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[英]Can I use setCurrentItem in viewPager and use onPageSelected?
[英]How can I make my arrows invisible by setCurrentItem method of Viewpager?
在我的MainActivity的Oncreate中,添加以下代码:
mDateAreaSlider.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageSelected(int arg0) {
// Hide right arrow if reach last position
if (arg0 == adapter.DateList.length - 1) {
mButtonNext.setVisibility(View.INVISIBLE);
mButtonBack.setVisibility(View.VISIBLE);
}
// Hide left arrow if reach first position
else if (arg0 == 0) {
mButtonBack.setVisibility(View.INVISIBLE);
mButtonNext.setVisibility(View.VISIBLE);
}
// Else show both arrows
else {
mButtonBack.setVisibility(View.VISIBLE);
mButtonNext.setVisibility(View.VISIBLE);
}
}
}
@Override
public void onPageScrolled(int arg0, float arg1, int arg2) {
// TODO Auto-generated method stub
ifSingding = true;
}
@Override
public void onPageScrollStateChanged(int arg0) {
// TODO Auto-generated method stub
}
});
然后在按钮上单击我添加以下代码:
mDateAreaSlider.setCurrentItem(0);
但问题是它可以滑动到我选择的页面,但不会使我的箭头不可见。
注意:这两个箭头是主布局中的ImageViews,不是膨胀布局。因此,它与适配器无关。
用以下代码替换原始代码:
final ViewPager.OnPageChangeListener onPageChangeListener = new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
if (position == adapter.DateList.length - 1) {
mButtonNext.setVisibility(View.INVISIBLE);
mButtonBack.setVisibility(View.VISIBLE);
}
// Hide left arrow if reach first position
else if (position == 0) {
mButtonBack.setVisibility(View.INVISIBLE);
mButtonNext.setVisibility(View.VISIBLE);
}
// Else show both arrows
else {
mButtonBack.setVisibility(View.VISIBLE);
mButtonNext.setVisibility(View.VISIBLE);
}
}
@Override
public void onPageScrollStateChanged(int state) {
}
};
mDateAreaSlider.addOnPageChangeListener(onPageChangeListener);
单击按钮执行此代码
mDateAreaSlider.setCurrentItem(0);
mDateAreaSlider.post(new Runnable() {
@Override
public void run() {
onPageChangeListener.onPageSelected(0);
}
});
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