Android 购物车加减功能的实现代码

public class adderView extends LinearLayout implements View.OnClickListener, TextWatcher {
private int amount = 0; //购买数量
private int goods_storage = Integer.MAX_VALUE; //商品库存
private OnAmountChangeListener mListener;
private EditText etAmount;
private Button btnDecrease;
private Button btnIncrease;
public adderView(Context context) {
this(context, null);
}
public adderView(Context context, AttributeSet attrs) {
super(context, attrs);
LayoutInflater.from(context).inflate(R.layout.number_adder, this);
etAmount = (EditText) findViewById(R.id.etAmount);
btnDecrease = (Button) findViewById(R.id.btnDecrease);
btnIncrease = (Button) findViewById(R.id.btnIncrease);
btnDecrease.setOnClickListener(this);
btnIncrease.setOnClickListener(this);
etAmount.addTextChangedListener(this);
TypedArray obtainStyledAttributes = getContext().obtainStyledAttributes(attrs, R.styleable.AmountView);
int btnWidth = obtainStyledAttributes.getDimensionPixelSize(R.styleable.AmountView_btnWidth, 100);
int tvWidth = obtainStyledAttributes.getDimensionPixelSize(R.styleable.AmountView_tvWidth, 200);
int tvTextSize = obtainStyledAttributes.getDimensionPixelSize(R.styleable.AmountView_tvTextSize, 0);
int btnTextSize = obtainStyledAttributes.getDimensionPixelSize(R.styleable.AmountView_btnTextSize, 0);
obtainStyledAttributes.recycle();
LayoutParams btnParams = new LayoutParams(btnWidth, LayoutParams.MATCH_PARENT);
btnDecrease.setLayoutParams(btnParams);
btnIncrease.setLayoutParams(btnParams);
if (btnTextSize != 0) {
btnDecrease.setTextSize(TypedValue.COMPLEX_UNIT_PX, btnTextSize);
btnIncrease.setTextSize(TypedValue.COMPLEX_UNIT_PX, btnTextSize);
}
LayoutParams textParams = new LayoutParams(tvWidth, LayoutParams.MATCH_PARENT);
etAmount.setLayoutParams(textParams);
if (tvTextSize != 0) {
etAmount.setTextSize(tvTextSize);
}
}
public void setOnAmountChangeListener(OnAmountChangeListener onAmountChangeListener) {
this.mListener = onAmountChangeListener;
}
public void setGoods_storage(int goods_storage) {
this.goods_storage = goods_storage;
}
public void setTextCount(int count){
this.amount = count;
this.etAmount.setText(amount+"");
}
@Override
public void onClick(View v) {
int i = v.getId();
if (i == R.id.btnDecrease) {
if (amount   0) {
amount--;
etAmount.setText(amount + "");
}
} else if (i == R.id.btnIncrease) {
if (amount < goods_storage) {
amount++;
etAmount.setText(amount + "");
}
}
etAmount.clearFocus();
if (mListener != null) {
mListener.onAmountChange(this, amount);
}
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
@Override
public void afterTextChanged(Editable s) {
if (s.toString().isEmpty())
return;
amount = Integer.valueOf(s.toString());
if (amount   goods_storage) {
etAmount.setText(goods_storage + "");
return;
}
if (amount == 0){
//   btnDecrease.setBackgroundResource(R.drawable.jian);
}
if (amount   0){
//   btnDecrease.setBackgroundResource(R.drawable.lvjian);
}
if (mListener != null) {
mListener.onAmountChange(this, amount);
}
}
public interface OnAmountChangeListener {
void onAmountChange(View view, int amount);
}

<?xml version="1.0" encoding="utf-8"? 
<com.zhy.autolayout.AutoLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="90px"
android:focusable="true"
android:divider="@drawable/divder"
android:background="@drawable/bg_amout_layout"
android:showDividers="middle"
android:orientation="horizontal" 
<Button
android:id="@+id/btnDecrease"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:background="@drawable/jian"/ 
<EditText
android:id="@+id/etAmount"
android:layout_width="200px"
android:layout_height="match_parent"
android:minWidth="150px"
android:layout_weight="2"
android:background="@null"
android:inputType="number"
android:textSize="13sp"
android:text="0"
android:gravity="center"/ 
<Button
android:id="@+id/btnIncrease"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center"
android:background="@drawable/jia"/ 
</com.zhy.autolayout.AutoLinearLayout