Android tutorial (13) -- Activity Switching

In this chapter, we will learn how to switch between activities.

So many of the previous tutorials are operated in an Activity-View, so we may feel quite depressed.

Go straight to the topic. In Android software development, an application is usually composed of multiple activities and views. How can these activities be switched? Android provides the Intent class for inter-Activity communication.

Now let's take a look at how this Intent is used.

 

Step 1: Create a project and call it Ep. changeActivity. The remaining names remain unchanged. After the Activity is created, a new Activity is created and named Main2Activity. If it is correctly created, the Activity automatically adds activity_main2 to the view.

Let's talk about this step.

,

OK to complete an Activity-View.

Step 2: Write the View. To make it easier for students to understand, my View is relatively simple:

Activity_main.xml

[Java]
<RelativeLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Xmlns: tools = "http://schemas.android.com/tools"
Android: layout_width = "match_parent"
Android: layout_height = "match_parent"
Android: paddingBottom = "@ dimen/activity_vertical_margin"
Android: paddingLeft = "@ dimen/activity_horizontal_margin"
Android: paddingRight = "@ dimen/activity_horizontal_margin"
Android: paddingTop = "@ dimen/activity_vertical_margin"
Tools: context = ". MainActivity">
 
<TextView
Android: id = "@ + id/textView1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "111111"/>
 
<Button
Android: id = "@ + id/button1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: layout_below = "@ + id/textView1"
Android: layout_centerHorizontal = "true"
Android: layout_marginTop = "63dp"
Android: text = "11111"/>
 
</RelativeLayout>

<RelativeLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Xmlns: tools = "http://schemas.android.com/tools"
Android: layout_width = "match_parent"
Android: layout_height = "match_parent"
Android: paddingBottom = "@ dimen/activity_vertical_margin"
Android: paddingLeft = "@ dimen/activity_horizontal_margin"
Android: paddingRight = "@ dimen/activity_horizontal_margin"
Android: paddingTop = "@ dimen/activity_vertical_margin"
Tools: context = ". MainActivity">

<TextView
Android: id = "@ + id/textView1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "111111"/>

<Button
Android: id = "@ + id/button1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: layout_below = "@ + id/textView1"
Android: layout_centerHorizontal = "true"
Android: layout_marginTop = "63dp"
Android: text = "11111"/>

</RelativeLayout>
Activity_main2.xml

[Java]
<RelativeLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Xmlns: tools = "http://schemas.android.com/tools"
Android: layout_width = "match_parent"
Android: layout_height = "match_parent"
Android: paddingBottom = "@ dimen/activity_vertical_margin"
Android: paddingLeft = "@ dimen/activity_horizontal_margin"
Android: paddingRight = "@ dimen/activity_horizontal_margin"
Android: paddingTop = "@ dimen/activity_vertical_margin"
Tools: context = ". Main2Activity">
 
<TextView
Android: id = "@ + id/textView1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "222222"/>
 
<Button
Android: id = "@ + id/button1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: layout_below = "@ + id/textView1"
Android: layout_centerHorizontal = "true"
Android: layout_marginTop = "64dp"
Android: text = "22222"/>
 
</RelativeLayout>

<RelativeLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Xmlns: tools = "http://schemas.android.com/tools"
Android: layout_width = "match_parent"
Android: layout_height = "match_parent"
Android: paddingBottom = "@ dimen/activity_vertical_margin"
Android: paddingLeft = "@ dimen/activity_horizontal_margin"
Android: paddingRight = "@ dimen/activity_horizontal_margin"
Android: paddingTop = "@ dimen/activity_vertical_margin"
Tools: context = ". Main2Activity">

<TextView
Android: id = "@ + id/textView1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "222222"/>

<Button
Android: id = "@ + id/button1"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: layout_below = "@ + id/textView1"
Android: layout_centerHorizontal = "true"
Android: layout_marginTop = "64dp"
Android: text = "22222"/>

</RelativeLayout>
It doesn't matter if you don't see it now. In the end, I will run it for you.

Step 3: CORE: Write activity:

MainActivity. java

[Java]
Package com. example. ep2.changeactivity;
 
Import android. OS. Bundle;
Import android. app. Activity;
Import android. content. Intent;
Import android. view. Menu;
Import android. view. View;
Import android. view. View. OnClickListener;
Import android. widget. Button;
 
Public class MainActivity extends Activity {
 
Private Button bt;
 
@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main );

Bt = (Button) findViewById (R. id. button1 );

Bt. setOnClickListener (new OnClickListener (){

@ Override
Public void onClick (View v ){
// TODO Auto-generated method stub
Intent it = new Intent ();
It. setClass (MainActivity. this, Main2Activity. class );
StartActivity (it );
MainActivity. this. finish ();

}
});
}
 
}

Package com. example. ep2.changeactivity;

Import android. OS. Bundle;
Import android. app. Activity;
Import android. content. Intent;
Import android. view. Menu;
Import android. view. View;
Import android. view. View. OnClickListener;
Import android. widget. Button;

Public class MainActivity extends Activity {

Private Button bt;

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

Bt = (Button) findViewById (R. id. button1 );

Bt. setOnClickListener (new OnClickListener (){

@ Override
Public void onClick (View v ){
// TODO Auto-generated method stub
Intent it = new Intent ();
It. setClass (MainActivity. this, Main2Activity. class );
StartActivity (it );
MainActivity. this. finish ();

}
});
}

}

Main2Activity. java

[Java]
Package com. example. ep2.changeactivity;
 
Import android. OS. Bundle;
Import android. app. Activity;
Import android. content. Intent;
Import android. view. View;
Import android. view. View. OnClickListener;
Import android. widget. Button;
 
Public class Main2Activity extends Activity {
 
Private Button bt;
 
@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main2 );

Bt = (Button) findViewById (R. id. button1 );

Bt. setOnClickListener (new OnClickListener (){

@ Override
Public void onClick (View v ){
// TODO Auto-generated method stub
Intent it = new Intent ();
It. setClass (Main2Activity. this, MainActivity. class );
StartActivity (it );
Main2Activity. this. finish ();
}
});
}
 
}

Package com. example. ep2.changeactivity;

Import android. OS. Bundle;
Import android. app. Activity;
Import android. content. Intent;
Import android. view. View;
Import android. view. View. OnClickListener;
Import android. widget. Button;

Public class Main2Activity extends Activity {

Private Button bt;

@ Override
Protected void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. activity_main2 );

Bt = (Button) findViewById (R. id. button1 );

Bt. setOnClickListener (new OnClickListener (){

@ Override
Public void onClick (View v ){
// TODO Auto-generated method stub
Intent it = new Intent ();
It. setClass (Main2Activity. this, MainActivity. class );
StartActivity (it );
Main2Activity. this. finish ();
}
});
}

}