Android Interview Questions Part 5

64. How to load bitmap to memory?

• Checkout this article on it. I couldn’t have explained it better myself.

65. What are the permission protection levels in Android?

• Normal — A lower-risk permission that gives requesting applications access to isolated application-level features, with minimal risk to other applications, the system, or the user. The system automatically grants this type of permission to a requesting application at installation, without asking for the user’s explicit approval.
• Dangerous — A higher-risk permission. Any dangerous permissions requested by an application may be displayed to the user and require confirmation before proceeding, or some other approach may be taken to avoid the user automatically allowing the use of such facilities.
• Signature — A permission that the system grants only if the requesting application is signed with the same certificate as the application that declared the permission. If the certificates match, the system automatically grants the permission without notifying the user or asking for the user’s explicit approval.
• SignatureOrSystem — A permission that the system grants only to applications that are in the Android system image or that are signed with the same certificate as the application that declared the permission.

66. What is an Application Not Responding (ANR) error, and how can you prevent them from occurring in an app?

An ANR dialog appears when your UI has been unresponsive for more than 5 seconds, usually because you’ve blocked the main thread. To avoid encountering ANR errors, you should move as much work off the main thread as possible.

67. What is a singleton class in Android?

A singleton class is a class which can create only an object that can be shared all other classes.

64. How to load bitmap to memory?

• Checkout this article on it. I couldn’t have explained it better myself.

65. What are the permission protection levels in Android?

• Normal — A lower-risk permission that gives requesting applications access to isolated application-level features, with minimal risk to other applications, the system, or the user. The system automatically grants this type of permission to a requesting application at installation, without asking for the user’s explicit approval.
• Dangerous — A higher-risk permission. Any dangerous permissions requested by an application may be displayed to the user and require confirmation before proceeding, or some other approach may be taken to avoid the user automatically allowing the use of such facilities.
• Signature — A permission that the system grants only if the requesting application is signed with the same certificate as the application that declared the permission. If the certificates match, the system automatically grants the permission without notifying the user or asking for the user’s explicit approval.
• SignatureOrSystem — A permission that the system grants only to applications that are in the Android system image or that are signed with the same certificate as the application that declared the permission.

66. What is an Application Not Responding (ANR) error, and how can you prevent them from occurring in an app?

An ANR dialog appears when your UI has been unresponsive for more than 5 seconds, usually because you’ve blocked the main thread. To avoid encountering ANR errors, you should move as much work off the main thread as possible.

67. What is a singleton class in Android?

A singleton class is a class which can create only an object that can be shared all other classes.