VIew-CoordinatorLayout 笔记

CoordinatorLayout

协调者：一般会是两个控件，一个Dependency一个child ，CoordinatorLayout的主要功能就是协调这两个控件，使child跟随Dependency的布局变化而变化（比如：位置，大小等）。其中变化的规则，则是由一个CoordinatorLayout.Behavior来决定。demo：

一：布局

<?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:orientation="vertical">

    <com.kxl.mydemo.view.CoordinaterDependencyView
        android:id="@+id/coor_layout"
        android:layout_width="60dp"
        android:text="Dependency"
        android:textColor="#000000"
        android:layout_height="60dp"
        android:background="#55ff55" />

    <Button
        android:layout_width="100dp"
        android:layout_height="50dp"
        android:background="#ff5555"
        android:text="child"
        app:layout_behavior="com.kxl.mydemo.coordinator.MoveBehavior" />

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

二。自定义的一个，可移动的view：com.kxl.mydemo.view.CoordinaterDependencyView

import android.content.Context;
import android.support.design.widget.CoordinatorLayout;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
 * Created by kxl on 2016/10/18.
 */
public class CoordinaterDependencyView extends TextView {
    private  String TAG = "CoordinaterDependencyView";
    private int width;
    private int height;
    int lastx;
    int lasty;
    public CoordinaterDependencyView(Context context) {
        super(context);
        DisplayMetrics displayMetrics = context.getResources().getDisplayMetrics();
        int displaywidth =  displayMetrics.widthPixels;
        int displayheight =  displayMetrics.heightPixels;
        Log.i(TAG,"displaywidth:"+displaywidth+"  displayheight:"+displayheight);
    }
    public CoordinaterDependencyView(Context context, AttributeSet attrs) {
        super(context, attrs);
        width = getMeasuredWidth();
        height = getMeasuredHeight();
    }
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        int x = (int)event.getRawX();
        int y = (int)event.getRawY();
        Log.i(TAG,"onTouchEvent x:"+x+"  y:"+y);
        switch (event.getAction()){
            case MotionEvent.ACTION_DOWN:
                break;
            case MotionEvent.ACTION_MOVE:
                ViewGroup.MarginLayoutParams layoutParams = (ViewGroup.MarginLayoutParams) getLayoutParams();
                int nx = layoutParams.leftMargin+x-lastx;
                int ny = layoutParams.topMargin+y-lasty;
                layoutParams.leftMargin = nx;
                layoutParams.topMargin = ny;
                setLayoutParams(layoutParams);
                requestLayout();
                break;
            case MotionEvent.ACTION_UP:
                break;
            default:
                break;
        }
        lastx = x;
        lasty = y;
        return true;
    }
}

三：协调规则。Behavior：

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

import com.kxl.mydemo.view.CoordinaterDependencyView;
http://www.90168.org/
/**
 * Created by kxl on 2016/10/18.
 */
public class MoveBehavior extends CoordinatorLayout.Behavior<View> {
    int  width;
    public MoveBehavior(Context context, AttributeSet attrs) {
        super(context, attrs);
        DisplayMetrics display = context.getResources().getDisplayMetrics();
        width  = display.widthPixels;
    }
    /**
     * @return 返回是否是child依赖的布局
     */
    @Override
    public boolean layoutDependsOn(CoordinatorLayout parent, View child, View dependency) {
        return dependency instanceof CoordinaterDependencyView;
    }
    /**
     *  dependency控件有变化时，会调用这个方法
     */
    @Override
    public boolean onDependentViewChanged(CoordinatorLayout parent, View child, View dependency) {
        ViewGroup.MarginLayoutParams pa = (ViewGroup.MarginLayoutParams) child.getLayoutParams();
        pa.leftMargin = width  - dependency.getLeft();
        pa.topMargin =  dependency.getTop();
        child.setLayoutParams(pa);
        return true;
    }
}