Why is the Android system more powerful than the previous mobile phone system?

Document directory

• 1. Libraries Layer
• 2. Dalvik Virtual Machine
• 3. Open source code for Android
• 4. Android Application Development

Some netizens mentioned this issue by sending private messages. They have made many mobile platforms, such as symbian, mtk, android, and ios, and simply wrote their own understandings of these issues, I hope I can answer this Netizen's question.

Ni ***** asked: I am not working on software, but I have such questions only because of my interest, hope you can advise the android platform to use java for applications, right? A mobile phone has a java simulator many years ago. Why didn't the mobile phone's java program feel that the current android Application has powerful functions? In addition to the upgrade of mobile phone hardware, what are the differences between software and android dalvik simulator ?? Thank you ~

 

First of all, you must know that java is only a programming language and it cannot make the android system powerful.

1. Hardware

The power of android phones is definitely related to hardware upgrades. Previously, the mobile phone processor was 100 Mhz, with dozens of megabytes of memory. The current mobile phone processor goes to 1-2 Ghz, there are dual-core, memory 1-2G. The current mobile phone is more powerful than the old PC, and it is now easy to think about things you did not dare to think about on the phone.

2. Software

The java simulator you mentioned many years ago was the java Virtual Machine at that time. the java on the mobile phone should be called j2_m2. it is a java virtual machine that can adapt to the small memory and simplify the processing capability of the mobile phone. Functions can only be used for simple interfaces and images, and can also be connected to the Internet. As you said, mobile phones may include mobile phones like symbian, mtk, Nokia symbian, and other chip manufacturers, such as M-star, there are also some phones that cannot be mentioned in the system, all of which are placed on a small j2_virtual machine, and the standards of these j2_virtual machines are different from those of each other. There are many virtual machine manufacturers, as a result, although they are all java applets, they can only run on a mobile phone, but not on other mobile phones.

3. Powerful Android system

Look at the architecture of Android. Why does Android analyze its strength:

1. Libraries Layer

Looking at the Libraries layer in the middle, android brings together a large number of excellent open-source Libraries in the world. Each open-source database has powerful functions. SQlite enables android to provide the database function. The WebKit library allows the android browser to browse webpages like a PC browser. OpenGL enables the mobile phone to have 3D graphics capabilities, The SGL 2D engine. FreeType fonts. Surface makes the rendering interface more beautiful. You can view the functions of other libraries on your own. These libraries are all written in C or C ++ and provide excellent functionality. The java language at the application layer connects to these libraries through JNI and plays the role of these libraries. This library layer did not have a mobile phone before and did not dare to have it.

2. Dalvik Virtual Machine

The Dalvik virtual machine directly connects to the Linux kernel and provides program core services: Additional threads and memory management. The program runs faster and more stably. Dalvik is also the runtime environment of the java language. It can be used to explain the java language. Dalvik collects a majority of java libraries, so that programmers can conveniently use classes in the java environment, such as string libraries, sorting, and searching. In the past, only a small part of java environment functions were used for 2me. What if the application layer does not use the java language? Certainly. For example, if you use python or other languages, google may have many java programmers, java is popular enough, and many documents are supported. This is a powerful tool for android development. Without the support of developers, there will be no rich application, no applications and games, and the smart phone function will return to making calls and sending text messages.

3. Open source code for Android

The opening of Android source code gives Lao Luo, who is trained in English, the opportunity to make mobile phones. You can. It can be seen that the power of Open Source (although android is not completely open source ). Nowadays, most mobile phone manufacturers all over the world are working on Android phones, and everyone is building a virtuous circle. As a result, there are many types of mobile phones in the Android world, there are several hundred or even thousands of items, and the android ipad has also come out. android has also made things like smart TV. In addition, the hardware abstraction layer (HAL layer) of Android allows device manufacturers to maintain the confidentiality of their own hardware drivers, and keeps their own drivers and interfaces of upper-layer applications unchanged, this increases the enthusiasm of equipment vendors. Device vendors can easily add their own specific hardware.

4. Android Application Development

Compared with Symbian development, Android provides a very complete development reference documentation (http://developer.android.com/index.html), design documentation and so on, the document is much more detailed than symbian. Allows developers to quickly get started with developing software. Development Tools mainly use Eclipse, which provides many powerful plug-ins developed by Android.

 

Rong Fangzhi (http://blog.csdn.net/totogo2010)

 

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