Stand on. NET perspective on Android's grass folk note 1

Java-. NET

WINFORM/WPF, Android

Class inherits activity--class inherits Form

① Android.

If you have 2 activity in Android, you can jump from one activity to another activity.

Intent t=New Intent (mainactivity.  this, otheractivity. class );            StartActivity (t);    

Using the intent, the jargon is called intent.

The back mainactivity is the first window, the next one is about to open

Intent t=new Intent (a.this,b.class)

Then startactivity (t);

②winform

To be opened the form, instantiate it, and then show opens the

FormA a=new FormA ();

A.show ();

So Android is much like. NET programming

The structure of Android

In the SRC folder of the project, where the source code of Java is, the Gen folder is where the compiled code is generated

. NET when writing code is a. cs file, Java is a. java file

The. dll file is compiled, and the. class file in Java

We see that there is a Com.android.helloword folder below Src, where the source code is placed below.

This com.android.helloworld, dot notation, at the time of visualization, is the 3-layer folder, under the HelloWorld folder under the Android file under the COM folder

This directory can be specified in your new class, specifying the file directory structure at 1.

2 can specify the parent class, inherit him, Java use extends, subclass use the parent class thing use Super, own use this

. NET use: Can, subclasses use the parent object to use base, their own this

3 Specify the implementation interface, Java uses implements,.net or:

Java inherits and implements the interface

4 Specify the generation of the class, the default with no constructors, do not tick also does not matter, in the class, you can also quickly build constructors

You can right-click on your code, choose Source, then a menu, you can quickly open the tool menu by Alt+shift+s, there is also a place to generate properties

For Java properties, see the following code

Here I only wrote 2 private. .. , then use Alt+shift+s, generate attributes, generate parameters of the constructor, so Java code is relatively fast, but there is no. NET to write the word real-time prompt code just. But in Java you use ALT +, you can prompt the code, but you give the IDE a few words to pay attention to the case, do not match.

Writing a code in. NET, it is convenient to use SHIFT+ALT+F10 to import namespaces quickly without introducing a namespace, and. NET uses using to manually import

Write a code in Java, you can use Ctrl+shift+o to achieve the same effect, Java import manually using import

There is also a common shortcut key is the format code, the code is not neat when the. NET use of Ctrl+e+d,java ctrl+shift+f can be

. NET annotations with Ctrl+e+c, uncomment ctrl+e+u

Java comments and uncomment using ctrl+\

Probably the most common shortcuts I know at the moment are so much.

Well, how do you test the debugging process?

1. I am currently using a real phone to test, very fast, right click on your project, open run configurations

2

Double-click Android application to create a new profile, then you select your project and click Target

The first option is the real machine test options, then did not find my phone, but my computer installed pea pod software, seemingly pea pod to my computer installed what ADB Drive East, and then my phone can communicate with the IDE, you can test, your phone to open developer options

Every time I write the code, click Run, the phone will open the program, see the latest effect, if not installed, he will first install

There are log4java,log4net and other logging tools for Java and. NET, with debug classes and visualizers in wirelessly (Logcat)

Use log. What can log, and there is the severity of the log, where I is a shorthand for the info level, before selling that tag I define a constant, defined above, this is like a log label, where the tag equals main

So I can define a log filter in Logcat.

So my logcat here is the log text for the main tag.

About log debugging Getting started here, you're welcome to study.

Create an activity below and let you combine. NET, knowing how the files on Android depend on the association

Before you do that, talk about the activity's life cycle.

7 Methods of Oncreate,onstart,onrestart,onresume,onstop,onpause,ondestroy

In each class, you can override these methods of the activity parent class, by default a new class that inherits activity contains a OnCreate method, equivalent to the Xxx_load method of WinForm

protected void onCreate (Bundle savedinstancestate) {        super. OnCreate (savedinstancestate);       }

Here Super.oncreate write a line of code can bind this window interface, such as we bind activity_main this android XML layout file

Setcontentview (R.layout.activity_main);

So the interface and the logic behind the binding, open the Activity_main.xml file, one is the interface mode, one is the XML file mode

Interface mode, is not much like the visual mode of WinForm

Next we'll look at the backend code behind Android.

It's really like the XAML language behind WPF, so comparing Android to. NET WPF is still very graphic.

With the background class, with the layout XML file in the layouts file, you also need to include this new activity in the Androidmanifest file.

This name is the same as the background class name, not the same as the layout file name, using dot + Plus background class name, to form an activity in the Android configuration name

This idea and WIN8 application development also very much like, WIN8 application development time also has the configuration manifest file, can set the icon, the propaganda picture, other system permission disposition and so on, this file function you can also understand as the. NET website the global file, OK, you know has this file the entry function to be possible.

Speaking so much, it is estimated that there should be an Android mobile phone in hand, simply look at the life cycle of Android

You can create a new project that overrides the 7 life cycle methods of the parent class in the default activity, using the markup that is executed by the LOG.I print method for each life cycle. Next Operation Android Program, we look at the log
①  Install the program, click on the icon to start

Summary: OnCreate  -   OnStart  Onresume

②  pressed the Little House button and went back to the desktop


Summary: OnPause    onStop

③ Press and hold the small house key to display the history opener list, and then select the program that you just opened, this way to open the program

Summary: Onrestart-   OnStart  Onresume

④ mobile phone for a long time, the default black screen, hang up the state, the same as the ② situation
OnPause  OnStop

⑤ Open after black screen, as in the case of ③

Onrestart-   OnStart  Onresume

⑥ point the Return key, exit the program

Onpause-onstop-ondestroy

Well, the first impressions about Android are roughly written here, if there are more than 10 people. NET Fellow with Android IDE build still have the problem I can write an Android 4.x development IDE alone to build notes