Android代码布局-工具封装

Android代码布局-工具封装

android中的xml十分方便，在大部分时候xml基本上都能解决问题了，不过有的时候还是不得不用上代码布局，比如动态布局， 或者是通过代码布局来获得更好的复用性。实际上代码布局是相对比较麻烦，因为设置View的属性的时候， 我们需要关心父布局到底是什么布局，才能设置相应的Param，本文讲讲，如何封装代码，让代码布局和xml布局变得一样简单。

效果图

我们要实现一个这样的简单的布局，用xml实现非常简单，不过xml的代码量也是不少了，但主要是复制粘贴，所以还是很快的。

xml实现

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:padding="10dp"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:layout_margin="10dp"
            android:background="@color/graycolor">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:text="No.1"
                android:gravity="center_vertical"
                android:layout_marginLeft="10dp"
                android:textSize="20dp"/>
        LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:layout_margin="10dp"
            android:background="@color/graycolor">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:text="No.2"
                android:gravity="center_vertical"
                android:layout_marginLeft="10dp"
                android:textSize="20dp"/>
        LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="100dp"
            android:layout_margin="10dp"
            android:background="@color/graycolor">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="match_parent"
                android:text="No.2"
                android:gravity="center_vertical"
                android:layout_marginLeft="10dp"
                android:textSize="20dp"/>
        LinearLayout>
    LinearLayout>
    <View
        android:layout_width="100dp"
        android:layout_height="100dp"
        android:background="@color/DarkGray2"
        android:layout_centerInParent="true"/>
RelativeLayout>

封装Util实现

public class TestView extends RelativeLayout {
    public TestView(Context context) {
        this(context,null);
    }

    public TestView(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public TestView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);

        LinearLayout ll_content = new LinearLayout(context);
        ParamUtil.rl_param(ll_content, WhType.match, WhType.match)
                .padding(10);
        ll_content.setOrientation(LinearLayout.VERTICAL);
        this.addView(ll_content);

        View center_view = new View(context);
        ParamUtil.rl_param(center_view, WhType.dp(20), WhType.dp(20))
                .centerInParent();
        center_view.setBackgroundColor(getResources().getColor(R.color.DarkGray2));
        this.addView(center_view);

        ll_content.addView(createLinear(context,"No.1"));
        ll_content.addView(createLinear(context,"No.2"));
        ll_content.addView(createLinear(context,"No.3"));
    }

    public LinearLayout createLinear(Context context, String text) {
        LinearLayout ll_cell = new LinearLayout(context);
        ParamUtil.ll_param(ll_cell, WhType.match, WhType.dp(100))
                .margin(10);
        TextView textView = new TextView(context);
        ParamUtil.ll_param(textView, WhType.wrap, WhType.match)
                .marginLeft(10);
        textView.setText(text);
        ll_cell.addView(textView);
        return ll_cell;
    }
}

看着是不是也还比较简单，代码量基本上差不太多，核心代码也就30行。
如果父布局是RelativeLayout，子布局就用ParamUtil.rl_param()去设置相关属性。
如果父布局是LinearLayout ，子布局就用ParamUtil.ll_param()去设置相关属性。
match，wrap，dp 直接输入就有提示，使用起来算是很方便了，dsl是没有用过，自己封装的也算是一个简易版的util吧。

封装代码

enum LayoutType{
    linear, relate,frame;
}

public class WhType {
    public static final WhType match = new WhType(ViewGroup.LayoutParams.MATCH_PARENT);
    public static final WhType wrap = new WhType(ViewGroup.LayoutParams.WRAP_CONTENT);

    public static WhType dp(int size) {
        return new WhType((int) dp2px(PanamaApplication.getmContext(), size));
    }

    int size = 0;

    public WhType(int size) {
        this.size = size;
    }

    static float dp2px(Context context, float dp) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return dp * scale + 0.5f;
    }
}

public class ParamUtil {
    View view;
    LayoutType type;
    ViewGroup.LayoutParams params;

    WhType width;
    WhType height;
    private float weight;

    private int margin;
    private int marginLeft;
    private int marginRight;
    private int marginTop;
    private int marginBottom;

    private int padding;
    private int paddingLeft;
    private int paddingRight;
    private int paddingTop;
    private int paddingBottom;

    public static ParamUtil ll_param(View view, WhType width, WhType height) {
        return new ParamUtil(LayoutType.linear, view, width, height);
    }

    public static ParamUtil fl_param(View view, WhType width, WhType height) {
        return new ParamUtil(LayoutType.frame, view, width, height);
    }

    public static ParamUtil rl_param(View view, WhType width, WhType height) {
        return new ParamUtil(LayoutType.relate, view, width, height);
    }

    public ParamUtil(LayoutType type, View view, WhType width, WhType height) {
        this.type = type;
        this.view = view;
        this.width = width;
        this.height = height;
        switch (type) {
            case linear:
                params = new LinearLayout.LayoutParams(
                        width.size,
                        height.size
                );
                break;
            case relate:
                params = new RelativeLayout.LayoutParams(
                        width.size,
                        height.size
                );
                break;
            case frame:
                params = new FrameLayout.LayoutParams(
                        width.size,
                        height.size
                );
                break;
        }
        view.setLayoutParams(params);
    }

    //只有LinearLayout才有
    public ParamUtil weight(float weight) {
        this.weight = weight;
        if (params instanceof LinearLayout.LayoutParams) {
            ((LinearLayout.LayoutParams) params).weight = weight;
        }
        return this;
    }


    //只有RelativeLayout才有
    public ParamUtil centerInParent() {
        if (params instanceof RelativeLayout.LayoutParams) {
            ((RelativeLayout.LayoutParams) params).addRule(RelativeLayout.CENTER_IN_PARENT, RelativeLayout.TRUE);
        }
        return this;
    }

    private void setPadding(int left, int top, int right, int bottom) {
        this.paddingLeft = left;
        this.paddingRight = right;
        this.paddingTop = top;
        this.paddingBottom = bottom;
        view.setPadding((int) dp2px(left), (int) dp2px(top), (int) dp2px(right), (int) dp2px(bottom));
    }

    private void setMargin(int left, int top, int right, int bottom) {
        this.marginLeft = left;
        this.marginRight = right;
        this.marginTop = top;
        this.marginBottom = bottom;
        if (params instanceof LinearLayout.LayoutParams) {
            ((LinearLayout.LayoutParams) params)
                    .setMargins((int) dp2px(left), (int) dp2px(top), (int) dp2px(right), (int) dp2px(bottom));
        } else if (params instanceof RelativeLayout.LayoutParams) {
            ((RelativeLayout.LayoutParams) params)
                    .setMargins((int) dp2px(left), (int) dp2px(top), (int) dp2px(right), (int) dp2px(bottom));
        } else if (params instanceof FrameLayout.LayoutParams) {
            ((FrameLayout.LayoutParams) params)
                    .setMargins((int) dp2px(left), (int) dp2px(top), (int) dp2px(right), (int) dp2px(bottom));
        }
    }

    public ParamUtil margin(int margin) {
        this.margin = margin;
        setMargin(margin, margin, margin, margin);
        view.setLayoutParams(params);
        return this;
    }

    public ParamUtil marginLeft(int marginLeft) {
        this.marginLeft = marginLeft;
        setMargin(marginLeft, marginTop, marginRight, marginBottom);
        view.setLayoutParams(params);
        return this;
    }

    public ParamUtil marginRight(int marginRight) {
        this.marginRight = marginRight;
        setMargin(marginLeft, marginTop, marginRight, marginBottom);
        view.setLayoutParams(params);
        return this;
    }

    public ParamUtil marginTop(int marginTop) {
        this.marginTop = marginTop;
        setMargin(marginLeft, marginTop, marginRight, marginBottom);
        view.setLayoutParams(params);
        return this;
    }

    public ParamUtil marginBottom(int marginBottom) {
        this.marginBottom = marginBottom;
        setMargin(marginLeft, marginTop, marginRight, marginBottom);
        view.setLayoutParams(params);
        return this;
    }

    public ParamUtil padding(int padding) {
        this.padding = padding;
        view.setPadding(padding, padding, padding, padding);
        return this;
    }

    public ParamUtil paddingLeft(int paddingLeft) {
        this.paddingLeft = paddingLeft;
        view.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
        return this;
    }

    public ParamUtil paddingTop(int paddingTop) {
        this.paddingTop = paddingTop;
        view.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
        return this;
    }

    public ParamUtil paddingRight(int paddingRight) {
        this.paddingRight = paddingRight;
        view.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
        return this;
    }

    public ParamUtil paddingBottom(int paddingBottom) {
        this.paddingBottom = paddingBottom;
        view.setPadding(paddingLeft, paddingTop, paddingRight, paddingBottom);
        return this;
    }

    private float dp2px(float dp) {
        final float scale = MyApplication.getmContext().getResources().getDisplayMetrics().density;
        return dp * scale + 0.5f;
    }
}

以上还只是一个非常基础的封装版本，需要的话，可以自行补充，扩展其实也是很简单的。

总结

希望能给需要的朋友一点提示一点帮助吧。