Android log graphic explanation (log. V, log. D, log. I, log. W, log. e)

InAndroidPeople in the group often ask me,Android logHow is it used? Today I willSDKLet's get started quickly. I hope to get started with you.Android logSome help.

Common android. util. Log methods include:5Items:Log. V () Log. D () Log. I () log. W ()AndLog. E (). Corresponds to the first letterVerbose,Debug, info, warn, and error.

1. the debugging color of log. V isBlack, Any message will be output. Here v stands for verbose, which is usually used as log. V ("","");

2. The output color of log. D isBlueOnly the meaning of DEBUG debugging is output, but the upper-layer information is output, which can be selected through the logcat tag of ddms.

3. The output of log. I isGreenGenerally, the prompt message information does not output the information of log. V and log. D, but displays the information of I, W, and E.

4. log. W meansOrangeIt can be seen as a warning of warning. Generally, we need to optimize the android code and select it to output log. e information.

5. If log. e is red, you can think of error errors. Here, only red error messages are displayed. We need to carefully analyze these errors and view stack information.

Below is a simple exampleLogdemo(Step by step ):

Step 1: Preparation (openLogcatWindows ).

StartEclipse, InWindow-> show ViewA dialog box is displayed. When we clickOKButton appears in the console windowLogcatWindows. For example:

 

 

 

Step 2: CreateAndroidProject, namedLogdemo.

 

Step 3:DesignUIInterface, we addButtonButtonLogLog information ).

Main. xmlThe Code is as follows:

<? XML version = "1.0" encoding = "UTF-8"?>
<Linearlayout xmlns: Android = "http://schemas.android.com/apk/res/android"
Android: Orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent"
>
<Textview
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: text = "@ string/hello"
/>
<Button
Android: Id = "@ + ID/BT"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "Presse me look log"
/>
</Linearlayout>

Step 4: Design the main classLogdemo. JavaThe Code is as follows:

 

Package com. Android. test;

Import Android. App. activity;
Import Android. OS. Bundle;
Import Android. util. log;
Import Android. View. view;
Import Android. widget. Button;

Public classLogdemoExtends activity {

 Private Static final string activity_tag = "logdemo ";
 Private button Bt;
Public void oncreate (bundle savedinstancestate ){
Super. oncreate (savedinstancestate );
Setcontentview (R. layout. Main );
// Find the button resource through findviewbyid
Bt = (button) findviewbyid (R. Id. bt );
// Add Event Response
Bt. setonclicklistener (New button. onclicklistener (){
@ Override
Public void onclick (view v ){
Log. V (logdemo. activity_tag, "this is verbose .");
Log. D (logdemo. activity_tag, "this is Debug .");
Log. I (logdemo. activity_tag, "this is information ");
Log. W (logdemo. activity_tag, "this is warnning .");
Log. E (logdemo. activity_tag, "this is error .");
}
 
});
}

}

 

Step 5: RunLogdemoProject, the effect is as follows:

 

 

When you click the button, the event is triggered. The following results are displayed in the logcat window: