argc argv

argc argc用法

int main(int argc, char **argv)

假設執行為:  test.exe  a b c

則輸出為:   argv[0] = test.exe, argv[1] = a, argv[2] = b, argv[3] = c

argc = 4

savedInstanceState Bundle 存值取值

savedInstanceState.putParcelable("名稱 A", 物件_A);
savedInstanceState.putInt("名稱 B", 物件_B);
物件_C.writeToBundle(savedInstanceState, "名稱 C");
物件_D.writeToBundle(savedInstanceState, "名稱 D");


super.onRestoreInstanceState(savedInstanceState);
物件_A = savedInstanceState.getParcelable("M名稱 A");
物件_B = savedInstanceState.getInt("名稱 B");
物件_C.readFromBundle(savedInstanceState, "名稱 C");
物件_D.readFromBundle(savedInstanceState, "名稱 D");

Broadcast 設計

Broadcast 廣播機制

//傳送廣播
public class SentBroadcas extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

Button b1 = (Button) findViewById(R.id.Button01);
//點擊Button後發送廣播
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent().setAction("android.intent.test")
sendBroadcast(intent);
}
});
}
}

//接收廣播
public class BroadcastReciever extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
if(intent.getAction().equals("android.intent.test")){
}
}
}


//在AndroidManifest.xml註冊
<receiver android:name="BroadcastReciever">
    <intent -filter="">
        <action android:name="android.intent.test">
        </action></intent>
</receiver>

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Android Handler

Handler

使用Handler的post方法，將要執行的執行緒物件加到佇列中

handler.post(updateThread); 馬上加入到消息佇列內

創造一個Handler物件

Handler handler = new Handler();

將要執行的功能寫到執行緒物件的run方法中

Runnable updateThread = new Runnable(){

        @override

        public void run(){

        System.out.println(“UpdareThread”);

        handler.postDelayed(updateThread, 3000); 每3000毫秒加一次

}

}

將Thread移除

handler.removeCallbacks(updateThread);

將ProgressBar加入到Handler

根據控制鍵ID取的代表控制鍵的物件，並為按鈕設置監聽器

Runnable updateThread = new Runnable(){

int i = 0 ;

        @Override

        public void run() {

            System.out.println("Begin Thread");

            i = i + 10 ;

                //取的一個消息物件，Message類別由Android操作系統提供

            Message msg = updateBarHandler.obtainMessage();

                //將msg物件的arg1參數設置為I，用arg1和arg2這兩個成員資料傳遞消息，優點為系統  性能消耗較少

            msg.arg1 = i ;

            try {

                        //設置當前執行緒睡眠1秒

                        Thread.sleep(1000);

            } catch (InterruptedException e) {

                        e.printStackTrace();

            }

                //將msg物件加入到消息佇列中

                updateBarHandler.sendMessage(msg);

            if( i == 100){ //當i值為100時，將執行緒物件從Handler中移除

                        updateBarHandler.removeCallbacks(updateThread);

            }

        }

};

//使用匿名內部類別來覆寫Handler中的handleMessage方法

Handler updateBarHandler = new Handler(){

@Override

public void handleMessage(Message msg) { //取得Message msg

bar.setProgress(msg.arg1);

updateBarHandler.post(updateThread);

}

sendMessage(msg); 送msg到佇列

handleMessage(Message msg) 從佇列取msg

Handler不是產生一個thread來執行而是直接使用runnable方法

Bundle 類似鍵值對

HandlerThread 實作了looper來處理消息佇列功能

這個類別由Android應用程序框架提供

HandlerThread  handlerThread = new HandlerThread(“handler_thread”);

handlerThread.start();

MyHandler myHandler = new MyHandler(handlerThread.getLooper());

Message msg = myHandler.obtainMessage(); //得到消息

Msg.sendToTarget(); //將msg發送到目標物件，所謂的目標物件就是生成msg物件的handler物件

class MyHandler exteands Handler{

        public MyHandler(){

}

Public MyHandler(Looper looper){ //將handler綁定到looper上

        super(looper);

}

}

傳送資料與取得資料

msg.obj=”abc”;

String s = (String)msg.obj;

傳送大量資料利用Bundle

Bundle b = new Bundle();

b.putInt(“age”, 20);

b.putString(“name”, “Jhon”);

msg.setData(b);

msg.sendToTarget();

取資料

Bundle b = msg.getData();

Int ag = b.getInt(“age”);

String name = b.getString(“name”);