The app you are developing can also match Intents in the same way as the home app. PackageManager has a query ... () method and a resolve ... () method. The query ... () method provides all the components that can receive the Intent, and the resolve ... () method determines the best component to respond to the Intent. For example, queryIntentActivities () provides all activities that can execute the argument Intent, and queryIntentService () provides a list of similar services. Neither method starts the component, it just provides a list. Broadcast receivers also have queryBroadcastReceivers () as a similar method.

General Intent

Alarm lock

calendar

camera

Contact / contact book app

Email

File storage

Local action

map

Music / video

New notebook

phone

Search

Setting

Text message

Web browser

Intent verification with Android Debug bridge

Sample Code (dereferenced from below)

Constitution

Project01

Manifest.java

Manifest.java

<activity android:name=".MainActivity">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

//■■■ Add ↓ ■■■
<activity android:name=".SubActivity">
    <intent-filter>
        <action android:name="sub_activity"/>
        <category android:name="android.intent.category.DEFAULT"/>
    </intent-filter>
</activity>
//■■■ Up to here ■■■

MainActivity layout (activity_main.xml)

activity_main.xml

<Button
   android:id="@+id/button01"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="Button01"
   />
<Button
   android:id="@+id/button02"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="Button02"
   />

MainActivity.java

MainActivity.java

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

   Button button01 = findViewById(R.id.button01);
   Button button02 = findViewById(R.id.button02);

   button01.setOnClickListener(new View.OnClickListener(){
      @Override 
      public void onClick(View v){
         Intent intent_sub = new Intent("sub_activity");
         startActivity(intent_sub);
      }
   });

   button02.setOnClickListener(new View.OnClickListener(){
      @Override 
      public void onClick(View v){
         Intent intent_pro02_main = new Intent("pro02_main_activity");
         startActivity(intent_pro02_main);
      }
   });
}

SubActivity layout

activity_sub.xml

<TextView
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   android:text="SubActivity in Project01"/>

SubActivity.java does nothing

Project02

Manifest.java

Manifest.java

<activity android:name=".MainActivity">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />

        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>

    //■■■ Add ↓ ■■■
    <intent-filter>
        <action android:name="pro02_main_activity"/>
        <category android:name="android.intent.category.DEFAULT"/>
    </intent-filter>
    //■■■ Up to here ■■■
</activity>

Main Activity layout

activity_main.xml

<TextView
   android:text="MainActivity in Project02"
   android:layout_width="wrap_content"
   android:layout_height="wrap_content"
   />

MainActivity.java does nothing