kotlin与java中简单使用dagger2对比

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kotlin

依赖

implementation 'com.google.dagger:dagger:2.17'
//kotlin使用kapt
kapt 'com.google.dagger:dagger-compiler:2.17'

class Person @Inject
constructor() {

    lateinit var name: String

}

@Component
interface MainComponent {
    fun inject(mainActivity: MainActivity)
}

class MainActivity : AppCompatActivity() {

    @JvmField
    @Inject
    var person: Person? = null

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

        DaggerMainComponent.builder().build().inject(this)

        person!!.name = "小明"
        tv.text = person!!.name

    }
}

Kotlin中使用Dagger2 可能导致错误"Dagger does not support injection into private fields"

Kotlin 生成.java文件时属性默认为 private，给属性添加@JvmField声明可以转成 public

java

implementation 'com.google.dagger:dagger:2.17'
//
annotationProcessor 'com.google.dagger:dagger-compiler:2.17'

public class User {

    public String name;

    @Inject
    public User() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

@Component()
public interface MainComponent {
    void inject(MainActivity mainActivity);
}

public class MainActivity extends AppCompatActivity {

    @Inject
    public User user;

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

        DaggerMainComponent.builder().build().inject(this);

        TextView textView = (TextView) this.findViewById(R.id.tv);
        user.setName("小明");
        textView.setText(user.getName());
    }
}