系出名门Android(4) - 活动(Activity), 服务(Service), 广播(Broadcast), 广播接收器(BroadcastReceiv - android

介绍
在 Android 中使用 Activity, Service, Broadcast, BroadcastReceiver
活动(Activity) - 用于表现功能
服务(Service) - 相当于后台运行的 Activity
广播(Broadcast) - 用于发送广播
广播接收器(BroadcastReceiver) - 用于接收广播
Intent - 用于连接以上各个组件，并在其间传递消息

1、演示 Activity 的基本用法，一个 Activity 启动另一个 Activity，启动另一个 Activity 时为其传递参数，被启动的 Activity 返回参数给启动者的 Activity
Main.java代码 package com.webabcd.activity;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.TextView;public class Main extends Activity {        TextView txt;        /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        this.setContentView(R.layout.main);        txt = (TextView) this.findViewById(R.id.txt);        txt.setText("Activity 1");        Button btn = (Button) this.findViewById(R.id.btn);        btn.setText("启动另一个Activity");        btn.setOnClickListener(new Button.OnClickListener() {            @Override            public void onClick(View v) {                                // 实例化 Intent，指定需要启动的 Activity                Intent intent = new Intent();                intent.setClass(Main.this, MyActivity.class);                // 实例化 Bundle，设置需要传递的参数                Bundle bundle = new Bundle();                bundle.putString("name", "webabcd");                bundle.putDouble("salary", 100.13);                // 将需要传递的参数赋值给 Intent 对象                intent.putExtras(bundle);                // startActivity(intent); // 启动指定的 Intent（不等待返回结果）                // Main.this.finish();                                // 启动指定的 Intent，并等待返回结果                // 其中第二个参数如果大于等于零，则返回结果时会回调 onActivityResult() 方法                startActivityForResult(intent, 0);            }        });                Log.d("MyDebug", "onCreate");    }        // 被启动的 Activity 返回结果时的回调函数    @Override    protected void onActivityResult(int requestCode, int resultCode, Intent data) {        if (resultCode == Activity.RESULT_OK){            Bundle bundle = data.getExtras();                        String name = bundle.getString("name");            double salary = bundle.getDouble("salary");                        txt.setText("Activity 1" + "\n名字：" + name + "\n薪水：" + String.valueOf(salary));        }    }    @Override    protected void onStart() {        // TODO Auto-generated method stub        super.onStart();                Log.d("MyDebug", "onStart");    }    @Override    protected void onStop() {        // TODO Auto-generated method stub        super.onStop();                Log.d("MyDebug", "onStop");    }    @Override    protected void onRestart() {        // TODO Auto-generated method stub        super.onRestart();                Log.d("MyDebug", "onRestart");    }        @Override    protected void onPause() {        // TODO Auto-generated method stub        super.onPause();                Log.d("MyDebug", "onPause");    }    @Override    protected void onResume() {        // TODO Auto-generated method stub        super.onResume();                Log.d("MyDebug", "onResume");    }        @Override    protected void onDestroy() {        // TODO Auto-generated method stub        super.onDestroy();                Log.d("MyDebug", "onDestroy");    }}MyActivity.java代码 package com.webabcd.activity;import android.app.Activity;import android.content.Intent;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;// 被另一个 Activity 所启动的 Activitypublic class MyActivity extends Activity {        Intent intent;        /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        this.setContentView(R.layout.main2);        // 获取启动者传递过来的参数        intent = this.getIntent();        Bundle bundle = intent.getExtras();                String name = bundle.getString("name");        double salary = bundle.getDouble("salary");                TextView txt = (TextView) this.findViewById(R.id.txt);        txt.setText("Activity 2" + "\n名字：" + name + "\n薪水：" + String.valueOf(salary));        Button btn = (Button) this.findViewById(R.id.btn);        btn.setText("返回前一个Activity");        btn.setOnClickListener(new Button.OnClickListener() {            public void onClick(View v) {                // 返回参数给启动者                MyActivity.this.setResult(Activity.RESULT_OK, intent);                MyActivity.this.finish();            }        });    }}AndroidManifest.xml代码 <?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.webabcd.activity" android:versionCode="1"    android:versionName="1.0">    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".Main" android:label="@string/app_name">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>        <!--            如果有需要用到的 Activity ，则都要在这里做相应的配置        -->        <activity android:name=".MyActivity" android:label="Activity 2" />    </application>    <uses-sdk android:minSdkVersion="3" /></manifest> 2、Service, Broadcast, BroadcastReceiver 的演示Main.java代码 package com.webabcd.service;import android.app.Activity;import android.content.BroadcastReceiver;import android.content.ComponentName;import android.content.Context;import android.content.Intent;import android.content.IntentFilter;import android.content.ServiceConnection;import android.os.Bundle;import android.os.IBinder;import android.view.View;import android.view.View.OnClickListener;import android.widget.TextView;/* * startService() 和 bindService() 的区别  * startService() - 正常理解就好 * bindService() - 使当前上下文对象（本例中就是 Activity）通过一个 ServiceConnection 对象邦定到指定的 Service 。这样，如果上下文对象销毁了的话，那么其对应的 Service 也会被销毁 */public class Main extends Activity implements OnClickListener {    private TextView txtMsg;        @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.main);        setTitle("android 之 service");        this.findViewById(R.id.btnStart).setOnClickListener(this);        this.findViewById(R.id.btnStop).setOnClickListener(this);        this.findViewById(R.id.btnBind).setOnClickListener(this);        this.findViewById(R.id.btnUnbind).setOnClickListener(this);                txtMsg = (TextView)this.findViewById(R.id.txtMsg);                // 实例化自定义的 BroadcastReceiver        receiver = new UpdateReceiver();        IntentFilter filter = new IntentFilter();        // 为 BroadcastReceiver 指定 action ，使之用于接收同 action 的广播        filter.addAction("com.webabcd.service.msg");                // 以编程方式注册  BroadcastReceiver 。配置方式注册 BroadcastReceiver 的例子见 AndroidManifest.xml 文件        // 一般在 OnStart 时注册，在 OnStop 时取消注册        this.registerReceiver(receiver, filter);        // this.unregisterReceiver(receiver);            }    @Override    public void onClick(View v) {        Intent intent = new Intent(Main.this, MyService.class);        switch (v.getId()) {        case R.id.btnStart:            this.startService(intent);            break;        case R.id.btnStop:            this.stopService(intent);            break;        case R.id.btnBind:            this.bindService(intent, conn, Context.BIND_AUTO_CREATE);            break;        case R.id.btnUnbind:            this.unbindService(conn);            break;        }    }    // bindService() 所需的 ServiceConnection 对象    private ServiceConnection conn = new ServiceConnection() {        @Override        public void onServiceConnected(ComponentName className, IBinder service) {                    }        @Override        public void onServiceDisconnected(ComponentName className) {                    }    };        private String msg="";    private UpdateReceiver receiver;    // 实现一个 BroadcastReceiver，用于接收指定的 Broadcast    public class UpdateReceiver extends BroadcastReceiver{        @Override        public void onReceive(Context context, Intent intent) {            msg = intent.getStringExtra("msg");                        txtMsg.append(msg + "\n");        }            }}MyService.java代码 package com.webabcd.service;import android.app.Service;import android.content.Intent;import android.os.IBinder;import android.util.Log;// 演示 Service 的生命周期。具体信息运行程序后在 LogCat 中查看public class MyService extends Service {    @Override    public IBinder onBind(Intent intent) {                Log.d("MyDebug", "onBind");        sendMsg("onBind");                // TODO Auto-generated method stub        return null;    }    @Override    public void onCreate() {        // TODO Auto-generated method stub        super.onCreate();                Log.d("MyDebug", "onCreate");        sendMsg("onCreate");    }    @Override    public void onDestroy() {        // TODO Auto-generated method stub        super.onDestroy();                Log.d("MyDebug", "onDestroy");        sendMsg("onDestroy");    }    @Override    public void onRebind(Intent intent) {        // TODO Auto-generated method stub        super.onRebind(intent);                Log.d("MyDebug", "onRebind");        sendMsg("onRebind");    }    @Override    public void onStart(Intent intent, int startId) {        super.onStart(intent, startId);                Log.d("MyDebug", "onStart");        sendMsg("onStart");    }        @Override    public boolean onUnbind(Intent intent) {                Log.d("MyDebug", "onUnbind");        sendMsg("onUnbind");                // TODO Auto-generated method stub        return super.onUnbind(intent);    }        // 发送广播信息    private void sendMsg(String msg){        // 指定广播目标的 action （注：指定了此 action 的 receiver 会接收此广播）        Intent intent = new Intent("com.webabcd.service.msg");        // 需要传递的参数        intent.putExtra("msg", msg);        // 发送广播        this.sendBroadcast(intent);    }}MyBootReceiver.java代码 package com.webabcd.service;import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import android.util.Log;public class MyBootReceiver extends BroadcastReceiver {    // 用于接收满足条件的 Broadcast（相应的 Broadcast 的注册信息详见 AndroidManifest.xml ，当系统启动完毕后会调用这个广播接收器）    @Override    public void onReceive(Context arg0, Intent arg1) {        Log.d("MyDebug", "onReceive");                // 启动服务        Intent service = new Intent(arg0, MyService.class);        arg0.startService(service);    }}AndroidManifest.xml代码 <?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.webabcd.service" android:versionCode="1"    android:versionName="1.0">    <application android:icon="@drawable/icon" android:label="@string/app_name">        <activity android:name=".Main" android:label="@string/app_name">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>                <!--            如果有需要用到的 service ，则都要在这里做相应的配置        -->        <service android:name=".MyService"></service>                <!--            注册一个 BroadcastReceiver            其 intent-filter 为 android.intent.action.BOOT_COMPLETED（用于接收系统启动完毕的 Broadcast）        -->        <receiver android:name=".MyBootReceiver">            <intent-filter>                <action android:name="android.intent.action.BOOT_COMPLETED" />            </intent-filter>        </receiver>    </application>        <!--        接受系统启动完毕的 Broadcast 的权限    -->    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />    <uses-sdk android:minSdkVersion="3" /></manifest> OK
系出名门Android(4) - 活动(Activity), 服务(Service), 广播(Broadcast), 广播接收器(BroadcastReceiv

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