By

文章目錄
  1. 1. bluetooth
  2. 2. problem to fix
  3. 3. dialog
  4. 4. sensor
    1. 4.1. example
  5. 5. media player
  6. 6. volley
    1. 6.1. POST image file
  7. 7. HttpURLConnection
    1. 7.1. POST image file
  8. 8. AsyncTask
  9. 9. 上架App
  10. 10. Providing Resource
  11. 11. Notification
  12. 12. java
  13. 13. convetion
  14. 14. Question
  15. 15. Java
    1. 15.1. java.net
    2. 15.2. 執行緒Thread
    3. 15.3. Collection
    4. 15.4. IO
    5. 15.5. Database
    6. 15.6. Annotation
    7. 15.7. CDI


趙老師的雲端分享資料夾

bluetooth

official guide

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<manifest ... >
  <uses-permission android:name="android.permission.BLUETOOTH" />
  <uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
  ...
</manifest>

problem to fix

Android uploading pictures to server in most efficient way

dialog

  1. ProgressDialog
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    ProgressDialog dialog = new ProgressDialog(this);
    dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
    dialog.setMessage("downloading...");
    dialog.show();
    dialog.dismiss();

sensor

  • 位移
  • 環境
  • 位置

example

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<!--設定device需有三軸加速感應器才可安裝-->
<uses-feature
    android:name="android.hardware.sensor.accelerometer"
    android:required="true" />
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protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);


    mgr = (SensorManager) getSystemService(SENSOR_SERVICE);
    List<Sensor> list = mgr.getSensorList(Sensor.TYPE_ALL);


    for (Sensor sensor:list) {
        Log.i("henry",sensor.getName()+" : "+sensor.getType()+" : "+sensor.getVendor());
    }

    sensor = mgr.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
    if (sensor!=null) {
        isSensorEnable=true;
    }
    /**
     * define
     */
    sensorEventListener = new SensorEventListener() {
        @Override
        public void onSensorChanged(SensorEvent event) {
            float[] values = event.values;

            ((TextView)findViewById(R.id.tv1)).setText("x : "+values[0]);
            ((TextView)findViewById(R.id.tv2)).setText("y : "+values[1]);
            ((TextView)findViewById(R.id.tv3)).setText("z : "+values[2]);

            MyView mv = (MyView) findViewById(R.id.mv);

        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int accuracy) {
        }
    };
}

@Override
protected void onResume() {
    super.onResume();
    if (isSensorEnable) {
        mgr.registerListener(sensorEventListener, sensor, SensorManager.SENSOR_DELAY_UI);
    }
}

@Override
protected void onStop() {
    super.onStop();
    if (isSensorEnable) {
        mgr.unregisterListener(sensorEventListener, sensor);
    }
}

media player

volley

POST image file

stackoverflow

HttpURLConnection

POST image file

Android HttpURLConnection 上傳檔案 (multipart/form-data)

AsyncTask

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class MyAsyncTask extends AsyncTask<String, Integer, Boolean> {
    /**
     * Creates a new asynchronous task. This constructor must be invoked on the UI thread.
     */
    public MyAsyncTask() {
        super();
    }


    /**
     * Runs on the UI thread before {@link #doInBackground}.
     *
     * @see #onPostExecute
     * @see #doInBackground
     */
    @Override
    protected void onPreExecute() {
        super.onPreExecute();
        Log.i("henry", "onPreExecute");

    }

    /**
     * Override this method to perform a computation on a background thread. The
     * specified parameters are the parameters passed to {@link #execute}
     * by the caller of this task.
     * <p/>
     * This method can call {@link #publishProgress} to publish updates
     * on the UI thread.
     *
     * @param names The parameters of the task.
     * @return A result, defined by the subclass of this task.
     * @see #onPreExecute()
     * @see #onPostExecute
     * @see #publishProgress
     */
    @Override
    protected Boolean doInBackground(String... names) {

        for (String name:names){
            intCounter++;
            Log.i("henry", "doInBackground");

            publishProgress(intCounter,intCounter*10,intCounter*100);

            if (isCancelled()) return false;

            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }
        return true;
    }

    /**
     * Runs on the UI thread after {@link #publishProgress} is invoked.
     * The specified values are the values passed to {@link #publishProgress}.
     *
     * @param values The values indicating progress.
     * @see #publishProgress
     * @see #doInBackground
     */
    @Override
    protected void onProgressUpdate(Integer... values) {
        super.onProgressUpdate(values);
        Log.i("henry", "onProgressUpdate");
        tv1.setText("OK"+values[0]);
        tv2.setText("OK"+values[1]);
        tv3.setText("OK"+values[2]);


    }

    /**
     * <p>Runs on the UI thread after {@link #doInBackground}. The
     * specified result is the value returned by {@link #doInBackground}.</p>
     * <p/>
     * <p>This method won't be invoked if the task was cancelled.</p>
     *
     * @param aVoid The result of the operation computed by {@link #doInBackground}.
     * @see #onPreExecute
     * @see #doInBackground
     * @see #onCancelled(Object)
     */
    @Override
    protected void onPostExecute(Boolean aVoid) {
        super.onPostExecute(aVoid);
        Log.i("henry", "onPostExecute");
        tv4.setText(aVoid?"Finished":"Cancelled");

    }



    /**
     * <p>Runs on the UI thread after {@link #cancel(boolean)} is invoked and
     * {@link #doInBackground(Object[])} has finished.</p>
     * <p/>
     * <p>The default implementation simply invokes {@link #onCancelled()} and
     * ignores the result. If you write your own implementation, do not call
     * <code>super.onCancelled(result)</code>.</p>
     *
     * @param aVoid The result, if any, computed in
     *              {@link #doInBackground(Object[])}, can be null
     * @see #cancel(boolean)
     * @see #isCancelled()
     */
    @Override
    protected void onCancelled(Boolean aVoid) {
        super.onCancelled(aVoid);
        Log.i("henry", "onCancelled");
        tv4.setText(aVoid?"Finished":"Cancelled");
    }

    /**
     * <p>Applications should preferably override {@link #onCancelled(Object)}.
     * This method is invoked by the default implementation of
     * {@link #onCancelled(Object)}.</p>
     * <p/>
     * <p>Runs on the UI thread after {@link #cancel(boolean)} is invoked and
     * {@link #doInBackground(Object[])} has finished.</p>
     *
     * @see #onCancelled(Object)
     * @see #cancel(boolean)
     * @see #isCancelled()
     */
    @Override
    protected void onCancelled() {
        super.onCancelled();
        Log.i("henry", "onCancelled2");

    }


}
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task = new MyAsyncTask();
task.execute("test1",
             "test2",
             "test2",
             "test2",
             "test2",
             "test2",
             "test2",
             "test3");

上架App

Google Play Developer Console
export signed package
keystore

Providing Resource

official
res/layout-land當device拿橫時，就會套用到此版面
res/values-zh-rTW當語系改為中文台灣時，就會套用此values設定

Notification

official

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mgr = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

// instantiate PendingIntent
TaskStackBuilder taskStackBuilder = TaskStackBuilder.create(this);
taskStackBuilder.addParentStack(NoticePageActivity.class);
taskStackBuilder.addNextIntent(new Intent(this,NoticePageActivity.class));
PendingIntent pendingIntent = taskStackBuilder.getPendingIntent(124,PendingIntent.FLAG_UPDATE_CURRENT);

// instantiate Notification.Builder
Notification.Builder builder = new Notification.Builder(this);
builder.setTicker("super important");
builder.setAutoCancel(true);
builder.setSmallIcon(android.R.drawable.sym_def_app_icon);
builder.setLargeIcon(BitmapFactory.decodeResource(getResources(), android.R.drawable.sym_def_app_icon));
builder.setSound(Uri.fromFile(new File(Environment.getExternalStorageDirectory(),"sound.wav")));
builder.setContentInfo("info");
builder.setContentText("text");
builder.setContentTitle("title");
builder.setContentIntent(pendingIntent);


// API Level 11+
//Notification notification = builder.getNotification();

// API Level 16+ (4.1.2+)
Notification notification = builder.build();
// send notification
mgr.notify(0,notification);

java

  • garbage collection

    物件沒有被reference時，System.gc();會要求系統做gc，但若系統沒空，還是要等到它有空才會做。

convetion

Official Code Style Guidelines for Android Contributors

Google Java Style

lint
在計算機科學中，lint是一種工具程序的名稱，它用來標記源代碼中，某些可疑的、不具結構性的段落。它是一種靜態程序分析工具，最早適用於C語言，在UNIX平台上開發出來。後來它成為通用術語，可用於描述在任何一種電腦編程語言中，用來標記源代碼中有疑義段落的工具。

Question

  • Content Provider的使用時機
  • Fragment的使用時機

  • FrameLayout的使用時機

  • Service的動作是否都能做在Activity
    跟UI無關的動作都放在Service

  • 啥是Context
    Activity/Service..等類別

  • QA

    1. coding完用JUnit單元測試，參考
    2. brad客製化QA測試工具做整體測試

  • 公司VersionControlSystem, gitignore

    內部git, vpn

  • API https

  • 程式架構文件-> PGM: Phase Gate Model
    1. 流程圖 -> brad
    2. 演算法 -> all
    3. coding -> member
    4. code review -> all

Java

brad@brad.tw

Apache Cordova is a platform for building native mobile applications using HTML, CSS and JavaScript
官網

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byte b; // [a-zA-Z$_][a-zA-Z0-9$_]
byte 成績=127; //8個位元組，-127~127，常用在圖形及網路streaming
System.out.println(成績);

Instances of StringBuilder are not safe for use by multiple threads. If such synchronization is required then it is recommended that StringBuffer be used.

FileInputStream: 一次讀取一個byte，適用於讀取影片、圖片…等檔案
FileReader: 一次讀取一個character，適用於讀取文件
BufferReader: 一次讀取一行readline()，適用於讀取文件，需串接InputStreamReader，再由InputStreamReader串接FileInputStream
FileOutputStream:

  • 最後要close前，要強制將buffer裡的資料寫入disk—->flush()

DataInputStream: 可存基本型態(primitive Java data types)
ObjectInputStream: 可存Object，前提是此Object需implements Serializable，另可再此Object屬性加上transient表示此屬性不可序列化

存取權

  • public: 全世界
  • protected:
    • 同package
    • 子類別
  • 沒寫: 同package
  • private: 本類別

java.net

InetAddress
UDP:

  • fast
  • unreliable
  • socket: 接口, DatagramSocket
  • packet: 封包, DatagramPacket
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//sender
byte[] buf = "hello, I'm Henry".getBytes();
DatagramSocket socket = new DatagramSocket();
DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress.getByName("10.2.24.156"), 9999);
socket.send(packet);
socket.close();
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//reciever
byte[] buf = new byte[4096];
DatagramSocket socket = new DatagramSocket(8888);
DatagramPacket packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);
socket.close();

TCP:
server socket: ServerSocket
client socket: Socket

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// reciever
ServerSocket server = new ServerSocket(8888);
Socket socket = server.accept();
InputStream is = socket.getInputStream();

InputStreamReader isr = new InputStreamReader(is);
int temp;
while ( (temp = isr.read())!=-1)
{
	System.out.print((char)temp);
}

is.close();
socket.close();
server.close();
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// sender
Socket socket = new Socket(ip, 8888);
OutputStream out = socket.getOutputStream();
out.write("Hi, I'm Henry!!".getBytes());
out.flush();
out.close();
socket.close();

執行緒Thread

  • 有生命週期之物件
  • 寫法一extends Thread
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public class ThreadObject {

	public static void main(String[] args) {
		ServerThreads st1 = new ServerThreads("bella");
		ServerThreads st2 = new ServerThreads("vivian");
		st1.start();
		st2.start();
		System.out.println("penny");
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		System.out.println("henry");
	    // trigger InterruptedException例外
		st1.interrupt();
	}

}

class ServerThreads extends Thread{
	private String name;
	public ServerThreads(String s) {
		name = s;
	}

	@Override
	public void run() {
		for (int i = 0; i < 20; i++) {
			try {
				Thread.sleep(200);
			} catch (InterruptedException e) {
			// trigger by st1.interrupt();
			    break;
			}
			System.out.println(name+":"+i);
		}
	}
}
  • 寫法二implements Runnable
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public class ThreadObject {

	public static void main(String[] args) {

		ServerRunnable sr1 = new ServerRunnable("bella");
		Thread t1 = new Thread(sr1);
		t1.start();
	}

}
class ServerRunnable implements Runnable{
	private String name;
	public ServerRunnable(String s) {
		name = s;
	}

	@Override
	public void run() {
		for (int i = 0; i < 20; i++) {
			try {
				Thread.sleep(200);
			} catch (InterruptedException e) {
			}
			System.out.println(name+":"+i);
		}
	}
}

Collection

IO

Database

  • PreparedStatement與Statement最大的差異在於SQL已預載入，因此執行時僅需bind variable即可，所以SQL是bind不同var頻繁執行時，使用PS會比較有效率；但若是不重覆執行頻繁更換SQL的用法時，效能基本上就跟S差不多。

Annotation

  • 將metadata, data, methods都放在程式裡, 易於分析/解讀.

CDI

  • 當沒有@ApplicationScoped, 會報錯Unsatisfied dependencies for type xxxxx with qualifiers @Default
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java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: org.apache.catalina.LifecycleException: org.jboss.weld.exceptions.DeploymentException: WELD-001408: Unsatisfied dependencies for type CdiServerJava with qualifiers @Default
  at injection point [BackedAnnotatedField] @Inject private tw.henry.test.JaxRsService.server
  at tw.henry.test.JaxRsService.server(JaxRsService.java:0)

參考

  • 當有兩個以上的@Default, 會報錯Ambiguous dependencies
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org.jboss.weld.exceptions.DeploymentException: WELD-001409: Ambiguous dependencies for type CdiServerIF with qualifiers @Default
  at injection point [BackedAnnotatedField] @Inject private tw.henry.test.JaxRsService.server
  at tw.henry.test.JaxRsService.server(JaxRsService.java:0)
  Possible dependencies:
  - Managed Bean [class tw.henry.test.CdiServerJava] with qualifiers [@Any @Default],
  - Managed Bean [class tw.henry.test.CdiServerPhp] with qualifiers [@Any @Default]
  • 管理物件生命週期, e.g. JDBC resource, client 無需開關
  • 没有 Scope 注解的情况下，default scope 是@Dependent, 而@Dependent Scope 中的 Bean 的生命周期取决于被注入的 Bean 的生命周期
文章目錄
  1. 1. bluetooth
  2. 2. problem to fix
  3. 3. dialog
  4. 4. sensor
    1. 4.1. example
  5. 5. media player
  6. 6. volley
    1. 6.1. POST image file
  7. 7. HttpURLConnection
    1. 7.1. POST image file
  8. 8. AsyncTask
  9. 9. 上架App
  10. 10. Providing Resource
  11. 11. Notification
  12. 12. java
  13. 13. convetion
  14. 14. Question
  15. 15. Java
    1. 15.1. java.net
    2. 15.2. 執行緒Thread
    3. 15.3. Collection
    4. 15.4. IO
    5. 15.5. Database
    6. 15.6. Annotation
    7. 15.7. CDI