Android记事本NotePad应用功能拓展

一、实现功能

1.NoteList中显示条目增加时间戳显示

2.添加笔记查询功能（根据标题查询）

3.设置功能（初步实现）

4.优化删除功能

二、项目代码分析以及源码

首先贴出大家最想要的源码吧！

源码（C币为防伸手党....认真阅读相关资料，细心的你会发现免费下载的途径）

1.NoteList中显示条目增加时间戳显示

 public boolean onKeyDown(int keyCode, KeyEvent event){
        if (keyCode == KeyEvent.KEYCODE_HOME){
            return true;
        }
        else if (keyCode == KeyEvent.KEYCODE_BACK){
            autoSetMessage();//自动保存
            setResult(RESULT_OK, intent);
            finish();
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }

    public void autoSetMessage(){
        if(openMode == 4){
            if(et.getText().toString().length() == 0){
                intent.putExtra("mode", -1); //nothing new happens.
            }
            else{
                intent.putExtra("mode", 0); // new one note;
                intent.putExtra("content", et.getText().toString());
                intent.putExtra("time", dateToStr());//保存时间
                intent.putExtra("tag", tag);
            }
        }
        else {
            if (et.getText().toString().equals(old_content) && !tagChange)
                intent.putExtra("mode", -1); // edit nothing
            else {
                intent.putExtra("mode", 1); //edit the content
                intent.putExtra("content", et.getText().toString());
                intent.putExtra("time", dateToStr());
                intent.putExtra("id", id);
                intent.putExtra("tag", tag);
            }
        }
    }

    public String dateToStr(){
        Date date = new Date();
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        return simpleDateFormat.format(date);
    }

2.添加笔记查询功能（根据标题查询）

@Override
    public View getView(int position, View convertView, ViewGroup parent) {
        SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(mContext);
        mContext.setTheme(R.style.DayTheme);
        View v = View.inflate(mContext, R.layout.note_layout, null);
        TextView tv_content = (TextView)v.findViewById(R.id.tv_content);
        TextView tv_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("\n")[0]);*/
        tv_content.setText(allText);
        tv_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;
        }
        //在publishResults方法中告诉适配器更新界面
        @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
            }
        }

3.设置功能（初步实现）

setting_layout.xml里面找找。

4.优化删除功能

部分删除

@Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()){
            case R.id.delete:
                new AlertDialog.Builder(EditActivity.this)
                        .setMessage("您确定删除吗？")
                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                if (openMode == 4){ // new note
                                    intent.putExtra("mode", -1);
                                    setResult(RESULT_OK, intent);
                                }
                                else { // existing note
                                    intent.putExtra("mode", 2);
                                    intent.putExtra("id", id);
                                    setResult(RESULT_OK, intent);
                                }
                                finish();
                            }
                        }).setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                }).create().show();
                break;
        }
        return super.onOptionsItemSelected(item);
    }

全部删除

@Override
    public boolean onOptionsItemSelected(MenuItem item){
        switch (item.getItemId()){
            case R.id.menu_clear:
                new AlertDialog.Builder(MainActivity.this)
                        .setMessage("您确定删除全部吗？")
                        .setPositiveButton(android.R.string.yes, new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                dbHelper = new NoteDatabase(context);
                                SQLiteDatabase db = dbHelper.getWritableDatabase();
                                db.delete("notes", null, null);
                                db.execSQL("update sqlite_sequence set seq=0 where name='notes'");
                                refreshListView();
                            }
                        }).setNegativeButton(android.R.string.no, new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                }).create().show();
                break;

        }
        return super.onOptionsItemSelected(item);
    }