Android SQLite存储——个人日记本开发（二）：添加、删除功能的实现
继续上一篇，个人日记本开发。通过上一篇，日记本的数据库部分已经完成，现在就来实现添加、删除功能：一：在String中定义：
<resources>
<string name="app_name">MyDiary01</string>
<string name="hello_world">Hello world!</string>
<string name="menu_add">添加一篇新日记</string>
<string name="menu_delete">删除一篇日记</string>
<string name="label_title">标题</string>
<string name="label_content">内容</string>
<string name="save">保存日记</string>
<string name="title_activity_diary">DiaryActivity</string>
</resources>
二：在menu中的activity_diary.xml中布局菜单：
<menu xmlns:android="http://schemas.android.com/apk/res/android">
<item android:id="@+id/menu_add"
android:title="@string/menu_add"
android:icon="@android:drawable/ic_menu_add"//引入添加图标
android:orderInCategory="100" />
<item android:id="@+id/menu_delete"
android:title="@string/menu_delete"
android:icon="@android:drawable/ic_menu_delete"//引入删除图标
android:orderInCategory="100" />
</menu>
三：(1)布局activity_diary.xml文件，显示日记内容页面：
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/star"
android:orientation="vertical" >
<ListView
android:id="@id/android:list"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
//当日记内容为空时： <TextView
android:id="@id/android:empty"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="你好懒啊，还没开始写日记呢" />
</LinearLayout>
(2)item.xml显示每一条日记内容布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal" >
<TextView
android:id="@+id/title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:textSize="20sp" />
<TextView
android:id="@+id/date"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="right"
android:textSize="12sp" />
</LinearLayout>
(3)edit.xml：添加日记页面布局
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/label_title" />
<EditText
android:id="@+id/title"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/label_content" />
<EditText
android:id="@+id/content"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="top"
android:layout_weight="1" />
<Button
android:id="@+id/confirm"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android://点击事件
android:text="@string/save" />
</LinearLayout>
四 完善DiaryService内容，增加添加、删除功能：
public class DiaryService {
private DBHelper dbHelper;
private SQLiteDatabase sqLiteDatabase;
public DiaryService(Context context) {
dbHelper = new DBHelper(context);
}
public void save(Diary diary) {
sqLiteDatabase = dbHelper.getWritableDatabase();
String sql = "insert into tb_diary(title,content,pubdate) values(?,?,?)";
sqLiteDatabase.execSQL(
sql,
new String[] { diary.getTitle(), diary.getContent(),
diary.getPubdate() });
}
public Cursor getAllDiaries(){
sqLiteDatabase=dbHelper.getReadableDatabase();
Cursor cursor=sqLiteDatabase.rawQuery("select * from tb_diary", null);
return cursor;
}//代替listview实现列表显示功能
public void delete(Integer id){
sqLiteDatabase=dbHelper.getWritableDatabase();
sqLiteDatabase.delete("tb_diary", "_id=?", new String[]{id.toString()});
}
}
五 完善DiaryTest文件实现添加、删除功能：
public class DiaryTest extends AndroidTestCase {
public void testOnCreate(){
DBHelper dbHelper=new DBHelper(getContext());
dbHelper.getWritableDatabase();
}
public void testSave(){
DiaryService diaryService=new DiaryService(getContext());
Diary diary1=new Diary("今天天气不错", "正在学习Sqlite", formate(new Date()));
Diary diary2=new Diary("今天天气阴", "心情很好", formate(new Date()));
diaryService.save(diary1);
diaryService.save(diary2);
}
public String formate(Date date){
SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy年MM月dd日");
return simpleDateFormat.format(date);
}
public void testDelete(){
DiaryService diaryService=new DiaryService(getContext());
diaryService.delete(1);
}
}
基于以上，添加tools包，工具类 DateFormatTools，方便使用：
public class DateFormatTools {
public static String format(Date date){
SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy年MM月dd日");
return simpleDateFormat.format(date);
}
}
六 完成处理文件(1)DiaryActivity：
public class DiaryActivity extends ListActivity {
private int idChoosed;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_diary);
refreshlist();
getListView().setOnItemSelectedListener(new OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> listview, View view,
int position, long id) {
System.out.println("id="+id);
idChoosed=(int) id;
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
}
});
}
private void refreshlist() {
DiaryService diaryService = new DiaryService(this);
Cursor cursor = diaryService.getAllDiaries();
//startManagingCursor(cursor);
SimpleCursorAdapter simpleCursorAdapter = new SimpleCursorAdapter(this,
R.layout.item, cursor, new String[] { "title", "pubdate" },
new int[] { R.id.title, R.id.date });
setListAdapter(simpleCursorAdapter);
}//实现快速刷新
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.activity_diary, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch(item.getItemId()){
case R.id.menu_add:
Toast.makeText(this, "add",Toast.LENGTH_LONG).show();
Intent intent=new Intent(this,DiaryAdd.class);
//startActivity(intent);
startActivityForResult(intent, 1);
break;
case R.id.menu_delete:
AlertDialog.Builder aBuilder=new AlertDialog.Builder(this);
aBuilder.setTitle("你确定要删除吗？");
aBuilder.setPositiveButton("确定", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
DiaryService diaryService=new DiaryService(DiaryActivity.this);
diaryService.delete(idChoosed);
refreshlist();
}
});
aBuilder.setNegativeButton("取消", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
});
aBuilder.show();
break;
}
return super.onOptionsItemSelected(item);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (resultCode) {
case RESULT_OK:
refreshlist();
break;
default:
break;
}
}
}
(2)DiaryAdd，添加页面：
public class DiaryAdd extends Activity {
private EditText titleText;
private EditText contentText;
private Button saveButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.edit);
titleText=(EditText) this.findViewById(R.id.title);
contentText=(EditText) this.findViewById(R.id.content);
saveButton=(Button) this.findViewById(R.id.confirm);
}
publicvoid diaryAdd(View view){
String title=titleText.getText().toString();
String content=contentText.getText().toString();
Diary diary=new Diary(title, content, DateFormatTools.format(new Date()));
DiaryService diaryService=new DiaryService(this);
diaryService.save(diary);
Toast.makeText(this, "保存成功", Toast.LENGTH_LONG).show();
setResult(RESULT_OK);
finish();
}
}
页面显示：
（1）如果日记本里没有内容：
（2）添加日记：
（3）日记保存成功：
页:
[1]