事件机制(经典案例+宅男福利)

——————————————————效果图如上————————————————

效果是：屏幕左中右都可以独立的上下拖动，前提是在高度一半的下方，在屏幕上半部分向上拖动，是整体图片向上拖动

activity_main.xml

<com.atguigu.pinterestlistview.MyLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/mll"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <ListView
        android:id="@+id/lv2"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:scrollbars="none" />

    <ListView
        android:id="@+id/lv1"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:scrollbars="none" />

    <ListView
        android:id="@+id/lv3"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="wrap_content"
        android:scrollbars="none" />

</com.atguigu.pinterestlistview.MyLinearLayout>

lv_item.xml

<ImageView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/iv"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:adjustViewBounds="true"
    android:src="@drawable/default1" />

MainActivity.java

package com.atguigu.pinterestlistview;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;

public class MainActivity extends Activity {
	/*
	 * 定义三个listview
	 */
	private ListView lv1;
	private ListView lv2;
	private ListView lv3;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		//获取listview
		lv1 = (ListView) findViewById(R.id.lv1);
		lv2 = (ListView) findViewById(R.id.lv2);
		lv3 = (ListView) findViewById(R.id.lv3);

		//设置适配器
		try {
			lv1.setAdapter(new MyAdapter1());
			lv2.setAdapter(new MyAdapter1());
			lv3.setAdapter(new MyAdapter1());
		} catch (Exception e) {
			e.printStackTrace();
		}

	}
	//准备需要的图片资源
	private int ids[] = new int[] { R.drawable.default1, R.drawable.girl1,
			R.drawable.girl2, R.drawable.girl3,R.drawable.girl4 };

	class MyAdapter1 extends BaseAdapter {

		@Override
		public int getCount() {
			return 3000;
		}

		@Override
		public Object getItem(int position) {
			return position;
		}

		@Override
		public long getItemId(int position) {
			return 0;
		}

		@Override
		public View getView(int position, View convertView, ViewGroup parent) {

			ImageView iv = (ImageView) View.inflate(getApplicationContext(),
					R.layout.lv_item, null);
			// 0<=Math.random() * 5<5
			int resId = (int) (Math.random() * 5);
			iv.setImageResource(ids[resId]);
			return iv;
		}
	}
}

MyLinearLayout.java

package com.atguigu.pinterestlistview;

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;

public class MyLinearLayout extends LinearLayout {

	/**
	 * 第一步执行构造器
	 */
	public MyLinearLayout(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	/**
	 * onInterceptTouchEvent();拦截触摸事件 1.如果返回的是true,将会触发当前View的onTouchEvent();
	 * 2.如果返回的是false,事件将会传给孩子
	 */
	@Override
	public boolean onInterceptTouchEvent(MotionEvent ev) {
		//导致ontouch事件执行
		return true;
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// 屏幕的三分之一
		int width = getWidth() / getChildCount();
		int height = getHeight();
		int count = getChildCount();
		//得到x坐标值
		float eventX = event.getX();

		// 滑动左边的 listView
		if (eventX < width) {
			//设置有效区间
			event.setLocation(width / 2, event.getY());
			//分发事件给listview
			getChildAt(0).dispatchTouchEvent(event);
			//返回true,说明list处理事件
			return true;

		} else if (eventX > width && eventX < 2 * width) { // 滑动中间的 listView
			//得到中间listview的点击y值
			float eventY = event.getY();
			//如果在屏幕的1/2之上（屏幕上半部分）
			if (eventY < height / 2) {
				event.setLocation(width / 2, event.getY());
				for (int i = 0; i < count; i++) {
					//获取三个listview视图
					View child = getChildAt(i);
					try {
						child.dispatchTouchEvent(event);
					} catch (Exception e) {
						e.printStackTrace();
					}
				}
				//返回true,说明list处理事件
				return true;
			} else if (eventY > height / 2) {
				event.setLocation(width / 2, event.getY());
				getChildAt(1).dispatchTouchEvent(event);
				return true;
			}
		} else if (eventX > 2 * width) {
			event.setLocation(width / 2, event.getY());
			getChildAt(2).dispatchTouchEvent(event);
			return true;
		}

		return true;
	}

}