将 jetpack compose 添加到现有项目

Question

I have an existing android studio project and I want to use jetpack compose in my project. The documentation says how to create a new project with jetpack compose, but how to use it with existing projects?

Answer 1

Jetpack compose requires a minSdkVersion of at least 21. So add/update the following in your app/build.gradle file

android{ 
   //...
   defaultConfig {       
      minSdkVersion 21
      targetSdkVersion 29
      //...
   }
  //...
 }

Also you need to use Android studio (from canary channel) in order to use jetpack-compose with the latest features.

Easiest method for existing projects

Step 1:

In project window, right click on the package you want to include the compose activity -> compose -> Empty compose activity .

or

File -> new -> compose -> Empty compose activity.

Step 2

A dialog window will appear. Fill up the required fields and click Finish .

That's all.

---

Manual configuration for existing projects

Step 1: Use latest version of kotlin and gradle plugins in your project/build.gradle file.

Example:

buildscript {
     ext {
    compose_version = '1.0.0-beta08'
}

    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:7.1.0-alpha02'
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:1.5.10"
    }
}

allprojects {
    repositories {
        google()
        jcenter()
    }
}

In your project/app/build.gradle , add the following

android{ 
   //...
   defaultConfig {       
      minSdkVersion 21
      targetSdkVersion 30
      //...
   }
  //...

  kotlinOptions {
       jvmTarget = "1.8"
        useIR = true
  }

  buildFeatures {
    compose true
  }
  composeOptions {
    kotlinCompilerExtensionVersion compose_version
    kotlinCompilerVersion '1.4.32'
}
}


dependencies {
  implementation 'androidx.core:core-ktx:1.5.2'
implementation 'androidx.appcompat:appcompat:1.3.0'
implementation 'com.google.android.material:material:1.3.0'
implementation "androidx.compose.ui:ui:$compose_version"
implementation "androidx.compose.material:material:$compose_version"
implementation "androidx.compose.ui:ui-tooling:$compose_version"
implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.3.1'
implementation 'androidx.activity:activity-compose:1.3.0-beta1'
testImplementation 'junit:junit:4.13.2'
androidTestImplementation 'androidx.test.ext:junit:1.1.2'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'
androidTestImplementation "androidx.compose.ui:ui-test-junit4:$compose_version"
}

Step 2: Add the compose activity into your manifest file.

 <application      
    android:label="@string/app_name"
     <!-- ... -->
     >
     <activity
        android:name=".MainActivity"
        android:exported="true"
        android:label="@string/app_name"
        android:theme="@style/Theme.MyApp.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

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

Step 3:

Create the jetpack-compose Activity.

import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import androidx.compose.Composable
import androidx.ui.foundation.Text
import androidx.ui.core.setContent
import androidx.ui.material.MaterialTheme
import androidx.ui.tooling.preview.Preview

class MainComposeActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MaterialTheme {
                Greeting("Android")
            }
        }
    }
}

@Composable
fun Greeting(name: String) {
    Text(text = "Hello $name!")
}

@Preview
@Composable
fun DefaultPreview() {
    MaterialTheme {
        Greeting("Android")
    }
}

That's all. Happy coding:)

Answer 2

Just follow theofficial setup . Add in your build.gradle :

plugins {
  id 'org.jetbrains.kotlin.android' version '1.4.0'
}

android {
    defaultConfig {
        ...
        minSdkVersion 21
    }

    buildFeatures {
        // Enables Jetpack Compose for this module
        compose true
    }
    ...

    // Set both the Java and Kotlin compilers to target Java 8.

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

    kotlinOptions {
        jvmTarget = "1.8"
        useIR = true
    }

    composeOptions {
        kotlinCompilerExtensionVersion "1.0.0-alpha01"
    }
}

dependencies {
    // You also need to include the following Compose toolkit dependencies.
    implementation 'androidx.compose.ui:ui:1.0.0-alpha01'
    implementation 'androidx.compose.material:material:1.0.0-alpha01'
    implementation 'androidx.ui:ui-tooling:1.0.0-alpha01'
    ...
}

Also starting with 1.0.0-alpha01 you can combine Compose with your existing UI design.

Add in your layout the ComposeView :

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
  
    <TextView/>

    <androidx.compose.ui.platform.ComposeView
        android:id="@+id/compose_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

In your Activity , set the ComposeView using the XML ID, and call setContent() to use Compose:

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main_std)
    .apply {
        findViewById<ComposeView>(R.id.compose_view).setContent {
           MaterialTheme () {
              Text(text = "Compose text", style = MaterialTheme.typography.body2)
           }
         }
    }
}

Answer 3

In your root level build.gradle Add compose version variable inside buildscript

ext {
    compose_version = '1.0.1'
}

Now in your app level build.gradle add buildFeatures and composeOptions inside your android { } block

buildFeatures {
    compose true
}
composeOptions {
    kotlinCompilerExtensionVersion compose_version
}

and in your depenendencies

// Jetpack dependencies
implementation "androidx.compose.ui:ui:$compose_version"
implementation "androidx.compose.material:material:$compose_version"
implementation 'androidx.activity:activity-compose:1.4.0'
// Jetpack debug dependencies
debugImplementation "androidx.compose.ui:ui-tooling:$compose_version"

Now you can start using compose in your existing/new project

class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContent {
        // your compose code goes here
    }
  }
}