Implement the addition and subtraction effect of the shopping cart to implement the shopping cart
Public class MainActivity extends AppCompatActivity {private ImageView img1, img2; private TextView tv1; private int mNumber = 0; private int mMaxNumber = 99; @ Overrideprotected void onCreate (Bundle savedInstanceState) {super. onCreate (savedInstanceState); setContentView (R. layout. activity_main); img1 = (ImageView) findViewById (R. id. iv1); img2 = (ImageView) findViewById (R. id. iv2); tv1 = (TextView) findViewBy Id (R. id. TV); img1.setOnClickListener (new View. onClickListener () {@ Overridepublic void onClick (View v) {if (mNumber> 0) {mNumber -- ;} setNumberText (mNumber + "");}}); img2.setOnClickListener (new View. onClickListener () {@ Overridepublic void onClick (View v) {if (mNumber <mMaxNumber) {mNumber ++ ;}setnumbertext (mNumber + "");}});} private void setNumberText (String s) {tv1.setText (s); mNumber = Integer. value Of (s); if (mAddAndSubtractOnClickListener! = Null) {mAddAndSubtractOnClickListener. numberChange (mNumber) ;}} private AddAndSubtractOnClickListener listener; public void setAddAndSubtractOnClickListener (AddAndSubtractOnClickListener addAndSubtractOnClickListener) {listener = addAndSubtractOnClickListener ;} /*** addition/subtraction button callback interface */public interface AddAndSubtractOnClickListener {void numberChange (int num );}}