3.5 毫米耳机：配件规范

3.5 毫米耳机：配件规范



https://source.android.com/devices/accessories/headset/plug-headset-spec

直接启动

直接启动

<action android:name="android.intent.action.LOCKED_BOOT_COMPLETED" />

https://developer.android.com/training/articles/direct-boot?hl=zh-cn

アルファベットArrayList作成

import java.util.*;

class chart {
public static void main(String[] args) {
ArrayList<String> keyList = new ArrayList<>();
for (int i = 0x41; i < 0x5B; i++) {
keyList.add(String.valueOf((char)i));
}

for (int i = 0x30; i < 0x3A; i++) {
keyList.add(String.valueOf((char)i));
}

System.out.println(keyList);


String x = keyList.toString();
char[] temp = x.toCharArray();
temp = x.toCharArray();
for (char cc : temp) {
System.out.println(cc);
}

StringBuffer temp2 = new StringBuffer();

for(String xx :keyList){
temp2.append(xx);
}

System.out.println(temp2);
}
}

【Android】快速切换到主线程更新UI的几种方法

【Android】快速切换到主线程更新UI的几种方法
方法一： view.post(Runnable action)
textView.post(new Runnable() {
        @Override
        public void run() {
            textView.setText("更新textView");
            //还可以更新其他的控件
            imageView.setBackgroundResource(R.drawable.update);
        }
    });

方法二： activity.runOnUiThread(Runnable action)
public void updateUI(final Context context) {
        ((MainActivity) context).runOnUiThread(new Runnable() {
            @Override
            public void run() {
                //此时已在主线程中，可以更新UI了
            }
        });
    }

方法三： Handler机制
...

java_Semaphore

java_Semaphore

import java.util.concurrent.Semaphore;
import java.lang.System;

class  M180717_Semaphore {
public static void main(String[] args) {
Semaphore semaphore = new Semaphore(8);
long s = System.currentTimeMillis();

A a = new A(semaphore);
a.start();

B b = new B(semaphore);
b.start();

B b2 = new B(semaphore);
b2.start();
}
}

class A extends Thread {
private Semaphore semaphore;
public A(Semaphore semaphore) {
this.semaphore = semaphore;
}

@Override
public void run() {
try {
semaphore.acquire();
System.out.println(Thread.currentThread().getName() + "-------");
for (int i = 0 ; i < 99 ; i++) {
System.out.print("a");
}
semaphore.release();
} catch (Exception e) {
System.out.println(semaphore.getQueueLength());
}
}
}

class B extends Thread {
private Semaphore semaphore;

public B(Semaphore semaphore) {
this.semaphore = semaphore;
}

@Override
public void run() {
try {
// System.out.println(semaphore.getQueueLength());
semaphore.acquire();
System.out.println(Thread.currentThread().getName() + "-------");
for (int i = 0 ; i < 99 ; i++) {
System.out.print("b");
}
semaphore.release();
} catch (Exception e) {
System.out.println(semaphore.getQueueLength());
}
}
}

class C extends Thread {
@Override
public void run() {
System.out.println(Thread.currentThread().getName() + "-------");
for (int i = 0 ; i < 99 ; i++) {
System.out.print("c");
}
}
}

class X implements Runnable {
@Override
public void run() {
System.out.println("xxxxx");
}
}

Android Handler Thread HandlerThread

Android Handler Thread HandlerThread

Handler.Callback callback = new Handler.Callback()


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    textView = findViewById(R.id.textView);
    button = findViewById(R.id.button);

    CC();
    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            handler.sendEmptyMessage(99);
        }
    });
}

protected void CC() {
    HandlerThread handlerThread = new HandlerThread("test");
    handlerThread.start();

    Handler.Callback callback = new Handler.Callback() {
        @Override
        public boolean handleMessage(Message message) {
            System.out.println();
            System.out.println(Thread.currentThread().getName());
            System.out.println("0000000000000000000000000000000000000");
            return false;
        }
    };
    handler = new Handler(handlerThread.getLooper(), callback);
}

Android Handler Thread HandlerThread

Android Handler Thread HandlerThread

從主線程發送消息到子線程。
子線程必須創建Looper，
handlerThread.getLooper()，
Looper.prepare()，Looper.loop()

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    button = findViewById(R.id.button2);

    Tthread tthread = new Tthread();
    tthread.start();
    T3();
    T4();

    button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            hh.sendEmptyMessage(12);
            handler.sendEmptyMessage(12);
            handlerT4.sendEmptyMessage(12);
        }
    });
}

protected void T3() {
    HandlerThread handlerThread = new HandlerThread("name-thread");
    handlerThread.start();
    handler = new Handler(handlerThread.getLooper()) {
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            System.out.println(Thread.currentThread().getName());
            System.out.println("T33333333333333333");
        }
    };
}

protected void T4() {
    Thread thread = new Thread() {
        @Override
        public void run() {
            super.run();
            Looper.prepare();
            handlerT4 = new Handler() {
                @Override
                public void handleMessage(Message msg) {
                    super.handleMessage(msg);
                    System.out.println("T44444444444444444444");
                }
            };
            Looper.loop();
        }
    };
    thread.start();
}

class Tthread extends Thread {
    @Override
    public void run() {
        super.run();
        Looper.prepare();
        hh = new HH();
        Looper.loop();
    }
}

class HH extends Handler {
    @Override
    public void handleMessage(Message msg) {
        super.handleMessage(msg);
        System.out.println("HHHHHHHHHHHHHHHHHHHHHHHH");
        System.out.println(Thread.currentThread().getName());
    }
}