Android development road-------traversal album

In some scenarios, the third-party album UI does not meet our expected requirements, so we must traverse the album ourselves to develop the corresponding functions and UI

1. First obtain the corresponding permissions:

   <!-- 读取权限相册 拍照 -->
    <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" />

2. Dynamic application permissions:

 /**
     * 检查权限
     * @param context
     * @param code
     * @param strings
     * @return
     */
    public static String[] checkpPermissionsApply(Context context,int code,String ...strings){
        List<String> premissionList = new ArrayList<>();
        boolean flag = false;

        for(int i = 0;i < strings.length;i++) {
            if(PermissionChecker.checkSelfPermission(context,strings[i]) != PermissionChecker.PERMISSION_GRANTED) {
                premissionList.add(strings[i]);
            }
        }
        String[] permissions = premissionList.toArray(new String[premissionList.size()]);
        if(premissionList.size() >0) {

            ActivityCompat.requestPermissions((Activity) context,permissions,code);
        }
        return permissions;
    }

transfer:

String[] pers = checkpPermissionsApply(this, 243, Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE);
 
        if (pers.length == 0) {
            //说明权限以及申请完成
            //业务逻辑放这里
        }

3. Traverse the album:

What is used here is the query database search syntax and the usage of the ContentResolver program content provider and the usage of the Cursor pointer.

  /**
     * 相册遍历
     */
    private void scanEgineAllImage() {
        allImagePathList.clear();
        Uri uriImage = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
        ContentResolver contentResolver = getContentResolver();
        Cursor mCursor = contentResolver.query(uriImage, null, MediaStore.Images.Media.MIME_TYPE + "=? or "
                        + MediaStore.Images.Media.MIME_TYPE + " =? ", new String[]{"image/jpeg", "image/png"},
                MediaStore.Images.Media.DATE_MODIFIED + " desc");
        mCursor.moveToPosition(mCurrentPosition);
        int i = 0; //查找300条索引图片
        //每次查询300张图片
        while (mCursor.moveToNext() && i < 300) {
            i++;
            //获取图片路径 DATA 常量 需要授予读写权限才可以读取图片
            String path = mCursor.getString(mCursor.getColumnIndex(MediaStore.Images.Media.DATA));
            if (new File(path).exists()) {
                //如果文件存在则加入到自己定义的List中 这里存入的是图片路径
                allImagePathList.add(new ImageSelectBean(path, false));
            }
        }
        //用完回收
        mCursor.close();
        mCurrentPosition += i;
        if (i < 300) {
            isScanFlag = true;//扫描完成
        }

    }