自定义组合控件

 这里先不具体介绍如何实现一个自定义组合控件，这里先介绍一下自定义组合控件带来的好处。

• 提高布局文件开发效率
• 降低布局文件维护成本
• 降低布局文件和Activity代码耦合性
• 容易扩展
• 简单易用

 如何实现一个自定义组合控件

1.）先定义一个布局文件

<merge xmlns:android="http://schemas.android.com/apk/res/android">    <Button        android:id="@+id/title_bar_left"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentLeft="true"        android:layout_centerVertical="true"        android:layout_marginLeft="5dp"        android:background="@null"        android:minHeight="45dp"        android:minWidth="45dp"        android:textSize="14sp" />    <TextView        android:id="@+id/title_bar_title"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_centerInParent="true"        android:singleLine="true"        android:textSize="17sp" />    <Button        android:id="@+id/title_bar_right"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentRight="true"        android:layout_centerVertical="true"        android:layout_marginRight="7dp"        android:background="@null"        android:minHeight="45dp"        android:minWidth="45dp"        android:textSize="14sp" /></merge>

注意：这里为何要使用merge标签，自定义组合控件时会继承RelativeLayout、LinearLayout等控件，这样导致布局的层级无形中增加了一层，如下是对比：

未使用merge标签

 

使用merge标签

2.）定义自定义属性

比如标题文字、标题栏左边按钮图标等。

 <declare-styleable name="CustomTitleBar">        <attr name="title_background_color" format="reference|integer" />        <attr name="left_button_visible" format="boolean" />        <attr name="right_button_visible" format="boolean" />        <attr name="title_text" format="string" />        <attr name="title_text_color" format="color" />        <attr name="title_text_drawable" format="reference|integer" />        <attr name="right_button_text" format="string" />        <attr name="right_button_text_color" format="color" />        <attr name="right_button_drawable" format="reference|integer" />        <attr name="left_button_text" format="string" />        <attr name="left_button_text_color" format="color" />        <attr name="left_button_drawable" format="reference|integer" />    </declare-styleable>

3.）自定义一个View根据需求继承不同的ViewGroup子类，比如：RelativeLayout、LinearLayout等，我们这里继承RelativeLayout。

public class CustomTitleBar extends RelativeLayout {    private Button titleBarLeftBtn;    private Button titleBarRightBtn;    private TextView titleBarTitle;    public CustomTitleBar(Context context, AttributeSet attrs) {        super(context, attrs);        LayoutInflater.from(context).inflate(R.layout.custom_title_bar, this, true);        titleBarLeftBtn = (Button) findViewById(R.id.title_bar_left);        titleBarRightBtn = (Button) findViewById(R.id.title_bar_right);        titleBarTitle = (TextView) findViewById(R.id.title_bar_title);        TypedArray attributes = context.obtainStyledAttributes(attrs, R.styleable.CustomTitleBar);        if (attributes != null) {            //处理titleBar背景色            int titleBarBackGround = attributes.getResourceId(R.styleable.CustomTitleBar_title_background_color, Color.GREEN);            setBackgroundResource(titleBarBackGround);            //先处理左边按钮            //获取是否要显示左边按钮            boolean leftButtonVisible = attributes.getBoolean(R.styleable.CustomTitleBar_left_button_visible, true);            if (leftButtonVisible) {                titleBarLeftBtn.setVisibility(View.VISIBLE);            } else {                titleBarLeftBtn.setVisibility(View.INVISIBLE);            }            //设置左边按钮的文字            String leftButtonText = attributes.getString(R.styleable.CustomTitleBar_left_button_text);            if (!TextUtils.isEmpty(leftButtonText)) {                titleBarLeftBtn.setText(leftButtonText);                //设置左边按钮文字颜色                int leftButtonTextColor = attributes.getColor(R.styleable.CustomTitleBar_left_button_text_color, Color.WHITE);                titleBarLeftBtn.setTextColor(leftButtonTextColor);            } else {                //设置左边图片icon 这里是二选一 要么只能是文字 要么只能是图片                int leftButtonDrawable = attributes.getResourceId(R.styleable.CustomTitleBar_left_button_drawable, R.mipmap.titlebar_back_icon);                if (leftButtonDrawable != -1) {                    titleBarLeftBtn.setBackgroundResource(leftButtonDrawable);                }            }            //处理标题            //先获取标题是否要显示图片icon            int titleTextDrawable = attributes.getResourceId(R.styleable.CustomTitleBar_title_text_drawable, -1);            if (titleTextDrawable != -1) {                titleBarTitle.setBackgroundResource(titleTextDrawable);            } else {                //如果不是图片标题 则获取文字标题                String titleText = attributes.getString(R.styleable.CustomTitleBar_title_text);                if (!TextUtils.isEmpty(titleText)) {                    titleBarTitle.setText(titleText);                }                //获取标题显示颜色                int titleTextColor = attributes.getColor(R.styleable.CustomTitleBar_title_text_color, Color.WHITE);                titleBarTitle.setTextColor(titleTextColor);            }            //先处理右边按钮            //获取是否要显示右边按钮            boolean rightButtonVisible = attributes.getBoolean(R.styleable.CustomTitleBar_right_button_visible, true);            if (rightButtonVisible) {                titleBarRightBtn.setVisibility(View.VISIBLE);            } else {                titleBarRightBtn.setVisibility(View.INVISIBLE);            }            //设置右边按钮的文字            String rightButtonText = attributes.getString(R.styleable.CustomTitleBar_right_button_text);            if (!TextUtils.isEmpty(rightButtonText)) {                titleBarRightBtn.setText(rightButtonText);                //设置右边按钮文字颜色                int rightButtonTextColor = attributes.getColor(R.styleable.CustomTitleBar_right_button_text_color, Color.WHITE);                titleBarRightBtn.setTextColor(rightButtonTextColor);            } else {                //设置右边图片icon 这里是二选一 要么只能是文字 要么只能是图片                int rightButtonDrawable = attributes.getResourceId(R.styleable.CustomTitleBar_right_button_drawable, -1);                if (rightButtonDrawable != -1) {                    titleBarRightBtn.setBackgroundResource(rightButtonDrawable);                }            }            attributes.recycle();        }    }    public void setTitleClickListener(OnClickListener onClickListener) {        if (onClickListener != null) {            titleBarLeftBtn.setOnClickListener(onClickListener);            titleBarRightBtn.setOnClickListener(onClickListener);        }    }    public Button getTitleBarLeftBtn() {        return titleBarLeftBtn;    }    public Button getTitleBarRightBtn() {        return titleBarRightBtn;    }    public TextView getTitleBarTitle() {        return titleBarTitle;    }}

4.）在不同的XML布局中引用

关于如何使用自定义属性这里就不再说明了，为了更加直观的查看效果，我这里在一个布局文件中实现不同要求的标题栏

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:lee="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical">    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:right_button_drawable="@mipmap/titlebar_add_icon"        lee:title_background_color="@color/green"        lee:title_text="标题1" />    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:right_button_visible="false"        lee:title_background_color="@color/green"        lee:title_text="标题2" />    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:left_button_text="左边"        lee:right_button_text="右边"        lee:title_background_color="@color/red"        lee:title_text="标题3" />    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:left_button_text="左边"        lee:right_button_drawable="@mipmap/titlebar_add_icon"        lee:title_background_color="@color/red"        lee:title_text="标题4" />    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:left_button_text="左边"        lee:left_button_text_color="@color/red"        lee:right_button_drawable="@mipmap/titlebar_add_icon"        lee:title_background_color="@color/blue"        lee:title_text="标题5" />    <com.whoislcj.views.CustomTitleBar        android:layout_width="match_parent"        android:layout_height="45dp"        android:layout_marginTop="10dp"        lee:left_button_text="左边"        lee:left_button_text_color="@color/red"        lee:right_button_drawable="@mipmap/titlebar_add_icon"        lee:title_background_color="@color/blue"        lee:title_text="标题6"        lee:title_text_color="@color/black" /></LinearLayout>