CoordinatorLayout使用（一）：Behavior简单理解

dodo_lihao

发布于 2018-09-12 10:40:28

1.1K0

发布于 2018-09-12 10:40:28

CoordinatorLayout介绍

CoordinatorLayout出来很久了，时间关系，一直没有怎么弄过看见简友的描述 r17171709 的 http://www.jianshu.com/p/b8828afded8a 文章自己抽出时间，简单看看

先访问外国网站到文档看看说明： https://developer.android.com/reference/android/support/design/widget/CoordinatorLayout.html 我们知道是一个 super-powered FrameLayout 【强大的FrameLayout】再就是大体有2个用途：

顶部的layout装饰
一个容器和其他一个或者多个子View的交互通常和 CoordinatorLayout.Behavior<V extends View> 一起使用。当然，如果是和固定关联，也可以用注解去操作。比如，@DefaultBehavior(MyBehavior.class)

自己只是简单使用和记录，有问题的地方，欢迎拍砖

简单说明

先写一个自定义的TextView 用于捕捉滑动使用

DodoMoveView

package com.aohuan.dodo.coordinator.view;

import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.TextView;

/**
 * Created by dodo on 2016/10/31.
 * qq: 2390183798
 */
public class DodoMoveView extends TextView {

    private int lastX;
    private int lastY;
//    private int mWidth;
//    private int mHeight;

    public DodoMoveView(Context context, AttributeSet attrs) {
        super(context, attrs);

//        mWidth = getMeasuredWidth();
//        mHeight = getMeasuredHeight();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        int x = (int) event.getRawX();
        int y = (int) event.getRawY();

        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                break;

            case MotionEvent.ACTION_MOVE:
                CoordinatorLayout.MarginLayoutParams layoutParams = (CoordinatorLayout.MarginLayoutParams) getLayoutParams();
                int left = layoutParams.leftMargin + x - lastX;
                int top = layoutParams.topMargin + y - lastY;

                layoutParams.leftMargin = left;
                layoutParams.topMargin = top;
                setLayoutParams(layoutParams);
                requestLayout();
                break;

            case MotionEvent.ACTION_UP:
                break;
        }
        lastX = x;
        lastY = y;
        return true;
    }

}

简单放置到一个 CoordinatorLayout 中对应的layout ：

activity_main0.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!--android:layout_gravity="top|right"-->

    <com.aohuan.dodo.coordinator.view.DodoMoveView
        android:layout_gravity="top"
        android:layout_width="150dp"
        android:layout_height="100dp"
        android:text="Main"
        android:gravity="center"
        android:background="#666666" />


    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="100dp"
        android:background="#888888"
        android:layout_gravity="top|left"
        android:text="  Dodo Follow  "
        />

</android.support.design.widget.CoordinatorLayout>

自定义的View

CoordinatorLayout 和 Behavior 的使用

这个时候我们还是用前面那个layout 需要先写一个Behavior 具体可以参考文档： https://developer.android.com/reference/android/support/design/widget/CoordinatorLayout.Behavior.html 对应的使用，后面会慢慢接触

这里，我们写一个 Behavior的子类

DodoBehavior0s

package com.aohuan.dodo.coordinator.utils;

import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.View;
import android.widget.Button;

import com.aohuan.dodo.coordinator.view.DodoMoveView;

/**
 * Created by dodo on 2016/10/31.
 * qq: 2390183798
 *
 * 在y轴 方向跟着移动的 Behavior
 */
public class DodoBehavior0s extends CoordinatorLayout.Behavior<Button> {

    public DodoBehavior0s(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, Button child, View dependency) {
        //如果dependency 是 DodoMoveView类型， 就依赖
        return dependency instanceof DodoMoveView;
    }

    //每次dependency位置发生变化，都会执行onDependentViewChanged方法
    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, Button btn, View dependency) {

        //根据dependency的位置，设置Button的位置
        int x = 0;
        int y = (int) dependency.getY();
        setPosition(btn, x, y);
        return true;
    }

    private void setPosition(View v, int x, int y) {
        CoordinatorLayout.MarginLayoutParams layoutParams = (CoordinatorLayout.MarginLayoutParams) v.getLayoutParams();
        layoutParams.leftMargin = x;
        layoutParams.topMargin = y;
        v.setLayoutParams(layoutParams);
    }

}

这里有2个方法

public boolean layoutDependsOn(CoordinatorLayout parent, Button child, View dependency)
- Determine whether the supplied child view has another specific sibling view as a layout dependency.
- 也就是，是否关联
- 这里，移动的是 DodoMoveView的时候，可以跟着触发
- 当然，也可以通过自定义View传入id 比对，或者别的方式，来设置是否跟着触发
boolean onDependentViewChanged(CoordinatorLayout parent, Button btn, View dependency)
- Respond to a change in a child's dependent view
- A view's dependency is determined by
- [layoutDependsOn(CoordinatorLayout, android.view.View, android.view.View)](https://developer.android.com/reference/android/support/design/widget/CoordinatorLayout.Behavior.html#layoutDependsOn(android.support.design.widget.CoordinatorLayout, V, android.view.View))
- or if child has set another view as it's anchor.
- boolean true if the Behavior changed the child view's size or position, false otherwise
- 也就是说，上面onDependentViewChanged 方法为true的时候
- 可以设置对应位置和大小
- 自己返回true，则改变，返回false，自己不改变位置和大小

对应的实现，也挺简单

对应的判断在这里，肯定是true
后面的位置，设置x为0， y为前面的MainView的Y值，即可

这个时候，我们给layout中前面的Button添加这个Behavior

activity_main1.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/btn"
        android:layout_width="wrap_content"
        android:layout_height="100dp"
        android:background="#888888"
        android:text="  Dodo Follow  "
        android:layout_gravity="top|left"
        app:layout_behavior="com.aohuan.dodo.coordinator.utils.DodoBehavior0s"
        />

    <!--android:layout_gravity="top|right"-->
    <com.aohuan.dodo.coordinator.view.DodoMoveView
        android:text="Main"
        android:gravity="center"
        android:layout_gravity="top"
        android:layout_width="150dp"
        android:layout_height="100dp"
        android:background="#666666" />

</android.support.design.widget.CoordinatorLayout>

我们来看一下效果：

如果我们简单把右边的固定一下（通过layout或者代码都可以）可以得到效果

Behavior的简单修改

这个时候，我们简单修改Behavior 再看看效果

package com.aohuan.dodo.coordinator.utils;

import android.content.Context;
import android.graphics.Rect;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.view.View;
import android.widget.Button;

import com.aohuan.dodo.coordinator.view.DodoMoveView;

/**
 * Created by dodo on 2016/10/31.
 * qq: 2390183798
 *
 * 可以跟着Main View 旋转， 对着
 */
public class DodoBehavior0z extends CoordinatorLayout.Behavior<Button> {

    private Context mContext;

    private int width;
    private int height;

    public DodoBehavior0z(Context context, AttributeSet attrs) {
        super(context, attrs);
        this.mContext = context;
        DisplayMetrics display = context.getResources().getDisplayMetrics();
        width = display.widthPixels;
        height = display.heightPixels;
    }

    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, Button child, View dependency) {
        //如果dependency是TempView的实例，说明它就是我们所需要的Dependency
        return dependency instanceof DodoMoveView;
    }

    //每次dependency位置发生变化，都会执行onDependentViewChanged方法
    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, Button btn, View dependency) {

        //根据dependency的位置，设置Button的位置

        int top = dependency.getTop();
        int left = dependency.getLeft();

        int x = width - left - btn.getWidth();
        int y = height - top - btn.getHeight();

        setPosition(btn, x, y);
        return true;
    }

    private void setPosition(View v, int x, int y) {
        CoordinatorLayout.MarginLayoutParams layoutParams = (CoordinatorLayout.MarginLayoutParams) v.getLayoutParams();
        layoutParams.leftMargin = x;
        layoutParams.topMargin = y;
        layoutParams.width = y/2;
        v.setLayoutParams(layoutParams);
    }
}

这里也就是只是把x，y值，动态计算一下再动态设置一下宽度

看一下效果：