如何在AndroidRecyclView中访问SQLite数据库?
我创建了一个SQLite数据库,其中包含两列:“标题”和“内容”,不知道如何在我的android RecyclerView中显示它,其中包含两个文本视图“卡片标题”和“卡片内容”。请帮我做这个。 这是我的回收器适配器:如何在AndroidRecyclView中访问SQLite数据库?,android,database,sqlite,database-connection,android-cardview,Android,Database,Sqlite,Database Connection,Android Cardview,我创建了一个SQLite数据库,其中包含两列:“标题”和“内容”,不知道如何在我的android RecyclerView中显示它,其中包含两个文本视图“卡片标题”和“卡片内容”。请帮我做这个。 这是我的回收器适配器: public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> { private ClipboardManager myClipboard;
public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ViewHolder> {
private ClipboardManager myClipboard;
private ClipData myClip;
private Context context;
public List<CardItemModel> cardItems;
public RecyclerAdapter(List<CardItemModel> cardItems){
this.cardItems = cardItems;
}
public static class ViewHolder extends RecyclerView.ViewHolder{
ImageView copyButton;
ImageView shareButton;
ToggleButton favButton;
TextView title;
TextView content;
public ViewHolder(View itemView) {
super(itemView);
this.title = (TextView)itemView.findViewById(R.id.card_title);
this.content = (TextView)itemView.findViewById(R.id.card_content);
this.copyButton= (ImageView) itemView.findViewById(R.id.copyButton);
this.shareButton=(ImageView) itemView.findViewById(R.id.shareButton);
this.favButton=(ToggleButton) itemView.findViewById(R.id.favButton);
favButton.setChecked(false);
favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(), R.mipmap.ic_launcher));
}
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item,parent,false);
ViewHolder viewHolder = new ViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(final ViewHolder holder, int position) {
holder.title.setText(cardItems.get(position).title);
holder.content.setText(cardItems.get(position).content);
holder.copyButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
myClipboard = (ClipboardManager) v.getContext().getSystemService(Context.CLIPBOARD_SERVICE);
myClip = ClipData.newPlainText("label", holder.content.getText().toString());
myClipboard.setPrimaryClip(myClip);
Toast.makeText(v.getContext(), "Copied to clipboard" , Toast.LENGTH_SHORT ).show();
}
});
holder.shareButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
Intent share = new Intent(Intent.ACTION_SEND);
share.setType("text/plain");
share.putExtra(Intent.EXTRA_TEXT, holder.content.getText().toString());
v.getContext().startActivity(Intent.createChooser(share, "Share Text"));
}
});
holder.favButton.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener(){
@Override
public void onCheckedChanged(CompoundButton favButton, boolean isChecked){
if (isChecked)
favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_launcher));
else
favButton.setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(), R.mipmap.ic_cart));
}
});
}
@Override
public int getItemCount() {
return cardItems.size();
}
}
公共类RecyclerAdapter扩展了RecyclerView.Adapter{
私人剪贴板管理器myClipboard;
私有clipdatamyclip;
私人语境;
公开列表目录;
公共回收适配器(列表项){
this.cardItems=cardItems;
}
公共静态类ViewHolder扩展了RecyclerView.ViewHolder{
ImageView复制按钮;
图像视图共享按钮;
切换按钮FAV按钮;
文本视图标题;
文本视图内容;
公共视图持有者(视图项视图){
超级(项目视图);
this.title=(TextView)itemView.findViewById(R.id.card\u title);
this.content=(TextView)itemView.findViewById(R.id.card\u content);
this.copyButton=(ImageView)itemView.findViewById(R.id.copyButton);
this.shareButton=(ImageView)itemView.findViewById(R.id.shareButton);
this.favButton=(ToggleButton)itemView.findViewById(R.id.favButton);
favButton.setChecked(false);
setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_启动器));
}
}
@凌驾
public ViewHolder onCreateViewHolder(视图组父级,int-viewType){
视图=LayoutFlater.from(parent.getContext()).flate(R.layout.recycler\u项,parent,false);
ViewHolder ViewHolder=新的ViewHolder(视图);
返回视图持有者;
}
@凌驾
公共无效onBindViewHolder(最终ViewHolder,内部位置){
holder.title.setText(cardItems.get(position.title));
holder.content.setText(cardItems.get(position.content));
holder.copyButton.setOnClickListener(新视图.OnClickListener(){
公共void onClick(视图v){
myClipboard=(ClipboardManager)v.getContext().getSystemService(Context.ClipboardManager\u服务);
myClip=ClipData.newPlainText(“标签”,holder.content.getText().toString());
myClipboard.setPrimaryClip(myClip);
Toast.makeText(v.getContext(),“复制到剪贴板”,Toast.LENGTH_SHORT).show();
}
});
holder.shareButton.setOnClickListener(新视图.OnClickListener(){
公共void onClick(视图v){
意向共享=新意向(意向.行动\发送);
share.setType(“文本/普通”);
share.putExtra(Intent.EXTRA_TEXT,holder.content.getText().toString());
v、 getContext().startActivity(Intent.createChooser(共享,“共享文本”);
}
});
holder.favButton.setOnCheckedChangeListener(新的CompoundButton.OnCheckedChangeListener(){
@凌驾
检查更改后的公共无效(复合按钮FAVBUTON,布尔值已检查){
如果(已检查)
setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_启动器));
其他的
setBackgroundDrawable(ContextCompat.getDrawable(favButton.getContext(),R.mipmap.ic_-cart));
}
});
}
@凌驾
public int getItemCount(){
返回cardItems.size();
}
}
在您的recyclerview adpter之前,在您的活动中尝试此功能
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
recyclerView.setLayoutManager(layoutManager);
RecyclerView.Adapter adapter = new DataAdapter(title,content);
recyclerView.setAdapter(adapter);
现在开始您的活动
ArrayList<String> title
ArrayList<String> content
SQLiteDatabase myDatabase;
content= new ArrayList<>();
title= new ArrayList<>();
现在设置recyclerview适配器
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
recyclerView.setHasFixedSize(true);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);
recyclerView.setLayoutManager(layoutManager);
RecyclerView.Adapter adapter = new DataAdapter(title,content);
recyclerView.setAdapter(adapter);
在活动中写下此功能
public ArrayList<CardItemModel> getAllElements() {
List<CardItemModel> cardItems = new ArrayList<>();
SQLiteDatabase db = this.getReadableDatabase();
Cursor cursor = db.rawQuery("select * from " + DATABASE_TABLE, null);
try {
try {
// looping through all rows and adding to list
if (cursor.moveToFirst()) {
do {
CardItemModel obj = new CardItemModel();
//only one column
obj.setTitle(cursor.getString(0));
obj.setContent(cursor.getString(1));
//you could add additional columns here..
cardItems.add(obj);
} while (cursor.moveToNext());
}
} finally {
try { cursor.close(); } catch (Exception ignore) {}
}
} finally {
try { db.close(); } catch (Exception ignore) {}
}
return cardItems;
}
public ArrayList getAllegements(){
List cardItems=new ArrayList();
SQLiteDatabase db=this.getReadableDatabase();
Cursor Cursor=db.rawQuery(“select*from”+数据库表,null);
试一试{
试一试{
//循环遍历所有行并添加到列表
if(cursor.moveToFirst()){
做{
CardItemModel obj=新的CardItemModel();
//只有一列
obj.setTitle(cursor.getString(0));
obj.setContent(cursor.getString(1));
//您可以在此处添加其他列。。
添加(obj);
}while(cursor.moveToNext());
}
}最后{
尝试{cursor.close();}捕获(异常忽略){}
}
}最后{
尝试{db.close();}捕获(异常忽略){}
}
回程心电图;
}
在活动的onCreate方法中调用此函数
List<CardItemModel> cardItems = getAllElements();
RecyclerAdapter adapter = new RecyclerAdapter(cardItems);
recyclerView.setAdapter(adapter);
List cardItems=getAllegements();
RecyclerAdapter适配器=新的RecyclerAdapter(cardItems);
recyclerView.setAdapter(适配器);
在加载recycler视图之前,您是否尝试从数据库中检索数据?因为您应该检索数据,然后通过传递从db检索到的列表来创建recycler视图