滚动时，RecyclerView中的多个倒数计时器闪烁 [英] Multiple count down timers in RecyclerView flickering when scrolled
问题描述
我为片段活动中的RecyclerView的每个项目实现了倒数计时器.倒数计时器显示剩余的剩余时间.倒数计时器工作正常，但向上滚动时会开始闪烁.搜索了很多，但没有得到很好的参考.有人可以帮我吗?
I have implemented count down timer for each item of RecyclerView which is in a fragment activity. The count down timer shows the time remaining for expiry. The count down timer is working fine but when scrolled up it starts flickering. Searched a lot but did not got the good reference. Can any one help me?
这是我的RecyclerView适配器
This is my RecyclerView adapter
public class MyOfferAdapter extends RecyclerView.Adapter<MyOfferAdapter.FeedViewHolder>{
private final Context mContext;
private final LayoutInflater mLayoutInflater;
private ArrayList<Transactions> mItems = new ArrayList<>();
private ImageLoader mImageLoader;
private String imageURL;
private View mView;
private String mUserEmail;
public MyOfferAdapter(Context context) {
mContext = context;
mLayoutInflater = LayoutInflater.from(context);
VolleySingleton mVolley = VolleySingleton.getInstance(mContext);
mImageLoader = mVolley.getImageLoader();
}
public void addItems(ArrayList<Transactions> items,String userEmail) {
int count = mItems.size();
mItems.addAll(items);
mUserEmail = userEmail;
notifyItemRangeChanged(count, items.size());
}
@Override
public FeedViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
mView = mLayoutInflater.inflate(R.layout.my_feed_item_layout, parent, false);
return new FeedViewHolder(mView);
}
@Override
public void onBindViewHolder(final FeedViewHolder holder, final int position) {
holder.desc.setText(mItems.get(position).getDescription());//replace by title
holder.scratchDes.setText(mItems.get(position).getScratchDescription());
long timer = mItems.get(position).getTimerExpiryTimeStamp();
Date today = new Date();
final long currentTime = today.getTime();
long expiryTime = timer - currentTime;
new CountDownTimer(expiryTime, 500) {
public void onTick(long millisUntilFinished) {
long seconds = millisUntilFinished / 1000;
long minutes = seconds / 60;
long hours = minutes / 60;
long days = hours / 24;
String time = days+" "+"days" +" :" +hours % 24 + ":" + minutes % 60 + ":" + seconds % 60;
holder.timerValueTimeStamp.setText(time);
}
public void onFinish() {
holder.timerValueTimeStamp.setText("Time up!");
}
}.start();
}
@Override
public int getItemCount() {
return mItems.size();
}
public static class FeedViewHolder extends RecyclerView.ViewHolder {
TextView desc;
TextView scratchDes;
TextView timerValueTimeStamp;
ImageView feedImage;
CardView mCv;
public FeedViewHolder(View itemView) {
super(itemView);
mCv = (CardView) itemView.findViewById(R.id.cv_fil);
desc = (TextView) itemView.findViewById(R.id.desc_tv_fil);
feedImage = (ImageView) itemView.findViewById(R.id.feed_iv_fil);
scratchDes = (TextView) itemView.findViewById(R.id.tv_scratch_description);
timerValueTimeStamp = (TextView) itemView.findViewById(R.id.tv_timer_value_time_stamp);
}
}
这是我在适配器中使用的xml文件
And this is my xml file used in adapter
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="@+id/cv_fil"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="@dimen/card_margin"
android:layout_gravity="center"
app:cardUseCompatPadding="true"
app:cardElevation="4dp"
android:elevation="6dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="@+id/feed_iv_fil"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_alignParentTop="true"
android:scaleType="fitXY"
android:tint="@color/grey_tint_color" />
<TextView
android:id="@+id/tv_scratch_description"
style="@style/ListItemText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center"
android:text="casul shoes"
android:fontFamily="sans-serif-light"
android:padding="10dp" />
<TextView
android:id="@+id/tv_timer_value_time_stamp"
style="@style/CardTitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
/>
<TextView
android:id="@+id/desc_tv_fil"
style="@style/VendorNameText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/feed_iv_fil"
android:textColor="#3f3e3f"
android:padding="10dp"
/>
</RelativeLayout>
</android.support.v7.widget.CardView>
这是我的RecyclerView的屏幕截图
And this is screen shot of my RecyclerView
推荐答案
此问题很简单.
RecyclerView重用持有者，每次调用bind来更新其中的数据.
RecyclerView reuses the holders, calling bind each time to update the data in them.
由于每次绑定任何数据都会创建一个CountDownTimer，因此最终将使用多个计时器来更新同一ViewHolder.
Since you create a CountDownTimer each time any data is bound, you will end up with multiple timers updating the same ViewHolder.
最好的做法是将CountDownTimer移到FeedViewHolder中作为参考，在绑定数据(如果已启动)之前将其取消，然后将其重新安排为所需的持续时间.
The best thing here would be to move the CountDownTimer in the FeedViewHolder as a reference, cancel it before binding the data (if started) and rescheduling to the desired duration.
public void onBindViewHolder(final FeedViewHolder holder, final int position) {
...
if (holder.timer != null) {
holder.timer.cancel();
}
holder.timer = new CountDownTimer(expiryTime, 500) {
...
}.start();
}
public static class FeedViewHolder extends RecyclerView.ViewHolder {
...
CountDownTimer timer;
public FeedViewHolder(View itemView) {
...
}
}
这样，您将在启动另一个计时器之前取消该ViewHolder的任何当前计时器实例.
This way you will cancel any current timer instance for that ViewHolder prior to starting another timer.
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