android MediaStore.ACTION_IMAGE_CAPTURE 调用照相机返回图片太小问题解决方法

问题描述：

val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
activity.startActivityForResult(intent,100)

调用上面的方法，照相成功之后返回的图片只有300多像素，是被压缩过的，我们需要获取原始图片。

改进如下：

1、启动照相机之前，增加MediaStore.EXTRA_OUTPUT参数配置：

 val intent = Intent(MediaStore.ACTION_IMAGE_CAPTURE)
 intent.putExtra(MediaStore.EXTRA_OUTPUT, getImageUri())
 activity.startActivityForResult(intent,100)

2、getImageUri的实现如下：

public static Uri getImageUri()
{
    File outFile = new File(context.getExternalCacheDir().getPath(), "image_test.png");
    Uri contentUri = FileProvider.getUriForFile(
            context,
            context.getPackageName() + ".ImageFileProvider",
            outFile
    );
    return contentUri;
}

3、定义ImageFileProvider

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="${applicationId}.ImageFileProvider"
    android:grantUriPermissions="true"
    android:exported="false">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

4、依赖的xml文件，创建file_paths.xml到res的xml目录

<?xml version="1.0" encoding="utf-8"?>
<paths>
    <external-path name="external_files" path="." />
    <external-files-path name="external_files" path="." />
    <cache-path name="cache_files" path="." />
    <files-path name="files" path="." />
    <external-path name="my_images" path="."/>
</paths>

5、UI那边实现这个方法

public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
if (resultCode != Activity.RESULT_OK) {
    return;
}
try {
    Uri uri = getImageUri();
    Bitmap bitmap = MediaStore.Images.Media.getBitmap(context.getContentResolver(), uri);
    InputStream inputStream = context.getContentResolver().openInputStream(uri);
    //获取旋转角度
    float photoRotation = getPhotoRotation(inputStream);
    //得到旋转后的图片
   Bitmap photoRotationBitmap = rotate(bitmap, photoRotation);
   //根据业务逻辑来处理这个photoRotationBitmap 

        //todo

} catch (Exception e) {
    e.printStackTrace();
}

}

6、getPhotoRotation定义如下：

fun getPhotoRotation(inputStream: InputStream): Float {
    try {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            val exifInterface = ExifInterface(inputStream)
            val orientation = exifInterface.getAttributeInt(
                ExifInterface.TAG_ORIENTATION,
                ExifInterface.ORIENTATION_NORMAL
            )
            return when (orientation) {
                ExifInterface.ORIENTATION_ROTATE_90 -> 90f
                ExifInterface.ORIENTATION_ROTATE_180 -> 180f
                ExifInterface.ORIENTATION_ROTATE_270 -> 270f
                else -> 0f
            }
        }
    } catch (e: java.lang.Exception) {
        LogUtil.e(">>>>>>>>>>>>", "获取图片旋转的角度报错:" + e.message)
    }
    return 0f
}

7、rotate方法定义如下：

fun rotate(rawBitmap: Bitmap, degree: Float): Bitmap {
    val matrix = Matrix()
    matrix.postRotate(degree)
    return Bitmap.createBitmap(rawBitmap, 0, 0, rawBitmap.width, rawBitmap.height, matrix, true)
}