viewpager的滑动事件总结（滑动在toolbar上显示页数，滑动到最后一页显示下载的dialog）

最新推荐文章于 2019-05-15 21:31:35 发布

Zuo_XP

最新推荐文章于 2019-05-15 21:31:35 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/Zuo_XP/article/details/65628086

本文介绍了一个杂志浏览页面的实现方式，使用Viewpager展示预览图片，并通过监听滑动事件提示用户下载完整内容。同时实现了下载功能。

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banner广告条，就是上面为一个viewpager,下面为一个viewgroup

***********************在BookPreviewActivity 杂志浏览页面：

代码如下：

@Override
protected void onResume() {
    super.onResume();
    final List<View> previewPictures = getPreviewPictures();
    title.setText(book.ecatalogName);
    count.setText(getCount());
    pager.setAdapter(new PagerAdapter() {              //给viewpager适配数据
        @Override
        public int getCount() {
            return previewPictures.size();
        }

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

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            View item = previewPictures.get(position);
            container.addView(item);
            return item;
        }

        @Override
        public void destroyItem(ViewGroup container, int position, Object object) {
            container.removeView(previewPictures.get(position));
        }
    });
    pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {     //pagerview滚动监听事件
        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
            currentPositionOffset = positionOffset;
        }

        @Override
        public void onPageSelected(int position) {                //页数赋值刷新
            currentPosition = position;
            count.setText(getCount());
        }

        @Override
        public void onPageScrollStateChanged(int state) {

        }
    });
    pager.setOnTouchListener(new View.OnTouchListener() {                    //向右滑动到最后一页显示下载的dialog
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            switch (event.getAction()) {
                case MotionEvent.ACTION_UP:
                case MotionEvent.ACTION_CANCEL:
                    if ((currentPosition >= MAX_PREVIEW_NUMBER - 1 || currentPosition <= 0) && currentPositionOffset == 0) {
                        showPreviewLimitTipsDialog();
                    }
                    break;
            }
            return false;
        }
    });
}

下面为下载功能的代码：

private void showPreviewLimitTipsDialog() {
    if (previewLimitTipsDialog == null) {
        previewLimitTipsDialog = new CommonTwoBtnDialog(this);
        previewLimitTipsDialog.setCancelBtnTextColor(getResources().getColor(R.color.color_333333));
        previewLimitTipsDialog.setCancelBtnText(R.string.button_cancel_text);
        previewLimitTipsDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
            @Override
            public void onCancel(DialogInterface dialog) {
                previewLimitTipsDialog.dismiss();
            }
        });
        previewLimitTipsDialog.setConfirmTextColor(getResources().getColor(R.color.color_409fff));
        previewLimitTipsDialog.setConfirmBtnText(R.string.button_download_text);
        previewLimitTipsDialog.setConfirmDialogListener(new CommonDialog.DialogClickListener() {
            @Override
            public void onDialogClick() {
                previewLimitTipsDialog.dismiss();
                showDialogOrDownload();
            }
        });
        previewLimitTipsDialog.buildSimpleDialog(15, R.color.color_333333, getString(R.string.book_preview_limit_tips));
    }
    previewLimitTipsDialog.show();
}

private void showDialogOrDownload() {
    DownloadManager.getInstance().showDownloadOnWifiOrDoAction(this, new DownloadManager.DefaultAction() {

        @Override
        public void execute() {
            download();
        }


    });

}

private void download() {
    DownloadManager.getInstance().addDownload(book.downloadUrl);
    setResult(RESULT_OK);
    finish();
}