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  • 团队冲刺02

      今天写了数据库的相关操作,可实现新笔记的添加

      遇到的问题:写了添加之后刷新页面的函数,运行时会闪退,已解决

      明天实现笔记显示界面的美化

    NoteDatabase.java:

    import android.content.Context;
    import android.database.sqlite.SQLiteDatabase;
    import android.database.sqlite.SQLiteOpenHelper;
    
    public class NoteDatabase extends SQLiteOpenHelper {
    
        public static final String TABLE_NAME = "notes";
        public static final String CONTENT = "content";
        public static final String ID = "_id";
        public static final String TIME = "time";
        public static final String MODE = "mode";
    
        public NoteDatabase(Context context){
            super(context, "notes", null, 1);
        }
    
        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE "+ TABLE_NAME
                    + "("
                    + ID + " INTEGER PRIMARY KEY AUTOINCREMENT,"
                    + CONTENT + " TEXT NOT NULL,"
                    + TIME + " TEXT NOT NULL,"
                    + MODE + " INTEGER DEFAULT 1)"
            );
        }
    
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
            /*for(int i = oldVersion; i < newVersion; i++) {
                switch (i) {
                    case 1:
                        break;
                    case 2:
                        updateMode(db);
                    default:
                        break;
                }
            }*/
        }
    }

    NoteAdapter.java:

    import android.content.Context;
    import android.content.SharedPreferences;
    import android.preference.PreferenceManager;
    import android.text.TextUtils;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.BaseAdapter;
    import android.widget.Filter;
    import android.widget.Filterable;
    import android.widget.TextView;
    
    import java.util.ArrayList;
    import java.util.List;
    
    public class NoteAdapter extends BaseAdapter implements Filterable {
    
        private Context context;
        private List<Note> backList; //备份原始数据
        private List<Note> noteList;
        private MyFilter mFilter;
    
        public NoteAdapter(Context mContext,List<Note> noteList){
            this.context = mContext;
            this.noteList = noteList;
            backList = noteList;
        }
    
        @Override
        public int getCount() {
            return noteList.size();
        }
    
        @Override
        public Object getItem(int position) {
            return noteList.get(position);
        }
    
        @Override
        public long getItemId(int position) {
            return position;
        }
    
        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
            context.setTheme(R.style.DayTheme);
            View v = View.inflate(context,R.layout.note_layout,null);
            TextView content = (TextView)v.findViewById(R.id.tv_content);
            TextView time = (TextView)v.findViewById(R.id.tv_time);
            //Set text for TextView
            String allText = noteList.get(position).getContent();
            /*if (sharedPreferences.getBoolean("noteTitle" ,true))
                tv_content.setText(allText.split("
    ")[0]);*/
            content.setText(allText);
            time.setText(noteList.get(position).getTime());
    
            //Save note id to tag
            v.setTag(noteList.get(position).getId());
    
            return v;
        }
    
    
        @Override
        public Filter getFilter() {
            if (mFilter ==null){
                mFilter = new MyFilter();
            }
            return mFilter;
        }
    
        class MyFilter extends Filter {
            //我们在performFiltering(CharSequence charSequence)这个方法中定义过滤规则
            @Override
            protected FilterResults performFiltering(CharSequence charSequence) {
                FilterResults result = new FilterResults();
                List<Note> list;
                if (TextUtils.isEmpty(charSequence)) {//当过滤的关键字为空的时候,我们则显示所有的数据
                    list = backList;
                } else {//否则把符合条件的数据对象添加到集合中
                    list = new ArrayList<>();
                    for (Note note : backList) {
                        if (note.getContent().contains(charSequence)) {
                            list.add(note);
                        }
    
                    }
                }
                result.values = list; //将得到的集合保存到FilterResults的value变量中
                result.count = list.size();//将集合的大小保存到FilterResults的count变量中
    
                return result;
            }
    
            @Override
            protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
                noteList = (List<Note>)filterResults.values;
                if (filterResults.count > 0){
                    notifyDataSetChanged();//通知数据发生了改变
                }else {
                    notifyDataSetInvalidated();//通知数据失效
                }
            }
        }
    
    
    }
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  • 原文地址:https://www.cnblogs.com/cfypd/p/12793698.html
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