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Jetpack
Jetpack 是一个由多个库组成的套件,可帮忙开发者遵循最佳做法,缩小样板代码并编写可在各种 Android 版本和设施中统一运行的代码,让开发者精力集中编写重要的代码。
Android Architecture Component (AAC)。
官网举荐架构
请留神,每个组件仅依赖于其下一级的组件。例如,Activity 和 Fragment 仅依赖于视图模型。存储区是惟一依赖于其余多个类的类;在本例中,存储区依赖于持久性数据模型和近程后端数据源。
MVVM
MVVM 即 Model – View – ViewModel 的缩写,它的呈现是为了将图形界面与业务逻辑,数据模型进行解耦。
MVVM 也是 Google 推崇的一种 Android 我的项目架构模型。
之前学习的 Jetpack 组建,大部分都是为了可能更好地架构 MVVM 应用程序而设计的。
API 接口
接口:https://api.github.com/users/…
工程构造
bean:实体类。
api:网络申请接口。
repository:仓储层。用于寄存 Room 数据,网络数据,本地数据等。
viewmodel:从仓储层获取数据,不须要关怀数据起源。
view:Activity,Fragment 和布局文件,用会用到 DataBinding 组件
dao:Room 数据库操作
application:实例化全局文件和获取全局上下文。
bindingAdapter:放一些
增加依赖
implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0'
implementation 'de.hdodenhof:circleimageview:3.0.1'
搭建我的项目
通过获取 GitHub API 获取个人信息进行展现。
1. 定义 User 实体类
@Entity(tableName = "user")
data class User(@PrimaryKey @ColumnInfo(name = "id", typeAffinity = ColumnInfo.INTEGER) var id: Int,
@ColumnInfo(name = "login", typeAffinity = ColumnInfo.TEXT) var login: String,
@ColumnInfo(name = "name", typeAffinity = ColumnInfo.TEXT) var name: String?,
@ColumnInfo(name = "avatar_url", typeAffinity = ColumnInfo.TEXT) @SerializedName("avatar_url")var avatar: String?,
@ColumnInfo(name = "blog", typeAffinity = ColumnInfo.TEXT) var blog: String,
@ColumnInfo(name = "company", typeAffinity = ColumnInfo.TEXT) var company: String?,
@ColumnInfo(name = "bio", typeAffinity = ColumnInfo.TEXT) var bio: String?,
@ColumnInfo(name = "location", typeAffinity = ColumnInfo.TEXT) var location: String?,
@ColumnInfo(name = "htmlUrl", typeAffinity = ColumnInfo.TEXT) @SerializedName("html_url") var htmlUrl: String?
)
```
####2. 定义 Dao 类
```
@Dao
interface UserDao {@Insert(onConflict = OnConflictStrategy.REPLACE)
fun insertUser(user: User)
@Delete
fun deleteUser(user: User)
@Query("select * from user where login =:name")
fun getUserByName(name: String): LiveData<User>
}
```
####3. 定义 DataBase 类
```
@Database(entities = [User::class], version =7)
abstract class AppDatabase : RoomDatabase() {abstract fun userDao(): UserDao
companion object {
private var instance: AppDatabase? = null
@Synchronized
fun getDatabase(context: Context): AppDatabase {
instance?.let {return it}
return Room.databaseBuilder(
context.applicationContext,
AppDatabase::class.java,
"user_db"
).fallbackToDestructiveMigration().build().apply {instance = this}
}
}
}
4. 定义 API 接口
interface Api {@GET("users/{userName}")
fun getUser(@Path("userName") userName: String): Call<User>
}
5. 定义 Retrofit 拜访网络
object RetrofitClient {
private const val BASE_URL = "https://api.github.com/"
var retrofit: Retrofit
init {
retrofit =
Retrofit.Builder().baseUrl(BASE_URL).addConverterFactory(GsonConverterFactory.create())
.build()}
fun getApi(): Api? {return retrofit.create(Api::class.java)
}
}
6. 定义 Application 类
class MyApplication : Application() {
companion object {lateinit var context: Context}
override fun onCreate() {super.onCreate()
context = applicationContext
}
}
7. 定义 Repository
object UserRepository {var userDao: UserDao = AppDatabase.getDatabase(MyApplication.context).userDao()
fun getUser(name: String): LiveData<User> {refresh(name)
return userDao.getUserByName(name)
}
fun refresh(name: String) {RetrofitClient.getApi()?.getUser(name)?.enqueue(object : Callback<User> {override fun onResponse(call: Call<User>, response: Response<User>) {if (response.body() != null) {insertUser(response.body()!!)
}
}
override fun onFailure(call: Call<User>, t: Throwable) {Log.d("UserRepository", "onFailure$t")
}
})
}
fun insertUser(user: User) {
thread {userDao.insertUser(user)
}
}
}
8. 定义 ViewModel
class MvvmViewModel : ViewModel() {
val userName = "yaoxin521123"
fun getUser() = UserRepository.getUser(userName)
fun refresh() = UserRepository.refresh(userName)
}
9. 绘制 xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:app="http://schemas.android.com/apk/res-auto">
<data>
<variable
name="user"
type="com.yx.androidseniorpreparetest.eighth.bean.User" />
</data>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/srl_SwipeRefreshLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".eighth.MvvmActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<de.hdodenhof.circleimageview.CircleImageView
android:layout_width="95dp"
android:layout_height="95dp"
android:layout_gravity="center"
android:layout_marginTop="20dp"
app:image="@{user.avatar}" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.name}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.login}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.blog}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.company}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.bio}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.location}"
android:textColor="#000000"
android:textSize="20sp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="@{user.htmlUrl}"
android:textColor="#000000"
android:textSize="20sp" />
</LinearLayout>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout
</layout>
10. 在 Activity 触发事件
class MvvmActivity : AppCompatActivity() {override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)
val binding =
DataBindingUtil.setContentView<ActivityMvvmBinding>(this, R.layout.activity_mvvm)
val viewModel = ViewModelProviders.of(this).get(MvvmViewModel::class.java)
viewModel.getUser().observe(this, {if (it != null) {binding.user = it}
})
binding.srlSwipeRefreshLayout.setOnRefreshListener {viewModel.refresh()
binding.srlSwipeRefreshLayout.isRefreshing = false
}
}
}
11. 定义 BindingAapter
class BindingAdapter {
companion object {
@JvmStatic
@BindingAdapter(value = ["image", "defaultImageResource"], requireAll = false)
fun setImage(imageView: ImageView, imageUrl: String?, imageResource: Int) {if (!TextUtils.isEmpty(imageUrl)) {Picasso.get()
.load(imageUrl)
.placeholder(R.drawable.ic_launcher_background)
.error(R.drawable.ic_launcher_background)
.into(imageView)
} else {imageView.setImageResource(imageResource)
}
}
}
}
结语:后续会继续更新哦,喜爱的话点赞关注一下吧。
相干视频
【Android 进阶】jetpack 教程
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