How to Print to the Console in Android Studio?
In computer technology, the console is simply a combination of a monitor and an input device. Generally, the input device is referred to here as the pair of mouse and keyboard. In order to proceed with the topic, we have to understand the terminology of computer science, which is an important part of the process of developing software, and it’s called debugging. Debugging is the process of identifying a bug or an error and fixing it properly for the software. We have to test the software before producing it on market in multiple phases. We have to debug the errors also, then only software will be pure error-free and it will be ready for production. The most of the things which computer does with our code is invisible for us. For Debugging, we have to identify the error first then only we can solve that error. If you want to see the error, then you have to print or log it to our console directly. There are many and different methods in different programming languages for doing it.
In C, We do it using printf(), in C++ we will use cout, and in Java, we generally use System.out.println. We all know, that in the android studio we have to code in a different way. Android has its own methods and components, we have to code the application using them. This is slightly different from normal programming. In today’s article we are going to learn about that how can we print to the console in Android Studio.
What is Logcat Window?
The Logcat is a window in android studio, which displays system information when a garbage collection occurs and also the messages which you have added to your Log class. It displays the message in real-time. It also keeps the history of the messages. You can also learn more about the Logcat window from Here.
Introduction and Types of Log Class
The log class is a pre-defined class in android studio which allows the developer to print messages in Logcat Window, which is the console for Android Studio. Every message is written using a log, Contains a special type or format that represents for what purpose the message is being written.
How to print to the console in Android Studio?
I just downloaded Android Studio for Linux from: http://developer.android.com/sdk/installing/studio.html I’m wondering how to print to the console? Neither System.out.print(. ) nor Log.e(. ) from android.util.Log seem to work.
You can also see print statements in Run window as I answered here.. stackoverflow.com/a/46843640/2462531
8 Answers 8
Run your application in debug mode by clicking on
in the upper menu of Android Studio.
In the bottom status bar, click 5: Debug button, next to the 4: Run button.
Now you should select the Logcat console.
In search box, you can type the tag of your message, and your message should appear, like in the following picture (where the tag is CREATION ):
Check this article for more information.
Android has its own method of printing messages (called logs ) to the console, known as the LogCat .
When you want to print something to the LogCat , you use a Log object, and specify the category of message.
You print a message by using a Log statement in your code, like the following example:
Log.d("myTag", "This is my message"); Within Android Studio, you can search for log messages labelled myTag to easily find the message in the LogCat . You can also choose to filter logs by category, such as «Debug» or «Warn».
Simple android app to print text
I recently started watching youtube videos about android development. I watched a few and tried to write my own app. Basically what it does is, the user enters a text in the text field and when the user presses the click button, the entered value is displayed on a text view. I am very confused as to where I should define variables and how to retrieve values and how to show values on a specific item. I want to know this stuff so I can correctly begin developing android apps. This is the code that I currently have:
package com.abihnav.numdisplayer; import android.os.Bundle; import android.app.Activity; import android.view.Menu; import android.widget.EditText; import android.widget.TextView; public class MainActivity extends Activity < public String YOUR_NUM = "YOUR_NUM"; EditText numEditText; TextView textView; @Override protected void onCreate(Bundle savedInstanceState) < super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); EditText numEditText = (EditText) findViewById(R.id.numEditText); TextView textView = (TextView) findViewById(R.id.textView1); >public void printNum() < YOUR_NUM = numEditText.getText().toString(); textView.setText(YOUR_NUM); >@Override public boolean onCreateOptionsMenu(Menu menu) < // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; >> Where is the button ? @Raghunandan YOUR_NUM is already a String variable, why do you want to call String.valueOf() on it ?.
You have two variables numEditText and textView that are duplicated (one local to onCreate() , the other global to MainActivity (that are never set)). you’re going to run into trouble with this!
Android App: How can I print out a String with java code?
but it doesnt work: Error:(13, 17) error: cannot assign a value to final variable Entscheidung Is there another way to do this? Thank you !
«it doesnt work» — we cannot help you with that if you do not provide a minimal reproducible example, showing what you tried and explaining in detail what went wrong.
Take into account that R is created at compile time and it only contains constants, you cannot modify those values from your code.
3 Answers 3
Firstly I’d just like to clarify the concept of String Resources and how they are used. For constant String values («Ja» and «Nein» in your case), you can define these values in a file called strings.xml , located within the res/values folder. As an example:
These values are finalized at compile time so can be used as constants throughout your app. In the case of XML layout files, yes you can refer to these String resources using the @string/ prefix. However, in your Java code you can only refer to these values using the getString() method using the R.string prefix. Because these R.string values are final , they cannot be changed at runtime, thus the error you’re getting. In your case your code would be:
// I'm assuming you have this declared in onCreate() TextView myTextView = (TextView)findViewById(R.id.mytextview); if (i < 1) < myTextView.setText(getString(R.string.antwort_ja)); >else
This also makes the assumption that you’re calling this from your Activity. If not, you may need to call it from an instance of Context e.g. context.getString(R.string.antwort_ja);