我们从事Android开发编写布局的时候大多数是使用XML来布局，这给我们带来了方便性，这样操作可以布局界面的代码和逻辑控制的Java代码分离出来，使程序的结构更加清晰、明了。特别的复杂的布局，但是这样操作也同样带来了另一些问题，例如屏幕的适应性，大多数Android开发人员都会遇到这个问题，还有一个就是内容问题，如果使用xml布局，Android的虚拟机首先解析xml布局，然后加载内存，如果布局越复杂，那加载的时间越慢，而用java代码布局，可以解决这些问题，不过比xml布局麻烦一点，而且必须运行才能看见结果。下面讲解一个开发过程中的一个例子:

下面是使用xml布局的代码:

 

直接在Eclipse里面查看的显示效果如下:

 

在真机上运行效果如下:

进行对比，真机是我们想要的结果，但是之前的编写的效果不对，而且对于不同的屏幕分辨率xml布局编写了三个xml布局来实现适应性。

下面使用java代码来实现布局，使用两个文件一个布局文件，另一个是布局参数文件

布局文件代码如下:

 

package com.pcareroute;import com.seuic.pcareroute.AppLog;import com.seuic.pcareroute.surface.CameraSurface;import com.seuic.pcareroute.util.PcareRouteParams;import com.seuic.pcareroute.util.ToolsUnility;import android.app.Activity;import android.os.Bundle;import android.widget.Button;import android.widget.LinearLayout;import android.widget.RelativeLayout;import android.widget.TextView;import android.widget.ToggleButton;public class PcareRouteMain extends Activity{	public static final String TAG = "PcareRouteMain";	public PcareRouteMain instance;	PcareRouteParams pRouteParams;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		ToolsUnility.getToolsUnilityInstance(this).noTitleAndStaBar(this); //去掉标题栏和状态栏		instance = this;		pRouteParams = new PcareRouteParams(instance);		AppLog.enableLogging(true);		initLayout();	}		//初始化布局和组件	public void initLayout(){		Parent = new RelativeLayout(getApplicationContext());		Parent.setBackgroundResource(R.drawable.info_back);		BottomInParent = new LinearLayout(getApplicationContext());		BottomInParent.setId(_R.id.bottom_in_parent);		BottomInParent.setBackgroundResource(R.drawable.button_bar);		ButtonInBottom = new ToggleButton[pRouteParams.Bottom_Button_Number];		for (int i = 0; i < pRouteParams.Bottom_Button_Number; i++) {			ButtonInBottom[i] = new ToggleButton(getApplicationContext());			ButtonInBottom[i].setBackgroundResource(ButtonInBottomImage[i]);			ButtonInBottom[i].setTextOff(" ");			ButtonInBottom[i].setTextOn(" ");			ButtonInBottom[i].setText(" ");			BottomInParent.addView(ButtonInBottom[i], pRouteParams.buttonInBottomParams);		}		Parent.addView(BottomInParent, pRouteParams.bottomInParentParams);				LeftInParent = new RelativeLayout(getApplicationContext());		LeftInParent.setId(_R.id.left_in_parent);		BottomInLeft = new LinearLayout(getApplicationContext());		BottomInLeft.setId(_R.id.bottom_in_left);		ButtonInLeft = new Button[pRouteParams.Left_Bottom_Button_Number];		for (int i = 0; i < pRouteParams.Left_Bottom_Button_Number; i++) {			ButtonInLeft[i] = new Button(getApplicationContext());			ButtonInLeft[i].setText(" ");			ButtonInLeft[i].setBackgroundResource(ButtonInLeftImage[i]);			BottomInLeft.addView(ButtonInLeft[i], pRouteParams.Left_Bottom_Button_Params);		}		LeftInParent.addView(BottomInLeft, pRouteParams.bottomInLeftParams);				tempView = new TextView(getApplicationContext());		tempView.setTextSize(pRouteParams.Left_Top_Temp_TextSize);		tempView.setText("T:");		tempView.setId(_R.id.tempview_in_left);		LeftInParent.addView(tempView, pRouteParams.Left_Top_Temp_Params);		tempRoll = new ToggleButton(getApplicationContext());		tempRoll.setBackgroundResource(R.drawable.max);		tempRoll.setText(" ");		tempRoll.setTextOff(" ");		tempRoll.setTextOn(" ");//		tempRoll.setVisibility(View.INVISIBLE);		LeftInParent.addView(tempRoll, pRouteParams.Left_Top_Temp_ToggButton_Params);				humidityView = new TextView(getApplicationContext());		humidityView.setText("H:");		humidityView.setId(_R.id.humiview_in_left);		humidityView.setTextSize(pRouteParams.Left_Top_Temp_TextSize);		LeftInParent.addView(humidityView, pRouteParams.Left_Top_Humi_Params);				CenterInLeft = new RelativeLayout(getApplicationContext());		ControlBtn = new Button[CtrolBtnNumber];		for (int i = 0; i < CtrolBtnNumber; i++) {			ControlBtn[i] = new Button(getApplicationContext());			ControlBtn[i].setBackgroundResource(Btn_Ctrol_In_Left_Image[i]);			CenterInLeft.addView(ControlBtn[i], pRouteParams.Left_Center_CtrolButtons_Params[i]);		}		LeftInParent.addView(CenterInLeft, pRouteParams.Left_Center_CtrolButton_Params);		Parent.addView(LeftInParent, pRouteParams.leftInParentParams);				RightInParent = new RelativeLayout(getApplicationContext());		cameraSurface = new CameraSurface(getApplicationContext());		RightInParent.addView(cameraSurface, pRouteParams.Right_Surface_Params);		ScaleBtn = new Button[ScaleBtnNumber];		for (int i = 0; i < ScaleBtnNumber; i++) {			ScaleBtn[i] = new Button(getApplicationContext());			ScaleBtn[i].setBackgroundResource(Btn_Scale_In_Right_Image[i]);			RightInParent.addView(ScaleBtn[i], pRouteParams.Right_Scale_Button_Params[i]);		}		scaleView = new TextView(getApplicationContext());		scaleView.setText("100%");		scaleView.getPaint().setFakeBoldText(true);//加粗		scaleView.setTextSize(20);		RightInParent.addView(scaleView, pRouteParams.Right_Scale_View_Params);		Parent.addView(RightInParent, pRouteParams.RightInParentParams);						setContentView(Parent, pRouteParams.paramentParams);	}		//声明组件和布局	public RelativeLayout	Parent;	public LinearLayout		BottomInParent;	public RelativeLayout	LeftInParent;	public LinearLayout		BottomInLeft;	public RelativeLayout	CenterInLeft;	public RelativeLayout	RightInParent;	public CameraSurface	cameraSurface;	public ToggleButton[]	ButtonInBottom;	public Button[] ButtonInLeft;	public Button[] ControlBtn;	public Button[] ScaleBtn;	public TextView tempView, humidityView;	public TextView scaleView;	public ToggleButton tempRoll;	//声明变量	public int[] ButtonInBottomImage = {R.drawable.talk_off, R.drawable.music_off, R.drawable.video_off, R.drawable.sound_mute, R.drawable.button_take_photo_icon, R.drawable.ir_off, R.drawable.share_off};//存储底部button的图片的数组	public int[] ButtonInLeftImage = {R.drawable.info_off, R.drawable.net_in_off, R.drawable.wifi_switch_off};//左边布局的下面三个Button按钮图片	public int[] Btn_Ctrol_In_Left_Image = {R.drawable.left_off, R.drawable.up_off, R.drawable.right_off, R.drawable.down_off};	public int CtrolBtnNumber = 4;	public int[] Btn_Scale_In_Right_Image = {R.drawable.zoom_out, R.drawable.zoom_in};	public int ScaleBtnNumber = 2;}

在上面的代码中如果我们有多个相同的按钮，则可以使用数组来存储，这样做的好处就是代码更加清晰，而且能够减少冗余代码

 

 

ControlBtn = new Button[CtrolBtnNumber];		for (int i = 0; i < CtrolBtnNumber; i++) {			ControlBtn[i] = new Button(getApplicationContext());			ControlBtn[i].setBackgroundResource(Btn_Ctrol_In_Left_Image[i]);			CenterInLeft.addView(ControlBtn[i], pRouteParams.Left_Center_CtrolButtons_Params[i]);		}

这样的代码，如果我们用平时的一个组件一个名称，就比现在多余 CtrolBtnNumber倍的代码冗余。

 

布局参数代码如下：

 

package com.seuic.pcareroute.util;import com.pcareroute._R;import android.app.Activity;import android.util.DisplayMetrics;import android.view.Gravity;import android.widget.LinearLayout;import android.widget.RelativeLayout;public class PcareRouteParams {	public static final String TAG = "PcareRouteParams";	Activity activity;	public PcareRouteParams(Activity activity){		this.activity = activity;		getDisplayMetrics();		initVar();		initLayoutParams();	}	//初始化變量	public void initVar(){		if (screenSize > 5.8) {			Bottom_Button_Width = dip2px(60);			Left_Bottom_Button_Width = dip2px(35);			Bottom_Back_Height = dip2px(70);			Left_Top_TopMarge = dip2px(20);			Left_Top_Temp_LeftMarge = dip2px(40);			Left_Top_Temp_TextSize = 35;			Left_Top_Temp_ToggButton_Width = dip2px(28);			Left_Top_Temp_ToggButton_Height = dip2px(30);			Left_Top_Temp_ToggButton_TopMarge = dip2px(20);			Left_Top_Humi_View_TopMarge = dip2px(5);			Left_Center_CtrolButton_Width = dip2px(300);			Left_Center_CtrolButton_Height = dip2px(250);			Left_Center_CtrolButton_LeftMarge = dip2px(20);			Left_Center_CtrolButton_BottomMarge = dip2px(20);			Right_Surface_LeftMarge = Left_Center_CtrolButton_LeftMarge;			Left_Center_CtrolButton_LeftBtn_Width = dip2px(135);			Left_Center_CtrolButton_LeftBtn_Height = dip2px(90);			Left_Center_CtrolButton_UpBtn_Width = dip2px(100);			Left_Center_CtrolButton_UpBtn_Height = dip2px(135);			Right_Scale_Button_Width = dip2px(50);			Right_Scale_Button_Marge = dip2px(7);			Right_Scale_View_BottomMarge = dip2px(40);		}else if(screenSize < 3.8){			Bottom_Button_Width = dip2px(35);			Left_Bottom_Button_Width = dip2px(18);			Bottom_Back_Height = dip2px(35);			Left_Top_TopMarge = dip2px(0);			Left_Top_Temp_LeftMarge = dip2px(10);			Left_Top_Temp_TextSize = 18;			Left_Top_Temp_ToggButton_Width = dip2px(15);			Left_Top_Temp_ToggButton_Height = dip2px(15);			Left_Top_Temp_ToggButton_TopMarge = dip2px(5);			Left_Top_Humi_View_TopMarge = dip2px(3);			Left_Center_CtrolButton_Width = dip2px(120);			Left_Center_CtrolButton_Height = dip2px(120);			Left_Center_CtrolButton_LeftMarge = dip2px(20);			Left_Center_CtrolButton_BottomMarge = dip2px(5);			Right_Surface_LeftMarge = Left_Center_CtrolButton_LeftMarge;			Left_Center_CtrolButton_LeftBtn_Width = dip2px(40);			Left_Center_CtrolButton_LeftBtn_Height = dip2px(30);			Left_Center_CtrolButton_UpBtn_Width = dip2px(30);			Left_Center_CtrolButton_UpBtn_Height = dip2px(40);			Right_Scale_Button_Width = dip2px(30);			Right_Scale_Button_Marge = dip2px(3);			Right_Scale_View_BottomMarge = dip2px(15);		}else {			Bottom_Button_Width = dip2px(40);			Left_Bottom_Button_Width = dip2px(27);			Bottom_Back_Height = dip2px(45);			Left_Top_TopMarge = dip2px(0);			Left_Top_Temp_LeftMarge = dip2px(20);			Left_Top_Temp_TextSize = 18;			Left_Top_Temp_ToggButton_Width = dip2px(15);			Left_Top_Temp_ToggButton_Height = dip2px(15);			Left_Top_Temp_ToggButton_TopMarge = dip2px(5);			Left_Top_Humi_View_TopMarge = dip2px(5);			Left_Center_CtrolButton_Width = dip2px(150);			Left_Center_CtrolButton_Height = dip2px(150);			Left_Center_CtrolButton_LeftMarge = dip2px(20);			Left_Center_CtrolButton_BottomMarge = dip2px(10);			Right_Surface_LeftMarge = Left_Center_CtrolButton_LeftMarge;			Left_Center_CtrolButton_LeftBtn_Width = dip2px(80);			Left_Center_CtrolButton_LeftBtn_Height = dip2px(50);			Left_Center_CtrolButton_UpBtn_Width = dip2px(50);			Left_Center_CtrolButton_UpBtn_Height = dip2px(60);			Right_Scale_Button_Width = dip2px(40);			Right_Scale_Button_Marge = dip2px(3);			Right_Scale_View_BottomMarge = dip2px(18);		}		Left_Bottom_Button_LeftMarge = dip2px(10);		BottomInLeft_BottomMarge = dip2px(5);	}	public int dip2px(float dpValue) {          return (int)(dpValue * scale + 0.5f);    }	//获取屏幕的宽度，高度和密度以及dp / px	 public void getDisplayMetrics() {  		DisplayMetrics dm = new DisplayMetrics();  		dm = activity.getApplicationContext().getResources().getDisplayMetrics();  		Screen_width = dm.widthPixels;  		Screen_height = dm.heightPixels;  		scale = activity.getResources().getDisplayMetrics().density;  		density = dm.density;  		double bb = Math.sqrt(Math.pow(Screen_width, 2)+ Math.pow(Screen_height, 2));  		screenSize = bb / (160 * dm.density);	}		 	//初始化布局参数	public void initLayoutParams(){		paramentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);		bottomInParentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, Bottom_Back_Height);		bottomInParentParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);		buttonInBottomParams = new LinearLayout.LayoutParams(Bottom_Button_Width, Bottom_Button_Width);		buttonInBottomParams.gravity = Gravity.CENTER_VERTICAL;		//底部包含组件布局参数		int jiange = (Screen_width - Bottom_Button_Width * Bottom_Button_Number)/(Bottom_Button_Number + 1);		buttonInBottomParams.leftMargin = jiange;				leftInParentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.MATCH_PARENT);		leftInParentParams.addRule(RelativeLayout.ABOVE, _R.id.bottom_in_parent);		bottomInLeftParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT,RelativeLayout.LayoutParams.WRAP_CONTENT);		bottomInLeftParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);		bottomInLeftParams.bottomMargin = BottomInLeft_BottomMarge;				Left_Bottom_Button_Params = new LinearLayout.LayoutParams(Left_Bottom_Button_Width, Left_Bottom_Button_Width);		Left_Bottom_Button_Params.leftMargin = Left_Bottom_Button_LeftMarge;		Left_Bottom_Button_Params.gravity = Gravity.CENTER_VERTICAL;				Left_Top_Temp_Params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);		Left_Top_Temp_Params.topMargin = Left_Top_TopMarge;		Left_Top_Temp_Params.leftMargin = Left_Top_Temp_LeftMarge;		Left_Top_Temp_ToggButton_Params = new RelativeLayout.LayoutParams(Left_Top_Temp_ToggButton_Width, Left_Top_Temp_ToggButton_Height);		Left_Top_Temp_ToggButton_Params.addRule(RelativeLayout.RIGHT_OF, _R.id.tempview_in_left);		Left_Top_Temp_ToggButton_Params.topMargin = Left_Top_Temp_ToggButton_TopMarge;				Left_Top_Humi_Params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);		Left_Top_Humi_Params.addRule(RelativeLayout.BELOW, _R.id.tempview_in_left);		Left_Top_Humi_Params.topMargin = Left_Top_Humi_View_TopMarge;		Left_Top_Humi_Params.addRule(RelativeLayout.ALIGN_LEFT, _R.id.tempview_in_left);				Left_Center_CtrolButton_Params = new RelativeLayout.LayoutParams(Left_Center_CtrolButton_Width, Left_Center_CtrolButton_Height);		Left_Center_CtrolButton_Params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);		Left_Center_CtrolButton_Params.bottomMargin = BottomInLeft_BottomMarge + Left_Center_CtrolButton_BottomMarge + Left_Bottom_Button_Width;		Left_Center_CtrolButton_Params.leftMargin = Left_Center_CtrolButton_LeftMarge;//		Left_Center_CtrolButton_Params.rightMargin = Left_Center_CtrolButton_LeftMarge;		Left_Center_CtrolButtons_Params = new RelativeLayout.LayoutParams[4];		Left_Center_CtrolButtons_Params[0] = new RelativeLayout.LayoutParams(Left_Center_CtrolButton_UpBtn_Height, Left_Center_CtrolButton_UpBtn_Width);		Left_Center_CtrolButtons_Params[0].addRule(RelativeLayout.CENTER_VERTICAL);		Left_Center_CtrolButtons_Params[1] = new RelativeLayout.LayoutParams(Left_Center_CtrolButton_UpBtn_Width, Left_Center_CtrolButton_UpBtn_Height);		Left_Center_CtrolButtons_Params[1].addRule(RelativeLayout.CENTER_HORIZONTAL);		Left_Center_CtrolButtons_Params[2] = new RelativeLayout.LayoutParams(Left_Center_CtrolButton_UpBtn_Height, Left_Center_CtrolButton_UpBtn_Width);		Left_Center_CtrolButtons_Params[2].addRule(RelativeLayout.ALIGN_PARENT_RIGHT);		Left_Center_CtrolButtons_Params[2].addRule(RelativeLayout.CENTER_VERTICAL);		Left_Center_CtrolButtons_Params[3] = new RelativeLayout.LayoutParams(Left_Center_CtrolButton_UpBtn_Width, Left_Center_CtrolButton_UpBtn_Height);		Left_Center_CtrolButtons_Params[3].addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);		Left_Center_CtrolButtons_Params[3].addRule(RelativeLayout.CENTER_HORIZONTAL);				RightInParentParams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);		RightInParentParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);		RightInParentParams.addRule(RelativeLayout.RIGHT_OF, _R.id.left_in_parent);		RightInParentParams.addRule(RelativeLayout.ABOVE, _R.id.bottom_in_parent);		RightInParentParams.leftMargin = Right_Surface_LeftMarge;		Right_Surface_Params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.MATCH_PARENT);				Right_Scale_Button_Params = new RelativeLayout.LayoutParams[2];		Right_Scale_Button_Params[0] = new RelativeLayout.LayoutParams(Right_Scale_Button_Width, Right_Scale_Button_Width);		Right_Scale_Button_Params[0].leftMargin = Right_Scale_Button_Marge;		Right_Scale_Button_Params[0].topMargin = Right_Scale_Button_Marge;		Right_Scale_Button_Params[1] = new RelativeLayout.LayoutParams(Right_Scale_Button_Width, Right_Scale_Button_Width);		Right_Scale_Button_Params[1].addRule(RelativeLayout.ALIGN_PARENT_RIGHT);		Right_Scale_Button_Params[1].rightMargin = Right_Scale_Button_Marge;		Right_Scale_Button_Params[1].topMargin = Right_Scale_Button_Marge;		Right_Scale_View_Params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);		Right_Scale_View_Params.addRule(RelativeLayout.CENTER_HORIZONTAL);		Right_Scale_View_Params.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);		Right_Scale_View_Params.bottomMargin = Right_Scale_View_BottomMarge;	}			//声明布局和组件	public RelativeLayout.LayoutParams paramentParams;	public RelativeLayout.LayoutParams bottomInParentParams;	public LinearLayout.LayoutParams	buttonInBottomParams;	public RelativeLayout.LayoutParams	leftInParentParams;	public RelativeLayout.LayoutParams	bottomInLeftParams;	public LinearLayout.LayoutParams	Left_Bottom_Button_Params;	public RelativeLayout.LayoutParams	topInLeftParams;	public RelativeLayout.LayoutParams	Left_Top_Temp_Params;	public RelativeLayout.LayoutParams	Left_Top_Temp_ToggButton_Params;	public RelativeLayout.LayoutParams	Left_Top_Humi_Params;	public RelativeLayout.LayoutParams	Left_Center_CtrolButton_Params;	public RelativeLayout.LayoutParams[] Left_Center_CtrolButtons_Params;//左上右下	public RelativeLayout.LayoutParams	RightInParentParams;	public RelativeLayout.LayoutParams	Right_Surface_Params;	public RelativeLayout.LayoutParams[] Right_Scale_Button_Params;//大小	public RelativeLayout.LayoutParams	Right_Scale_View_Params;		//声明变量	public float scale;//dp -- px	public double screenSize;	public float density;	public int Screen_width;	public int Screen_height;	public int Bottom_Button_Width = 40;//dp	public int Bottom_Back_Height = 5;//dp	public int Bottom_Button_Number = 7;	public int Left_Bottom_Button_Width = 27;//dp	public int BottomInLeft_BottomMarge = 5;//5dp	public int Left_Bottom_Button_LeftMarge = 10;//dp	public int Left_Bottom_Button_Number = 3;	public int Left_Top_TopMarge = 5;	public int Left_Top_Temp_LeftMarge = 5;	public int Left_Top_Temp_TextSize = 18;	public int Left_Top_Temp_ToggButton_Width = 15;	public int Left_Top_Temp_ToggButton_Height = 15;	public int Left_Top_Temp_ToggButton_TopMarge = 5;	public int Left_Top_Humi_View_TopMarge = 5;	public int Left_Center_CtrolButton_Width = 150;	public int Left_Center_CtrolButton_Height = 150;	public int Left_Center_CtrolButton_LeftMarge = 20;	public int Left_Center_CtrolButton_BottomMarge = 20;	public int Right_Surface_LeftMarge = 5;	public int Left_Center_CtrolButton_LeftBtn_Width = 80;	public int Left_Center_CtrolButton_LeftBtn_Height = 50;	public int Left_Center_CtrolButton_UpBtn_Width = 50;	public int Left_Center_CtrolButton_UpBtn_Height = 60;	public int Right_Scale_Button_Width = 20;	public int Right_Scale_Button_Marge = 3;	public int Right_Scale_View_BottomMarge = 18;}

真机的显示效果如下：

 

两者虽然在真机上的效果差不多，但是实际是两种不同的实现方式。