Android棉花糖有新的权限系统。你需要在运行时请求权限，使用如下代码-其中一部分我从http://developer.android.com/training/permissions/requesting.html复制过来-

@Override public void onClick(View v) {
    switch (v.getId()){
        case R.id.tv_contact:{
            askForContactPermission();
            break;
        }
    }  }

private void getContact(){
    Intent intent = new Intent(Intent.ACTION_PICK, ContactsContract.Contacts.CONTENT_URI);
    startActivityForResult(intent, PICK_CONTACT); }

 public void askForContactPermission(){
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (ContextCompat.checkSelfPermission(getActivity(),Manifest.permission.READ_CONTACTS)
!= PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(),
                    Manifest.permission.READ_CONTACTS)) {
                AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
                builder.setTitle("Contacts access needed");
                builder.setPositiveButton(android.R.string.ok, null);
                builder.setMessage("please confirm Contacts access");//TODO put real question
                builder.setOnDismissListener(new DialogInterface.OnDismissListener() {
                    @TargetApi(Build.VERSION_CODES.M)
                    @Override
                    public void onDismiss(DialogInterface dialog) {
                        requestPermissions(
                                new String[]
                                        {Manifest.permission.READ_CONTACTS}
                                , PERMISSION_REQUEST_CONTACT);
                    }
                });
                builder.show();
                // Show an expanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.

            } else {

                // No explanation needed, we can request the permission.

                ActivityCompat.requestPermissions(getActivity(),
                        new String[]{Manifest.permission.READ_CONTACTS},
                        PERMISSION_REQUEST_CONTACT);

                // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
                // app-defined int constant. The callback method gets the
                // result of the request.
            }
        }else{
            getContact();
        }
    }
    else{
        getContact();
    } }

@Override public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    switch (requestCode) {
        case PERMISSION_REQUEST_CONTACT: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                getContact();
                // permission was granted, yay! Do the
                // contacts-related task you need to do.

            } else {
                ToastMaster.showMessage(getActivity(),"No permission for contacts");
                // permission denied, boo! Disable the
                // functionality that depends on this permission.
            }
            return;
        }

        // other 'case' lines to check for other
        // permissions this app might request
    } }