Android 10.0調用相機和相冊

首先判斷版本，判斷是否授權，如果未授權，採用彈出框動態授權。

如果版本號大於7.0採用虛擬路徑臨時保存，如果版本號小於7.0採用絕對路徑。

先使用PackageManager.checkPermission檢測對方的app有沒有取得文件讀寫權限。如果有的話，給對方發送file://格式URI。如果沒有的話，給對方發送FileProvider生成的URI並臨時授權

1.easypermissions動態權限申請框架

implementation 'pub.devrel:easypermissions:3.0.0'

2.相關權限AndroidMainfast.xml
FileProvider的使用（Android 7.0 行爲變更 通過FileProvider在應用間共享文件）
第一步 聲明FIleProvider
爲什麼要聲明呢？
因爲FileProvider是ContentProvider子類
注意需要設置一個meta-data，裏面指向一個xml文件。

   <uses-permission android:name="android.permission.CAMERA" />
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application>
······
<provider
            android:name="androidx.core.content.FileProvider"
            android:authorities="com.baoming.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true"
            tools:replace="android:authorities">
            <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/provider_paths" />
        </provider>
    </application>

3.xml文件provider_paths.xml
爲什麼要寫這麼個xml文件？
因爲要使用content://uri替代file://uri，那麼，content://的uri如何定義呢？總不能使用文件路徑。
所以，需要一個虛擬的路徑對文件路徑進行映射，所以需要編寫個xml文件，通過path以及xml節點確定可訪問的目錄，通過name屬性來映射真實的文件路徑。

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="camera_photos" path="."/>
</paths>

4.MainActivity.java,佈局類代碼省略，2個按鈕一個imageview控件

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.content.FileProvider;
import pub.devrel.easypermissions.AfterPermissionGranted;
import pub.devrel.easypermissions.AppSettingsDialog;
import pub.devrel.easypermissions.EasyPermissions;

import android.Manifest;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Build;
import android.os.Bundle;
import android.os.Environment;
import android.os.StrictMode;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

import java.io.File;
import java.util.List;

public class MainActivity extends AppCompatActivity  implements EasyPermissions.PermissionCallbacks{
    private static final int RC_EXTERNAL_STORAGE_PERM = 100;
    private String bitmappath;
    private Uri cramuri;
    private File file2;
    private File currentImageFile = null;
    private Context context;
    private ImageView imageView;
    private Button btcamera;
    private Button btablum;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        context=this;

        imageView=findViewById(R.id.imageView);
        btablum=findViewById(R.id.btablum);
        btcamera=findViewById(R.id.btcamera);

        requiresPermission();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
            StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
            StrictMode.setVmPolicy(builder.build());
            builder.detectFileUriExposure();
        }

        btcamera.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
                    currentImageFile = new File(context.getExternalFilesDir(Environment.DIRECTORY_PICTURES), System.currentTimeMillis() + ".jpg");
                }
                // 啓動系統相機
                Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                    cramuri = FileProvider.getUriForFile(MainActivity.this, "com.fileprovider", currentImageFile);
                    intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION | Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
                } else {
                    cramuri = Uri.fromFile(currentImageFile);
                }
                intent.putExtra(MediaStore.EXTRA_OUTPUT, cramuri);
                startActivityForResult(intent,2);
            }
        });

        btablum.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(Intent.ACTION_PICK, null);
                intent.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "image/*");
                startActivityForResult(intent,1);
            }
        });
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        switch (requestCode) {
            // 調用相機後返回
            case 1:
                if (resultCode == RESULT_OK) {
                    if (data != null) {
                        // 得到圖片的全路徑
                        Uri uri = data.getData();
                        startPhotoZoom(uri);
                    }
                }
                break;
            case 2:
                if (resultCode == RESULT_OK) {
                    startPhotoZoom(cramuri);
                }
                break;
            case 3:
                imageView.setImageURI(Uri.fromFile(file2));
                String file = ImageUtils.getRealPathFromUri(MainActivity.this, Uri.fromFile(file2));
                //轉base64
                bitmappath = ImageUtils.getImgStr(file);
        }
    }

    //裁剪並壓縮圖片
    public void startPhotoZoom(Uri uri) {
        if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
            file2 = new File(context.getExternalFilesDir(Environment.DIRECTORY_PICTURES), System.currentTimeMillis() + ".jpg");
        }

        Intent intent = new Intent("com.android.camera.action.CROP"); // 裁剪圖片意圖
        intent.setDataAndType(uri, "image/*");
        intent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION);
        intent.addFlags(Intent.FLAG_GRANT_WRITE_URI_PERMISSION);
        intent.putExtra("crop", "true");
        intent.putExtra("aspectX", 1);//裁剪框 X 比值
        intent.putExtra("aspectY", 1);
        intent.putExtra("outputX", 600);//裁剪後輸出寬度
        intent.putExtra("outputY", 600);
        intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file2));
        intent.putExtra("return-data", false); //是否在Intent中返回數據
        intent.putExtra("outputFormat", Bitmap.CompressFormat.JPEG.toString());// 圖片格式
        intent.putExtra("noFaceDetection", true);// 取消人臉識別
        startActivityForResult(intent, 3);
    }


    @AfterPermissionGranted(RC_EXTERNAL_STORAGE_PERM)
    private void requiresPermission() {
        String[] perms = {Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.CAMERA};
        if (EasyPermissions.hasPermissions(MainActivity.this, perms)) {
        } else {
            EasyPermissions.requestPermissions(this,  getResources().getString(R.string.tips_crema), RC_EXTERNAL_STORAGE_PERM, perms);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }


    @Override
    public void onPermissionsGranted(int requestCode, @NonNull List<String> perms) {

    }

    @Override
    public void onPermissionsDenied(int requestCode, @NonNull List<String> perms) {
        new AppSettingsDialog.Builder(this)
                .setTitle(getResources().getString(R.string.tips_limit))
                .setPositiveButton(getResources().getString(R.string.tips_limit_true))
                .setNegativeButton(getResources().getString(R.string.tips_limit_false))
                .setRationale(getResources().getString(R.string.tips_limit_crema))
                .setRequestCode(RC_EXTERNAL_STORAGE_PERM)
                .build()
                .show();
    }
}

4.ImageUtils.java工具類

public class ImageUtils {

    /**
     * 根據圖片的Uri獲取圖片的絕對路徑。@uri 圖片的uri
     * @return 如果Uri對應的圖片存在,那麼返回該圖片的絕對路徑,否則返回null
     */
    public static String getRealPathFromUri(Context context, Uri uri) {
        if(context == null || uri == null) {
            return null;
        }
        if("file".equalsIgnoreCase(uri.getScheme())) {
            return getRealPathFromUri_Byfile(context,uri);
        } else if("content".equalsIgnoreCase(uri.getScheme())) {
            return getRealPathFromUri_Api11To18(context,uri);
        }
        return getRealPathFromUri_AboveApi19(context, uri);//沒用到
    }

    //針對圖片URI格式爲Uri:: file:///storage/emulated/0/DCIM/Camera/IMG_20170613_132837.jpg
    private static String getRealPathFromUri_Byfile(Context context,Uri uri){
        String uri2Str = uri.toString();
        String filePath = uri2Str.substring(uri2Str.indexOf(":") + 3);
        return filePath;
    }

    /**
     * 適配api19以上,根據uri獲取圖片的絕對路徑
     */
    @SuppressLint("NewApi")
    private static String getRealPathFromUri_AboveApi19(Context context, Uri uri) {
        String filePath = null;
        String wholeID = null;

        wholeID = DocumentsContract.getDocumentId(uri);

        // 使用':'分割
        String id = wholeID.split(":")[1];

        String[] projection = { MediaStore.Images.Media.DATA };
        String selection = MediaStore.Images.Media._ID + "=?";
        String[] selectionArgs = { id };

        Cursor cursor = context.getContentResolver().query(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, projection,
                selection, selectionArgs, null);
        int columnIndex = cursor.getColumnIndex(projection[0]);

        if (cursor.moveToFirst()) {
            filePath = cursor.getString(columnIndex);
        }
        cursor.close();
        return filePath;
    }

    /**
     * //適配api11-api18,根據uri獲取圖片的絕對路徑。
     * 針對圖片URI格式爲Uri:: content://media/external/images/media/1028
     */
    private static String getRealPathFromUri_Api11To18(Context context, Uri uri) {
        String filePath = null;
        String[] projection = { MediaStore.Images.Media.DATA };

        CursorLoader loader = new CursorLoader(context, uri, projection, null,
                null, null);
        Cursor cursor = loader.loadInBackground();

        if (cursor != null) {
            cursor.moveToFirst();
            filePath = cursor.getString(cursor.getColumnIndex(projection[0]));
            cursor.close();
        }
        return filePath;
    }

    /**
     * 適配api11以下(不包括api11),根據uri獲取圖片的絕對路徑
     */
    private static String getRealPathFromUri_BelowApi11(Context context, Uri uri) {
        String filePath = null;
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = context.getContentResolver().query(uri, projection,
                null, null, null);
        if (cursor != null) {
            cursor.moveToFirst();
            filePath = cursor.getString(cursor.getColumnIndex(projection[0]));
            cursor.close();
        }
        return filePath;
    }


    /**
     * 將圖片轉換成Base64編碼
     * @param path 待處理圖片
     * @return
     */

    public static String getImgStr(String path) {
        //將圖片文件轉化爲字節數組字符串，並對其進行Base64編碼處理
        //imgFile = "D:\\testPhoto.jpg";
        if(TextUtils.isEmpty(path)){
            return null;
        }
        InputStream is = null;
        byte[] data = null;
        String result = null;
        try{
            is = new FileInputStream(path);
            //創建一個字符流大小的數組。
            data = new byte[is.available()];
            //寫入數組
            is.read(data);
            //用默認的編碼格式進行編碼
            result = Base64.encodeToString(data,Base64.DEFAULT);
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if(null !=is){
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return result;
    }

    public static String bitmapToBase64(Bitmap bitmap) {

        String result = null;
        ByteArrayOutputStream baos = null;
        try {
            if (bitmap != null) {
                baos = new ByteArrayOutputStream();
                bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);

                baos.flush();
                baos.close();

                byte[] bitmapBytes = baos.toByteArray();
                result = Base64.encodeToString(bitmapBytes, Base64.DEFAULT);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (baos != null) {
                    baos.flush();
                    baos.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return result;
    }


}

 <string name="tips_crema">當前App需要申請讀寫文件和調用相機權限才能運行</string>
    <string name="tips_limit">權限申請</string>
    <string name="tips_limit_true">確認</string>
    <string name="tips_limit_false">取消</string>
    <string name="tips_limit_crema">當前App需要申請讀寫文件和調用相機權限,需要打開設置頁面麼?</string>