前言

• 通过一段时间对Kotlin的使用，总结一下Android版kotlin各种语法的写法
• 顺便发几个常用工具类的写法，希望大家指正

正文

######1、 Thread

• Java写法

new Thread(new Runnable() {@Overridepublic void run() {}
}).start();
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• Kotlin写法

Thread(Runnable {}).start()
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######2、Handler

• Java

private Handler handler=new Handler(new Handler.Callback() {@Overridepublic boolean handleMessage(Message msg) {switch(msg.what){case 0:break;default:break; }return false;}});
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• kotlin

private val handler=Handler(Handler.Callback{msg->when(msg.what){0->{}else->{}}false
})
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3、setOnClickListener

• Java

btn.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {}
});
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• Kotlin

btn.setOnClickListener{}
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4、RadioGroup setOnCheckedChangeListener

• Java

RadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() { @Override public void onCheckedChanged(RadioGroup group, int checkedId) { switch(checkedId){case R.id.nav_bottom_menu_1:break;case R.id.nav_bottom_menu_2:break;case R.id.nav_bottom_menu_3:break;case R.id.nav_bottom_menu_4:break;}} });
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• Kotlin

radioMenu.setOnCheckedChangeListener { _, checkedId ->when (checkedId) {R.id.nav_bottom_menu_1 -> {}R.id.nav_bottom_menu_2 -> {}R.id.nav_bottom_menu_3 -> {}R.id.nav_bottom_menu_4 -> {}}}
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5、JavaBean写法

• Java

public class Student{private String name;private int age;public String getName(){return name;}public void setName(String name){this.name=name;}public String getAge(){return age;}public void setAge(String age){this.age=age;}@Overridepublic String toString() {return "Student{" +"name='" + name+ '\'' +", age='" + age+ '\'' +'}';}
}
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• kotlin

data class Student(var name:String,var age:Int) {override fun toString(): String {return "Student(name='$name', age=$age)"}
}
//注意:
//1、声明为var类型后系统自动实现get\set方法 如果是val类型则无法用xx.name调用
//2、该类默认实现了Student(name,age)构造器，如果想在调用中以空构造器实现，需要给该类赋初值如：
data class Student(var name:String="",var age:Int=0) {//::::::
}
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####常用工具类（Kotlin版本）：

• SharePreference工具类

import android.content.Context
import android.content.SharedPreferences
import android.support.v4.content.SharedPreferencesCompat/*** Function:* author: limh* time:2017/7/24*/
object SharePreferUtils {val FILE_NAME: String = "xxx"//文件名称fun put(context: Context, key: String, any: Any) {val sp: SharedPreferences = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE)val editer: SharedPreferences.Editor = sp.edit()if (any is String)editer.putString(key, any)else if (any is Int)editer.putInt(key, any)else if (any is Float)editer.putFloat(key, any)else if (any is Long)editer.putLong(key, any)else if (any is Boolean)editer.putBoolean(key, any)SharedPreferencesCompat.EditorCompat.getInstance().apply(editer)}fun get(context: Context, key: String, default: Any): Any {val sp: SharedPreferences = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE)if (default is String)return sp.getString(key, default)else if (default is Int)return sp.getInt(key, default)else if (default is Float)return sp.getFloat(key, default)else if (default is Long)return sp.getLong(key, default)else if (default is Boolean)return sp.getBoolean(key, default)return ""}fun putSet(context: Context, key: String, value: Set<String>) {val sp: SharedPreferences = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE)val editer: SharedPreferences.Editor = sp.edit()editer.putStringSet(key, value)SharedPreferencesCompat.EditorCompat.getInstance().apply(editer)}fun getSet(context: Context, key: String): Set<String> {val sp: SharedPreferences = context.getSharedPreferences(FILE_NAME, Context.MODE_PRIVATE)return sp.getStringSet(key, null)}
}
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• Gson转换工具类

import com.google.gson.Gson
import com.google.gson.JsonArray
import com.google.gson.JsonParser
import org.json.JSONException
/*** Function:* author: limh* time:2017/7/11*/
object GsonUtils {var gson: Gson = Gson()/*** Bean转String*/fun <T> Gson2Str(gs: T): String {return gson.toJson(gs)}/*** string转Bean*/fun <T> str2Bean(gsonString: String, cls: Class<T>): T {return gson.fromJson(gsonString, cls)}/*** list<T>转String*/fun <T> list2Str(list: List<T>): String {val arry = JsonArray()for (item in list)arry.add(Gson2Str(item))return arry.toString()}/*** str转List<T>*/fun <T> str2List(str: String, cls: Class<T>): MutableList<T> {val datas = ArrayList<T>()try {val array = JsonParser().parse(str).asJsonArraySystem.out.println("数组长度=" + array.size())for (i in 0..array.size() - 1) {datas.add(str2Bean(array.get(i).asString, cls))}} catch (e: JSONException) {System.out.println("异常=" + e.message)e.printStackTrace()}return datas}/*** str转List<T>*/fun <T> str2List(str: List<String>, cls: Class<T>): ArrayList<T> {val datas = ArrayList<T>()try {for (item in str) {datas.add(str2Bean(item, cls))}} catch (e: JSONException) {System.out.println("异常=" + e.message)e.printStackTrace()}return datas}
}
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• BaseActivity

abstract class BaseActivity : AppCompatActivity() {private var appConfig: AppConfig?=nulloverride fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)findView()appConfig = AppConfig.getInstance()initViews()initDatas()}abstract fun findView()abstract fun initViews()abstract fun initDatas()/*** 启动一个Activity*/fun openActivity(tagClass: Class<*>) {val intent = Intent()intent.setClass(this, tagClass)startActivity(intent)}/*** 启动Service*/fun openService(tagClass: Class<*>) {val intent = Intent()intent.setClass(this, tagClass)startService(intent)}/*** 稍长时间展示toast*/fun showToastLong(msg: String) {Toast.makeText(this, msg, Toast.LENGTH_LONG).show()}/*** 短时间展示toast*/fun showToastShort(msg: String) {Toast.makeText(this, msg, Toast.LENGTH_SHORT).show()}/*** 发送消息* 需要在继承的activity中定义一个handler* 例如：* private val handler = Handler(Handler.Callback { msg ->**   false* })*/fun sendMsg(msg: String, what: Int, handler: Handler) {val bundle = Bundle()bundle.putString("msg", msg)val message = Message()message.what = whatmessage.data = bundlehandler.sendMessage(message)}/*** 隐藏软件盘*/fun Activity.hideKeyboard(): Boolean {val view = currentFocusview?.let {val inputMethodManager = getSystemService(Context.INPUT_METHOD_SERVICE)as InputMethodManagerreturn inputMethodManager.hideSoftInputFromWindow(view.windowToken, InputMethodManager.HIDE_NOT_ALWAYS)}return false}override fun onDestroy() {super.onDestroy()}
}
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