Android开发之保存图片到相册的三种方法详解

 /**
     * 保存bitmap到本地
     *
     * @param bitmap Bitmap
     */
    public static void saveBitmap(Bitmap bitmap, String path) {
        String savePath;
        File filePic;
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            savePath = path;
        } else {
            Log.e("tag", "saveBitmap failure : sdcard not mounted");
            return;
        }
        try {
            filePic = new File(savePath);
            if (!filePic.exists()) {
                filePic.getParentFile().mkdirs();
                filePic.createNewFile();
            }
            FileOutputStream fos = new FileOutputStream(filePic);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
            fos.flush();
            fos.close();
        } catch (IOException e) {
            Log.e("tag", "saveBitmap: "   e.getMessage());
            return;
        }
        Log.i("tag", "saveBitmap success: "   filePic.getAbsolutePath());
    }

 
    /**
     * API 29及以下保存图片到相册的方法
     *
     * @param toBitmap 要保存的图片
     */
    private void saveImage(Bitmap toBitmap) {
        String insertImage = MediaStore.Images.Media.insertImage(getContentResolver(), toBitmap, "壁纸", "搜索猫相关图片后保存的图片");
        if (!TextUtils.isEmpty(insertImage)) {
            Toast.makeText(this, "图片保存成功!"   insertImage, Toast.LENGTH_SHORT).show();
            Log.e("打印保存路径", insertImage   "-");
        }
    }

  /**
     * API29 中的最新保存图片到相册的方法
     */
    private void saveImage29(Bitmap toBitmap) {
        //开始一个新的进程执行保存图片的操作
        Uri insertUri = getContentResolver().insert(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, new ContentValues());
        //使用use可以自动关闭流
        try {
            OutputStream outputStream = getContentResolver().openOutputStream(insertUri, "rw");
            if (toBitmap.compress(Bitmap.CompressFormat.JPEG, 90, outputStream)) {
                Log.e("保存成功", "success");
            } else {
                Log.e("保存失败", "fail");
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }

package com.xiayiye.jetpackstudy.gallery


import android.Manifest
import android.content.ContentValues
import android.content.pm.PackageManager
import android.graphics.Bitmap
import android.os.Build
import android.os.Bundle
import android.provider.MediaStore
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.Toast
import androidx.core.content.ContextCompat
import androidx.core.graphics.drawable.toBitmap
import androidx.core.view.get
import androidx.fragment.app.Fragment
import androidx.lifecycle.lifecycleScope
import androidx.recyclerview.widget.RecyclerView
import androidx.viewpager2.widget.ViewPager2
import com.xiayiye.jetpackstudy.R
import kotlinx.android.synthetic.main.fragment_view_pager2_image.*
import kotlinx.android.synthetic.main.pager_photo_view.view.*
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.MainScope
import kotlinx.coroutines.launch
import kotlinx.coroutines.withContext

/**
 * 显示轮播大图和保存图片的页面
 */

class ViewPager2ImageFragment : Fragment() {
    companion object {
        const val REQUEST_WRITE_EXTERNAL_STORAGE_CODE = 1000
    }

    override fun onCreateView(
        inflater: LayoutInflater, container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View? {
        return inflater.inflate(R.layout.fragment_view_pager2_image, container, false)
    }

    override fun onActivityCreated(savedInstanceState: Bundle?) {
        super.onActivityCreated(savedInstanceState)
        val photoList = arguments?.getParcelableArrayList<PhotoItem>("photo_list")
        val currentPosition = arguments?.getInt("photo_position", 0)
        PagerPhotoListAdapter().apply {
            vp2Banner.adapter = this
            submitList(photoList)
        }
        //设置轮播图片后的滑动当前页
        vp2Banner.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
            override fun onPageSelected(position: Int) {
                super.onPageSelected(position)
                tvShowImagePage.text =
                    StringBuffer().append(position   1).append("/").append(photoList?.size)
            }
        })
        //设置 ViewPager2 的当前页要在设置 ViewPager2 的数据后在设置当前页面,否则不生效
        vp2Banner.setCurrentItem(currentPosition ?: 0, false)
        //设置纵向滚动的方法
        vp2Banner.orientation = ViewPager2.ORIENTATION_VERTICAL
        //保存图片的方法
        ivSaveImg.setOnClickListener {
            if (Build.VERSION.SDK_INT < 29 && ContextCompat.checkSelfPermission(
                    requireContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE
                ) != PackageManager.PERMISSION_GRANTED
            ) {
                requestPermissions(
                    arrayOf<String>(Manifest.permission.WRITE_EXTERNAL_STORAGE),
                    REQUEST_WRITE_EXTERNAL_STORAGE_CODE
                )
            } else {
                viewLifecycleOwner.lifecycleScope.launch { saveImage29() }
            }
        }
    }

    override fun onRequestPermissionsResult(
        requestCode: Int,
        permissions: Array<out String>,
        grantResults: IntArray
    ) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        if (requestCode == REQUEST_WRITE_EXTERNAL_STORAGE_CODE && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            //权限申请成功可以保存图片
            viewLifecycleOwner.lifecycleScope.launch { saveImage29() }
        }
    }

    /**
     * 保存图片到相册的方法
     *  API29 后此方法已废弃
     */
    private fun saveImage() {
        val holder =
            (vp2Banner[0] as RecyclerView).findViewHolderForAdapterPosition(vp2Banner.currentItem) as PagerPhotoListAdapter.PagerPhotoViewHolder
        val toBitmap = holder.itemView.ivPagerView.drawable.toBitmap()
        val insertImage = MediaStore.Images.Media.insertImage(
            requireActivity().contentResolver, toBitmap, "壁纸", "搜索猫相关图片后保存的图片"
        )
        if (insertImage.isNotEmpty()) {
            Toast.makeText(requireActivity(), "图片保存成功！-${insertImage}", Toast.LENGTH_SHORT).show()
        } else {
            Toast.makeText(requireActivity(), "图片保存失败！}", Toast.LENGTH_SHORT).show()
        }
    }

    /**
     * API29 中的最新保存图片到相册的方法
     */
    private suspend fun saveImage29() {
        //开始一个新的进程执行保存图片的操作
        withContext(Dispatchers.IO) {
            val holder =
                (vp2Banner[0] as RecyclerView).findViewHolderForAdapterPosition(vp2Banner.currentItem) as PagerPhotoListAdapter.PagerPhotoViewHolder
            val toBitmap = holder.itemView.ivPagerView.drawable.toBitmap()
            val insertUri = requireActivity().contentResolver.insert(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, ContentValues()
            ) ?: kotlin.run {
                showSaveToast("保存失败！")
                return@withContext
            }
            //使用use可以自动关闭流
            requireActivity().contentResolver.openOutputStream(insertUri).use {
                if (toBitmap.compress(Bitmap.CompressFormat.JPEG, 90, it)) {
                    showSaveToast("保存成功！")
                } else {
                    showSaveToast("保存失败！")
                }
            }
        }
    }

    /**
     * 显示保存图片结果的方法
     */
    private fun showSaveToast(showMsg: String) =
        MainScope().launch {
            Toast.makeText(requireActivity(), showMsg, Toast.LENGTH_SHORT).show()
        }
}