Question

我使用此autoscroll viewpager library和PagerAdapter来显示图像和文本。然后我使用动画将文本从左侧移动到右侧。问题是viewpager的每个页面都没有出现动画。如何为每个页面设置文本动画？

public class MainActivity extends AppCompatActivity {

    ArrayList<ModelObject> arrayList = new ArrayList<>();
    String[] country = new String[] { "China", "India", "United States",
            "Indonesia", "Brazil", "Pakistan", "Nigeria"};

    int[] flag = new int[] { R.drawable.china, R.drawable.india,
            R.drawable.unitedstates, R.drawable.indonesia,
            R.drawable.brazil, R.drawable.pakistan, R.drawable.nigeria};

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
        ViewPagerAdapter swipeAdapter = new ViewPagerAdapter(this, country, flag);
        viewPager.setAdapter(swipeAdapter);
        viewPager.setPageTransformer(false, new ViewPager.PageTransformer() {
            @Override
            public void transformPage(View page, float position) {
                final float normalizedposition = Math.abs(Math.abs(position) - 1);
                page.setAlpha(normalizedposition);
            }
        });
    }

    public class ViewPagerAdapter extends PagerAdapter {
        // Declare Variables
        Context context;
        String[] country;
        int[] flag;
        LayoutInflater inflater;

        public ViewPagerAdapter(Context context, String[] country, int[] flag) {
            this.context = context;

            this.country = country;
            this.flag = flag;
        }

        @Override
        public int getCount() {
            return flag.length;
        }

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((RelativeLayout) object);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {

            // Declare Variables

            TextView txtcountry;
            ImageView imgflag;

            inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            View itemView = inflater.inflate(R.layout.pagefrag, container, false);

            // Locate the TextViews in viewpager_item.xml

            txtcountry = (TextView) itemView.findViewById(R.id.country);

            // Capture position and set to the TextViews

            txtcountry.setText(country[position]);
            txtcountry.startAnimation(AnimationUtils.loadAnimation(context, R.anim.myanim));

            // Locate the ImageView in viewpager_item.xml
            imgflag = (ImageView) itemView.findViewById(R.id.flag);
            // Capture position and set to the ImageView
            imgflag.setImageResource(flag[position]);

            // Add viewpager_item.xml to ViewPager
            ((ViewPager) container).addView(itemView);

            return itemView;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            // Remove viewpager_item.xml from ViewPager
            ((ViewPager) container).removeView((RelativeLayout) object);

        }
    }



}

Answer 1

您可以使用ViewPager.PageTransformer界面为页面内的视图设置动画

class MyPageTransformer implements ViewPager.PageTransformer {

    @Override
    public void transformPage(View page, float position) {
        float pageTimesPosition = page.getWidth() * position;
        View text = page.findViewById(R.id.text);
        if (text != null) {
            text.setAlpha(1.0f - position);
        }
    }
}

然后用viewPager.setPageTransformer(false, new MyPageTransformer());设置Transformer

在viewpager中滑动动画文本

1 个答案: