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Android 中 Bitmap 对象与 URI、URL、File、String、Byte、Drawable 对象的相互转换

2023-08-24 07:48:36

一、URI 转 Bitmap

public static Bitmap decodeUri(Context context, Uri uri, int maxWidth, int maxHeight) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true; //只读取图片尺寸
    readBitmapScale(context, uri, options);

    //计算实际缩放比例
    int scale = 1;
    for (int i = 0; i < Integer.MAX_VALUE; i++) {
        if ((options.outWidth / scale > maxWidth &&
                options.outWidth / scale > maxWidth * 1.4) ||
                (options.outHeight / scale > maxHeight &&
                        options.outHeight / scale > maxHeight * 1.4)) {
            scale++;
        } else {
            break;
        }
    }

    options.inSampleSize = scale;
    options.inJustDecodeBounds = false;//读取图片内容
    options.inPreferredConfig = Bitmap.Config.RGB_565; //根据情况进行修改
    Bitmap bitmap = null;
    try {
        bitmap = readBitmapData(context, uri, options);
    } catch (Throwable e) {
        e.printStackTrace();
    }
    return bitmap;
}

二、URL 转 Bitmap

方法一：

Bitmap bitmap;
public Bitmap returnBitMap(final String url){
 
    new Thread(new Runnable() {
        @Override
        public void run() {
            URL imageurl = null;
 
            try {
                imageurl = new URL(url);
            } catch (MalformedURLException e) {
                e.printStackTrace();
            }
            try {
                HttpURLConnection conn = (HttpURLConnection)imageurl.openConnection();
                conn.setDoInput(true);
                conn.connect();
                InputStream is = conn.getInputStream();
                bitmap = BitmapFactory.decodeStream(is);
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }).start();
 
    return bitmap;
}

方法二：

public Bitmap getBitmap(String url) {
    Bitmap bm = null;
    try {
        URL iconUrl = new URL(url);
        URLConnection conn = iconUrl.openConnection();
        HttpURLConnection http = (HttpURLConnection) conn;

        int length = http.getContentLength();

        conn.connect();
        // 获得图像的字符流
        InputStream is = conn.getInputStream();
        BufferedInputStream bis = new BufferedInputStream(is, length);
        bm = BitmapFactory.decodeStream(bis);
        bis.close();
        is.close();// 关闭流
    }
    catch (Exception e) {
        e.printStackTrace();
    }
    return bm;
}

可配合前台线程显示

private Handler mHandler = new Handler() {
    public void handleMessage(android.os.Message msg) {
        switch (msg.what) {
            case REFRESH_COMPLETE:
                myheadimage.setImageBitmap(bitmap);//显示
                break;
        }
    }
};
String imageUrl = "http://www.pp3.cn/uploads/201511/2015111212.jpg";
bitmap= returnBitMap(imageUrl);
mHandler.sendEmptyMessageDelayed(REFRESH_COMPLETE, 1000);


三、File 与 Bitmap

1、File 转 Bitmap

File param = new File();

Bitmap bitmap= BitmapFactory.decodeFile(param.getPath(）);
drawable转bitmap
Bitmap    bmp = BitmapFactory.decodeResource(getResources(),R.mipmap.jcss_03 );

2、Bitmap 转 File

private  String SAVE_PIC_PATH = Environment.getExternalStorageState().equalsIgnoreCase(Environment.MEDIA_MOUNTED)
                ? Environment.getExternalStorageDirectory().getAbsolutePath() : "/mnt/sdcard";//
 
private  String SAVE_REAL_PATH = SAVE_PIC_PATH + "/good/savePic";//保存的确
saveFile(bmp, System.currentTimeMillis() + ".png");
//保存方法
private void saveFile(Bitmap bm, String fileName) throws IOException {
        String subForder = SAVE_REAL_PATH;
        File foder = new File(subForder);
        if (!foder.exists()) foder.mkdirs();
 
        File myCaptureFile = new File(subForder, fileName);
        Log.e("lgq","图片保持。。。。wwww。。。。"+myCaptureFile);
        ends = myCaptureFile.getPath();
        if (!myCaptureFile.exists()) myCaptureFile.createNewFile();
        BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(myCaptureFile));
        bm.compress(Bitmap.CompressFormat.JPEG, 100, bos);
        bos.flush();
        bos.close();

        ToastUtil.showSuccess(getApplicationContext(), "已保存在/good/savePic目录下", Toast.LENGTH_SHORT);
        //发送广播通知系统
        Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
        Uri uri = Uri.fromFile(myCaptureFile);
        intent.setData(uri);
        this.sendBroadcast(intent);
}

if(mbitmap != null){
        if(Build.VERSION.SDK_INT > Build.VERSION_CODES.Q){
                saveImage29(mbitmap);
        }else{
                if ( saveImage(file, mbitmap)){
                        LgqLogPlus.e("路径---3-- "+file);
                        //发送广播通知系统
                        Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
                        Uri uri = Uri.fromFile(new File(file));
                        intent.setData(uri);
                        this.sendBroadcast(intent);


                }
        }
}

/**
 * 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();
        }
}

//统一方法将图片Bitmap保存在文件中
public static boolean saveImageToFile(Context mContext,String fileName, Bitmap frame) {
        if (fileName == null || fileName.length() <= 0)
                return false;
        if (frame == null || frame.getByteCount() <= 0)
                return false;

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        frame.compress(Bitmap.CompressFormat.JPEG, 100, baos);//质量压缩方法，这里100表示不压缩，把压缩后的数据存放到baos中
        int options = 100;
        while (baos.toByteArray().length / 1024 > 100) {  //循环判断如果压缩后图片是否大于100kb,大于继续压缩
                baos.reset();//重置baos即清空baos
                //第一个参数 ：图片格式 ，第二个参数： 图片质量，100为最高，0为最差  ，第三个参数：保存压缩后的数据的流
                frame.compress(Bitmap.CompressFormat.JPEG, options, baos);//这里压缩options%，把压缩后的数据存放到baos中
                options -= 10;//每次都减少10
        }
        ByteArrayInputStream isBm = new ByteArrayInputStream(baos.toByteArray());//把压缩后的数据baos存放到ByteArrayInputStream中
        Bitmap bitmap = BitmapFactory.decodeStream(isBm, null, null);//把ByteArrayInputStream数据生成图片

        if(bitmap!=null){
                      AppLog.Loge("压缩后图片大小为："+bitmap.getByteCount() + "---路径："+fileName);
                saveBitmap(bitmap,fileName);

        }
        return true;
}


public static void saveBitmap(Bitmap bitmap,String path) {
        new Thread(new Runnable() {
                @Override
                public void run() {
                        String savePath;
                        File filePic;
                        if (Environment.getExternalStorageState().equals(
                                        Environment.MEDIA_MOUNTED)) {
                                savePath = path;
                        } else {
                                      AppLog.Loge( "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) {
                                      AppLog.Loge( "保存图片失败 saveBitmap: " + e.getMessage());
                                return;
                        }
                              AppLog.Loge( "saveBitmap success: " + filePic.getAbsolutePath());
                }
        }).start();
}

四、Bitmap 与 String

Bitmap frame = BitmapFactory.decodeResource(getResources(),R.mipmap.iv_charge2 );
byte[] snapshot = getByteArrayFromBitmap(frame);

if (snapshot!=null){
    String imageString = new String(Base64.encode(snapshot,Base64.DEFAULT));

    if (imageString!=null){
        byte[] bytsSnapshot = Base64.decode(imageString.getBytes(), Base64.DEFAULT);
        Bitmap snapshot2 = (bytsSnapshot != null && bytsSnapshot.length > 0) ? getBitmapFromByteArray(bytsSnapshot) : null;
        imageView.setImageBitmap(snapshot2);
    }
}

工具： 

public static byte[] getByteArrayFromBitmap(Bitmap bitmap) {
    if (bitmap != null && !bitmap.isRecycled()) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 0, bos);
        return bos.toByteArray();
    } else {
        return null;
    }
}

public static Bitmap getBitmapFromByteArray(byte[] byts) {

    InputStream is = new ByteArrayInputStream(byts);
    return BitmapFactory.decodeStream(is, null, getBitmapOptions(2));
}

public static BitmapFactory.Options getBitmapOptions(int scale) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPurgeable = true;
    options.inInputShareable = true;
    options.inSampleSize = scale;

    try {
        BitmapFactory.Options.class.getField("inNativeAlloc").setBoolean(options, true);
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (NoSuchFieldException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return options;
}

private static void readBitmapScale(Context context, Uri uri, BitmapFactory.Options options) {
    if (uri == null) {
        return;
    }
    String scheme = uri.getScheme();
    if (ContentResolver.SCHEME_CONTENT.equals(scheme) ||
            ContentResolver.SCHEME_FILE.equals(scheme)) {
        InputStream stream = null;
        try {
            stream = context.getContentResolver().openInputStream(uri);
            BitmapFactory.decodeStream(stream, null, options);
        } catch (Exception e) {
            Log.w("readBitmapScale", "Unable to open content: " + uri, e);
        } finally {
            if (stream != null) {
                try {
                    stream.close();
                } catch (IOException e) {
                    Log.e("readBitmapScale", "Unable to close content: " + uri, e);
                }
            }
        }
    } else if (ContentResolver.SCHEME_ANDROID_RESOURCE.equals(scheme)) {
        Log.e("readBitmapScale", "Unable to close content: " + uri);
    } else {
        Log.e("readBitmapScale", "Unable to close content: " + uri);
    }
}

private static Bitmap readBitmapData(Context context, Uri uri, BitmapFactory.Options options) {
    if (uri == null) {
        return null;
    }
    Bitmap bitmap = null;
    String scheme = uri.getScheme();
    if (ContentResolver.SCHEME_CONTENT.equals(scheme) ||
            ContentResolver.SCHEME_FILE.equals(scheme)) {
        InputStream stream = null;
        try {
            stream = context.getContentResolver().openInputStream(uri);
            bitmap = BitmapFactory.decodeStream(stream, null, options);
        } catch (Exception e) {
            Log.e("readBitmapData", "Unable to open content: " + uri, e);
        } finally {
            if (stream != null) {
                try {
                    stream.close();
                } catch (IOException e) {
                    Log.e("readBitmapData", "Unable to close content: " + uri, e);
                }
            }
        }
    } else if (ContentResolver.SCHEME_ANDROID_RESOURCE.equals(scheme)) {
        Log.e("readBitmapData", "Unable to close content: " + uri);
    } else {
        Log.e("readBitmapData", "Unable to close content: " + uri);
    }
    return bitmap;
}

五、byte[] 与 Bitmap

方法一

1、Bitmap 转 byte[]

private byte[] Bitmap2Bytes(Bitmap bm) {
    ByteArrayOutputStream baos = new ByteArrayOutputStream();
    bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
    return baos.toByteArray();
}

2、byte[] 转 Bitmap

private Bitmap Bytes2Bimap(byte[] b) {
    if (b.length != 0) {
        return BitmapFactory.decodeByteArray(b, 0, b.length);
    } else {
        return null;
    }
}

方法二

1、Bitmap 转 byte[]

Bitmap frame = mCamera != null ? mCamera.Snapshot(mSelectedChannel) : null;
frame = rotate(frame, 90);
byte[] snapshot = getByteArrayFromBitmap(frame);
if (snapshot!=null){
    tring imageString = new String(Base64.encode(snapshot,Base64.DEFAULT));
    LgqLogPlus.e("获取到imgstring保存了===== "+imageString);
    SharedPreUtil.putString(mDevUID,imageString);
}

public static byte[] getByteArrayFromBitmap(Bitmap bitmap) {

    if (bitmap != null && !bitmap.isRecycled()) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.PNG, 0, bos);
        return bos.toByteArray();
    } else {
        return null;
    }
}

2、byte[] 转 Bitmap

String imgstring = SharedPreUtil.getString(this,mDevUID);
LgqLogPlus.e("获取到imgstring==== "+imgstring);
if (imgstring!=null){
    byte[] bytsSnapshot = Base64.decode(imgstring.getBytes(), Base64.DEFAULT);
    Bitmap snapshot = (bytsSnapshot != null && bytsSnapshot.length > 0) ? getBitmapFromByteArray(bytsSnapshot) : null;
    bgimg.setImageBitmap(snapshot);
}

public static Bitmap getBitmapFromByteArray(byte[] byts) {

    InputStream is = new ByteArrayInputStream(byts);
    return BitmapFactory.decodeStream(is, null, getBitmapOptions(2));
}

public static BitmapFactory.Options getBitmapOptions(int scale) {
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inPurgeable = true;
    options.inInputShareable = true;
    options.inSampleSize = scale;

    try {
        BitmapFactory.Options.class.getField("inNativeAlloc").setBoolean(options, true);
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (NoSuchFieldException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    return options;
}