自定义控件（18）---自定义控件之面板思想---addRule

attrs.xml（第一步，在这里）

 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <!-- R.styleable.TopBar_titleTextColor在R文件中是这样的形式 -->
     <declare-styleable name="TopBar">

         <!-- 文字 -->
         <attr name="leftText" format="string" />
         <attr name="rightText" format="string" />
         <attr name="titleText" format="string" />
         <!-- 文字颜色 -->
         <attr name="leftTextColor" format="color" />
         <attr name="rightTextColor" format="color" />
         <attr name="titleTextColor" format="color" />
         <!-- 文字大小 -->
         <attr name="titleTextSize" format="dimension" />
         <!-- 背景色 -->
         <attr name="leftBackground" format="reference|color" />
         <attr name="rightBackground" format="reference|color" />
     </declare-styleable>

 </resources>

activity_main.xml（命名空间需要注意）

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res/com.example.custometopbarui"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     tools:context="com.sloop.topbar.MainActivity" >

     <com.example.custometopbarui.TopBar
         android:id="@+id/topbar"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:minHeight="48dp"
         app:leftBackground="@drawable/ic_launcher"
         app:leftText="左侧"
         app:rightBackground="@drawable/ic_launcher"
         app:rightText="右侧"
         app:titleText="自定义标题"
         app:titleTextColor="#ffffff"
         app:titleTextSize="8sp" >
     </com.example.custometopbarui.TopBar>

 </RelativeLayout>

TopBar（注释很详细）

 package com.example.custometopbarui;

 import android.content.Context;
 import android.content.res.TypedArray;
 import android.graphics.Color;
 import android.graphics.drawable.Drawable;
 import android.util.AttributeSet;
 import android.view.Gravity;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.Button;
 import android.widget.RelativeLayout;
 import android.widget.TextView;



 public class TopBar extends RelativeLayout {

     /**
      * 定义三个控件，
      */
     private Button leftButton, rightButton;
     private TextView title;

     //左侧button属性
     private int leftTextColor;
     private Drawable leftBackground;
     private String leftText;

     //右侧button属性
     private int rightTextColor;
     private Drawable rightBackground;
     private String rightText;

     //title属性
     private int titleTextColor;
     private float titleTextSize;
     private String titleText;

     //因为容器
     private LayoutParams leftParams, rirhtParams, titleParams;

     //定义接口对象
     private TopBarClickListener listener;

     /**
      * 点击事件监听器接口
      * @author Administrator
      *
      */
     public interface TopBarClickListener {

         public void leftclick();

         public void rightclick();
     }

     //设置监听器
     public void setOnTopBarClickListener(TopBarClickListener listener){
         this.listener = listener;
     }

     /**
      * 对外暴露的方法
      * @param visible
      */
     public void setLeftIsVisible(boolean visible){
         if (visible) {
             leftButton.setVisibility(View.VISIBLE);
         } else {
             leftButton.setVisibility(View.GONE);
         }
     }
     public void setRightIsVisible(boolean visible){
         if (visible) {
             rightButton.setVisibility(View.VISIBLE);
         } else {
             rightButton.setVisibility(View.GONE);
         }
     }

     /**
      * 构造器
      * @param context
      * @param attrs
      */
     public TopBar(Context context, AttributeSet attrs){

         super(context, attrs);
         //获取自定义属性和值的映射集合
         TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.TopBar);

         //取出自定义属性 - 左侧
         leftTextColor = ta.getColor(R.styleable.TopBar_leftTextColor, Color.BLACK);
         leftBackground = ta.getDrawable(R.styleable.TopBar_leftBackground);
         leftText = ta.getString(R.styleable.TopBar_leftText);

         //取出自定义属性 - 右侧
         rightTextColor = ta.getColor(R.styleable.TopBar_rightTextColor, Color.BLACK);
         rightBackground = ta.getDrawable(R.styleable.TopBar_rightBackground);
         rightText = ta.getString(R.styleable.TopBar_rightText);

         //取出自定义属性 - 标题
         titleTextColor = ta.getColor(R.styleable.TopBar_titleTextColor, Color.BLACK);
         titleTextSize = ta.getDimension(R.styleable.TopBar_titleTextSize, 12);
         titleText = ta.getString(R.styleable.TopBar_titleText);
         //回收TypedArray（避免浪费资源，避免因为缓存导致的错误）

         ta.recycle();

         /**
          * 创建控件对象
          */
         leftButton = new Button(context);
         rightButton = new Button(context);
         title = new TextView(context);

         /**
          * 为各个控件设置属性 - 左侧
          */
         leftButton.setText(leftText);
         leftButton.setTextColor(leftTextColor);
         leftButton.setBackground(leftBackground);

         //设置属性 - 右侧
         rightButton.setText(rightText);
         rightButton.setTextColor(rightTextColor);
         rightButton.setBackground(rightBackground);

         //设置属性 - 标题
         title.setText(titleText);
         title.setTextSize(titleTextSize);
         title.setTextColor(titleTextColor);
         title.setGravity(Gravity.CENTER);

         //设置整体背景颜色
         setBackgroundColor(0xfff59563);

         /**
          * 为各个控件设置布局 - 左
          */
         //设置宽高
         leftParams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
         //添加规则
         leftParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT, TRUE);
         leftParams.addRule(RelativeLayout.CENTER_VERTICAL, TRUE);
         addView(leftButton, leftParams);//将按钮添加进布局中

         //设置布局 - 右
         rirhtParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
         rirhtParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, TRUE);
         rirhtParams.addRule(RelativeLayout.CENTER_VERTICAL, TRUE);
         addView(rightButton, rirhtParams);//将按钮添加进布局中

         //设置布局 - 标题
         titleParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
         titleParams.addRule(RelativeLayout.CENTER_IN_PARENT, TRUE);
         addView(title, titleParams);//将按钮添加进布局中

         /**
          * 设置监听器
          */
         leftButton.setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v){

                 //这里写一个接口回调方法，让外部去实现即可
                 listener.leftclick();
             }
         });
         rightButton.setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v){

                 listener.rightclick();
             }
         });
     }

 }

MainActivity

 package com.example.custometopbarui;

 import com.example.custometopbarui.TopBar.TopBarClickListener;

 import android.app.Activity;
 import android.os.Bundle;
 import android.widget.Toast;



 public class MainActivity extends Activity {

     @Override
     protected void onCreate(Bundle savedInstanceState){

         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);
         TopBar topBar = (TopBar) findViewById(R.id.topbar);
         topBar.setLeftIsVisible(false);
 //      topBar.setRightIsVisible(false);
         topBar.setOnTopBarClickListener(new TopBarClickListener() {

             @Override
             public void rightclick(){
                 Toast.makeText(MainActivity.this, "Right Clicked", Toast.LENGTH_SHORT).show();
             }

             @Override
             public void leftclick(){
                 Toast.makeText(MainActivity.this, "Left Clicked", Toast.LENGTH_SHORT).show();
             }
         });
     }

 }