Android Note项目

前面我们提到了Android sqlite的一个工具类，这次呢，我们利用这个工具类写个Note项目

      好了，先上图

那么，主要实现的功能有，分页查询，添加Note，修改Note，删除Note。

      先从分页查询开始讲起，代码如下：

public class MainActivity extends AppCompatActivity implements MainAdapter.OnItemClickListener{    public final static String TAG = "MainActivity";    public final static int REQUEST_ADD_OK = 1;    public final static int REQUEST_MODIFY_OK = 2;    private Toolbar mToolbar;    private RecyclerView mRecyclerView;    private MainAdapter adapter;    private List<Note> listDatas;    private DatabaseAdapter dbAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        ButterKnife.bind(this);        mRecyclerView = ButterKnife.findById(this, R.id.recycler_view);        dbAdapter = new DatabaseAdapter(this);        listDatas = new ArrayList<Note>();        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);        mRecyclerView.setLayoutManager(linearLayoutManager);        adapter = new MainAdapter(listDatas);        adapter.setOnItemClickListener(this);        mRecyclerView.setAdapter(adapter);        setupToolbar();//        setupDatas();        initDatas();    }    /**     * 设置toolbar     */    private void setupToolbar() {        mToolbar = ButterKnife.findById(this, R.id.toolbar);        setSupportActionBar(mToolbar);    }    /**     * 添加测试数据     */    private void setupDatas() {        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        Date curDate = new Date(System.currentTimeMillis());//获取当前时间        String createDate = format.format(curDate);        String updateDate = createDate;        String title = "Believe";        String content = "Believe in yourself.";        Note note = new Note(title, content, createDate, updateDate);        dbAdapter.create(note);    }    /**     * 初始化数据     */    private void initDatas() {        listDatas.clear();        ArrayList<Note> list = dbAdapter.findLimit(15, 0);        if (list.size() > 0) {            for (Note note : list) {                listDatas.add(note);//                Log.d(TAG, note.toString());            }            adapter.notifyDataSetChanged();        }    }    @Override    public void onItemClick(View view, int position) {        Note note = listDatas.get(position);        Intent intent = new Intent(this, ModifyNoteActivity.class);        intent.putExtra("id", note.getId());        intent.putExtra("title", note.getTitle());        intent.putExtra("content", note.getContent());        startActivityForResult(intent, REQUEST_MODIFY_OK);    }    /**     * 为添加按钮添加点击事件     */    @OnClick (R.id.btn_add) void add() {        Intent intent = new Intent(this, AddNoteActivity.class);        startActivityForResult(intent, REQUEST_ADD_OK);    }    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        if (requestCode == REQUEST_ADD_OK && resultCode == REQUEST_ADD_OK) {            initDatas();        }        if (requestCode == REQUEST_MODIFY_OK && resultCode == REQUEST_MODIFY_OK) {            initDatas();        }    }}

主界面布局代码如下：

<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">    <include layout="@layout/toolbar_layout"/>    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent">        <android.support.v7.widget.RecyclerView            android:id="@+id/recycler_view"            android:layout_width="match_parent"            android:layout_height="match_parent" />        <android.support.design.widget.FloatingActionButton            android:id="@+id/btn_add"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:src="@drawable/add_note"            android:layout_alignParentBottom="true"            android:layout_alignParentRight="true"            android:layout_margin="20dp"            app:backgroundTint="@color/colorPrimary"            app:rippleColor="@color/colorPrimaryDark"/>    </RelativeLayout></LinearLayout>

以上代码的列表主要使用RecyclerView来实现，毕竟是Google的新东西，也是Google推荐使用的，所有就多拿来用用。同时还用到个开源的ButterKnife框架，主要是用来代替findById功能的，感兴趣的可以去github上看看，点击打开链接

接下来实现的是增，也就是添加Note，代码如下：

public class AddNoteActivity extends AppCompatActivity {    public final static String TAG = "AddNoteActivity";    public final static int RESULT_ADD_OK = 1;    private Toolbar mToolbar;    @Bind(R.id.et_title)    EditText etTitle;    @Bind(R.id.et_content)    EditText etContent;    private DatabaseAdapter dbAdapter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_add_note);        ButterKnife.bind(this);        setupToolbar();    }    /**     * 设置toolbar     */    private void setupToolbar() {        mToolbar = ButterKnife.findById(this, R.id.toolbar);        mToolbar.setTitle("");        setSupportActionBar(mToolbar);        ActionBar actionBar = getSupportActionBar();        actionBar.setDisplayHomeAsUpEnabled(true);    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int id = item.getItemId();        //noinspection SimplifiableIfStatement        if (id == android.R.id.home) {            finish();        }        return super.onOptionsItemSelected(item);    }    @OnClick(R.id.btn_save) void save() {        dbAdapter = new DatabaseAdapter(this);        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        Date curDate = new Date(System.currentTimeMillis());//获取当前时间        String createDate = format.format(curDate);        String updateDate = createDate;        String title = etTitle.getText().toString();        String content = etContent.getText().toString();        Note note = new Note(title, content, createDate, updateDate);        dbAdapter.create(note);        setResult(RESULT_ADD_OK);        finish();    }

布局代码:

<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"    android:background="@color/white">    <include layout="@layout/toolbar_layout"/>    <EditText        android:id="@+id/et_title"        android:layout_width="match_parent"        android:layout_height="50dp"        android:hint="标题"        android:textColor="@color/edit_text"        android:background="@null"        android:singleLine="true"        android:paddingLeft="10dp"        android:paddingRight="10dp"        android:gravity="center_vertical"/>    <View        android:layout_width="match_parent"        android:layout_height="1dp"        android:background="@color/divider"/>    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent">        <EditText            android:id="@+id/et_content"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:hint="内容"            android:textColor="@color/edit_text"            android:background="@null"            android:gravity="top"            android:padding="10dp"/>        <android.support.design.widget.FloatingActionButton            android:id="@+id/btn_save"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:src="@drawable/save"            android:layout_alignParentBottom="true"            android:layout_alignParentRight="true"            android:layout_margin="20dp"            app:backgroundTint="@color/colorPrimary"            app:rippleColor="@color/colorPrimaryDark"/>    </RelativeLayout></LinearLayout>

这部分类容比较简单，涉及的主要是UI的布局。

接下来的改和删，代码如下:

public class ModifyNoteActivity extends AppCompatActivity {    public final static String TAG = "ModifyNoteActivity";    public final static int RESULT_MODIFY_OK = 2;    private Toolbar mToolbar;    @Bind(R.id.et_title)    EditText etTitle;    @Bind(R.id.et_content)    EditText etContent;    private DatabaseAdapter dbAdapter;    //id    private int id;    //要修改的title    private String title;    //要修改的内容    private String content;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_modify_note);        ButterKnife.bind(this);        dbAdapter = new DatabaseAdapter(this);        initDatas();        setupToolbar();    }    /**     * 初始化数据     */    private void initDatas() {        id = getIntent().getIntExtra("id", 1);        title = getIntent().getStringExtra("title");        content = getIntent().getStringExtra("content");        etTitle.setText(title);        etTitle.setSelection(title.length());        etContent.setText(content);    }    /**     * 设置toolbar     */    private void setupToolbar() {        mToolbar = ButterKnife.findById(this, R.id.toolbar);        mToolbar.setTitle("");        setSupportActionBar(mToolbar);        ActionBar actionBar = getSupportActionBar();        actionBar.setDisplayHomeAsUpEnabled(true);    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.menu_modify_note, menu);        return true;    }    @Override    public boolean onOptionsItemSelected(MenuItem item) {        // Handle action bar item clicks here. The action bar will        // automatically handle clicks on the Home/Up button, so long        // as you specify a parent activity in AndroidManifest.xml.        int _id = item.getItemId();        //noinspection SimplifiableIfStatement        if (_id == android.R.id.home) {            finish();        }        if (_id == R.id.action_delete) {            dbAdapter.remove(id);            setResult(RESULT_MODIFY_OK);            finish();        }        return super.onOptionsItemSelected(item);    }    @OnClick(R.id.btn_modify) void modify() {        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        Date curDate = new Date(System.currentTimeMillis());//获取当前时间        String updateDate = format.format(curDate);        String title = etTitle.getText().toString();        String content = etContent.getText().toString();        Note note = new Note(id, title, content, updateDate);        dbAdapter.update(note);        setResult(RESULT_MODIFY_OK);        finish();    }}

布局代码如下:

<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"    android:background="@color/white">    <include layout="@layout/toolbar_layout"/>    <EditText        android:id="@+id/et_title"        android:layout_width="match_parent"        android:layout_height="50dp"        android:hint="标题"        android:textColor="@color/edit_text"        android:background="@null"        android:singleLine="true"        android:paddingLeft="10dp"        android:paddingRight="10dp"        android:gravity="center_vertical"/>    <View        android:layout_width="match_parent"        android:layout_height="1dp"        android:background="@color/divider"/>    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="match_parent">        <EditText            android:id="@+id/et_content"            android:layout_width="match_parent"            android:layout_height="match_parent"            android:hint="内容"            android:textColor="@color/edit_text"            android:background="@null"            android:gravity="top"            android:padding="10dp"/>        <android.support.design.widget.FloatingActionButton            android:id="@+id/btn_modify"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:src="@drawable/save"            android:layout_alignParentBottom="true"            android:layout_alignParentRight="true"            android:layout_margin="20dp"            app:backgroundTint="@color/colorPrimary"            app:rippleColor="@color/colorPrimaryDark"/>    </RelativeLayout></LinearLayout>

好了，通过以上三个步骤我们就可以实现一个基于sqlite的Note项目，代码比较简单，有什么不懂得地方可以随时留言。项目源码链接: http://pan.baidu.com/s/1bn7HJ23 密码: f2eu