Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
327 views
in Technique[技术] by (71.8m points)

java - Android: Bitmap to Byte Array and back: SkImageDecoder::Factory returned null

The goal is to convert a Bitmap to a byte [], pass it between activities in a Bundle of data, then reconvert it back to a Bitmap at a later stage for display in an Imageview.

The issue is that whenever I try this, I just get a null bitmap and the non-descriptive, unhelpful log output:

12-07 17:01:33.282: D/skia(2971): --- SkImageDecoder::Factory returned null

I have looked at the following solutions:

Solution supplies the bitmap to byte[] code used

Highlighted that copyPixelsToBuffer() is essential over .compress

(Especially seeing as it is not necessary in this case).

I have run up the following test case which definitely narrows down the problem to the converting and restoring code. Based on my debugging, there is correct decoding, the byte array is the correct size and full, Bitmap configs are forced to be the same, decodeByteArray is just failing:

package com.example.debug;

import java.nio.ByteBuffer;

import android.os.Bundle;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.widget.ImageView;
import android.widget.RelativeLayout;

public class MainActivity extends Activity {
    RelativeLayout rl = null;
    RelativeLayout.LayoutParams rlp = null;

    ImageView ivBef = null;
    ImageView ivAft = null;

    Bitmap bmBef = null;
    Bitmap bmAft = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // TEST
        BitmapFactory.Options bmo = new BitmapFactory.Options();
        bmo.inPreferredConfig = Config.ARGB_8888;

        bmBef = BitmapFactory.decodeFile("/mnt/sdcard/Debug/001.png", bmo);
        byte[] b = bitmapToByteArray(bmBef);
        bmAft = BitmapFactory.decodeByteArray(b, 0, b.length, bmo);

        LinearLayout ll = new LinearLayout(this);

        ivBef = new ImageView(this);
        ivBef.setImageBitmap(bmBef);

        ivAft = new ImageView(this);
        ivAft.setImageBitmap(bmAft);

        ll.addView(ivBef);
        ll.addView(ivAft);

        setContentView(ll);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

    public static byte[] bitmapToByteArray(Bitmap bm) {
        // Create the buffer with the correct size
        int iBytes = bm.getWidth() * bm.getHeight() * 4;
        ByteBuffer buffer = ByteBuffer.allocate(iBytes);

        // Log.e("DBG", buffer.remaining()+""); -- Returns a correct number based on dimensions
        // Copy to buffer and then into byte array
        bm.copyPixelsToBuffer(buffer);
        // Log.e("DBG", buffer.remaining()+""); -- Returns 0
        return buffer.array();
    }

}

The before Imageview correctly displays the image, the after ImageView shows nothing (as you would expect with a null bitmap

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

You are passing Bitmap into Intent and get bitmap in next activity from bundle, but the problem is if your Bitmap/Image size is big at that time the image is not load in next activity.

Use below 2 Solutions to solve this issue.

1) First Convert Image into Byte Array and then pass into Intent and in next activity get byte array from Bundle and Convert into Image(Bitmap) and set into ImageView.

Convert Bitmap to Byte Array:-

Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, stream);
byte[] byteArray = stream.toByteArray();

Pass byte array into intent:-

Intent intent = new Intent(this, NextActivity.class);
intent.putExtra("picture", byteArray);
startActivity(intent);

Get Byte Array from Bundle and Convert into Bitmap Image:-

Bundle extras = getIntent().getExtras();
byte[] byteArray = extras.getByteArray("picture");

Bitmap bmp = BitmapFactory.decodeByteArray(byteArray, 0, byteArray.length);
ImageView image = (ImageView) findViewById(R.id.imageView1);

image.setImageBitmap(bmp);

2) First Save image into SDCard and in next activity set this image into ImageView.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...