android 程序執行logcat 指令並保存到文件裏

在android 程序裏執行adb logcat 指令,並把執行結果保存到文件裏.
代碼如下:

java.lang.Process process;
    private void logcat(){
        try {
            process = Runtime.getRuntime().exec("logcat");
            new Thread() {
                @Override
                public void run() {
                    BufferedWriter os = null;
                    String mLine = "";
                    try {
                        BufferedReader mReader = new BufferedReader(
                                new InputStreamReader(process.getInputStream()));
                        os = new BufferedWriter(new FileWriter("/sdcard/writelog.txt"));
                        while ((mLine = mReader.readLine())!=null) {
                            if(mLine.contains("wifi")|| mLine.contains("dhcp")||mLine.contains("wlan")|| mLine.contains("wpa")){
                                os.write(mLine+"\n");
                                os.flush();
                            }
                        }

                    } catch (Exception e) {
                        Log.d("writelog", "read logcat process failed. message: " + e.getMessage());
                    } finally {
                        if (null != os) {
                            try {
                                os.close(); os = null;
                            } catch (IOException e) {
                                // Do nothing
                            }
                        }
          
                    }
                }
            }.start();
        } catch (Exception e) {
            Log.d("writelog", "open logcat process failed. message: " + e.getMessage());
        }
    }