android6.0以后动态申请权限

int permission_write=ContextCompat.checkSelfPermission(MainActivity.this,

Manifest.permission.WRITE_EXTERNAL_STORAGE);

int permission_read=ContextCompat.checkSelfPermission(MainActivity.this,

Manifest.permission.READ_EXTERNAL_STORAGE);

if(permission_write!= PackageManager.PERMISSION_GRANTED

|| permission_read!=PackageManager.PERMISSION_GRANTED){

Toast.makeText(this, "正在请求权限", Toast.LENGTH_SHORT).show();

//申请权限，特征码自定义为1，可在回调时进行相关判断

ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},1);

}else{

//TODO

}

重写方法OnRequestPermissionResult，其中常量1是申请权限时填入的特征码

@Override

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

switch (requestCode){

case 1:

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

//权限已成功申请

}else{

//用户拒绝授权

Toast.makeText(this, "无法获取SD卡读写权限", Toast.LENGTH_SHORT).show();

finish();

}

break;

default:

super.onRequestPermissionsResult(requestCode, permissions, grantResults);

}

}