便签列表活动

职责

• 显示便签内容
• 添加便签
• 删除便签
• 修改便签

组件

• public static final int ADD = 1; 添加请求编码
• public static final int EDIT = 2;修改请求编码
• RecyclerView recyclerView; 列表
• LinearLayoutManager linearLayoutManager; 列表布局
• NodeAdapter myAdapter;列表适配器
• ArrayList datas;当前便签集合
• NoteDAO noteDAO;数据层

事件

• 需要实现项容器RelativeLayout单击事件
• 需要实现项容器RelativeLayout长按事件

MainActivity的onCreate时序图

res/layout/activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context=".MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_height="wrap_content"
        android:layout_width="match_parent"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            android:theme="@style/AppTheme.AppBarOverlay"
            app:popupTheme="@style/AppTheme.PopupOverlay"/>

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main"/>


</android.support.design.widget.CoordinatorLayout>

res/layout/content_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/activity_main"
    tools:context=".MainActivity">

    <android.support.v7.widget.RecyclerView


        android:paddingLeft="@dimen/activity_horizontal_margin"
        android:paddingRight="@dimen/activity_horizontal_margin"
        android:paddingTop="@dimen/activity_vertical_margin"
        android:paddingBottom="@dimen/activity_vertical_margin"

        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"

        >
    </android.support.v7.widget.RecyclerView>


</LinearLayout>

res/menu/menu_main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      xmlns:tools="http://schemas.android.com/tools"
      tools:context=".MainActivity">
    <item android:id="@+id/add"
          android:title="@string/add"
          android:orderInCategory="100"
          android:icon="@drawable/ic_add"
          app:showAsAction="always"/>
</menu>

MainActivity.java

package com.hzj163.mysqlitedb;

import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Toast;

import com.hzj163.mysqlitedb.adapter.NodeAdapter;
import com.hzj163.mysqlitedb.beans.Note;
import com.hzj163.mysqlitedb.db.NoteDAO;
import com.hzj163.mysqlitedb.viewholder.NoteViewHolder;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity implements NoteViewHolder.ItemonClick, NoteViewHolder.ItemonLongClick {

    //添加的code
    public static final int ADD = 1;
    //修改的code
    public static final int EDIT = 2;

    RecyclerView recyclerView;

    LinearLayoutManager linearLayoutManager;

    NodeAdapter myAdapter;

    ArrayList<Note> datas;
    NoteDAO noteDAO;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //实例化Toolbar
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        //设置Toolbar属性
        toolbar.setTitle("小便签");
        //激活Toolbar
        setSupportActionBar(toolbar);
        //实例化noteDAO
        noteDAO = new NoteDAO(this);
        //初始化数据集合
        datas = noteDAO.selectByAll();
        //初始化recyclerView
        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        //初始化linearLayoutManager
        linearLayoutManager = new LinearLayoutManager(this);
        //设置recyclerView布局
        recyclerView.setLayoutManager(linearLayoutManager);
        //初始化适配器
        myAdapter = new NodeAdapter(datas, this, this);
        //设置recyclerView适配器
        recyclerView.setAdapter(myAdapter);
    }

    //菜单创建
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        //设置菜单【让xml文件变成menu对象】
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    //菜单事件【添加便签】
    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        //获得当前点击的菜单的ID
        int id = item.getItemId();
        //添加便签事件
        if (id == R.id.add) {

            //跳转到一个活动
            Intent intent = new Intent(this, AddActivity.class);
            //具备返回值的跳转
            startActivityForResult(intent, ADD);

            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    //活动返回
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {


        //处理添加便签
        if (requestCode == ADD && resultCode == ADD) {
            //需要Note支持序列化
            Note temp = (Note) data.getSerializableExtra("note");
            //判断内容是否不为空
            if (temp.getInfo().trim().equals("")) {
                Toast.makeText(this, "便签内容不可以为空", Toast.LENGTH_LONG).show();
                return;
            }

            //数据库添加
            noteDAO.insert(temp);
            //集合添加【需要在最上面一行插入】
            datas.add(0, temp);
            //更新
            myAdapter.notifyDataSetChanged();
        }
        //处理修改便签
        if (requestCode == EDIT && resultCode == EDIT) {

            Note temp = (Note) data.getSerializableExtra("note");
            if (temp.getInfo().trim().equals("")) {
                Toast.makeText(this, "便签内容不可以为空", Toast.LENGTH_LONG).show();
                return;
            }
            noteDAO.update(temp);

            //这里需要Note对象的equals方法给出相等规则
            //datas.indexOf(temp)按照对象查询出所在集合的下标,依据的标准是对象的equals方法
            int position = datas.indexOf(temp);
            //修改集合
            datas.set(position, temp);
            //更新【采取局部更新notifyItemChanged】
            myAdapter.notifyItemChanged(position);
        }
    }

    //每一项的点击事件
    @Override
    public void onClick(View v, int position) {
        //修改便签
        Intent intent = new Intent(this, EditActicity.class);
        //携带当前选中的便签对象，传递给修改界面
        intent.putExtra("note", datas.get(position));
        startActivityForResult(intent, EDIT);
    }

    //每一项的长按事件
    @Override
    public void onLongClick(View v, int position) {
        //删除便签
        final int tempPosition = position;
        AlertDialog.Builder builder = new AlertDialog.Builder(this);
        builder.setTitle("删除确认");
        builder.setMessage("你确实要删除吗?");
        builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {

                //数据库删除
                noteDAO.del(datas.get(tempPosition).getId());
                //集合维护
                datas.remove(tempPosition);
                //更新【采取局部删除notifyItemRemoved】
                myAdapter.notifyItemRemoved(tempPosition);
            }
        });
        builder.setNegativeButton("取消", null);
        AlertDialog alertDialog = builder.create();
        alertDialog.show();
    }
}