如果您在API级别23或更高级别上运行应用程序,则必须在运行时请求权限.

请求许可：

String[] permissions = {Manifest.permission.WRITE_EXTERNAL_STORAGE};

requestPermissions(permissions, WRITE_REQUEST_CODE);

然后处理结果：

@Override

public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {

switch (requestCode) {

case WRITE_REQUEST_CODE:

if(grantResults[0] == PackageManager.PERMISSION_GRANTED){

//Granted.

}

else{

//Denied.

}

break;

}

}