自定义View 购物车加减数量

首先我们需要的是 加(botton) 减 (botton) 输入数量(editText) 【这里我还设置了最大值】

然后

对 加减按钮设置监听，点击对editText的内容进行修改。

布局代码：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:focusable="true"
android:showDividers="middle">
//android:showDividers="middle"在每个子View间加入分隔线

<TextView
android:id="@+id/add"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:background="@color/gray"
android:gravity="center"
android:minWidth="30dp"
android:text="+"
android:textColor="@color/write" />

<EditText
android:id="@+id/count"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:background="@null"
android:gravity="center"
android:inputType="number"
android:minWidth="40dp"
android:text="1"
android:textColor="@color/gray" />

<TextView
android:id="@+id/delete"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="match_parent"
android:background="@color/gray"
android:gravity="center"
android:minWidth="30dp"
android:text="-"
android:textColor="@color/write" />
</LinearLayout>

再写我们需要在调用这个自定义View的时候设置它的属性【res -> values -> attrs.xml】写入

<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="AddDeleteCount">
<attr name="maxCount" format="integer"/>
<attr name="btnWidth" format="dimension"/>
<attr name="editWidth" format="dimension"/>
<attr name="AddDeleteBackgroungColor" format="color"/>
<attr name="isEditCount" format="boolean"/>
<attr name="textSize" format="dimension"/>
</declare-styleable>
</resources>

最后我们写自定义的LinearLayout，代码如下：

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Color;
import android.support.annotation.Nullable;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

import cn.jhc.startdemo.R;

/**
* Created by Administrator on 2017/10/14.
*/

public class AddDeleteCount extends LinearLayout implements View.OnClickListener, TextWatcher {

private int max, btnWidth, edtWidth, addOrDeleteBg;
private EditText edt_count;
//edit控件是否可以修改
private boolean IsEdtCountEdited = false;

public AddDeleteCount(Context context) {
this(context, null);
}

public AddDeleteCount(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
LayoutInflater.from(context).inflate(R.layout.add_or_delete, this);
TextView add = findViewById(R.id.add);
add.setOnClickListener(this);
TextView delete = findViewById(R.id.delete);
delete.setOnClickListener(this);
edt_count = findViewById(R.id.count);
edt_count.addTextChangedListener(this);
if (attrs != null) {
TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.AddDeleteCount);
max = array.getInt(R.styleable.AddDeleteCount_maxCount, -1);
btnWidth = array.getDimensionPixelOffset(R.styleable.AddDeleteCount_btnWidth, 100);
edtWidth = array.getDimensionPixelOffset(R.styleable.AddDeleteCount_editWidth, 80);
addOrDeleteBg = array.getColor(R.styleable.AddDeleteCount_AddDeleteBackgroungColor, Color.GRAY);
IsEdtCountEdited = array.getBoolean(R.styleable.AddDeleteCount_isEditCount, false);
array.recycle();
}
edt_count.setEnabled(IsEdtCountEdited);
LayoutParams params = new LayoutParams(btnWidth, ViewGroup.LayoutParams.MATCH_PARENT);
add.setLayoutParams(params);
delete.setLayoutParams(params);
LayoutParams params1 = new LayoutParams(edtWidth, ViewGroup.LayoutParams.MATCH_PARENT);
edt_count.setLayoutParams(params1);
add.setBackgroundColor(addOrDeleteBg);
delete.setBackgroundColor(addOrDeleteBg);
}

@Override
public void onClick(View view) {
int currentCount = Integer.parseInt(edt_count.getText().toString());
switch (view.getId()) {
case R.id.add:
if (currentCount < max) {
edt_count.setText(String.valueOf(currentCount + 1));
}
break;
case R.id.delete:
if (currentCount > 1) {
edt_count.setText(String.valueOf(currentCount - 1));
}
break;
}
}

@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {

}

@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {

}

@Override
public void afterTextChanged(Editable editable) {
if (edt_count.getText().toString().isEmpty()) {
return;
} else {
if (Integer.parseInt(edt_count.getText().toString()) > max) {
edt_count.setText(String.valueOf(max));
}
}
}

public void setEdtCountEdited(boolean edtCountEdited) {
edt_count.setEnabled(edtCountEdited);
}

public int getCount() {
if (!edt_count.getText().toString().isEmpty()) {
return Integer.parseInt(edt_count.getText().toString());
}
return 1;
}
}

最后在MainActivity布局中调用：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="cn.jhc.startdemo.duty.DutyActivity"
android:orientation="vertical">

<cn.jhc.startdemo.common.view.AddDeleteCount
android:id="@+id/add_delete"
android:layout_width="300dp"
android:layout_height="40dp"
app:maxCount="5"
app:btnWidth="100dp"
app:editWidth="100dp"
app:isEditCount="false"
app:AddDeleteBackgroungColor="@color/gray"
app:textSize="14dp"/>

</LinearLayout>