Camera基础

Building a Camera App

The general steps for creating a custom camera interface for your application are as follows:

• Detect and Access Camera- Create code to check for the existence of cameras and request access.
• Create a Preview Class- Create a camera preview class that extendsSurfaceViewand implements theSurfaceHolderinterface. This class previews the live images from the camera.
• Build a Preview Layout- Once you have the camera preview class, create a view layout that incorporates the preview and the user interface controls you want.
• Setup Listeners for Capture- Connect listeners for your interface controls to start image or video capture in response to user actions, such as pressing a button.
• Capture and Save Files- Setup the code for capturing pictures or videos and saving the output.
• Release the Camera- After using the camera, your application must properly release it for use by other applications.

遇到的问题，启动后crash，发现oncreat都过了，后来才想到是因为权限问题，需要加上权限.

<uses-permission android:name="android.permission.CAMERA" />