ReadLog.java

Read the log through the following code:

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);
      }
      TextView tv = (TextView)findViewById(R.id.textView1);
      tv.setText(log.toString());
    } catch (IOException e) {
    }
  }
}
The above code reads the log and displays it in a textview.

You should define:

<uses-permission android:name="android.permission.READ_LOGS" />
permission in your manifest.

To copy the log directly to a file,use the following method:

public static void copyLogcatToFile(Context context) {    
    String fileName = "log_cat"+System.currentTimeMillis()+".txt";
    File outputFile = new File(context.getExternalCacheDir(),fileName);
    @SuppressWarnings("unused")
    Process process = Runtime.getRuntime().exec("logcat -f "+outputFile.getAbsolutePath());
}