Android使用View.getDrawingCache截取的图像变成黑底黑屏的解决方法备忘

效果(解决方法在最后)：

image.png

代码生成bitmap

 /**
     * 该方式原理主要是：View组件显示的内容可以通过cache机制保存为bitmap
     */
    fun createBitmapFromView(view: View): Bitmap? {
        var bitmap: Bitmap? = null
        //开启view缓存bitmap
        view.setDrawingCacheEnabled(true)
        //设置view缓存Bitmap质量
        view.setDrawingCacheQuality(DRAWING_CACHE_QUALITY_HIGH)
        //获取缓存的bitmap
        val cache: Bitmap = view.getDrawingCache()
        if (cache != null && !cache.isRecycled) {
            bitmap = Bitmap.createBitmap(cache)
            bitmap.copy(Bitmap.Config.ARGB_8888, true)
        }
        //销毁view缓存bitmap
        view.destroyDrawingCache()
        //关闭view缓存bitmap
        view.setDrawingCacheEnabled(false)
        return bitmap
    }

创建File

 /**
     * 创建保存图片的文件
     */
    public fun createImageFile(context: Context): File? {
        val imageName: String =
            SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(Date())
        val storageDir = context.getExternalFilesDir(Environment.DIRECTORY_PICTURES)
        if (!storageDir!!.exists()) {
            storageDir.mkdir()
        }
        val tempFile = File.createTempFile(imageName, ".jpg", storageDir)
        return if (Environment.MEDIA_MOUNTED != EnvironmentCompat.getStorageState(tempFile)) {
            null
        } else tempFile
    }

更新图库

val bmp = PublicTools.tools.createBitmapFromView(llPostLay)
val file = PublicTools.tools.createImageFile(context)
try {
       val fos = FileOutputStream(file)
        bmp?.compress(Bitmap.CompressFormat.JPEG, 100, fos)
        fos.flush()
        fos.close()
      }catch (e:Exception){
         e.printStackTrace()
         Toast.makeText(context, "保存海报失败", Toast.LENGTH_SHORT).show()
   }
   // 其次把文件插入到系统图库
try {
     MediaStore.Images.Media.insertImage(InnerAPI.context.contentResolver,file!!.absolutePath, file.name, null)
     } catch (e: Exception) {
       e.printStackTrace()
    Toast.makeText(context, "保存海报失败", Toast.LENGTH_SHORT).show()
    }
    context.sendBroadcast(Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, Uri.fromFile(file)))
    Toast.makeText(context, "保存海报成功", Toast.LENGTH_SHORT).show()

View.getDrawingCache截取的图像变成黑底黑屏的解决方法

$\color{red}{activity_xxxx.xml里，View新增background属性为白色即可。}$

<LinearLayout
        android:id="@+id/ll_context"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical"
        android:background="#ffffff">

    <!--要生成Bitmap的布局-->
    <View .../>

</LinearLayout>