将位图保存到文件功能

Question

我正在尝试使用我创建的函数直接将位图保存到文件和特定文件.它不起作用.它在bitmap.compress部分之后崩溃(在here3之前).

    File dir = new File(filepath);

    if(!dir.exists())dir.mkdirs();

    File file = new File(Environment.getExternalStorageDirectory() + filepath, side + ".png");
    FileOutputStream fOut = new FileOutputStream(file);

    bitmap.compress(Bitmap.CompressFormat.PNG, 85, fOut);
    fOut.flush();
    fOut.close();

    System.out.println(filepath);

    bitmap.recycle();
    System.gc();

---

错误日志:

06-29 00:16:38.089: D/AndroidRuntime(3260): Shutting down VM
06-29 00:16:38.089: W/dalvikvm(3260): threadid=1: thread exiting with uncaught exception (group=0xb587f4f0)
06-29 00:16:38.089: E/AndroidRuntime(3260): FATAL EXCEPTION: main
06-29 00:16:38.089: E/AndroidRuntime(3260): java.lang.RuntimeException: Failure delivering result ResultInfo{who=null, request=0, result=-1, data=Intent { act=android.intent.action.VIEW dat=content://org.openintents.filemanager/mimetype//mnt/sdcard/download/02977_awreckedboatintheocean_1280x1024.jpg }} to activity {com.polygonattraction.testbirds/com.polygonattraction.testbirds.functions.SelectImageSource}: java.lang.IllegalStateException: Can't compress a recycled bitmap
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread.deliverResults(ActivityThread.java:2532)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread.handleSendResult(ActivityThread.java:2574)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread.access$2000(ActivityThread.java:117)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:961)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.os.Handler.dispatchMessage(Handler.java:99)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.os.Looper.loop(Looper.java:130)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread.main(ActivityThread.java:3683)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at java.lang.reflect.Method.invokeNative(Native Method)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at java.lang.reflect.Method.invoke(Method.java:507)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at dalvik.system.NativeStart.main(Native Method)
06-29 00:16:38.089: E/AndroidRuntime(3260): Caused by: java.lang.IllegalStateException: Can't compress a recycled bitmap
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.graphics.Bitmap.checkRecycled(Bitmap.java:180)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.graphics.Bitmap.compress(Bitmap.java:581)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at com.polygonattraction.testbirds.functions.Functions.SaveToFile(Functions.java:144)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at com.polygonattraction.testbirds.functions.SelectImageSource.onActivityResult(SelectImageSource.java:113)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.Activity.dispatchActivityResult(Activity.java:3908)
06-29 00:16:38.089: E/AndroidRuntime(3260):     at android.app.ActivityThread.deliverResults(ActivityThread.java:2528)

Answer 1

1. 您需要适当的权限manifest.xml:

   <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
   

2. out.flush()检查out是不是空..

3. String file_path = Environment.getExternalStorageDirectory().getAbsolutePath() + 
                               "/PhysicsSketchpad";
   File dir = new File(file_path);
   if(!dir.exists())
       dir.mkdirs();
   File file = new File(dir, "sketchpad" + pad.t_id + ".png");
   FileOutputStream fOut = new FileOutputStream(file);
   
   bmp.compress(Bitmap.CompressFormat.PNG, 85, fOut);
   fOut.flush();
   fOut.close();
   

Answer 2

两个示例适合我,供您参考.

Bitmap bitmap = Utils.decodeBase64(base64);
try {
    File file = new File(filePath);
    FileOutputStream fOut = new FileOutputStream(file);
    bitmap.compress(Bitmap.CompressFormat.PNG, 85, fOut);
    fOut.flush();
    fOut.close();
}
catch (Exception e) {
    e.printStackTrace();
    LOG.i(null, "Save file error!");
    return false;
}

还有这个

Bitmap savePic = Utils.decodeBase64(base64);
File file = new File(filePath);
File path = new File(file.getParent());

if (savePic != null) {
    try {
        // build directory
        if (file.getParent() != null && !path.isDirectory()) {
            path.mkdirs();
        }
        // output image to file
        FileOutputStream fos = new FileOutputStream(filePath);
        savePic.compress(Bitmap.CompressFormat.PNG, 90, fos);
        fos.close();
        ret = true;
    } catch (Exception e) {
        e.printStackTrace();
    }
} else {
    LOG.i(TAG, "savePicture image parsing error");
}

Answer 3

在科特林：

private fun File.writeBitmap(bitmap: Bitmap, format: Bitmap.CompressFormat, quality: Int) {
    outputStream().use { out ->
        bitmap.compress(format, quality, out)
        out.flush()
    }
}

用法示例：

File(exportDir, "map.png").writeBitmap(bitmap, Bitmap.CompressFormat.PNG, 85)

Answer 4

这是帮助您的功能

private void saveBitmap(Bitmap bitmap,String path){
        if(bitmap!=null){
            try {
                FileOutputStream outputStream = null;
                try {
                    outputStream = new FileOutputStream(path); //here is set your file path where you want to save or also here you can set file object directly

                    bitmap.compress(Bitmap.CompressFormat.PNG, 100, outputStream); // bitmap is your Bitmap instance, if you want to compress it you can compress reduce percentage
                    // PNG is a lossless format, the compression factor (100) is ignored
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    try {
                        if (outputStream != null) {
                            outputStream.close();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            } catch (Exception e) {
                e.printStackTrace();
            }    
        }
    }