Listvie简单实现购物车功能

public class MyView extends LinearLayout implements View.OnClickListener {   private OnAmountChangeListener mListener;  private int count;  private TextView numText;   public MyView(Context context) {    this(context,null);  }   public MyView(Context context, @Nullable AttributeSet attrs) {    this(context, attrs,0);  }   public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {    super(context, attrs, defStyleAttr);     View view = View.inflate(context, R.layout.add, this);    initView(view);    }  public void setText(int num){    numText.setText(""+num);  }  public int getText(){    getTextString();    return count;  }   private void initView(View view) {     Button addBtn = view.findViewById(R.id.btn_add);    Button jianBtn = view.findViewById(R.id.btn_jian);    numText = view.findViewById(R.id.txt_num);    getTextString();    addBtn.setOnClickListener(this);    jianBtn.setOnClickListener(this);  }   public void setOnclickNum(OnAmountChangeListener mListener){    this.mListener = mListener;  }  @Override  public void onClick(View view) {    getTextString();    switch (view.getId()){      case R.id.btn_add:        count++;        break;      case R.id.btn_jian:        if(count>0){          count--;        }        break;    }    numText.setText(""+count);    if(mListener!=null) {      mListener.onAmountChange(view, count);    }  }   public void getTextString() {    String numStr = numText.getText().toString().trim();    count = Integer.parseInt(numStr);  }  public interface OnAmountChangeListener {    void onAmountChange(View view, int amount);  }}

public class MyAdapter extends BaseAdapter {  private List<Text> mList;  private Context context ;  private GaroupClick garoupClick;  private int index;  private CountClick countClick;   public MyAdapter(Context context) {    this.context = context;  }   @Override  public int getCount() {    return mList.size();  }  public void setData(List<Text> mList){    this.mList = mList;    notifyDataSetChanged();  }  @Override  public Object getItem(int i) {    return mList.get(i);  }   @Override  public long getItemId(int i) {    return i;  }   public void setOnCountClick(CountClick click){    this.countClick = click;  }  public void setOnGroupclick(GaroupClick groupclick){    this.garoupClick = groupclick;  }  @Override  public View getView(final int i, View view, ViewGroup viewGroup) {    final ViewHolder holder ;    if(view==null){      holder = new ViewHolder();      view = View.inflate(context, R.layout.item, null);      holder.childCheck = view.findViewById(R.id.cb_chid_checked);      holder.txtPrice = view.findViewById(R.id.txt_price);      holder.myView = view.findViewById(R.id.myview);      view.setTag(holder);    }else{      holder = (ViewHolder)view.getTag();    }    final Text text = mList. get(i);     holder.childCheck.setChecked(text.isChoose());    holder.txtPrice.setText(""+text.getPrice());    holder.myView.setText(text.getCount());    holder.myView.setOnclickNum(new MyView.OnAmountChangeListener() {      @Override      public void onAmountChange(View view, int amount) {        text.setCount(amount);      }    });    boolean checked = holder.childCheck.isChecked();    if(checked){      holder.myView.setOnclickNum(new MyView.OnAmountChangeListener() {        @Override        public void onAmountChange(View view, int amount) {          if(countClick!=null){            countClick.onNumClick(i,amount);          }        }      });    }     holder.childCheck.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        text.setChoose(((CheckBox)view).isChecked());         if(garoupClick!=null){          garoupClick.onItemClick(i,((CheckBox)view).isChecked());        }        }    });    return view;  }  class ViewHolder{    CheckBox childCheck;    TextView txtPrice;    MyView myView;  }  public interface GaroupClick{    void onItemClick(int position, boolean isChoose);  }  public interface CountClick{    void onNumClick(int position, int count);  }  }

public class MainActivity extends AppCompatActivity implements MyAdapter.GaroupClick, MyAdapter.CountClick {   private Button jiesuanBtn;  private ListView mListView;  private CheckBox allCheck;  private TextView priceText;  private List<Text> mList = new ArrayList<>();  private int numPrice = 0;  private int count = 0;  private MyAdapter adapter;   @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    initView();    initData();    }   private void initData() {    for (int i = 0; i < 30; i++) {      Text txt = new Text();      txt.setPrice(20);      txt.setCount(1);      mList.add(txt);    }     adapter = new MyAdapter(this);    adapter.setData(mList);    mListView.setAdapter(adapter);    adapter.setOnGroupclick(this);    adapter.setOnCountClick(this);  }   public boolean isAllChecked(){    for (Text text : mList) {      if(!text.isChoose()){//遍历集合，有一个不选return false        return false;      }    }    return true;  }  private void initView() {    jiesuanBtn = (Button) findViewById(R.id.btn_num);    mListView = (ListView) findViewById(R.id.listview);    allCheck = (CheckBox) findViewById(R.id.cb_all_checked);    priceText = (TextView) findViewById(R.id.txt_price_sum);    allCheck.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        if(mList.size()!=0) {          if(allCheck.isChecked()) {            for (int i = 0; i < mList.size(); i++) {              mList.get(i).setChoose(true);              adapter.notifyDataSetChanged();            }          }else{            for (int i = 0; i < mList.size(); i++) {              mList.get(i).setChoose(false);              adapter.notifyDataSetChanged();            }          }          upDate();        }      }     });     jiesuanBtn.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View view) {        Intent intent = new Intent(MainActivity.this, PayDemoActivity.class);        startActivity(intent);      }    });  }   private void upDate() {    numPrice = 0;    count = 0;    for (int i = 0; i < mList.size(); i++) {      Text text = mList.get(i);      if(text.isChoose()){        count++;        numPrice += text.getPrice()*text.getCount();      }    }    jiesuanBtn.setText("结算（"+count+"）");    priceText.setText("合计:"+numPrice);  }    @Override  public void onItemClick(int position, boolean isChoose) {    mList.get(position).setChoose(isChoose);    if(isAllChecked()){      allCheck.setChecked(true);    }else{      allCheck.setChecked(false);    }    adapter.notifyDataSetChanged();    upDate();  }   @Override  public void onNumClick(int position, int count) {    mList.get(position).setCount(count);    adapter.notifyDataSetChanged();    upDate();  }}