自定义控件实现一个UpDownView(1)

 package com.ql.view;

 import java.text.DecimalFormat;

 import com.ql.app.R;
 import android.content.Context;
 import android.util.AttributeSet;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.widget.EditText;
 import android.widget.ImageView;
 import android.widget.LinearLayout;

 public class UpDownView extends LinearLayout {
     private final static String tag="UpDownView";
     private ImageView iv_minus,iv_plus;
     private EditText et_input;

     public UpDownView(Context context) {
         super(context);
         // TODO Auto-generated constructor stub
         Log.i(tag, "UpDownView1");
     }
     public UpDownView(Context context, AttributeSet attrs) {
         super(context, attrs);
         // TODO Auto-generated constructor stub
         Log.i(tag, "UpDownView2");
     }
     @Override
     protected void onFinishInflate() {
         // TODO Auto-generated method stub
         super.onFinishInflate();
         Log.i(tag, "onFinishInflate");
         View view=LayoutInflater.from(getContext()).inflate(R.layout.up_down_view, this);
         iv_minus=(ImageView)view.findViewById(R.id.iv_minus);
         iv_plus=(ImageView)view.findViewById(R.id.iv_plus);
         et_input=(EditText)view.findViewById(R.id.et_input);

         iv_minus.setOnClickListener(listener);
         iv_plus.setOnClickListener(listener);
     }

     OnClickListener listener=new OnClickListener() {

         @Override
         public void onClick(View v) {
             // TODO Auto-generated method stub
             switch (v.getId()) {
             case R.id.iv_minus:
                 doMinus();
                 break;
             case R.id.iv_plus:
                 doPlus();
                 break;

             default:
                 break;
             }
         }
     };

     private double number;//当前量
     private double step=1000;//步长，每次加减的量
     private double max=10000;//最大量
     private double min=-10000;//最小量

     private void doPlus(){
         String temp=et_input.getText().toString();
         if(temp.length()==0){
             number=0;
         }else{
             number=Double.parseDouble(temp);
         }
         number+=step;
         if(number>max){
             number=max;
         }
         et_input.setText(convertNumberToString(number,pattern));
     }

     private void doMinus(){
         String temp=et_input.getText().toString();
         if(temp.length()==0){
             number=0;
         }else{
             number=Double.parseDouble(temp);
         }
         number-=step;
         if(number<min){
             number=min;
         }
         et_input.setText(convertNumberToString(number,pattern));
     }

     private String pattern = "############.##";
     /**
      * Util
      * @param value
      * @param pattern
      * @return
      */
     public static String convertNumberToString(Number value, String pattern) {
         try {
             DecimalFormat decimalFormat = new DecimalFormat(pattern);
             return decimalFormat.format(value);
         } catch (Exception e) {
             e.printStackTrace();
         }
         return null;
     }

     public double getNumber() {
         return number;
     }
     public void setNumber(double number) {
                 et_input.setText(convertNumberToString(number,pattern));
         this.number = number;
     }
     public double getStep() {
         return step;
     }
     public void setStep(double step) {
         this.step = step;
     }
     public double getMax() {
         return max;
     }
     public void setMax(double max) {
         this.max = max;
     }
     public double getMin() {
         return min;
     }
     public void setMin(double min) {
         this.min = min;
     }
 }

其实挺简单的，只要在onFinishInflate中加载一个布局就可以了。 
布局up_down_view.xml如下： 

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:layout_gravity="center_vertical"
     android:orientation="horizontal"
     >
     <ImageView android:id="@+id/iv_minus"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="center_vertical"
     android:src="@drawable/sh_trade_minus"
     android:scaleType="fitCenter"
     />
     <EditText  android:id="@+id/et_input"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:layout_weight="1"
     android:text=""
     android:singleLine="true"
     android:inputType="numberDecimal"
     />
     <ImageView android:id="@+id/iv_plus"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_gravity="center_vertical"
     android:src="@drawable/sh_trade_plus"
     android:scaleType="fitCenter"
     />
 </LinearLayout>

使用： 
在布局文件中引入： 

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     >
     <TextView
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="@string/hello"
     />
     <com.ql.view.UpDownView android:id="@+id/upDownView"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     />
 </LinearLayout>

然后可以通过UpDownView提供的setter/getter函数对它进行初始化需要的数据了。 

 UpDownView view=(UpDownView)findViewById(R.id.upDownView);
 view.setMax(100);
 view.setStep(1);
 view.setMin(0);
 view.setNumber(90.01);//没有的话显示为""

此控件支持小数，看源码中pattern = "############.##"就知道了。该控件适合对金额的显示。 
用到的两张图：