Saving Logcat to a text file in Android Device

I had found some crashes while running the application in android device, which is not showing in emulator. So i need to save the Logcat in a text file in my device's memory or SD card. Could you please suggest me good method to do this?

Use an Application class at the beginning of your app. That allows a proper file and log handling.

Code below creates a log file at the following location:

/ExternalStorage/MyPersonalAppFolder/logs/logcat_XXX.txt

XXX is the current time in milliseconds. Every time you run your app, a new logcat_XXX.txt file will be created.

public class MyPersonalApp extends Application {

    /**
     * Called when the application is starting, before any activity, service, or receiver objects (excluding content providers) have been created.
     */
    public void onCreate() {
        super.onCreate();

        if ( isExternalStorageWritable() ) {

            File appDirectory = new File( Environment.getExternalStorageDirectory() + "/MyPersonalAppFolder" );
            File logDirectory = new File( appDirectory + "/logs" );
            File logFile = new File( logDirectory, "logcat_" + System.currentTimeMillis() + ".txt" );

            // create app folder
            if ( !appDirectory.exists() ) {
                appDirectory.mkdir();
            }

            // create log folder
            if ( !logDirectory.exists() ) {
                logDirectory.mkdir();
            }

            // clear the previous logcat and then write the new one to the file
            try {
                Process process = Runtime.getRuntime().exec("logcat -c");
                process = Runtime.getRuntime().exec("logcat -f " + logFile);
            } catch ( IOException e ) {
                e.printStackTrace();
            }

        } else if ( isExternalStorageReadable() ) {
            // only readable
        } else {
            // not accessible
        }
    }

    /* Checks if external storage is available for read and write */
    public boolean isExternalStorageWritable() {
        String state = Environment.getExternalStorageState();
        if ( Environment.MEDIA_MOUNTED.equals( state ) ) {
            return true;
        }
        return false;
    }

    /* Checks if external storage is available to at least read */
    public boolean isExternalStorageReadable() {
        String state = Environment.getExternalStorageState();
        if ( Environment.MEDIA_MOUNTED.equals( state ) ||
                Environment.MEDIA_MOUNTED_READ_ONLY.equals( state ) ) {
            return true;
        }
        return false;
    }
}

you need the correct permissions and name of your application class in your .manifest file:

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

<application
    android:name=".MyPersonalApp"
    ... >

Edit:

if you want to save log of only some particular activities..

replace:

process = Runtime.getRuntime().exec("logcat -f " + logFile);

with:

process = Runtime.getRuntime().exec( "logcat -f " + logFile + " *:S MyActivity:D MyActivity2:D");