Question

我不是最好的程序员，实际上，我很糟糕:( 我需要帮助解决让我疯狂的事情。基本上我有一个tcpdump进程，我想提取输出并将其放入textview，每隔几毫秒更新一次，我已经尝试了所有的东西而且无法让它工作。

我没有收到任何错误，它似乎在后台运行，但只在我进入主屏幕并返回应用程序后才显示文本块。但是，它不会不断更新textview，有时会挂起和崩溃。

我已经创建了一个简单的处理程序，它可以使用纯文本更新textview而没有任何问题，但是我遇到了让它阅读过程的主要问题。

开始按钮

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.capture);

    this.LiveTraffic = (TextView) findViewById(R.id.LiveTraffic);
    this.CaptureText = (TextView) findViewById(R.id.CaptureText);
    ((TextView) findViewById(R.id.ipv4)).setText(getLocalIpv4Address());
    ((TextView) findViewById(R.id.ipv6)).setText(getLocalIpv6Address());


    //Begin button              
    final Button startButton = (Button) findViewById(R.id.start);
    startButton.setOnClickListener(new OnClickListener() {

        public void onClick(View v) {
            Toast.makeText(getApplicationContext(), "Now Capturing Packets", Toast.LENGTH_LONG).show();
            try {

                process = Runtime.getRuntime().exec("su");
                DataOutputStream os = new DataOutputStream(process.getOutputStream());
                os.writeBytes("/data/local/tcpdump -q\n");
                os.flush();
                os.writeBytes("exit\n");
                os.flush();
                os.close();

                inputStream = new DataInputStream(process.getInputStream());

                Thread.sleep(1000);
                Process process2 = Runtime.getRuntime().exec("ps tcpdump");

                DataInputStream in = new DataInputStream(process2.getInputStream());
                String temp = in.readLine();
                temp = in.readLine();
                temp = temp.replaceAll("^root *([0-9]*).*", "$1");
                pid = Integer.parseInt(temp);
                Log.e("MyTemp", "" + pid);
                process2.destroy();

                CaptureActivity.this.thisActivity.CaptureText.setText("Active");
            } catch (Exception e) {
            }
            ListenThread thread = new ListenThread(new BufferedReader(new InputStreamReader(inputStream)));
            thread.start();
        }
    });
}

ListenThread类

public class ListenThread extends Thread {

    public ListenThread(BufferedReader reader) {
        this.reader = reader;
    }
    private BufferedReader reader = null;

    @Override
    public void run() {

        reader = new BufferedReader(new InputStreamReader(inputStream));
        while (true) {
            try {
                CaptureActivity.this.thisActivity.CaptureText.setText("exec");
                int a = 1;
                String received = reader.readLine();
                while (a == 1) {
                    CaptureActivity.this.thisActivity.LiveTraffic.append(received);
                    CaptureActivity.this.thisActivity.LiveTraffic.append("\n");
                    received = reader.readLine();
                    CaptureActivity.this.thisActivity.CaptureText.setText("in loop");

                }
                CaptureActivity.this.thisActivity.CaptureText.setText("out loop");

            } catch (Exception e) {
                Log.e("FSE", "", e);
            }
        }
    }
}

Answer 1

我不是专家，但我注意到：

您正在UI线程中运行I / O操作 - 这将冻结您的GUI，直到I / O操作完成==＆gt;在一个单独的线程中运行它们。
您从ListenThread中的UI线程外部更新UI，这可能会导致意外结果

你可以在this tutorial中阅读更多相关信息（请确保你阅读了2个例子，因为第一个例子已被破坏（故意））。

修改
总之，在第一段代码中你应该有类似的东西：

startButton.setOnClickListener(new OnClickListener() { public void onClick(View v) { Toast.makeText(getApplicationContext(), "Now Capturing Packets", Toast.LENGTH_LONG).show(); new Thread(new Runnable() { public void run() { try { process = Runtime.getRuntime().exec("su"); ... CaptureActivity.this.runOnUiThread(new Runnable() { public void run() { CaptureActivity.this.thisActivity.CaptureText.setText("Active"); } }); } catch (Exception e) { } ListenThread thread = new ListenThread(new BufferedReader(new InputStreamReader(inputStream))); thread.start(); } }).start(); } });

在第二个：

while (true) { try { CaptureActivity.this.runOnUiThread(new Runnable() { public void run() { CaptureActivity.this.thisActivity.CaptureText.setText("exec"); } }); int a = 1; String received = reader.readLine(); while (a == 1) { CaptureActivity.this.runOnUiThread(new Runnable() { public void run() { CaptureActivity.this.thisActivity.LiveTraffic.append(received); CaptureActivity.this.thisActivity.LiveTraffic.append("\n"); CaptureActivity.this.thisActivity.CaptureText.setText("in loop"); } }); received = reader.readLine(); } CaptureActivity.this.runOnUiThread(new Runnable() { public void run() { CaptureActivity.this.thisActivity.CaptureText.setText("out loop"); } }); } catch (Exception e) { Log.e("FSE", "", e); } }

这应解决特定的UI交互问题。但是你的代码中存在其他逻辑问题，这些问题超出了这个问题（例如，如果你到达了正在阅读的文件的末尾，那么你永远不会测试，而while（a == 1）是无限循环的事实因为你永远不会改变等等的价值。）。

如何将流程输出链接到textview并实时自动更新？

1 个答案: