(1) passing Activity parameters and activity parameters

(1) passing Activity parameters and activity parameters

1. Main Activity, used to start another Activity ()
Public class MainActivity extends Activity {@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );
System. out. println ("onCreate ");

FindViewById (R. id. btnStartBAct). setOnClickListener (new View. OnClickListener (){
@ Override
Public void onClick (View view ){
Intent intent = new Intent (MainActivity. this, BActivity. class );
Intent. putExtra ("data", "Hello Henry"); // PASS Parameters
// StartActivity (new Intent (MainActivity. this, BActivity. class ));
StartActivity (intent );
}
});
}

@ Override
Protected void onStart ()
{
Super. onStart ();
System. out. println ("onStrart ");
}
@ Override
Protected void onRestart ()
{
Super. onRestart ();
System. out. println ("onRestart ");
}
@ Override
Protected void onStop ()
{
Super. onStart ();
System. out. println ("onStop ");
}
@ Override
Protected void onResume ()
{
Super. onResume ();
System. out. println ("onResume ");
}
@ Override
Protected void onPause ()
{
Super. onPause ();
System. out. println ("onPause ");
}
@ Override
Protected void onDestroy ()
{
Super. onDestroy ();
System. out. println ("onDestroy ");
}

@ Override
Public boolean onCreateOptionsMenu (Menu menu ){
// Inflate the menu; this adds items to the action bar if it is present.
GetMenuInflater (). inflate (R. menu. menu_main, menu );
Return true;
}

@ Override
Public boolean onOptionsItemSelected (MenuItem item ){
// Handle action bar item clicks here. The action bar will
// Automatically handle clicks on the Home/Up button, so long
// As you specify a parent activity in AndroidManifest. xml.
Int id = item. getItemId ();

// Noinspection SimplifiableIfStatement
If (id = R. id. action_settings ){
Return true;
}

Return super. onOptionsItemSelected (item );
}
}
2. Start from Activity by MainActivity

Public class BActivity extends Activity {

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_ B );
System. out. println ("B onCreate ");

Intent intent = getIntent (); // get the Intent passed by MainActivity

TextView TV = (TextView) findViewById (R. id. TV );
TV. setText (intent. getStringExtra ("data"); // call the getStringExtra ("data") method of Intent to retrieve data

}

@ Override
Protected void onStart ()
{
Super. onStart ();
System. out. println ("B onStrart ");
}
@ Override
Protected void onRestart ()
{
Super. onRestart ();
System. out. println ("B onRestart ");
}
@ Override
Protected void onStop ()
{
Super. onStart ();
System. out. println ("B onStop ");
}
@ Override
Protected void onResume ()
{
Super. onResume ();
System. out. println ("B onResume ");
}
@ Override
Protected void onPause ()
{
Super. onPause ();
System. out. println ("B onPause ");
}
@ Override
Protected void onDestroy ()
{
Super. onDestroy ();
System. out. println ("B onDestroy ");
}


@ Override
Public boolean onCreateOptionsMenu (Menu menu ){
// Inflate the menu; this adds items to the action bar if it is present.
GetMenuInflater (). inflate (R. menu. menu_ B, menu );
Return true;
}

@ Override
Public boolean onOptionsItemSelected (MenuItem item ){
// Handle action bar item clicks here. The action bar will
// Automatically handle clicks on the Home/Up button, so long
// As you specify a parent activity in AndroidManifest. xml.
Int id = item. getItemId ();

// Noinspection SimplifiableIfStatement
If (id = R. id. action_settings ){
Return true;
}

Return super. onOptionsItemSelected (item );
}
}
3. Transfer Data Packet Bundle
3.1 In MainActivity

FindViewById (R. id. btnStartBAct). setOnClickListener (new View. OnClickListener (){

@ Override
Public void onClick (View view ){
Intent intent = new Intent (MainActivity. this, BActivity. class );
// Intent. putExtra ("data", "Hello Henry ");

// Transfer data packets
Bundle bundle = new Bundle ();
Bundle. putString ("name", "henry"); // Add data to the data packet
Bundle. putInt ("age", 24 );
Intent. putExtras (bundle); // Add data packets to Intent

// StartActivity (new Intent (MainActivity. this, BActivity. class ));
StartActivity (intent );
}
});
}
3.2 In BActivity

Intent intent = getIntent ();
Bundle bundle = intent. getExtras (); // receives data packets

TextView TV = (TextView) findViewById (R. id. TV );
// TV. setText (intent. getStringExtra ("data "));
TV. setText (String. format ("name = % s, age = % d", bundle. getString ("name"), (int) bundle. get ("age"); // call the getXXX () function of Bundle to obtain data

4. Pass reference
4.1 Use serialization to pass reference classes
Custom class:

Public class User implements Serializable {// use the serialization method provided by java
Private String name;
Private int age;

Public void setName (String name ){
This. name = name;
}

Public void setAge (int age ){
This. age = age;
}

Public String getName (){
Return name;
}

Public int getAge (){
Return age;
}
Public User (String name, int age)
{
This. name = name;
This. age = age;
}
}
Main Activity:

Public class MainActivity extends Activity {

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );

FindViewById (R. id. btnStartBAct). setOnClickListener (new View. OnClickListener (){
@ Override
Public void onClick (View view ){
Intent intent = new Intent (MainActivity. this, BActivity. class );


Intent. putExtra ("user", (Serializable) new User ("henryQL", 24); // Add a custom reference Class Object
StartActivity (intent );
}
});
}

}
Called Activity:

Public class BActivity extends Activity {

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_ B );

Intent intent = getIntent ();
User user = (User) intent. getSerializableExtra ("user"); // get serialized data

TextView TV = (TextView) findViewById (R. id. TV );
TV. setText (String. format ("nmae = % s, age = % d", user. getName (), user. getAge ()));
}
}
4.2 Use the Parcelable interface provided by Android

Public class User implements Parcelable {
Private String name;
Private int age;

Public void setName (String name ){
This. name = name;
}

Public void setAge (int age ){
This. age = age;
}

Public String getName (){
Return name;
}

Public int getAge (){
Return age;
}
Public User (String name, int age)
{
This. name = name;
This. age = age;
}


@ Override
Public int describeContents (){
Return 0;
}

@ Override
Public void writeToParcel (Parcel parcel, int I ){
Parcel. writeString (getName ());
Parcel. writeInt (getAge ());
}

Public static final Parcelable. Creator <User> CREATOR = new Parcelable. Creator <User> () // The name must be "CREATOR ".
{

@ Override
Public User createFromParcel (Parcel parcel ){
Return new User (parcel. readString (), parcel. readInt ());
}

@ Override
Public User [] newArray (int I ){
Return new User [I];
}
};
}

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        System.out.println("onCreate");

        findViewById(R.id.btnStartBAct).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent=new Intent(MainActivity.this,BActivity.class);               

                intent.putExtra("user",new User("Qianlong",24));

                //startActivity(new Intent(MainActivity.this,BActivity.class));
                startActivity(intent);
            }
        });
    }
}

Public class BActivity extends Activity {

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_ B );
System. out. println ("B onCreate ");


Intent intent = getIntent ();
User user = intent. getParcelableExtra ("user"); // get the Parcelable object

TextView TV = (TextView) findViewById (R. id. TV );
// TV. setText (intent. getStringExtra ("data "));
// TV. setText (String. format ("name = % s, age = % d", bundle. getString ("name"), (int) bundle. get ("age ")));
TV. setText (String. format ("nmae = % s, age = % d", user. getName (), user. getAge ()));
}
}