Android fundamentals 02.3:Implicit intents⭐

Android fundamentals 02.3:Implicit intents

이 포스팅은 아래 구글 코드랩을 개인 학습용으로 정리한 글입니다.

• 2.3: 암시적 인텐트

1. Welcome

• Implicit intent
  • you initiate an activity without knowing which app or activity will handle the task
  • ex. if you want your app to take a photo, send email, or display a location on a map
  • you typically don't care which app or activity performs the task

➖

• your activity can declare one or more intent filters in the AndroidManifest.xml file
  -> to advertise that the activity can accept implicit intents
  -> and to define the types of intents that the activity will accept

➖

• To match your request with an app installed on the device
  -> the Android system matches your implicit intent with an activity whose intent filters indicate that they can perform the action

• If multiple apps match
  -> the user is presented with an app chooser
  -> lets them select which app they want to use to handle the intent.
  

2. App overview

• In this section you create a new app with one Activity and three options for actions
  • open a web site
  • open a location on a map
  • share a snippet of text

3. Task 1: Create the project and layout

1.1 Create the project

1.2 Create the layout

4. Task 2: Implement the Open Website button

2.1 Define openWebsite()

2.2 Add code to openWebsite()

1. Add a statement to the new openWebsite() method that gets the string value of the EditText

String url = mWebsiteEditText.getText().toString();

2. Encode and parse a string into a Uri object:

Uri webpage = Uri.parse(url);

3. Create a new Intent with Intent.ACTION_VIEW as the action* and the URI as the data*:

Intent intent = new Intent(Intent.ACTION_VIEW, webpage);

4. Use the resolveActivity() method and the Android package manager to find an Activity that can handle your implicit Intent.

if (intent.resolveActivity(getPackageManager()) != null) {
}

• This request matches your Intent action and data with the Intent filters for installed apps on the device.
  -> You use it to make sure there is at least one Activity that can handle your requests.

MainActivity.kt

class MainActivity : AppCompatActivity() {
    lateinit var mWebsiteEditText : EditText

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        mWebsiteEditText = findViewById(R.id.website_edittext)
    }

    fun openWebsite(view: View) {
        val url = mWebsiteEditText.text.toString()
        val webpage : Uri = Uri.parse(url)
        val intent : Intent = Intent(Intent.ACTION_VIEW, webpage)

        if(intent.resolveActivity(packageManager) != null) {
            startActivity(intent)
        }else{
            Log.d("Implicit Intents", "Can't handle this intent!")
        }
    }
}

5. Task 3: Implement the Open Location button

3.1 Define openLocation()

3.2 Add code to openLocation()

1. In the new openLocation() method, add a statement to get the string value of the mLocationEditText EditText.

String loc = mLocationEditText.getText().toString();

2. Parse that string into a Uri object with a geo search query:

Uri addressUri = Uri.parse("geo:0,0?q=" + loc);

3. Create a new Intent with Intent.ACTION_VIEW as the action and loc as the data.

Intent intent = new Intent(Intent.ACTION_VIEW, addressUri);

MainActivity.kt

  fun openLocation(view: View) {
        val loc = mLocationEditText.text.toString()
        val adressUri = Uri.parse("geo:0,0?q=$loc")
        val intent = Intent(Intent.ACTION_VIEW, adressUri)

        if(intent.resolveActivity(packageManager) != null){
            startActivity(intent)
        }else{
            Log.d("Implicit Intents", "Can't handle this intent!")
        }
    }

6. Task 4: Implement the Share This Text button

• A share action:
  an easy way for users to share items in your app with social networks and other apps.

• Android provides the ShareCompat.IntentBuilder helper class
  -> You can use ShareCompat.IntentBuilder to build an Intent and launch a chooser to let the user choose the destination app for sharing.

4.1 Define shareText()

4.2 Add code to shareText()

1. In the new shareText() method, add a statement to get the string value of the mShareTextEditText EditText.

String txt = mShareTextEditText.getText().toString();

2. Define the mime type of the text to share:

String mimeType = "text/plain";

3. Call ShareCompat.IntentBuilder with these methods:

ShareCompat.IntentBuilder
           .from(this)
           .setType(mimeType)
           .setChooserTitle("Share this text with: ")
           .setText(txt)
           .startChooser();

• from():
  The Activity that launches this share Intent (this).

• setType():
  The MIME type of the item to be shared.

• setChooserTitle():
  The title that appears on the system app chooser.

• setText():
  The actual text to be shared

• startChooser():
  Show the system app chooser and send the Intent.

MainActivity.kt

 fun shareText(view: View) {
        val txt : String = mShareEditText.text.toString()
        val mimeType = "text/plain"
        ShareCompat.IntentBuilder
            .from(this)
            .setType(mimeType)
            .setChooserTitle(R.string.share_text_with)
            .setText(txt)
            .startChooser()
    }

4.3 Run the app

➕ shareText()는 정상적으로 작동하지만, openWebsite()와 openLocation()는 암시적 인텐트를 실행시킬 수 있는 액티비티/앱을 찾지 못함

• 해결 방법:
  • 매니페스트에 $<$queries$>$ 요소를 추가
  • intent.resolveActivity() 대신 packageManager.queryIntentActivities() 호출

AndroidManifest.xml

<queries>
	<intent>
            <action android:name="android.intent.action.VIEW" />
            <category android:name="android.intent.category.BROWSABLE" />
            <data android:scheme="https" />
	</intent>
</queries>  

MainActivity.kt

fun openWebsite(view: View) {
        val url = mWebsiteEditText.text.toString()
        val webpage : Uri = Uri.parse(url)
        val intent : Intent = Intent(Intent.ACTION_VIEW, webpage)
        
        if(packageManager.queryIntentActivities(intent, PackageManager.MATCH_ALL) != null) {
            startActivity(intent)
        }else{
            Log.d("Implicit Intents", "Can't handle this intent!")
        }
    }
    
    fun openLocation(view: View) {
        val loc = mLocationEditText.text.toString()
        val adressUri = Uri.parse("geo:0,0?q=$loc")
        val intent = Intent(Intent.ACTION_VIEW, adressUri)
        
        if(packageManager.queryIntentActivities(intent, PackageManager.MATCH_ALL) != null){
            startActivity(intent)
        }else{
            Log.d("Implicit Intents", "Can't handle this intent!")
        }
    }

📌참고자료

• Android 11의 패키지 공개 상태

• Android 11에서는 앱이 사용자가 기기에 설치한 다른 앱을 쿼리하고 상호작용하는 방법을 변경
• 요소를 사용하여 앱은 액세스할 수 있는 다른 패키지 집합을 정의

• 사용 사례별로 패키지 공개 상태 구성

브라우저 또는 다른 앱에서 URL 열기

• 앱에서 URL을 열려고 하기 전에 기기에 사용 가능한 브라우저가 최소 하나 이상 있는지 또는 특정 브라우저가 기본 브라우저인지 확인하는 것이 좋습니다.

  <!-- Place inside the <queries> element. -->
  <intent>
  <action android:name="android.intent.action.VIEW" />
  <category android:name="android.intent.category.BROWSABLE" />
  <data android:scheme="https" />
  </intent>

• queryIntentActivities()를 호출하고 웹 인텐트를 인수로 전달하면 경우에 따라 반환된 목록에 사용 가능한 브라우저 앱이 포함됩니다.