在Android中图片的自动切换不仅可以实现自动切换，而且还可以使用手动切换。而且一般在切换的时候，在图片下方还带有其他内容的切换，用来标记是第几个图片的切换。
这种效果在我们日常生活中很常见，例如某宝购物，一些商城都可以使用到，用户体验度极好，今天小编就通过实例代码给大家分享android 图片自动切换功能的实现。
实现效果如下：
具体的示例代码如下：
布局代码：
<?xml version="1.0" encoding="utf-8"?>
<ScrollView
android:layout_height="match_parent"
android:layout_width="match_parent"
android:orientation="vertical"
xmlns:android="http://schemas.android.com/apk/res/android">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="250dp"
android:padding="20dp"
android:orientation="vertical">
<androidx.viewpager.widget.ViewPager
android:id="@+id/viewContent"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="25dp"
android:orientation="horizontal"
android:layout_gravity="bottom"
android:gravity="center"
android:layout_marginTop="5dp"
android:background="#E6E6E6">
<View
android:id="@+id/p1"
android:layout_width="5dp"
android:layout_height="5dp"
android:layout_marginLeft="2dp"
android:layout_marginRight="2dp"
android:background="@drawable/dot_focus"/>
<View
android:id="@+id/p2"
android:layout_width="5dp"
android:layout_height="5dp"
android:layout_marginLeft="2dp"
android:layout_marginRight="2dp"
android:background="@drawable/dot_normal"/>
<View
android:id="@+id/p3"
android:layout_width="5dp"
android:layout_height="5dp"
android:layout_marginLeft="2dp"
android:layout_marginRight="2dp"
android:background="@drawable/dot_normal"/>
</LinearLayout>
</FrameLayout>
</RelativeLayout>
</ScrollView>
dot_focus.xml文件代码如下：
<?xml version="1.0" encoding="utf-8"?> <shape android:shape="oval" xmlns:android="http://schemas.android.com/apk/res/android"> <corners android:radius="5dp"/> <solid android:color="@color/white"/> </shape>
dot_normal.xml文件代码如下：
<?xml version="1.0" encoding="utf-8"?> <shape android:shape="oval" xmlns:android="http://schemas.android.com/apk/res/android"> <corners android:radius="5dp"/> <solid android:color="@color/blue"/> </shape>
Activity代码：
public class MainActivity extends AppCompatActivity {
private ArrayList<ImageView> imageViews= new ArrayList<>();
private ArrayList<View>dots=new ArrayList<>();
private ViewPager vp;
private int image[]={R.drawable.denglu,R.drawable.disanye,R.drawable.hhh};
private int oldPosition=0;
private int currentItem;
private ScheduledExecutorService scheduledExecutorService;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取图片资源
for (int i=0;i<image.length;i++){
ImageView imageView=new ImageView(this);
imageView.setImageResource(image[i]);
imageViews.add(imageView);
}
//显示的点的集合
dots.add(findViewById(R.id.p1));
dots.add(findViewById(R.id.p2));
dots.add(findViewById(R.id.p3));
vp=findViewById(R.id.viewContent);
vp.setAdapter(new ViewPagerAdapter());
vp.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
//点的效果切换
dots.get(oldPosition).setBackgroundResource(R.drawable.dot_normal);
dots.get(position).setBackgroundResource(R.drawable.dot_fouced);
oldPosition=position;
currentItem=position;
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
class ViewPagerAdapter extends PagerAdapter {
@Override
public int getCount() {
return imageViews.size();
}
@Override
public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
return view==object;
}
@Override
public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
View v=imageViews.get(position);
container.removeView(v);
}
@NonNull
@Override
public Object instantiateItem(@NonNull ViewGroup container, int position) {
View v=imageViews.get(position);
container.addView(v);
return v;
}
}
@Override
protected void onStart() {
super.onStart();
scheduledExecutorService= Executors.newSingleThreadScheduledExecutor();
scheduledExecutorService.scheduleWithFixedDelay(new ViewPagerTask(),2,2, TimeUnit.SECONDS);
}
class ViewPagerTask implements Runnable{
@Override
public void run() {
currentItem=(currentItem+1)%image.length;
handler.obtainMessage().sendToTarget();
}
}
Handler handler=new Handler(){
@Override
public void handleMessage(@NonNull Message msg) {
vp.setCurrentItem(currentItem);
}
};
}
总结
