Android 7.0动态权限方法

1. 基本方法

1.1 注册表申请（安卓6.0以下的手机需要）

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

1.2 添加provider标签

      需要修改当前module的AndroidManifest.xml文件，添加provider标签，映射路径

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="com.example.hanglidemo.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_paths" />
</provider>

     上文代码里，name，exported字段是固定写法，官网就是这么说的，别乱试了。android:resource标签的值是main/res/xml/path_file.xml文件，即在 res下新建xml文件夹，再新建一个xml文件。

1.3 创建path_file.xml

     在res/xml下新建一个path_file.xml文件，但是与上步骤一致即可。

<?xml version="1.0" encoding="utf-8"?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <external-path name="my_images" path="" />
</paths>

     这里我写了一个文件层，可以直接使用，不限制机型。

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <paths>
        <root-path name="root" path="" />
        <files-path name="files" path="" />
        <cache-path name="cache" path="" />
        <external-path name="external" path="" />
        <external-files-path name="external_files" path="" />
        <external-cache-path name="external_cache" path="" />
    </paths>
</resources>

各个含义：

      <files-path/>代表的根目录： Context.getFilesDir()

      <cache-path/>代表的根目录: getCacheDir()

      <external-path/>代表的根目录: Environment.getExternalStorageDirectory()

      <external-files-path/>代表的根目录: Context.getExternalFilesDir(String) Context.getExternalFilesDir(null).

      <external-cache-path />代表的根目录: Context.getExternalCacheDir().

      <root-path />代表设备的根目录new File("/");

1.4 activity中动态请求权限

private void PermissionCamera() {
    // 创建File对象，用于存储拍照后的图片
    File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
    try {
        if (outputImage.exists()) {
            outputImage.delete();
        }
        outputImage.createNewFile();
    } catch (IOException e) {
        e.printStackTrace();
    }
    // 判断api的类型
    if (Build.VERSION.SDK_INT < 24) {
        imageUri = Uri.fromFile(outputImage);
    } else {
        imageUri = android.support.v4.content.FileProvider.getUriForFile(MineCenterActivity.this, "com.example.hanglidemo.fileprovider", outputImage);
    }
    // 启动相机程序
    Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
    intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
    startActivityForResult(intent, TAKE_PHOTO);
}

1.5 重写onActivityResult方法

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    switch (requestCode) {
        case TAKE_PHOTO:
            if (resultCode == RESULT_OK) {
                try {
                    // 将拍摄的照片显示出来
                    Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                    headicon.setImageBitmap(bitmap);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
            break;
        case CHOOSE_PHOTO:
            if (resultCode == RESULT_OK) {
                // 判断手机系统版本号
                if (Build.VERSION.SDK_INT >= 19) {
                    // 4.4及以上系统使用这个方法处理图片
                    handleImageOnKitKat(data);
                } else {
                    // 4.4以下系统使用这个方法处理图片
                    handleImageBeforeKitKat(data);
                }
            }
            break;
        default:
            break;
    }
}

完整代码

public class MineCenterActivity extends AppCompatActivity {

    public static final int CHOOSE_PHOTO = 2;

    public static final int TAKE_PHOTO = 1;

    private ImageView headicon;
    private Uri imageUri;
    private ImageView mineBackIv;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_minecenter);
        headicon = (ImageView) findViewById(R.id.headCv);
        mineBackIv = (ImageView)findViewById(R.id.mineBackIv);
        initView();
        setOnClick();
    }

    private void setOnClick() {
        mineBackIv.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
    }

    private void initView() {
        headicon.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                showSelectDialog();
            }
        });
    }

    private void showSelectDialog() {
        DialogUtils.getInstance().showSelectPhotoDialog(this, new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (v.getId() == R.id.tv_camera) {
                    // 请求相机拍照
                    PermissionCamera();
                } else if (v.getId() == R.id.tv_file) {
                    if (ContextCompat.checkSelfPermission(MineCenterActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
                        ActivityCompat.requestPermissions(MineCenterActivity.this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
                    } else {
                        openAlbum();  // 去相册选择
                    }
                } else {
                    finish();
                }
            }

        });
    }


    private void openAlbum() {
        Intent intent = new Intent("android.intent.action.GET_CONTENT");
        intent.setType("image/*");
        startActivityForResult(intent, CHOOSE_PHOTO); // 打开相册
    }


    private void PermissionCamera() {
        // 创建File对象，用于存储拍照后的图片
        File outputImage = new File(getExternalCacheDir(), "output_image.jpg");
        try {
            if (outputImage.exists()) {
                outputImage.delete();
            }
            outputImage.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
        if (Build.VERSION.SDK_INT < 24) {
            imageUri = Uri.fromFile(outputImage);
        } else {
            imageUri = android.support.v4.content.FileProvider.getUriForFile(MineCenterActivity.this, "com.example.hanglidemo.fileprovider", outputImage);
        }
        // 启动相机程序
        Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
        intent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(intent, TAKE_PHOTO);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
            case TAKE_PHOTO:
                if (resultCode == RESULT_OK) {
                    try {
                        // 将拍摄的照片显示出来
                        Bitmap bitmap = BitmapFactory.decodeStream(getContentResolver().openInputStream(imageUri));
                        headicon.setImageBitmap(bitmap);
                    } catch (Exception e) {
                        e.printStackTrace();
                    }
                }
                break;
            case CHOOSE_PHOTO:
                if (resultCode == RESULT_OK) {
                    // 判断手机系统版本号
                    if (Build.VERSION.SDK_INT >= 19) {
                        // 4.4及以上系统使用这个方法处理图片
                        handleImageOnKitKat(data);
                    } else {
                        // 4.4以下系统使用这个方法处理图片
                        handleImageBeforeKitKat(data);
                    }
                }
                break;
            default:
                break;
        }
    }

    @TargetApi(19)
    private void handleImageOnKitKat(Intent data) {
        String imagePath = null;
        Uri uri = data.getData();
        Log.d("TAG", "handleImageOnKitKat: uri is " + uri);
        if (DocumentsContract.isDocumentUri(this, uri)) {
            // 如果是document类型的Uri，则通过document id处理
            String docId = DocumentsContract.getDocumentId(uri);
            if("com.android.providers.media.documents".equals(uri.getAuthority())) {
                String id = docId.split(":")[1]; // 解析出数字格式的id
                String selection = MediaStore.Images.Media._ID + "=" + id;
                imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);
            } else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())) {
                Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(docId));
                imagePath = getImagePath(contentUri, null);
            }
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {
            // 如果是content类型的Uri，则使用普通方式处理
            imagePath = getImagePath(uri, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {
            // 如果是file类型的Uri，直接获取图片路径即可
            imagePath = uri.getPath();
        }
        displayImage(imagePath); // 根据图片路径显示图片
    }

    private void handleImageBeforeKitKat(Intent data) {
        Uri uri = data.getData();
        String imagePath = getImagePath(uri, null);
        displayImage(imagePath);
    }


    private String getImagePath(Uri uri, String selection) {
        String path = null;
        // 通过Uri和selection来获取真实的图片路径
        Cursor cursor = getContentResolver().query(uri, null, selection, null, null);
        if (cursor != null) {
            if (cursor.moveToFirst()) {
                path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));
            }
            cursor.close();
        }
        return path;
    }

    private void displayImage(String imagePath) {
        if (imagePath != null) {
            Bitmap bitmap = BitmapFactory.decodeFile(imagePath);
            headicon.setImageBitmap(bitmap);
        } else {
            Toast.makeText(this, "failed to get image", Toast.LENGTH_SHORT).show();
        }
    }

}