android自定义View&&简单布局&&回调方法

2023-08-15 12:15:10

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>

</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：

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

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