startActivityForResult替代方案

startActivityForResult过时

替代方案：ActivityResultContract

1、如何使用

1.1 定义ActivityResultContract

//泛型    1-ActivityResultLauncher.launch调用时需要的参数类型
//泛型    2-回调ActivityResultCallback返回类型
val activityResultContract = object : ActivityResultContract<Intent, ActivityResult>() {
    override fun createIntent(context: Context, input: Intent): Intent {
        return input
    }
​
    override fun parseResult(resultCode: Int, intent: Intent?): ActivityResult {
        return ActivityResult(resultCode,intent)
    }
}

1.2 定义ActivityResultCallback

//页面返回回调
val activityResultCallback = object : ActivityResultCallback<ActivityResult> {
    override fun onActivityResult(result: ActivityResult?) {
        if (result != null && result.resultCode == RESULT_OK) {
            //todo
        }
    }
}

1.3 activity或者fragment中进行注册

//参数     ActivityResultContract  ActivityResultCallback
//返回值   ActivityResultLauncher
registerForActivityResult = registerForActivityResult(activityResultContract, activityResultCallback)

1.4 ActivityResultLauncher合适时机调用

//调用       
registerForActivityResult?.launch(Intent(this,DetainmentActivityActivity::class.java))

2、预置实现

2.1 调用

val registerForActivityResult=registerForActivityResult(ActivityResultContracts.StartActivityForResult(),object : ActivityResultCallback<ActivityResult> {
            override fun onActivityResult(result: ActivityResult?) {
                if (result != null && result.resultCode == RESULT_OK) {
                    finish()
                }
            }
        })
        registerForActivityResult.launch(Intent(this,DetainmentActivityActivity::class.java))

2.2 StartActivityForResult代码

​
public static final class StartActivityForResult
    extends ActivityResultContract<Intent, ActivityResult> {
​
    @NonNull
    @Override
    public Intent createIntent(@NonNull Context context, @NonNull Intent input) {
        return input;
    }
​
    @NonNull
    @Override
    public ActivityResult parseResult(
        int resultCode, @Nullable Intent intent) {
        return new ActivityResult(resultCode, intent);
    }
}