Android problem summary

1.

What is the role of "@ + id" in Android? What is the difference between Android and Android: ID? Android: Like @ ID, the ID references an existing ID, while @ + id is a new ID.
2.

What is the difference between charsequence and string?

CharsequenceIt is a readable sequence of char values. This interface provides unified read-only access to many different types of char Sequences (In my personal understanding, it should be regarded as a set of Char Types and an interface) The string class represents a string. All character strings (such as "ABC") in Java programs are implemented as such instances.

3.Setcontentview (R. layout. Main) is in Android. What does this sentence mean?

R. layout. main is a layout file, that is, how to display controls. setcontentview is used to set the display interface of an activity. In this case, R is used for the activity. layout

4."ADB is neither an internal or external command, nor a program or batch file that can be run ."

The main command to run is the adb.exefile. You can add the file path of adb.exe to the environment variable. For example,
The environment variable name is path and the value is E: \ Android-SDK-Windows \ tools. The variable name upstairs is path,

5. Android project reports an errorEmulator-5554Disconnected!Cancelling'Com.Mine.Androidactivity
Activity launch '5 .! What does it mean? Why? How can this problem be solved? Thank you.
Satisfactory answer
Favorable rating:100%
Android simulators often encounter many problems, such as failures and one disconnection.
 

In this case, restart ADB:
In eclipse:
Window-> show views-> device-> View menu-> Reset ADB
Or in the command line status:
ADB kill-server --- then ADB start-Server