在 上一節 中在onFinishInflate方法中使用了View view=LayoutInflater.from(getContext()).inflate(R.layout.up_down_view, this);來加載一個布局文件。
這樣會多一個up_down_view.xml文件，有點浪費。
這節采用動態布局（就是利用代碼）實現同樣的效果。

    
package com.ql.view;

import java.text.DecimalFormat;

import com.ql.app.R;
import android.content.Context;
import android.content.res.TypedArray;
import android.text.InputType;
import android.util.AttributeSet;
import android.util.Log;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.ImageView.ScaleType;

public class UpDownView extends LinearLayout {
	private final static String tag="UpDownView";
	private final int id_minus=1;
	private final int id_plus=2;
	private ImageView iv_minus,iv_plus;
	private EditText et_input;
	private Context context;
	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");
		TypedArray a=context.obtainStyledAttributes(attrs,R.styleable.updownview);
		min=a.getFloat(R.styleable.updownview_min, -10000);
		max=a.getFloat(R.styleable.updownview_max, 10000);
		step=a.getFloat(R.styleable.updownview_step, 1000);
		number=a.getFloat(R.styleable.updownview_number, 0);
		
		a.recycle();
	}
	@Override
	protected void onFinishInflate() {
		// TODO Auto-generated method stub
		super.onFinishInflate();
		Log.i(tag, "onFinishInflate");
		context=getContext();
		LinearLayout.LayoutParams params_iv=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT,LinearLayout.LayoutParams.WRAP_CONTENT);
		params_iv.gravity=Gravity.CENTER_VERTICAL;
		LinearLayout.LayoutParams params=new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT,LinearLayout.LayoutParams.WRAP_CONTENT);
		
		LinearLayout layout=new LinearLayout(context);
		layout.setOrientation(LinearLayout.HORIZONTAL);
		layout.setLayoutParams(params);
		
		params.weight=1;
		
		iv_minus=new ImageView(context);
		iv_minus.setId(id_minus);
		iv_minus.setImageResource(R.drawable.sh_trade_minus);
		iv_minus.setScaleType(ScaleType.FIT_CENTER);
		iv_plus=new ImageView(context);
		iv_plus.setId(id_plus);
		iv_plus.setImageResource(R.drawable.sh_trade_plus);
		iv_plus.setScaleType(ScaleType.FIT_CENTER);
		
		et_input=new EditText(context);
	et_input.setImeOptions(EditorInfo.IME_ACTION_DONE|EditorInfo.IME_FLAG_NO_EXTRACT_UI);
	et_input.setInputType(InputType.TYPE_CLASS_NUMBER|InputType.TYPE_NUMBER_FLAG_DECIMAL);
		
		if(number!=0){
			et_input.setText(convertNumberToString(number,pattern));
		}
		
		iv_minus.setOnClickListener(listener);
		iv_plus.setOnClickListener(listener);
		
		
		layout.addView(iv_minus, params_iv);
		layout.addView(et_input, params);
		layout.addView(iv_plus, params_iv);
		
		addView(layout);
	}
	
	OnClickListener listener=new OnClickListener() {
		
		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			switch (v.getId()) {
			case id_minus:
				doMinus();
				break;
			case id_plus:
				doPlus();
				break;

			default:
				break;
			}
		}
	};
	
	private double number;//當前量
	private double step=1000;//步長，每次加減的量
	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;
	}
}

  

注意onFinishInflate方法中最后別忘了addView(layout);

其他同第二節都一樣，就不羅嗦了。

最后來個大結局：

自定義控件實現一個UpDownView(3)