Andriod Learning-01

Android Studio project directory structure

App/build/app Module build compiled output directory

gradle compilation file for App/build.gradle app module

APP/APP.IML app module configuration file

App/proguard-rules.pro app module proguard file

gradle compilation file for Build.gradle project

Settings.gradle Define which modules the project contains

Gradlew compile scripts that can be packaged at the command line

Local.properties configuration sdk/ndk

configuration file for MYAPPLICATION.IML project

External Libraries Project dependent Lib, compile-time automatic download

Module Structure Type

App/manifests androidmanifest.xml configuration file directory

App/java Source Directory

App/res resource file directory

Gradle Scripts Gradle Compilation-related scripts

 

Activity Life cycle

1. start Activity: The system calls the onCreate method First, then calls the onStart method, and finally calls the onresume, theActivity enters the running state.

2. current activity is overwritten by other activity or Locked screen: The system calls the onPause method, pausing the current The execution of the Activity.

3. The current Activity is returned to the foreground or unlock screen by the overwritten state: The system calls the onresume method and enters the running state again.

4. The current activity goes to the new activity interface or press the home key to return to the main screen, itself back to the background: the system will first call onPause method, and then calls the onStop method to enter a stagnant state.

5. the user backs back to this Activity: The system calls the Onrestart method First and then calls the OnStart method, and finally calls the onresume method, again into the running state.

6. current activity 2 Steps and 4 step, system memory is low, kill current activity activity : Call again oncreate method, onstart method, onresume method, enter the running state.

7. The user exits the current Activity: The system calls the onPause method First, then calls the onStop method, and finally calls the ondestory method to end the current Activity.

Control

all controls in Android are inherited from Android.view.View, where android.view.ViewGroup is An important subclass of View, most of the layouts are inherited from viewgroup.

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