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位置。它不工作。它在 bitmap.compress 部分（在 here3 之前）之后崩溃。

     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)

原文由 Oliver Dixon 发布，翻译遵循 CC BY-SA 4.0 许可协议

Answer 1

1. 您需要在 manifest.xml 中获得适当的权限：

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

1. out.flush() 检查 out 不为空..

2. ”` 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();

”`

原文由 Dheeresh Singh 发布，翻译遵循 CC BY-SA 3.0 许可协议

Answer 2

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)

编辑：这是我原来的答案，很好，但最近我用这个：

 fun File.createFileAndDirs() = apply {
    parentFile?.mkdirs()
    createNewFile()
}

fun File.write(
    bitmap: Bitmap, format: Bitmap.CompressFormat = Bitmap.CompressFormat.JPEG, quality: Int = 80
) = apply {
    createFileAndDirs()
    outputStream().use {
        bitmap.compress(format, quality, it)
        it.flush()
    }
}

更好的是，因为有一些有用的默认设置，如果文件不存在，它也会创建文件。

原文由 Renetik 发布，翻译遵循 CC BY-SA 4.0 许可协议