android - 文件路径的位图 decodefile() 显示为空

问题描述

我是使用 Kotlin 进行 Android 开发的新手。我正在尝试使用以下代码中的一些方法将图像从手机上传到我的应用程序。在某些过程中一切正常，例如我可以在 imageview 上选择然后屏幕弹出窗口可以让我在手机中选择图像。不幸的是，选择图像后，它显示为空/空白，在应用程序中不显示任何内容。我试图寻求帮助，但没有成功。希望我能在这里得到帮助。提前致谢！

活动代码

package student

import android.content.Intent
import android.content.pm.PackageManager
import android.graphics.BitmapFactory
import android.os.Build
import android.os.Bundle
import android.provider.MediaStore
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import androidx.core.app.ActivityCompat
import com.example.amazontutoringcenter.databinding.ActivityMainBinding
import com.example.amazontutoringcenter.databinding.ActivityStudentClassroomBinding
import com.squareup.picasso.Picasso



class StudentClassroomActivity: AppCompatActivity() {

    private lateinit var binding: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityMainBinding.inflate(layoutInflater)
        val view = binding.root
        setContentView(view)

        binding.imageView.setOnClickListener {
            checkPermission()

        }

    }

    val READ_IMAGE:Int=338
    private fun checkPermission(){

        if(Build.VERSION.SDK_INT>=23){
            if(ActivityCompat.checkSelfPermission(this,
                    android.Manifest.permission.READ_EXTERNAL_STORAGE)!=
                PackageManager.PERMISSION_GRANTED){

                requestPermissions(arrayOf( android.Manifest.permission.READ_EXTERNAL_STORAGE),READ_IMAGE)
                return
            }
        }

        loadImage()
    }

    override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {

        when(requestCode){
            READ_IMAGE->{
                if(grantResults[0]==PackageManager.PERMISSION_GRANTED){
                    loadImage()
                }else{
                    Toast.makeText(applicationContext,"Cannot access your images",Toast.LENGTH_LONG).show()
                }
            }
            else-> super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        }


    }

    val PICK_IMAGE_CODE=123
    private fun loadImage(){

        var intent=Intent(Intent.ACTION_PICK,
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI)
        startActivityForResult(intent,PICK_IMAGE_CODE)
    }

    override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
        super.onActivityResult(requestCode, resultCode, data)

        if(requestCode==PICK_IMAGE_CODE  && data!=null && resultCode == RESULT_OK){

            val selectedImage=data.data
            val filePathColum= arrayOf(MediaStore.Images.Media.DATA)
            val cursor= contentResolver.query(selectedImage!!,filePathColum,null,null,null)
            cursor!!.moveToFirst()
            val coulomIndex=cursor!!.getColumnIndex(filePathColum[0])
            val picturePath=cursor!!.getString(coulomIndex)
            cursor!!.close()
            //.load(picturePath).into(binding.imageStudentProfile)
            //Picasso.get().load(picturePath).fit().into(binding.imageStudentProfile)
            binding.imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath))



        }

    }

}

XML 文件

<?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">

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Test Layout"
        android:layout_marginTop="50dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView2"
        android:src="@drawable/ic_attendant"/>
</androidx.constraintlayout.widget.ConstraintLayout>

标签： androidkotlin

android - 文件路径的位图 decodefile() 显示为空

问题描述

解决方案

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