android自定义View&&简单布局&&回调方法

一、内容描述

根据“慕课网”上的教程，实现一个自定义的View,且该View中使用自定义的属性，同时为该自定义的View定义点击事件的回调方法。

二、定义自定义的属性

在res/valus/ 文件夹下创建一个 attrs.xml 的属性定义文件，内容如下：

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <declare-styleable name="HeadBar">
        <attr name="leftButtonText" format="string" />
        <attr name="leftButtonTextColor" format="color|reference" />
        <attr name="leftButtonTextSize" format="dimension"></attr>
        <attr name="centerTextViewText" format="string"></attr>
        <attr name="centerTextViewTextSize" format="dimension"></attr>
        <attr name="centerTextViewColor" format="color|reference"></attr>
        <attr name="rightButtonText" format="string" />
        <attr name="rightButtonTextColor" format="color|reference" />
        <attr name="rightButtonTextSize" format="dimension"></attr>
    </declare-styleable>

<attr name="backgroud_color" format="string"></attr>
   <attr name="bc" format="color|reference"></attr>

</resources>

三、定义使用它的布局文件

这里使用MainActivity的activity_main.xml,内容如下，

其中  xmlns:lib="http://schemas.android.com/apk/res-auto"  一行是定义一个第三方库的名字空间，本例中即为了可以使用自定义的属性

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <com.baidu.lulei.customview.HeadBar
        xmlns:lib="http://schemas.android.com/apk/res/com.baidu.lulei.customview"
        android:id="@+id/headbar"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        lib:backgroud_color="backgroud_color"
        lib:bc="#000011"
        lib:centerTextViewColor="#ff00ff"
        lib:centerTextViewText="标题"
        lib:centerTextViewTextSize="20sp"
        lib:leftButtonText="返回"
        lib:leftButtonTextColor="#ff0000"
        lib:leftButtonTextSize="20sp"
        lib:rightButtonText="分享"
        lib:rightButtonTextColor="#0000ff"
        lib:rightButtonTextSize="20sp" >
    </com.baidu.lulei.customview.HeadBar>

</RelativeLayout>

四、自定义 HeadBar  类型的View

本例中是它继承自RelativeLayout，因为本例中自定义的View本质上它类似一个容器，为了方便布局，这里使用才集成字RelativeLayout，当然你也可以继承自其它类型的ViewGroup

istener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.leftButtonClick(v);
            }
        });

        rightButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.rightButtonClick(v);
            }
        });

        this.centerText.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.centerTextViewClick(v);
            }
        });
    }

    public static interface ClickListerner {
        public void leftButtonClick(View v);

        public void rightButtonClick(View v);

        public void centerTextViewClick(View v);
    }
}

五、测试它

从上面的activity_main.xml 布局文件中可以看到，它内部使用了一个自定义类型的HeadBar的View,所以可以在MainActivity中测试它，可以看到我们可以在外部定一个回调方法给自定义的View使用。

package com.baidu.lulei.customview;

import android.content.Context;
import android.content.res.TypedArray;
import android.util.AttributeSet;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.RelativeLayout;
import android.widget.TextView;

public class HeadBar extends RelativeLayout {
    private Button leftButton;
    private Button rightButton;
    private TextView centerText;

    private ClickListerner listener;

    public void setListener(ClickListerner listener) {
        this.listener = listener;
    }

    public HeadBar(Context context, AttributeSet attrs) {
        super(context, attrs);
        leftButton = new Button(context);
        rightButton = new Button(context);
        centerText = new TextView(context);
        TypedArray ta = context.obtainStyledAttributes(attrs,
                R.styleable.HeadBar);

        String backgroundcolor = attrs
                .getAttributeValue(
                        "http://schemas.android.com/apk/res/com.baidu.lulei.customview",
                        "backgroud_color");
        int bc = attrs
                .getAttributeIntValue(
                        "http://schemas.android.com/apk/res/com.baidu.lulei.customview",
                        "bc", 0xff0000ff);
        Log.e("Log", "bc :" + bc);
        Log.e("Log", "backgroundcolor :" + backgroundcolor);
        // 初始化左边的那个button
        int leftButtonTextColor = ta.getColor(
                R.styleable.HeadBar_leftButtonTextColor, 0x000011);
        String leftButtonText = ta
                .getString(R.styleable.HeadBar_leftButtonText);

        float leftButtonTextSize = ta.getDimension(
                R.styleable.HeadBar_leftButtonTextSize, );

        leftButton.setText(leftButtonText);
        leftButton.setTextSize(leftButtonTextSize);
        leftButton.setTextColor(leftButtonTextColor);

        // 初始化右边的那个button

        int rightButtonTextColor = ta.getColor(
                R.styleable.HeadBar_rightButtonTextColor, 0xff0000ff);
        String rightButtonText = ta
                .getString(R.styleable.HeadBar_rightButtonText);

        float rightButtonTextSize = ta.getDimension(
                R.styleable.HeadBar_rightButtonTextSize, );
        rightButton.setText(rightButtonText);
        rightButton.setTextSize(rightButtonTextSize);
        rightButton.setTextColor(rightButtonTextColor);

        // 初始化中间的TextView
        int centerTextColor = ta.getColor(
                R.styleable.HeadBar_centerTextViewColor, 0xff000000);
        String centerText = ta
                .getString(R.styleable.HeadBar_centerTextViewText);
        float centerTextSize = ta.getDimension(
                R.styleable.HeadBar_centerTextViewTextSize, );
        this.centerText.setText(centerText);
        this.centerText.setTextSize(centerTextSize);
        this.centerText.setTextColor(centerTextColor);
        // 释放TypedArray
        ta.recycle();

        // 开始布局

        RelativeLayout.LayoutParams leftButtonLayoutParams = new LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        leftButtonLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
        leftButton.setLayoutParams(leftButtonLayoutParams);

        RelativeLayout.LayoutParams rightButtonLayoutParams = new LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

        rightButtonLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT);
        rightButton.setLayoutParams(rightButtonLayoutParams);

        RelativeLayout.LayoutParams centerTextLayoutParams = new LayoutParams(
                LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
        centerTextLayoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
        centerTextLayoutParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);

        this.centerText.setLayoutParams(centerTextLayoutParams);
        Log.e("Tag", "" + leftButton.getId());
        // 将布局好的三个控件放入自定义的view中去
        addView(leftButton);
        addView(rightButton);
        addView(this.centerText);

        // 添加点击事件
        leftButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.leftButtonClick(v);
            }
        });

        rightButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.rightButtonClick(v);
            }
        });

        this.centerText.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                if (listener != null)
                    listener.centerTextViewClick(v);
            }
        });
    }

    public static interface ClickListerner {
        public void leftButtonClick(View v);

        public void rightButtonClick(View v);

        public void centerTextViewClick(View v);
    }
}

六、效果

  

七、注意

1. 常见自定义属性的值类型有哪些？

属性类型	使用demo
<attr name = "background" format = "reference" />	android:background = "@drawable/图片ID"
<attr name = "textColor" format = "color" />	android:textColor = "#00FF00"
<attr name = "focusable" format = "boolean" />	android:focusable = "true|false"
<attr name = "layout_width" format = "dimension" />	android:layout_width = "42dip|42sp|42px"
<attr name = "fromAlpha" format = "float" />	android:fromAlpha = "1.0"
<attr name = "frameDuration" weight="integer" />	android:weight = "12"
<attr name = "apiKey" format = "string" />	android:apiKey = "this_is_a_string"
<attr name = "pivotX" format = "fraction" />	android:pivotX = "200%"
<attr name="orientation"> <enum name="horizontal" value="0" /> <enum name="vertical" value="1" /> </attr>	android:orientation = "vertical"
<attr name="windowSoftInputMode"> <flag name = "stateUnspecified" value = "0" /> <flag name = "stateUnchanged" value = "1" /> <flag name = "stateHidden" value = "2" /> <flag name = "stateAlwaysHidden" value = "3" /> <flag name = "stateVisible" value = "4" /> <flag name = "stateAlwaysVisible" value = "5" /> </attr>	android:windowSoftInputMode = "stateHidden">

2. attrs.xml中自己使用<attr/>标签的属性怎么获取?

如下两个属性，声明在declare-styleable之外，获取它的值呢？

声明：

<attr name="backgroud_color" format="string"></attr>
<attr name="bc" format="color|reference"></attr>

使用：

注意现在lib是 名字空间   xmlns:lib="http://schemas.android.com/apk/res/"+"应用包名"   的形式

lib:bc="#000011"
lib:backgroud_color="backgroud_color"

获取：

String backgroundcolor = attrs.getAttributeValue("http://schemas.android.com/apk/res/com.baidu.lulei.customview","backgroud_color");
int bc = attrs.getAttributeIntValue("http://schemas.android.com/apk/res/com.baidu.lulei.customview","bc", 0xff0000ff);

3. 读取自定义属性时使用的自定义空间命名规则如何？

如果都是在declare-styleable中声明的属性，那么名字空间可以使用

http://schemas.android.com/apk/res/+”应用包名” 或者 http://schemas.android.com/apk/res-auto

而如果你使用自定义属性是在attr中单独定义的，那么请你使用前者。

4. 附源代码下载  https://github.com/LuLei2013/CustomView.git