Activity jump and value transfer for Android Learning

Activity jumps and transfers values mainly through the Intent class. Intent is used to activate components and accompanying data.

1. Activity jump

Method 1
Intent intent = new Intent (A. this, B. class );
StartActivity (intent)

Method 2
Intent intent = new Intent ();
Intent. setClass (A. this, B. class );
StartActivity (intent );

Implement jump from A to B (A and B are inherited from Activity)

Ii. Data Transmission

Activity A transmits data

Method 1
Intent intent = new Intent ();
Intent. setClass (A. this, B. class );
Intent. putExtra ("name", "xy ");
Intent. putExtra ("age", 22 );

StartActivity (intent );

Method 2
Intent intent = new Intent (A. this, B. class );
Bundle bundle = new Bundle ();
Bundle. putString ("name", "xy ");
Bundle. putInt ("age", 22 );

Intent. putExtras (bundle );
StartActivity (intent );

Activity B receives data

// Obtain parameter 1
Intent intent = this. getIntent ();
String name = intent. getStringExtra ("name ");
Int age = intent. getIntExtra ("age", 22); // The default value is 22.

// Obtain parameter 2
Bundle bundle = intent. getExtras ();
String name2 = bundle. getString ("name ");
Int age2 = bundle. getInt ("age", 22 );

Both methods can be used to obtain parameters. They are not exactly the same as the method for passing parameters 1 and 2.