Android Kotlin 打开相册选择图片(多选)

1. 核心代码

打开系统相册功能，本代码使用两种方式打开本地相册，startActivityForResult 已经废弃，可以使用新的方式。

package com.example.facedetectordemoimport android.content.pm.PackageManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle
import android.util.Log
import android.view.View
import android.widget.TextView
import androidx.activity.result.contract.ActivityResultContracts
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat
import com.example.facedetectordemo.databinding.ActivityMainBinding
import com.example.facedetectordemo.entity.FaceInfo
import android.Manifest;
import android.annotation.SuppressLint
import android.annotation.TargetApi
import android.app.Activity
import android.content.ContentUris
import android.content.Intent
import android.graphics.BitmapFactory
import android.net.Uri
import android.os.Build
import android.provider.DocumentsContract
import android.provider.MediaStore
import com.google.android.material.snackbar.Snackbarclass MainActivity : AppCompatActivity() {private lateinit var binding: ActivityMainBindingprivate val CHOOSE_PHOTO = 1private val requestPermissionLauncher =registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted: Boolean ->if (isGranted) {Log.i("Permission: ", "Granted")} else {Log.i("Permission: ", "Denied")}}private val launcherActivity = registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {val data = it.dataif (it.resultCode == Activity.RESULT_OK) {// 判断手机系统版本号if (Build.VERSION.SDK_INT >= 19) {// 4.4及以上系统使用这个方法处理图片if (data != null) {if(data.clipData != null) {handleImageOnKitKat(data.clipData!!.getItemAt(0).uri)} else if(data.data != null) {handleImageOnKitKat(data.data!!)}}}}}override fun onCreate(savedInstanceState: Bundle?) {super.onCreate(savedInstanceState)binding = ActivityMainBinding.inflate(layoutInflater)setContentView(binding.root)// Example of a call to a native methodbinding.openGallery.setOnClickListener{val intent = Intent("android.intent.action.GET_CONTENT")intent.type = "image/*" // */intent.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true)//startActivityForResult(intent, CHOOSE_PHOTO) // 打开相册, 废弃APIlauncherActivity.launch(intent)}val infos = getFaceInfoList()Log.d("zhouyong", "onCreate: size " + infos.size)requestPermission();}override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {super.onActivityResult(requestCode, resultCode, data)when (requestCode) {CHOOSE_PHOTO -> if (resultCode == Activity.RESULT_OK) {// 判断手机系统版本号if (Build.VERSION.SDK_INT >= 19) {// 4.4及以上系统使用这个方法处理图片if (data != null) {if(data.clipData != null) {handleImageOnKitKat(data.clipData!!.getItemAt(0).uri)} else if(data.data != null) {handleImageOnKitKat(data.data!!)}}} else {}}else -> {}}}@TargetApi(19)private fun handleImageOnKitKat(uri: Uri) {var imagePath: String? = null//val uri = data.dataLog.d("TAG", "handleImageOnKitKat: uri is $uri")if (DocumentsContract.isDocumentUri(this, uri)) {// 如果是document类型的Uri，则通过document id处理val docId = DocumentsContract.getDocumentId(uri)if ("com.android.providers.media.documents" == uri!!.authority) {val id = docId.split(":".toRegex()).toTypedArray()[1] // 解析出数字格式的idval selection = MediaStore.Images.Media._ID + "=" + idimagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection)} else if ("com.android.providers.downloads.documents" == uri.authority) {val contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), java.lang.Long.valueOf(docId))imagePath = getImagePath(contentUri, null)}} else if ("content".equals(uri!!.scheme, ignoreCase = true)) {// 如果是content类型的Uri，则使用普通方式处理imagePath = getImagePath(uri, null)} else if ("file".equals(uri.scheme, ignoreCase = true)) {// 如果是file类型的Uri，直接获取图片路径即可imagePath = uri.path}displayImage(imagePath) // 根据图片路径显示图片}@SuppressLint("Range")private fun getImagePath(uri: Uri?, selection: String?): String? {var path: String? = null// 通过Uri和selection来获取真实的图片路径val cursor = contentResolver.query(uri!!, null, selection, null, null)if (cursor != null) {if (cursor.moveToFirst()) {path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA))}cursor.close()}return path}private fun displayImage(imagePath: String?) {if (imagePath != null) {val bitmap = BitmapFactory.decodeFile(imagePath)binding.imageView.setImageBitmap(bitmap)} else {//Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show()}}fun requestPermission() {when {ContextCompat.checkSelfPermission(this,Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED -> {}ActivityCompat.shouldShowRequestPermissionRationale(this,Manifest.permission.CAMERA) -> {requestPermissionLauncher.launch(Manifest.permission.CAMERA)requestPermissionLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)requestPermissionLauncher.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE)}else -> {requestPermissionLauncher.launch(Manifest.permission.CAMERA)requestPermissionLauncher.launch(Manifest.permission.READ_EXTERNAL_STORAGE)requestPermissionLauncher.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE)}}}fun View.showSnackbar(view: View,msg: String,length: Int,actionMessage: CharSequence?,action: (View) -> Unit) {val snackbar = Snackbar.make(view, msg, length)if (actionMessage != null) {snackbar.setAction(actionMessage) {action(this)}.show()} else {snackbar.show()}}/*** A native method that is implemented by the 'facedetectordemo' native library,* which is packaged with this application.*/external fun stringFromJNI(): Stringexternal fun getFaceInfoList(): Array<FaceInfo>companion object {// Used to load the 'facedetectordemo' library on application startup.init {System.loadLibrary("facedetectordemo")}}
}

2. main_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".MainActivity"><Buttonandroid:id="@+id/openGallery"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginBottom="212dp"android:text="打开相册"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintHorizontal_bias="0.498"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/imageView"app:layout_constraintVertical_bias="1.0" /><ImageViewandroid:id="@+id/imageView"android:layout_width="200dp"android:layout_height="200dp"android:layout_marginTop="96dp"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"tools:srcCompat="@tools:sample/avatars" /></androidx.constraintlayout.widget.ConstraintLayout>