java - 构造此函数的正确方法

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嗯，我正在开发通过蓝牙与另一个 PCB 进行通信的应用程序。它由 3 个搜索栏组成，可调节 PCB 的 3 个参数值。

结构是这样的:

1. Send petition string for read the first value
2. Receive the first value
3. Send petition string for read the second value
4. Receive the second value
5. Send petition string for the third value
6. Receive the third value

我已经做到了，就像我这样的新手可以做到最好的方式。它可以工作，但有时会崩溃，所以，我知道还有其他方法可以使其完美工作。

所以，这是对一位慷慨的人的请求，希望查看代码并帮助我。

当我们按下“读取值”按钮时，就会发生这样的情况。必须注意的是，我使用可运行处理程序在传输之间等待 1 秒，以便让应用程序读取每个请求的答案:

public void receiveValues() {       

    /**Petition string that is sent to the PCB to request the variable's value*/
    final String message_full1 = 2b e1 b4 e9 ff 1f b5;  //variable 1
    final String message_full2 = 2b e1 b8 e9 ff 1f b3;  //variable 2
    final String message_full3 = 2b e1 bc e9 ff 1f b1;  //variable 3
    final String message_full4 = 2b e0 bc f3 ff 1f 7c;  //save request
    final String message_full5 = 2b e0 be f3 ff 1f 7a;  //save status


    /*Send the first string to the PCB*/
    byte[] send1 = message_full1.getBytes();
    GlobalVar.mTransmission.write(send1);


    /**Delay to wait until it receives the answer to the petition above*/
    read1_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**Read write confirmation after 1s = 1000ms*/
            String inpuRead = "2b 00 ff fe c7 80";  //This string is what I receive as an answer via bluetooth

            /**We check that the received string is not null, to avoid program crash*/
            if (inpuRead != null) { //|| !inpuRead.equals("")) {

                /*If it nos null, then we call the next function*/
                int splitInt = splitReceivedString (inpuRead);  //This function is declared below and extracts from the string , only the chars that we need.
                receive1 = splitInt;
                Toast.makeText(getApplicationContext(), "Loading values", Toast.LENGTH_LONG).show();
            }
            else {
                Toast.makeText(getApplicationContext(), "Communication error", Toast.LENGTH_SHORT).show();
            }
        }
    }, 1000);


    /**Delay to wait to send de second petition string*/
    write2_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**write message 2 after 1s = 1000ms*/
            byte[] send2 = message_full2.getBytes();
            GlobalVar.mTransmission.write(send2);
        }
    }, 2000);

    /**Delay to wait until it receives the answer to the second petition string*/
    read2_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**Read write confirmation after 1s = 1000ms*/
            String inpuRead = "2b 00 ff fe c7 80";

            if (inpuRead != null) {
                int splitInt = splitReceivedString (inpuRead);
                receive2 = splitInt;
            }
            else {
                Toast.makeText(getApplicationContext(), Communication error, Toast.LENGTH_SHORT).show();
            }
        }
    }, 3000);

    /**Delay to wait to send de third petition string*/
    write3_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**write message 3 after 1s = 1000ms*/
            byte[] send3 = message_full3.getBytes();
            GlobalVar.mTransmission.write(send3);
        }
    }, 4000);

    /**Delay to wait until it receives the answer to the third petition string*/
    read3_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**Read write confirmation after 1s = 1000ms*/
            String inpuRead = "2b 00 ff fe c7 80";

            if (inpuRead != null) {
                int splitInt = splitReceivedString (inpuRead);
                receive3 = splitInt;

                /**Set loaded values on seekbars*/
                bar1.setProgress(receive1);
                bar2.setProgress(receive2);
                bar3.setProgress(receive3);

                /**Message indicating the end of the transmission*/
                Toast.makeText(getApplicationContext(), "Values loaded!", Toast.LENGTH_SHORT).show();
            }
            else {
                Toast.makeText(getApplicationContext(), "Communication error", Toast.LENGTH_SHORT).show();
            }
        }
    }, 5000);

    /**This makes a save request on the pCB*/
    write4_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**write message 3 after 1s = 1000ms*/
            byte[] send4 = message_full4.getBytes();
            GlobalVar.mTransmission.write(send4);
        }
    }, 6000);

    /**This request a save statos on the PCB*/
    write5_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            /**write message 3 after 1s = 1000ms*/
            byte[] send5 = message_full5.getBytes();
            GlobalVar.mTransmission.write(send5);

            /**Reset out string buffer to zero*/
            GlobalVar.mOutStringBuffer.setLength(0);
        }
    }, 7000);
}


/**
 * FUNCTION THAT SPLITS THE RECEIVED STRING TO GET THE DESIRED VALUES
 */

private int splitReceivedString (String s) {  //For example, s = 2b 00 ff fe c7 80

    StringTokenizer tokens = new StringTokenizer(s," ");
    String one = tokens.nextToken();
    String two = tokens.nextToken();
    String three = tokens.nextToken();
    String four = tokens.nextToken();
    String five = tokens.nextToken();
    String six = tokens.nextToken();

    /**The next strings are whose got the seekbar's value*/  //f.e: "fffec780"
    received_hexValue = three + four + five + six;
    received_hexValue = received_hexValue.trim();


    /**Conversion from hex to int to set the seekbar's values*/
    int_value_receive = (int)Long.parseLong(received_hexValue, 16);
    int_value_receive = -200000 - int_value_receive;
    newIntValue = (int_value_receive * 100) / (200000 * (-1));

    return newIntValue;  //For this hex value, the int value to introduce in the seekbar is "60"
}

已更新 - 添加了问题

我想做的第一件事，但我不知道怎么做，当它进入 if 时，如果这是真的，那么它必须继续执行代码，但如果不是真的，那么它应该退出该函数并停止执行代码。但按照我的做法，它会继续执行。

我的意思是我有时会遇到的崩溃是有时，而不是以这种方式获得结构:

1. Send petition string for read the first value
2. Receive the first value
3. Send petition string for read the second value
4. Receive the second value
...

它的作用如下:

1. Send petition string for read the first value
2. Send petition string for read the second value
3. Receive the first value
...

这就是它崩溃的地方。

Answer 1

如果您希望轮流执行这些任务，则不需要所有 7 个额外线程。只需将它们组合到一个 Runnable 中，事情就会变得容易得多。
我的意思是，您所有的 /**Delay to wait until...*/ 注释都是错误的，您在上一个操作开始后等待 1 秒。因此，您只是在“发送请愿字符串以读取第二个值”之前没有完成“接收第一个值”，因为它花费了超过 1 秒的时间。

示例:
您的代码已简化:

private Handler read1_handler = new Handler();
private Handler write2_handler = new Handler();
private Handler read2_handler = new Handler();

public void receiveValues() {
  /**Delay to wait until it receives the answer to the petition above*/
    read1_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            String inpuRead = "2b 00 ff fe c7 80";  //This string is what I receive as an answer via bluetooth
            if (inpuRead != null) { //|| !inpuRead.equals("")) {
                int splitInt = splitReceivedString (inpuRead);
                receive1 = splitInt;
                Toast.makeText(getApplicationContext(), "Loading values", Toast.LENGTH_LONG).show();
            }
            else {
                Toast.makeText(getApplicationContext(), "Communication error", Toast.LENGTH_SHORT).show();
            }
        }
    }, 1000);

    /**Delay to wait to send de second petition string*/
    write2_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            byte[] send2 = message_full2.getBytes();
            GlobalVar.mTransmission.write(send2);
        }
    }, 2000);

    /**Delay to wait until it receives the answer to the second petition string*/
    read2_handler.postDelayed(new Runnable() {
        @Override
        public void run() {
            String inpuRead = "2b 00 ff fe c7 80";
            if (inpuRead != null) {
                int splitInt = splitReceivedString (inpuRead);
                receive2 = splitInt;
            }
            else {
                Toast.makeText(getApplicationContext(), Communication error, Toast.LENGTH_SHORT).show();
            }
        }
    }, 3000);
}

具有正确执行顺序的代码:

private Handler handler = new Handler();

//TODO: don't call functions read1, write2 etc, call it something like "readSomeValue" where "SomeValue" is what you're trying to read
private void read1() throws IOException {
    String inpuRead = "2b 00 ff fe c7 80";  //This string is what I receive as an answer via bluetooth
    if (inpuRead != null) { //|| !inpuRead.equals("")) {
        int splitInt = splitReceivedString (inpuRead);
        receive1 = splitInt;
        Toast.makeText(getApplicationContext(), "Loading values", Toast.LENGTH_LONG).show();
    }
    else {
        throw new IOException("Error in read1");
    }
}

private void write2() {
    byte[] send2 = message_full2.getBytes();
    GlobalVar.mTransmission.write(send2);
}

private void read2() throws IOException {
    String inpuRead = "2b 00 ff fe c7 80";
    if (inpuRead != null) {
        int splitInt = splitReceivedString (inpuRead);
        receive2 = splitInt;
    }
    else {
        throw new IOException("Error in read2");
    }
}

public void receiveValues() {
    handler.post(new Runnable() {
        @Override
        public void run() {
            try {
                read1();
                read2();
                read3();
            } catch (IOException e) {
                Toast.makeText(getApplicationContext(), "Communication error! " + e.getMessage(), Toast.LENGTH_SHORT).show();
            }
        }
    });
}