Show log messages on screen for Android application

Question

Is it possible to display the log messages (which I print using android.util.Log) on screen in an Android application?

Is there any other better method to just output lines on the screen?

Something like System.out.println?

Answer 1

Yes zero4

what you are attempting to do is dropping 'logcat' comand on android shell & getting command output as output stream.This link will help you.

Answer 2

Like others have suggested, you can use log cat. If you are using the emulator or debugging a device, you can use adb logcat to view the messages. In Eclipse debug perspective, there is a window that will do that for you.

Another way, without a debugger attached, is to use the CatLog - Logcat Reader application.

Answer 3

I use "android.widget.Toast.makeText(Context context, CharSequence text, int duration)" to do something like what you are asking. Seems like the easiest way to get some quick messages on the screen and make it go away automatically (based on the last parameter).

:-)

Answer 4

Well, there is a solution to log anything you want on screen using this lib. It didn't worked for me, so I develop my own solution you can find an example of it here. It's really simple, just add a class OnScreenLog to your project

package br.com.ideiageni.onscreenlogSample;

import android.app.Activity;
import android.graphics.Color;
import android.os.Handler;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;


/**
 * Created by ariel on 07/07/2016.
 */
    public class OnScreenLog {
    private static int timeoutTime = 1000;
    private static TextView tvLog;
    private static int logCount = 0;
    private static int logCountMax = 30;
    private static String[] logs = new String[logCountMax];
    private static int cntClicks = 0;
    private static boolean visibility = false;
    private static Activity activity;
    private int maxClicks = 5;

    public OnScreenLog(){}

    public OnScreenLog(Activity activity, int ViewID){
        OnScreenLog.activity = activity;
        tvLog = new TextView(activity.getApplicationContext());
        maintainLog("Log is working");
        tvLog.setLayoutParams(new RelativeLayout.LayoutParams(
            RelativeLayout.LayoutParams.WRAP_CONTENT,
            RelativeLayout.LayoutParams.WRAP_CONTENT));
        tvLog.setTextColor(Color.BLACK);
        tvLog.setBackgroundColor(Color.LTGRAY);
        tvLog.setAlpha((float) 0.4);

        View v = null;
        LinearLayout linearLayout;
        RelativeLayout relativeLayout;
        try {
            linearLayout = (LinearLayout) activity.findViewById(ViewID);
        } catch (ClassCastException e) {linearLayout = null;};

        try {
            relativeLayout = (RelativeLayout) activity.findViewById(ViewID);
        } catch (ClassCastException e) {relativeLayout = null;};
        if(linearLayout != null) {
            linearLayout.addView(tvLog);
            v = linearLayout;
        } else if(relativeLayout != null) {
            relativeLayout.addView(tvLog);
            v = relativeLayout;
        }

        if(v != null) {
            v.setOnTouchListener(new View.OnTouchListener() {
                @Override
                public boolean onTouch(View v, MotionEvent event) {
                    switch (event.getAction()) {
                        case MotionEvent.ACTION_DOWN:
                            cntClicks++;
                            timerHandler.removeCallbacks(rTimeout);
                            timerHandler.postDelayed(rTimeout, timeoutTime);

                            if (cntClicks > maxClicks-1) {
                                setLogVisible(!visibility);
                                timerHandler.removeCallbacks(rTimeout);
                                cntClicks = 0;
                            }
                            break;

                    }
                    return false;
                }
            });
        }

    }

    public void log (String text){
        String logText = text;
        maintainLog(logText);
    }

    public void log (int text){
        String logText = String.valueOf(text);
        maintainLog(logText);
    }

    public void log (int[] text){
        StringBuilder builder = new StringBuilder();
        for (int i : text) {
            builder.append(i);
            builder.append("-");
        }
        String logText = builder.toString();
        maintainLog(logText);
    }

    public void log (byte[] text){
        StringBuilder builder = new StringBuilder();
        for (int i : text) {
            builder.append(i);
            builder.append("-");
        }
        String logText = builder.toString();
        maintainLog(logText);
    }

    private void maintainLog(String newText){
        String logText = "";
        if(logCount<logCountMax) logCount++;
        for(int i=logCount-1; i>0; i--){
            logs[i] = logs[i-1];
        }
        logs[0] = newText;
        for(int i=0; i<logCount; i++){
            if(i<logCount-1) logText+=logs[i]+System.getProperty("line.separator");
            else logText+=logs[i];
        }
        tvLog.setText(logText);
    }

    public void clearLog(){
        tvLog.setText("");
    }

    public void setLogVisible(boolean visibility){
        if(visibility) tvLog.setVisibility(View.VISIBLE);
        else tvLog.setVisibility(View.INVISIBLE);
        OnScreenLog.visibility = visibility;
    }

    public static int getLogCountMax() {
        return logCountMax;
    }

    public static void setLogCountMax(int logCountMax) {
        OnScreenLog.logCountMax = logCountMax;
        logs = new String[logCountMax];
    }

    public int getMaxClicks() {
        return maxClicks;
    }

    public void setMaxClicks(int maxClicks) {
        this.maxClicks = maxClicks;
    }

    Handler timerHandler = new Handler();
    Runnable rTimeout = new Runnable() {

        @Override
        public void run() {
            cntClicks = 0;
        }
    };
}

then, for instance:

public class Activity1 extends AppCompatActivity {

private OnScreenLog log;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_1);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    log = new OnScreenLog(this, R.id.content_1);
    log.log("Started log on Activity 1");

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent(getApplicationContext(), Activity2.class);
            startActivity(intent);
            log.log("Starting Activity 2");
            Snackbar.make(view, "Starting Activity 2", Snackbar.LENGTH_LONG)
                    .setAction("Action", null).show();
        }
    });
}

Where R.id.content_1 is the name of the main LinearLayout or RelativeLayout of your activity.

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/content_1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="br.com.ideiageni.onscreenlogSample.Activity1"
tools:showIn="@layout/activity_1">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Activity 1!" />

</RelativeLayout>

Neither solutions print the current log messages, so you'll need to tell it to log to screen the same informations you log today on your current log.

Work not finished yet but can be used for anyone in need. Missing some directions on how to use. Suggestions are welcome.