How to read my application logcat and write in to file?

Question

Writing logs into logcat from your application is very easy. Reading logs is usually used for bug report purposes.

The following code reads logs and write it to file:

public class LogTest extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        try {
            Process process = Runtime.getRuntime().exec("logcat -d");
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(process.getInputStream()));

            StringBuilder log = new StringBuilder();
            String line;
            while ((line = bufferedReader.readLine()) != null) {
                log.append(line);
            }

            String logFilePath = Environment.getExternalStorageDirectory() + File.separator + "LogTest.txt";

            File logFile = new File(logFilePath);
            if (!logFile.exists())
                logFile.createNewFile();

            FileOutputStream outStream = new FileOutputStream(logFile, true);
            byte[] buffer = log.toString().getBytes();

            outStream.write(buffer);
            outStream.close();
        } catch (Exception ex) {
            ex.printStackTrace();

        }
    }
}

And also you needs two permission for reading logs and write file to external storage:

<uses-permission android:name="android.permission.READ_LOGS"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

You can add any more parameters to the logcat command string.More info in android developer.

When implementing a bug report feature, with sending logs to yourself, don't forget that many applications outputs personal information into the logcat, so a policy about them is definitely needed.

I hope this post is useful ;-)