
view.setBackgroundResource(images[i]);
imageViews.add(view);
}
}
class VpAdapter extends PagerAdapter{

@Override
public int getCount() {
return imageViews.size();
}

@Override
public boolean isViewFromObject(View view, Object object) {
return view==object;
}

@Override
public Object instantiateItem(ViewGroup container, int position) {
ImageView view=imageViews.get(position);
container.addView(view);
return view;
}

@Override
public void destroyItem(ViewGroup container, int position, Object object) {
container.removeView((View) object);
}
}
}