Android BitmapFactory.decodeFile vs ImageDecoder.decodeBitmap,Kotlin

Android BitmapFactory.decodeFile vs ImageDecoder.decodeBitmap,Kotlin

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.READ_MEDIA_IMAGES" />
    <uses-permission android:name="android.permission.READ_MEDIA_VIDEO" />

import android.content.ContentUris
import android.content.Context
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.graphics.ImageDecoder
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.util.Log
import androidx.appcompat.app.AppCompatActivity
import androidx.lifecycle.lifecycleScope
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.launch
import java.io.File

class ImageActivity : AppCompatActivity() {
    companion object {
        const val TAG = "fly/ImageActivity"
        const val SIZE = 400
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)

        val ctx = this
        lifecycleScope.launch(Dispatchers.IO) {
            val imgList = readAllImage(ctx)
            val videoList = readAllVideo(ctx)

            Log.d(TAG, "readAllImage size=${imgList.size}")
            Log.d(TAG, "readAllVideo size=${videoList.size}")

            val lists = arrayListOf<MyData>()
            lists.addAll(imgList)
            lists.addAll(videoList)
            lists.shuffle()

            var ec = 0
            var t = System.currentTimeMillis()
            lists.take(3000).forEachIndexed { index, myData ->
                val b = bitmapFactoryDecodeFile(myData.path)
                if (b == null) {
                    ec++
                }
            }
            val ec1 = ec
            val t1 = System.currentTimeMillis() - t

            ec = 0

            t = System.currentTimeMillis()
            lists.take(3000).forEachIndexed { index, myData ->
                try {
                    imageDecoder(myData.path)
                } catch (e: Exception) {
                    ec++
                }
            }
            val ec2 = ec
            val t2 = System.currentTimeMillis() - t

            Log.d(TAG, "BitmapFactory 耗时=${t1}ms $ec1")
            Log.d(TAG, "ImageDecoder 耗时=${t2}ms $ec2")
        }
    }


    private fun bitmapFactoryDecodeFile(path: String): Bitmap? {
        val option = BitmapFactory.Options()
        option.outWidth = SIZE
        option.outHeight = SIZE
        option.inPreferredConfig = Bitmap.Config.ARGB_8888
        return BitmapFactory.decodeFile(path, option)
    }

    private fun imageDecoder(path: String) {
        val src = ImageDecoder.createSource(File(path))
        ImageDecoder.decodeBitmap(src, object : ImageDecoder.OnHeaderDecodedListener {
            override fun onHeaderDecoded(decoder: ImageDecoder, info: ImageDecoder.ImageInfo, source: ImageDecoder.Source) {
                decoder.setTargetSize(SIZE, SIZE)
                //decoder.isMutableRequired = false
            }
        })
    }


    class MyData(var path: String, var uri: Uri)

    private fun readAllImage(ctx: Context): ArrayList<MyData> {
        val photos = ArrayList<MyData>()

        //读取所有图
        val cursor = ctx.contentResolver.query(
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI, null, null, null, null
        )

        while (cursor!!.moveToNext()) {
            //路径
            val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA))

            val id = cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)
            val imageUri: Uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getLong(id))

            //名称
            //val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DISPLAY_NAME))

            //大小
            //val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Images.Media.SIZE))

            photos.add(MyData(path, imageUri))
        }
        cursor.close()

        return photos
    }

    private fun readAllVideo(context: Context): ArrayList<MyData> {
        val videos = ArrayList<MyData>()

        //读取视频Video
        val cursor = context.contentResolver.query(
            MediaStore.Video.Media.EXTERNAL_CONTENT_URI,
            null,
            null,
            null,
            null
        )

        while (cursor!!.moveToNext()) {
            //路径
            val path = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA))

            val id = cursor.getColumnIndex(MediaStore.Images.ImageColumns._ID)
            val videoUri: Uri = ContentUris.withAppendedId(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, cursor.getLong(id))

            //名称
            //val name = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DISPLAY_NAME))

            //大小
            //val size = cursor.getLong(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.SIZE))

            videos.add(MyData(path, videoUri))
        }
        cursor.close()

        return videos
    }
}

Android ImageDecoder把瘦高/扁平大图相当于fitCenter模式decode成目标小尺寸Bitmap，Kotlin-CSDN博客文章浏览阅读580次，点赞3次，收藏10次。Android拼接合并图片生成长图代码实现合并两张图片，以第一张图片的宽度为标准，如果被合并的第二张图片宽度和第一张不同，那么就以第一张图片的宽度为准线，对第二张图片进行缩放。Android拼接合并图片生成长图代码实现合并两张图片，以第一张图片的宽度为标准，如果被合并的第二张图片宽度和第一张不同，那么就以第一张图片的宽度为准线，对第二张图片进行缩放。基础上，把剪切的区域从矩形Rect变为圆形的Path，当手指在上面的ImageView移动时候，下面同等大小对应的坐标区域显示“剪切”出来的圆形图。_android imagedecoderhttps://blog.csdn.net/zhangphil/article/details/140153545