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  • 为简单而努力:Android封装类详解

    一、简单说明

    1, IntentService 

    IntentService继承自Service,并在其内部创建了工作线程,用来处理耗时操作,其中onHandleIntent方法就是在子线程执行的,我们可以在这里处理耗时操作。

    启动时与正常service一样,可以调用startservice来启动IntentService。

    注意:(1),在无参构造函数里,必须调用父类一个参数的构造方法; (2),与普通服务不同,IntentService的子线程处理完耗时操作,服务便销毁。

    2, HandlerThread 

    HandlerThread 继承自Thread, 本质上就是一个Thread,内部封装了Looper,不用我们再处理Looper的初始化与消息循环。

    我们可以通过获取HandlerThread 内部的looper来构建一个子线程的handler,从而与主线程交互。

    常见使用方法:

    // 1,创建handlerThread并启动该线程
    HandlerThread MyThread = new HandlerThread("MyThread");
    MyThread.start();

    //2,获取子线程的looper

    Looper looper = MyThread.getLooper();

    //3,通过子线程的looper创建handler,从而该handler便与子线程绑定
    handler = new Handler(looper);
    handler#doSomeThing...

    3, AsyncQueryHandler 

    异步查询类,常见使用方法:

    //1,继承AsyncQueryHandler并重写onXXXComplete方法,以便增删改查等操作执行完毕后进行下一步操作。

    private static class QueryHandler extends AsyncQueryHandler {

    public QueryHandler(ContentResolver cr) {
    super(cr);
    }

    @Override
    protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
    super.onQueryComplete(token, cookie, cursor);
    System.out.println("查询完毕: " + System.currentTimeMillis());
    }

    }

    //2,调用startXXX方法执行增删改查操作

    Uri uri = Sms.CONTENT_URI;
    QueryHandler mQueryHandler = new QueryHandler(getContentResolver());
    mQueryHandler.startQuery(100, "cookie", uri, null, null, null, Sms.DEFAULT_SORT_ORDER);

    4, Loader 

    主要用来异步加载数据,常见的有AsyncLoader, CursorLoader,详情请参考:Android Loader使用详解

    5, AsyncTask

    异步任务类,常见,不再赘述

    二、代码Demo

    //java code

    package com.wytiger.goodclass;

    import android.annotation.TargetApi;
    import android.app.Activity;
    import android.content.AsyncQueryHandler;
    import android.content.ContentResolver;
    import android.content.Intent;
    import android.database.Cursor;
    import android.net.Uri;
    import android.os.Build;
    import android.os.Bundle;
    import android.os.Handler;
    import android.os.HandlerThread;
    import android.os.Looper;
    import android.os.SystemClock;
    import android.provider.Telephony.Sms;
    import android.util.Log;
    import android.view.View;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.Toast;

    public class MainActivity extends Activity implements OnClickListener {

    protected static final String TAG = "MainActivity";
    private int count = 0;
    private Handler handler;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button button1 = (Button) findViewById(R.id.button1);
    Button button2 = (Button) findViewById(R.id.button2);
    Button button3 = (Button) findViewById(R.id.button3);
    button1.setOnClickListener(this);
    button2.setOnClickListener(this);
    button3.setOnClickListener(this);
    }

    @Override
    public void onClick(View v) {
    switch (v.getId()) {
    case R.id.button1:
    // 启动MyIntentService
    startService(new Intent(this, MyIntentService.class));
    Toast.makeText(this, "点击IntentService", 0).show();
    break;
    case R.id.button2:
    testHandlerThread();
    Toast.makeText(this, "点击HandlerThread", 0).show();
    break;
    case R.id.button3:
    startQuery();
    Toast.makeText(this, "点击AsyncQueryHandler", 0).show();
    break;

    default:
    break;
    }

    }

    private void testHandlerThread() {
    // 创建handlerThread
    HandlerThread MyThread = new HandlerThread("MyThread");
    MyThread.start();
    System.out.println("当前线程:" + Thread.currentThread().getName());
    System.out.println("handler线程:" + MyThread.getName());

    Looper looper = MyThread.getLooper();
    // 子线程的handler
    handler = new Handler(looper);
    handler.post(mRunnable);
    }

    /**
    * 这在子线程执行
    */
    private Runnable mRunnable = new Runnable() {

    public void run() {
    count++;
    // 为了方便 查看,我们用Log打印出来
    Log.e(TAG, Thread.currentThread().getName() + ": " + count);
    SystemClock.sleep(1000);
    // 每2秒执行一次
    handler.post(mRunnable);
    }

    };

    @TargetApi(Build.VERSION_CODES.KITKAT)
    private void startQuery() {
    Uri uri = Sms.CONTENT_URI;
    QueryHandler mQueryHandler = new QueryHandler(getContentResolver());
    mQueryHandler.startQuery(100, "cookie", uri, null, null, null, Sms.DEFAULT_SORT_ORDER);
    System.out.println("开始查询: " + System.currentTimeMillis());
    }

    /**
    * 异步查询类
    *
    * @author wytiger
    * @date 2016-5-26
    */
    private static class QueryHandler extends AsyncQueryHandler {

    public QueryHandler(ContentResolver cr) {
    super(cr);
    }

    @Override
    protected void onQueryComplete(int token, Object cookie, Cursor cursor) {
    super.onQueryComplete(token, cookie, cursor);
    System.out.println("查询完毕: " + System.currentTimeMillis());
    }

    @Override
    protected void onInsertComplete(int token, Object cookie, Uri uri) {
    super.onInsertComplete(token, cookie, uri);
    }

    @Override
    protected void onUpdateComplete(int token, Object cookie, int result) {
    super.onUpdateComplete(token, cookie, result);
    }

    @Override
    protected void onDeleteComplete(int token, Object cookie, int result) {
    super.onDeleteComplete(token, cookie, result);
    }

    }

    @Override
    protected void onDestroy() {
    super.onDestroy();
    handler.removeCallbacksAndMessages(mRunnable);
    }
    }

    //xml文件

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <Button
    android:id="@+id/button1"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="IntentService" />

    <Button
    android:id="@+id/button2"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="HandlerThread" />

    <Button
    android:id="@+id/button3"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="AsyncQueryHandler" />

    <Button
    android:id="@+id/button4"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Loader" />
    <Button
    android:id="@+id/button5"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="AsyncTask" />

    </LinearLayout>

    //权限声明

    <uses-permission android:name="android.permission.READ_SMS" />
    <uses-permission android:name="android.permission.WRITE_SMS" />

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  • 原文地址:https://www.cnblogs.com/wytiger/p/5530111.html
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