安卓kotiln 打开手机相册

在Android Kotlin中，要打开手机相册，你可以使用系统的`ACTION_PICK`或`ACTION_GET_CONTENT` intent。首先，你需要导入相关的权限并创建一个Intent：

import android.Manifest
import android.content.Intent
import android.content.pm.PackageManager
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.widget.Button
import android.widget.Toast

class MainActivity : AppCompatActivity(), ActivityResultContracts.PickImageCallback {

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

        val openGalleryButton = findViewById<Button>(R.id.open_gallery_button)
        openGalleryButton.setOnClickListener {
            if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                requestPermissions(arrayOf(Manifest.permission.READ_EXTERNAL_STORAGE), MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE)
                return
            }

            val pickImageIntent = Intent(Intent.ACTION_PICK, MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
            startActivityForResult(pickImageIntent, REQUEST_IMAGE_PICK)
        }
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)
        when (requestCode) {
            REQUEST_IMAGE_PICK -> {
                if (resultCode == RESULT_OK && data != null) {
                    val imageUri = data.data
                    // 这里可以处理选中的图片，比如显示在一个ImageView或下载到本地
                    Toast.makeText(this, "Selected Image: ${imageUri}", Toast.LENGTH_SHORT).show()
                } else {
                    Toast.makeText(this, "No image selected", Toast.LENGTH_SHORT).show()
                }
            }
            else -> {
                super.onActivityResult(requestCode, resultCode, data)
            }
        }
    }

    private const val MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 100
}

在这个例子中，我们检查了存储权限，并在用户同意后启动了一个选择图片的activity。当用户从相册选择完图片后，我们会收到回调并获取所选图片的uri。