Android组合式自定义控件实现购物车加减商品操作

public class MainActivity extends AppCompatActivity {

    private Addand mAddand;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      mAddand= findViewById(R.id.add);
  
      mAddand.setOnNumberChangedListener(new Addand.OnNumberChangedListener() {
        @Override
        public void OnNumberChanged(int vs) {
          Toast.makeText(MainActivity.this, vs+\"\", Toast.LENGTH_SHORT).show();
        }
      });
    }
  }

<android.support.constraint.ConstraintLayout  ns:android=\"http://schemas.android.com/apk/res/android\"
   ns:app=\"http://schemas.android.com/apk/res-auto\"
   ns:tools=\"http://schemas.android.com/tools\"
  android:layout_width=\"match_parent\"
  android:layout_height=\"match_parent\"
  tools:context=\".MainActivity\"
  android:orientation=\"horizontal\">

  <fanruiqi.www.com.jia.Addand
    android:id=\"@+id/add\"
    android:layout_width=\"wrap_content\"
    android:layout_height=\"wrap_content\"/>

</android.support.constraint.ConstraintLayout>

public class Addand extends  Layout implements View. Listener{
  private ImageView mImage1;
  private ImageView mImage2;
  private TextView mText;
  int value;

  public Addand(@NonNull Context context) {
    this(context,null);
  }

  public Addand(@NonNull Context context, @Nullable AttributeSet attrs) {
    this(context, attrs,0);
  }

  public Addand(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);

    findView(context);
  }

  private void findView(Context context) {
    View view = View.inflate(context, R.layout.add, this);

     mImage1 =view.findViewById(R.id.image1);
     mImage2 = view.findViewById(R.id.image2);
     mText = view.findViewById(R.id.text);

     value=getValue();

     setValue(value);

     mImage1.set Listener(this);
     mImage2.set Listener(this);
  }
  private int vs=1;
  public int getValue() { //获取值

    String trim = mText.getText().toString().trim();
    if (!TextUtils.isEmpty(trim)){
      Integer.valueOf(vs);
    }
    return vs;
  }

  public void setValue(int value) {
    mText.setText(value+\"\");
  }

  @Override
  public void  (View view) {

    switch (view.getId()){
      case R.id.image1:
        add();
        break;
      case R.id.image2:
        jian();
        break;
    }
  }

  private void jian() {
    if (vs>1){
      vs--;
      setValue(vs);
    }

    mOnNumberChangedListener.OnNumberChanged(vs);
  }

  private void add() {

    if (vs<6){
      vs++;
      setValue(vs);
    }

    mOnNumberChangedListener.OnNumberChanged(vs);
  }

  public interface OnNumberChangedListener{
    void OnNumberChanged(int vs);
  }

  private OnNumberChangedListener mOnNumberChangedListener;

  public void setOnNumberChangedListener(OnNumberChangedListener onNumberChangedListener){
      mOnNumberChangedListener=onNumberChangedListener;
  }

}

<LinearLayout  ns:android=\"http://schemas.android.com/apk/res/android\"
  android:layout_width=\"match_parent\"
  android:layout_height=\"match_parent\"
  android:orientation=\"horizontal\">

  <ImageView
    android:id=\"@+id/image1\"
    android:layout_width=\"20dp\"
    android:layout_height=\"20dp\"
    android:src=\"@drawable/ic_launcher_background\"/>

  <TextView
    android:id=\"@+id/text\"
    android:layout_width=\"50dp\"
    android:layout_height=\"20dp\"
    android:gravity=\"center\"
    android:text=\"1\"/>

  <ImageView
    android:id=\"@+id/image2\"
    android:layout_width=\"20dp\"
    android:layout_height=\"20dp\"
    android:src=\"@drawable/ic_launcher_background\"/>
</LinearLayout>