Question

我的logcat打印第一次在重复此方法后取位置0并取位置1，我不需要重复此方法。

public  Object instantiateItem(ViewGroup container, int position) {

    Context context = MainActivity.this;

 Log.d("position","position" +position);
  ImageView imageView = new ImageView(context);

  int padding = context.getResources().getDimensionPixelSize(
      R.dimen.padding_medium);
  imageView.setPadding(padding, padding, padding, padding);
  imageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
  imageView.setImageResource(mImages[position]);

  ((ViewPager) container).addView(imageView, 0);

  return imageView;

}

图像幻灯片中的这段代码成功运行但是图像的第一次滑动和最后一次错误打印的位置在logcat.please帮助我。感谢。

编辑：

public class MainActivity extends Activity {

  ViewPager viewPager;
    @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


     viewPager = (ViewPager) findViewById(R.id.view_pager);
    ImagePagerAdapter adapter = new ImagePagerAdapter();
    adapter.notifyDataSetChanged();
    viewPager.setAdapter(adapter);

  }

  private class ImagePagerAdapter extends PagerAdapter {

    private int[] mImages = new int[] {
        R.drawable.chiang_mai,
        R.drawable.himeji,
        R.drawable.petronas_twin_tower,
        R.drawable.ulm
    };
     @Override
    public int getItemPosition(Object object) {
        // TODO Auto-generated method stub
        return POSITION_NONE;
    }


    @Override
    public int getCount() {
      return mImages.length;
    }

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

    @Override
    public  Object instantiateItem(ViewGroup container, int position) {

        Context context = MainActivity.this;

     Log.d("position","position" +position);
      ImageView imageView = new ImageView(context);

      int padding = context.getResources().getDimensionPixelSize(
          R.dimen.padding_medium);
      imageView.setPadding(padding, padding, padding, padding);
      imageView.setScaleType(ImageView.ScaleType.CENTER_INSIDE);
      imageView.setImageResource(mImages[position]);

      ((ViewPager) container).addView(imageView, 0);

      return imageView;

    }

    @Override
    public void destroyItem(ViewGroup container, int position, Object object) {
       // viewPager.getAdapter().notifyDataSetChanged();
      ((ViewPager) container).removeView((ImageView) object);
    }
  }

@Override
protected void onDestroy() {
    // TODO Auto-generated method stub

    super.onDestroy();
}

}

当我向右侧和左侧滑动图像时，此代码在logcat中的错误打印位置。当位置增量和左侧滑动图像减少位置时，我需要右侧滑动图像。请帮助我。谢谢。

Answer 1

您需要在此代码中解决问题

public class MainAdapter extends BaseAdapter {
        public Activity activity;
        ArrayList<String> data = new ArrayList<String>();

        public MainAdapter(Activity a, ArrayList<String> d) {
            activity = a;
            data = d;

        }    

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            View cellView = convertView;
             if (cellView == null)
               { 
                   cellView = new View(activity);
                   Log.d(TAG, "cellView null");
               } else
               {
                   Log.d(TAG, "cellView not null");
                   cellView = (View) convertView;
               }
               LayoutInflater inflater = (LayoutInflater) activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
               cellView = inflater.inflate(R.layout.textviewinfo, null);

               textView = (TextView) cellView.findViewById(R.id.textView1);

               /*LinearLayout layout = (LinearLayout)cellView.findViewById(R.id.l1);
               layout.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, 100));*/

               LinearLayout.LayoutParams parms2 = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
               parms2.gravity=Gravity.CENTER_HORIZONTAL;
               //parms2.gravity=Gravity.CENTER_VERTICAL;
               textView.setLayoutParams(parms2); 
               textView.setText(data.get(position));
                textView.setGravity(Gravity.CENTER_VERTICAL);   
                 textView.setTextColor(Color.YELLOW);
              return cellView;
        }
        @Override
        public int getCount() {
            // TODO Auto-generated method stub
             return data.size();
            //return 0;
        }

        @Override
        public Object getItem(int position) {
            // TODO Auto-generated method stub
            return position;
            //return 0;
        }

        @Override
        public long getItemId(int position) {
            // TODO Auto-generated method stub
             return position;
            //return 0;
        }
    }

如何在Android中的PagerAdapter中重复对象instantiateItem（）

1 个答案: