关于Android权限申请

1、手动申请
Android6.0之后系统对权限的管理更加严格了，不但要在AndroidManifest中添加，还要在应用运行的时候动态申请。下面是动态申请SD卡读写的权限
在AndroidManifest中添加SD卡读写的权限

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

动态申请权限

private static final int REQUEST_EXTERNAL_STORAGE = 1;
    private static String[] PERMISSIONS_STORAGE = {
            "android.permission.READ_EXTERNAL_STORAGE",
            "android.permission.WRITE_EXTERNAL_STORAGE" };


    public static void verifyStoragePermissions(Activity activity) {

        try {
        //检测是否有写的权限
            int permission = ActivityCompat.checkSelfPermission(activity,
                    "android.permission.WRITE_EXTERNAL_STORAGE");
            if (permission != PackageManager.PERMISSION_GRANTED) {
        // 没有写的权限，去申请写的权限，会弹出对话框
                ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

把verifyStoragePermissions方法放在onCreate方法中即可。

2、默认申请
https://github.com/Karumi/Dexter
通过上面库，接入方式：
在build.gradle加入

dependencies{
    implementation 'com.karumi:dexter:5.0.0'
}

然后在mainactivity加入

static final String[] PERMISSIONS = new String[]{
            Manifest.permission.WRITE_EXTERNAL_STORAGE,
            Manifest.permission.READ_EXTERNAL_STORAGE,
    };
private void initPermissions() {
        Dexter.withActivity(this).withPermissions(PERMISSIONS)
                .withListener(new MultiplePermissionsListener() {
                    @Override
                    public void onPermissionsChecked(MultiplePermissionsReport report) {
                        if (report.areAllPermissionsGranted()){
                            Toast.makeText(getApplication(),"权限获取成功！",Toast.LENGTH_LONG).show();
                        }
                    }

                    @Override
                    public void onPermissionRationaleShouldBeShown(List<PermissionRequest> permissions, PermissionToken token) {
                    }
                }).check();
    }

然后在oncreate()中加入initPermissions()就行了

以上两种方法，亲测可用。