Android實(shí)現(xiàn)記事本小功能

更新時(shí)間：2020年07月22日 11:43:46 作者：bossshp

這篇文章主要為大家詳細(xì)介紹了Android實(shí)現(xiàn)記事本功能，文中示例代碼介紹的非常詳細(xì)，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

本文實(shí)例為大家分享了Android實(shí)現(xiàn)記事本功能的具體代碼，供大家參考，具體內(nèi)容如下

首先聲明，本人是android的小白，主要是新人項(xiàng)目寫了這個(gè)程序，思路可能不是很清晰，可優(yōu)化的地方也有很多，望路過(guò)的大佬不吝賜教。
該記事本包含創(chuàng)建新條目，數(shù)據(jù)庫(kù)增刪改查，條目可編輯，滑動(dòng)刪除與拖拽排序，簡(jiǎn)單鬧鐘實(shí)現(xiàn)（還有個(gè)簡(jiǎn)陋背景音樂(lè)開關(guān)就不提了太簡(jiǎn)單），接下來(lái)逐一介紹一下。

build.gradle導(dǎo)入

apply plugin: 'kotlin-kapt'
'''
implementation 'com.google.android.material:material:1.0.0'
 implementation 'de.hdodenhof:circleimageview:3.0.1'
 implementation 'com.android.support.constraint:constraint-layout:1.1.3'
 implementation 'androidx.room:room-runtime:2.1.0'
 implementation 'androidx.lifecycle:lifecycle-extensions:2.1.0'
 implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.2.0'
 implementation 'androidx.recyclerview:recyclerview:1.0.0'
 kapt "androidx.room:room-compiler:2.1.0"

沒(méi)什么多說(shuō)的。

Room數(shù)據(jù)庫(kù)

room數(shù)據(jù)庫(kù)相比于sqlite來(lái)說(shuō)對(duì)新人確實(shí)友好很多，在沒(méi)有SQL基礎(chǔ)的前提下，增刪改查等實(shí)現(xiàn)都很簡(jiǎn)單，只需創(chuàng)建一個(gè)實(shí)例，便可在線程中進(jìn)行。具體代碼為

①接口：

@Dao
interface NoteDao {


 @Update
 fun updateNote(newNote: Note)

 @Query("select * from Note")
 fun loadAllNotes(): List<Note>

 @Query("select * from Note where title > :title")
 fun loadNotesLongerThan(title:String) : List<Note>

 @Query("select * from Note where id == :id")
 fun loadById(id:Long) :Note

 @Delete
 fun deleteNote(note: Note)

 @Query("delete from Note where title == :title")
 fun deleteNoteByTitle(title: String): Int

 @Insert
 fun insertNote(note: Note)


}

②Appdatabase類（獲取實(shí)例

@Database(version = 1, entities = [Note::class])
abstract class AppDatabase: RoomDatabase(){

 abstract fun noteDao() : NoteDao

 companion object{
 //訪問(wèn)實(shí)例
 private var instance : AppDatabase? = null

 @Synchronized//同步化
 fun getDatabase(context: Context):AppDatabase{
  instance?.let {
  return it
  }
  return Room.databaseBuilder(context.applicationContext,
  AppDatabase::class.java, "app_database")
  .build().apply {
   instance = this
  }
 }
 }
}

滑動(dòng)刪除和拖拽排序

class RecycleItemTouchHelper(private val helperCallback: ItemTouchHelperCallback) :
 ItemTouchHelper.Callback() {

 //設(shè)置滑動(dòng)類型標(biāo)記
 override fun getMovementFlags(
 recyclerView: RecyclerView,
 viewHolder: RecyclerView.ViewHolder
 ): Int {
 return makeMovementFlags(ItemTouchHelper.UP or ItemTouchHelper.DOWN,
  ItemTouchHelper.END or ItemTouchHelper.START )
 }


 override fun isLongPressDragEnabled(): Boolean {
 return true
 }

 //滑動(dòng)
 override fun isItemViewSwipeEnabled(): Boolean {
 return true
 }

 //拖拽回調(diào)
 override fun onMove(
 recyclerView: RecyclerView,
 viewHolder: RecyclerView.ViewHolder,
 target: RecyclerView.ViewHolder
 ): Boolean {
 helperCallback.onMove(viewHolder.adapterPosition, target.adapterPosition)
 return true
 }

 //滑動(dòng)
 override fun onSwiped(viewHolder: RecyclerView.ViewHolder, direction: Int): Unit {
 helperCallback.onItemDelete(viewHolder.adapterPosition)
 }

 //狀態(tài)回調(diào)
 override fun onSelectedChanged(
 viewHolder: RecyclerView.ViewHolder?,
 actionState: Int
 ) {
 super.onSelectedChanged(viewHolder, actionState)
 }

 interface ItemTouchHelperCallback {
 fun onItemDelete(positon: Int)
 fun onMove(fromPosition: Int, toPosition: Int)
 }


}

NoteAdapter接口實(shí)現(xiàn)

拖拽排序和滑動(dòng)刪除后即更新一次，這種方法并不好，畢竟沒(méi)有用到MVVM中的高級(jí)組件，包括觀察者，Livedata，ViewModel察覺(jué)數(shù)據(jù)變化并提示更新。建議在這種方法的前提下可以考慮在從Activity離開后，再數(shù)據(jù)更新。
注：千萬(wàn)不要在**onPause()**中涉及數(shù)據(jù)更新和保存?。。?/p>

//拖拽排序
 override fun onMove(fromPosition: Int, toPosition: Int) {
 val noteDao = AppDatabase.getDatabase(context).noteDao()
  if (fromPosition < toPosition) {
  for (i in fromPosition until toPosition) {
   Collections.swap(noteList, i, i + 1)
   for (i in noteList){
   Log.d("title", i.title)
   }
   Log.d("tag2", fromPosition.toString()+"->"+toPosition)  
  }
  } else {
  for (i in fromPosition downTo toPosition + 1) {
   Collections.swap(noteList, i, i - 1)
  }
  }
 //排序后的數(shù)據(jù)更新
 thread {
  var templist = noteDao.loadAllNotes().toMutableList()
  for (i in 0 until templist.size){
  templist[i].title = noteList[i].title
  templist[i].content = noteList[i].content
  noteDao.updateNote(templist[i])
  }
 }

 notifyItemMoved(fromPosition, toPosition)

 }

簡(jiǎn)易鬧鐘實(shí)現(xiàn)

broadcast類需要自己實(shí)現(xiàn)

class MyReceiver : BroadcastReceiver() {

 override fun onReceive(context: Context, intent: Intent) {
 // This method is called when the BroadcastReceiver is receiving an Intent broadcast.
 Toast.makeText(context,"You have a task to do!!!", Toast.LENGTH_LONG).show()
 }
}

這里只是發(fā)個(gè)廣播通知，并沒(méi)有提示聲音，可以采取發(fā)到通知欄的方式，系統(tǒng)會(huì)有提示音。涉及到AlarmManager類
NoteActivity中的實(shí)現(xiàn)：

setBtn.setOnClickListener { view ->
  val c = Calendar.getInstance()
  //調(diào)整為中國(guó)時(shí)區(qū)，不然有8小時(shí)差比較麻煩
  val tz = TimeZone.getTimeZone("Asia/Shanghai")
  c.timeZone = tz
  //獲取當(dāng)前時(shí)間
  if (setHour.text.toString()!=""&&setMin.text.toString()!="") {
  c.set(Calendar.HOUR_OF_DAY, setHour.text.toString().toInt());//小時(shí)
  c.set(
   Calendar.MINUTE, setMin.text.toString().toInt()
  );//分鐘
  c.set(Calendar.SECOND, 0);//秒
  }
  //計(jì)時(shí)發(fā)送通知
  val mIntent = Intent(this, MyReceiver::class.java)
  val mPendingIntent =
  PendingIntent.getBroadcast(this, 0, mIntent, PendingIntent.FLAG_UPDATE_CURRENT)
  am = this
  .getSystemService(Context.ALARM_SERVICE) as AlarmManager
  if (setHour.text.toString()==""||setMin.text.toString()==""||
  setHour.text.toString().toInt() > 24 || setMin.text.toString().toInt() > 60) {
  Toast.makeText(this, "請(qǐng)輸入正確的時(shí)間格式！", Toast.LENGTH_SHORT).show()
  } else {
  Log.d("fuck10", c.timeInMillis.toString())
  am!!.setExactAndAllowWhileIdle(
   AlarmManager.RTC_WAKEUP, c.timeInMillis,
   mPendingIntent
  )
  Toast.makeText(this, "設(shè)置成功", Toast.LENGTH_SHORT).show()
  }
 }

其它方面如點(diǎn)擊recyclerView中的Item重新編輯時(shí)對(duì)原數(shù)據(jù)的展現(xiàn)，用到了setText()，這里注意不要跟kotlin中setText()和getText()搞混。

大概所有功能差不多就這些了，畢竟只是個(gè)記事本應(yīng)用。
所有代碼放在github上面了，如有需要，請(qǐng)自取

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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