Android N下用摄像头和相册获取图片

Android

原文：https://www.zybuluo.com/Tyhj/note/730704
之前已经写过用摄像头和相册获取图片了，每一次都觉得是正解，每一次后来都发现自己很菜。最近发现项目在Android 7.0时候发生了一些权限问题。主要是Uri的获取，还有访问文件夹出了问题。

首先看使用相机来获取图片

String path;//保存图片，
public static final int TAKE_PHOTO = 1;
public static final int CROP_PHOTO = 2;
public static final int PICK_PHOTO = 0;
String date;//根据时间来获取的图片的名字
 //随机获取文件名字
    public void getDate() {
        date = System.currentTimeMillis() + ".JPEG";
    }
   path = getExternalCacheDir() + "/Jubaoji";//写在onCreate中,用这个路径可以避过访问文件夹的权限

引用：
我先科普一个概念叫做应用关联缓存目录：就是指SD卡中专门用于存放当前应用缓存数据的位置，调用getExternalCacheDir()可以得到这个目录。具体路径是：/sdcard/Android/data//cache
那么为什么要使用应用关联缓存目录来存放图片呢？因为从android6.0开始读写SD卡被列为了危险权限，如果将图片放在SD卡的其他地方，都要进行运行时权限处理才行，而使用应用缓存数据的位置则可以跳过这一步

打开相机获取图象,并保存到file这个文件，path和date就不会改变了

getDate();
                File file = new File(path, date);
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {//7.0及以上
                    Uri uriForFile = FileProvider.getUriForFile(PersonalSetting.this, "demand.example.tyhj.jubao.fileProvider", file);
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, uriForFile);
                    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                    intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
                } else {
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
                }
                startActivityForResult(intent, TAKE_PHOTO);

获取到相机的数据后，把file转成Uri调用系统工具剪裁图片

//这是从相机返回的数据
            case TAKE_PHOTO:
                if (resultCode == PersonalSetting.RESULT_OK) {
                    File file = new File(path, date);
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                        Uri inputUri = FileProvider.getUriForFile(PersonalSetting.this, "demand.example.tyhj.jubao.fileProvider", file);//通过FileProvider创建一个content类型的Uri
                        cropPhoto(inputUri);
                    } else {
                        cropPhoto(Uri.fromFile(file));
                    }
                }
                break;

剪裁图片，

 //剪裁图片
    public void cropPhoto(Uri imageUri) {
        Intent intent = new Intent("com.android.camera.action.CROP");
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            File file = new File(path, date);
            Uri outPutUri = FileProvider.getUriForFile(PersonalSetting.this, "demand.example.tyhj.jubao.fileProvider", file);
            intent.setDataAndType(imageUri, "image/*");
            intent.putExtra(MediaStore.EXTRA_OUTPUT, outPutUri);
            intent.putExtra("noFaceDetection", false);//去除默认的人脸识别，否则和剪裁匡重叠
            intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
            intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        } else {
            intent.setDataAndType(imageUri, "image/*");
            intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        }
        // aspectX aspectY 是宽高的比例
        intent.putExtra("aspectX", 1);
        intent.putExtra("aspectY", 1);
        startActivityForResult(intent, CROP_PHOTO);
    }

//剪裁后返回的图片

 //剪裁图片返回数据,就是原来的文件
            case CROP_PHOTO:
                if (resultCode == PersonalSetting.RESULT_OK) {
                    String fileName = path + "/" + date;
                    File newFile = new File(path, date);
                    //我在这里压缩了一下图片
                    Defined.ImgCompress(fileName, newFile, 500, 500, 300);
                    //获取到的就是new File或fileName
                }

从相册获取图片

打开相册选取图片

getDate();
                dialog.cancel();
                Intent intent = new Intent(ACTION_GET_CONTENT);
                intent.addCategory(Intent.CATEGORY_OPENABLE);
                intent.setType("image/*");
                intent.putExtra("crop", true);
                intent.putExtra("scale", true);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {//如果大于等于7.0使用FileProvider
                    Uri uriForFile = FileProvider.getUriForFile(PersonalSetting.this, "demand.example.tyhj.jubao.fileProvider", new File(path,date));
                    intent.putExtra(MediaStore.EXTRA_OUTPUT, uriForFile);
                    intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
                    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
                } else {
                }
                startActivityForResult(intent, PICK_PHOTO);

//获取从相册返回的图片，为了避免破坏原来的图片，复制一份，再获取Uri，然后拿去剪裁

//这是从相册返回的数据
            case PICK_PHOTO:
                if (resultCode == PersonalSetting.RESULT_OK) {
                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {//如果大于等于7.0使用FileProvider
                        File path_pre = new File(GetImagePath.getPath(PersonalSetting.this, data.getData()));
                        File newFile = new File(path, date);
                        Toast.makeText(PersonalSetting.this, getString(R.string.msg_loading), Toast.LENGTH_SHORT).show();
                        try {
                            Defined.copyFile(path_pre, newFile);
                            Uri dataUri = FileProvider.getUriForFile(PersonalSetting.this, "demand.example.tyhj.jubao.fileProvider", newFile);
                            cropPhoto(dataUri);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    } else {
                        String path_pre = GetImagePath.getPath(PersonalSetting.this, data.getData());
                        File newFile = new File(path, date);
                        Toast.makeText(PersonalSetting.this, getString(R.string.msg_loading), Toast.LENGTH_SHORT).show();
                        try {
                            Defined.copyFile(new File(path_pre), newFile);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                        cropPhoto(Uri.fromFile(newFile));
                    }
                }
                break;

之后和相机返回的是一样的,然后通过Uri获取文件路径方法也不是很简单，如下应该是比较好的，国外大神的方法

package tools;
import android.annotation.SuppressLint;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
public class GetImagePath {
//  4.4以上  content://com.android.providers.media.documents/document/image:3952
//  4.4以下  content://media/external/images/media/3951
    @SuppressLint("NewApi")
    public static String getPath(final Context context, final Uri uri) {
        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
        // DocumentProvider
        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
            // ExternalStorageProvider
            if (isExternalStorageDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];
                if ("primary".equalsIgnoreCase(type)) {
                    return Environment.getExternalStorageDirectory() + "/" + split[1];
                }
            }
            // DownloadsProvider
            else if (isDownloadsDocument(uri)) {
                final String id = DocumentsContract.getDocumentId(uri);
                final Uri contentUri = ContentUris.withAppendedId(
                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));
                return getDataColumn(context, contentUri, null, null);
            }
            // MediaProvider
            else if (isMediaDocument(uri)) {
                final String docId = DocumentsContract.getDocumentId(uri);
                final String[] split = docId.split(":");
                final String type = split[0];
                Uri contentUri = null;
                if ("image".equals(type)) {
                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
                } else if ("video".equals(type)) {
                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
                } else if ("audio".equals(type)) {
                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
                }
                final String selection = "_id=?";
                final String[] selectionArgs = new String[]{
                        split[1]
                };
                return getDataColumn(context, contentUri, selection, selectionArgs);
            }
        }
        // MediaStore (and general)
        else if ("content".equalsIgnoreCase(uri.getScheme())) {
            // Return the remote address
            if (isGooglePhotosUri(uri))
                return uri.getLastPathSegment();
            return getDataColumn(context, uri, null, null);
        }
        // File
        else if ("file".equalsIgnoreCase(uri.getScheme())) {
            return uri.getPath();
        }
        return null;
    }
    //Android 4.4以下版本自动使用该方法
    public static String getDataColumn(Context context, Uri uri, String selection,
                                       String[] selectionArgs) {
        Cursor cursor = null;
        final String column = "_data";
        final String[] projection = {
                column
        };
        try {
            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,
                    null);
            if (cursor != null && cursor.moveToFirst()) {
                final int index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(index);
            }
        } finally {
            if (cursor != null)
                cursor.close();
        }
        return null;
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is ExternalStorageProvider.
     */
    public static boolean isExternalStorageDocument(Uri uri) {
        return "com.android.externalstorage.documents".equals(uri.getAuthority());
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is DownloadsProvider.
     */
    public static boolean isDownloadsDocument(Uri uri) {
        return "com.android.providers.downloads.documents".equals(uri.getAuthority());
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is MediaProvider.
     */
    public static boolean isMediaDocument(Uri uri) {
        return "com.android.providers.media.documents".equals(uri.getAuthority());
    }
    /**
     * @param uri The Uri to check.
     * @return Whether the Uri authority is Google Photos.
     */
    public static boolean isGooglePhotosUri(Uri uri) {
        return "com.google.android.apps.photos.content".equals(uri.getAuthority());
    }
}