我正在尝试从recyclerview数据库中的数据更新SQLite项，而这些数据又会不时使用从API提取的数据进行更新。
我有一个TabLayout，其中包含三个fragments。
现在在一个片段中，我以recyclerView的形式展示用户玩的游戏。 recyclerView的每个项目均包含用户名，其高分和编号。击败他的高分的其他用户。
现在在该片段中，我正在调用API更新AsyncTask内的数据库，然后再次使用RecyclerView适配器类中的相同数据库来检索另一个AsyncTask中的数据。使用AsyncTask和Handler定期调用TimerTask。
@TargetApi(Build.VERSION_CODES.CUPCAKE)
@RequiresApi(api = Build.VERSION_CODES.CUPCAKE)
public class PerformBackgroundTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... gameID) {
try{
SQLiteDatabase challengeDatabase = mContext.openOrCreateDatabase("Challenge", Context.MODE_PRIVATE, null);
challengeDatabase.execSQL("CREATE TABLE IF NOT EXISTS DISPLAY_MESSAGE (gameID VARCHAR, highestScorer VARCHAR, count INT)");
Cursor d = challengeDatabase.rawQuery("SELECT * FROM DISPLAY_MESSAGE WHERE gameID", null);
int gameCode = d.getColumnIndex("gameID");
int highestScorer = d.getColumnIndex("highestScorer");
int count = d.getColumnIndex("count");
d.moveToFirst();
while(d!=null&&d.getCount()>0){
if((d.getString(gameCode)).equals(gameID)){
int k = Integer.parseInt(d.getString(count));
if(k>0)
{
return d.getString(highestScorer) + " and " + k + " others have beaten your highscore.";
}else if(k==0){
return d.getString(highestScorer) + " has beaten your highscore.";
}
else{
return "Yay! you have beaten all your opponents!";
}
}
d.moveToNext();
}
challengeDatabase.close();
}catch (Exception e){
e.printStackTrace();
}
return null;
}
}
public GridAdapterChallenge(Context c, List<CardContainer> listCards, Vector<Object> cardDetails, String sname) {
//selectedCards = new HashSet<Integer>();
inflater = (LayoutInflater) c.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
mContext = c;
this.listCards = listCards;
this.sname = sname;
cards = cardDetails;
//notifyDataSetChanged();
}
public class ViewHolder extends RecyclerView.ViewHolder {
private int viewType;
private ImageView imageView;
private Button increaseScore, challengeFriend;
private TextView challengeDetails, points, name, challengeCode;
private ImageView nativeAdIcon;
private TextView nativeAdTitle;
private TextView nativeAdBody;
private MediaView nativeAdMedia;
private TextView nativeAdSocialContext;
private Button nativeAdCallToAction;
private ProgressBar detailProgress;
public ViewHolder(@NonNull View itemView, int viewType) {
super(itemView);
view = itemView;
this.viewType = viewType;
if (viewType == 1) {
this.imageView = (ImageView) itemView.findViewById(R.id.thumb);
this.name = (TextView) itemView.findViewById(R.id.gameName);
this.challengeCode = itemView.findViewById(R.id.challengeCode);
this.points = itemView.findViewById(R.id.points);
this.challengeDetails = itemView.findViewById(R.id.challengeDetail);
this.increaseScore = itemView.findViewById(R.id.increaseScore);
this.challengeFriend = itemView.findViewById(R.id.challengeFriend);
this.challengeDetails = itemView.findViewById(R.id.challengeDetail);
this.detailProgress = itemView.findViewById(R.id.detailProgressBar);
} else {
this.nativeAdIcon = (ImageView) itemView.findViewById(R.id.native_ad_icon);
this.nativeAdTitle = (TextView) itemView.findViewById(R.id.native_ad_title);
this.nativeAdBody = (TextView) itemView.findViewById(R.id.native_ad_body);
this.nativeAdMedia = (MediaView) itemView.findViewById(R.id.native_ad_media);
this.nativeAdSocialContext = (TextView) itemView.findViewById(R.id.native_ad_social_context);
this.nativeAdCallToAction = (Button) itemView.findViewById(R.id.native_ad_call_to_action);
}
}
}
public void updateDetails(final TextView challengeDetails, final String gameId) {
final Handler handler;
handler = new Handler();
Timer timer = new Timer();
doAsynchronousTask = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
try {
PerformBackgroundTask performBackgroundTask = new PerformBackgroundTask();
challengeDetails.setText((CharSequence) performBackgroundTask.execute(gameId));
} catch (Exception e) {
}
}
});
}
};
timer.schedule(doAsynchronousTask, 4000, 5000); //execute in every 1000 ms
}
@Override
public void onBindViewHolder(@NonNull final ViewHolder viewHolder, final int i) {
if (viewHolder.viewType == 0) {
if (adList != null && adList.size() > (i+1)/5 - 1 && adList.get((i+1)/5 - 1) != null) {
NativeAd ad = adList.get((i+1)/5 - 1);
viewHolder.nativeAdSocialContext.setText(ad.getAdSocialContext());
viewHolder.nativeAdCallToAction.setText(ad.getAdCallToAction());
viewHolder.nativeAdCallToAction.setVisibility(View.VISIBLE);
viewHolder.nativeAdTitle.setText(ad.getAdHeadline());
viewHolder.nativeAdBody.setText(ad.getAdBodyText());
ad.registerViewForInteraction(viewHolder.itemView, viewHolder.nativeAdMedia, viewHolder.nativeAdIcon, Arrays.asList(viewHolder.nativeAdCallToAction, viewHolder.nativeAdMedia));
NativeAd.Image adCoverImage = ad.getAdCoverImage();
int bannerWidth = adCoverImage.getWidth();
int bannerHeight = adCoverImage.getHeight();
DisplayMetrics metrics = mContext.getResources().getDisplayMetrics();
int mediaWidth = viewHolder.itemView.getWidth() > 0 ? viewHolder.itemView.getWidth() : metrics.widthPixels;
viewHolder.nativeAdMedia.setLayoutParams(new LinearLayout.LayoutParams(mediaWidth, Math.min(
(int) (((double) mediaWidth / (double) bannerWidth) * bannerHeight), metrics.heightPixels / 3)));
ad.registerViewForInteraction(viewHolder.itemView, viewHolder.nativeAdMedia, Arrays.asList(viewHolder.nativeAdCallToAction, viewHolder.nativeAdMedia));
ad.registerViewForInteraction(viewHolder.itemView, viewHolder.nativeAdMedia);
}
} else{
viewHolder.name.setText(((CardContainer)cards.get(i)).name);
challengeCode = getChallengeCode(i);
viewHolder.challengeCode.setText(challengeCode);
DisplayMetrics displayMetrics = new DisplayMetrics();
((Activity) mContext).getWindowManager().getDefaultDisplay().getMetrics(displayMetrics);
if(getHighScore(((CardContainer)cards.get(i)).gameId)>0){
PerformBackgroundTask performBackgroundTask = new PerformBackgroundTask();
viewHolder.challengeDetails.setText(performBackgroundTask.execute(gameId).toString());
//updateDetails(viewHolder.challengeDetails, ((CardContainer)cards.get(i)).gameId);
}
else{
viewHolder.challengeDetails.setText("Press Increase Score To Play the Game");
}
viewHolder.detailProgress.setVisibility(View.GONE);
int width = displayMetrics.widthPixels;
try {
final String uri = ((CardContainer) cards.get(i)).imageurl;
if (uri != null) {
Picasso.get().load(uri)
.placeholder(R.mipmap.place)
.error(R.mipmap.place)
.resize(width / 2, width / 2)
.centerCrop()
.into(viewHolder.imageView);
}
}
catch (Exception e){
final String uri = null;
}
viewHolder.points.setText(String.valueOf(getHighScore(((CardContainer)cards.get(i)).gameId)));
viewHolder.increaseScore.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View arg0) {
if (((CardContainer) cards.get(i)).link.contains("play.google.com")) {
openAppRating(mContext,((CardContainer) cards.get(i)).link.split("id=", 2)[1]);
}
else{
name = ((CardContainer) cards.get(i)).name;
link = ((CardContainer) cards.get(i)).link;
imageurl = ((CardContainer) cards.get(i)).imageurl;
type = ((CardContainer) cards.get(i)).type;
packageName = ((CardContainer) cards.get(i)).packageName;
gameId = ((CardContainer)cards.get(i)).gameId;
challengeNames.add(name);
updateDatabase(name, gameId, Config.uid+"@"+gameId, 0, viewHolder.points);
//String gameName, String gameId, String mychCode, int myHighScore
}
}
});
viewHolder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
String name = ((CardContainer) cards.get(i)).name;
String link = ((CardContainer) cards.get(i)).link;
String imageurl = ((CardContainer) cards.get(i)).imageurl;
String type = ((CardContainer) cards.get(i)).type;
String packageName = ((CardContainer) cards.get(i)).packageName;
Bitmap bitmap = null;
Integer xyz = android.os.Build.VERSION.SDK_INT;
@Override
public boolean onLongClick(View view) {
bitmap = ((BitmapDrawable) viewHolder.imageView.getDrawable()).getBitmap();
if (sname.equals("fav")) {
// Toast.makeText(mContext, "in fav", Toast.LENGTH_SHORT).show();
final Dialog dialog = new Dialog(mContext);
dialog.setContentView(R.layout.custom_dialog);
TextView dialogText=dialog.findViewById(R.id.txt_dia);
dialogText.setText("Do you want to remove "+name+" from your favorites?");
dialog.show();
Button yes_button = (Button) dialog.findViewById(R.id.btn_yes);
yes_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
favf = new FavFunction(mContext);
int resultFav=favf.removeFromFavorite(link);
if (resultFav>=0){
cards.remove(resultFav);
notifyDataSetChanged();
}
dialog.dismiss();
}
});
Button no_button = (Button) dialog.findViewById(R.id.btn_no);
no_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
dialog.dismiss();
}
});
return true;
}
else{
final Dialog dialog = new Dialog(mContext);
dialog.setContentView(R.layout.custom_dialog);
TextView dialogText=dialog.findViewById(R.id.txt_dia);
dialogText.setText("Adding "+name+" to favorites... Do you also want to create it's homescreen shortcut?");
dialog.show();
Button yes_button = (Button) dialog.findViewById(R.id.btn_yes);
yes_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
favf = new FavFunction(mContext);
Boolean favstatus=favf.addToFavorite(imageurl, link ,name,type,packageName);
favf.addShortcut(name, link , imageurl,type,packageName,bitmap);
if(favstatus){
((Activity) mContext).recreate();
}
dialog.dismiss();
}
});
Button no_button = (Button) dialog.findViewById(R.id.btn_no);
no_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
favf = new FavFunction(mContext);
Boolean favstatus=favf.addToFavorite(imageurl, link, name,type,packageName);
if(favstatus){
((Activity) mContext).recreate();
}
dialog.dismiss();
}
});
return true;
}
}
});
viewHolder.challengeFriend.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent sendIntent = new Intent();
sendIntent.setAction(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_TEXT, "Hey! I challenge you to beat my highscore " + getHighScore(gameId) + " in this awesome game. Enter my challenge code " + challengeCode + " in the \"Challenges\" Tab of 101 Game Store App. You can download the app from bit.ly/101gamestore");
sendIntent.setType("text/plain");
mContext.startActivity(sendIntent);
}
});
}
}
我要更新编号。 recyclerView的每个项目中得分高者的得分。但是，发生的情况是TimerTask一开始，UI就会冻结。数据已成功获取。任何解决方案都比我的更好。
答案 0 :(得分：0)
在这里看看....
class MyAsyncTask extends AsyncTask<String, Void, String> {
Context mContext;
ArrayList<String> values= new ArrayList<String>();
public MyAsyncTask(Context context) {
mContext = context;
}
@Override
protected String doInBackground(String... params) {
// do your all database operation here and try to stroe in arraylist
values.add("Data comes from database");
return "";
}
@Override
protected void onPostExecute(String list) {
// Do your View update here.
// All your Recycle View here
yourRecycleView.setAdapter(new MyAdapter(context,values))
}
}
注意：-在AsynTask中，所有绑定工作都以onPreExecute()方法执行，所有数据库或长线程都以doInBackground()方法执行（例如从数据库中获取数据，下载文件或上传文件等）并以onPostExecute()方法更新视图。
如何使用AsyncTask更新RecyclerView项目？
按照相同的过程，以doInBackground()方法获取数据，并以onPostExecute()方法通知适配器。在其他AsynTask中执行此操作
答案 1 :(得分：0)
要更新适配器，应在主线程中进行。 AsyncTask提供onPostExecute方法。
请勿替换适配器，而应替换适配器中的数据。
migrationBuilder.CreateTable(
name: "Students",
columns: table => new
{
Id = table.Column<int>(nullable: false)
.Annotation("SqlServer:ValueGenerationStrategy", SqlServerValueGenerationStrategy.IdentityColumn),
DateCreated = table.Column<DateTime>(nullable: true, defaultValueSql: "GETDATE()"),
UserCreated = table.Column<string>(nullable: true),
DateModified = table.Column<DateTime>(nullable: true, defaultValueSql: "GETDATE()"),
UserModified = table.Column<string>(nullable: true),
Name = table.Column<string>(nullable: true)
},
constraints: table =>
{
table.PrimaryKey("PK_Students", x => x.Id);
});