Android中Drag and Drop拖拽功能的使用2-----交换布局中子控件的位置

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/zhaihaohao1/article/details/85608380

Android中的拖拽功能是有自带的api的；（很多时候会误以为要自定义控件，所以我放到了，自定义目录下）
参考文档：
http://www.android-doc.com/guide/topics/ui/drag-drop.html
我写了一个例子分析:
效果图：

思路：
1主要用到了View的startDrag（startDragAndDrop API24+） 方法
2拖拽的监听OnDragListener方法

该讲的在上一篇已经讲过了，这里直接贴代码了：
上一篇路径：https://blog.csdn.net/zhaihaohao1/article/details/85605326

SecondActivity中

package com.zhh.android;

import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.os.SystemClock;
import android.util.Log;
import android.util.TypedValue;
import android.view.DragEvent;
import android.view.HapticFeedbackConstants;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

/**
 * 布局文件中子控件，拖拽交换位置
 */
public class SecondActivity extends Activity {
    private ImageView imageView0;
    private ImageView imageView1;
    private ImageView imageView2;
    private ImageView imageView3;
    private LinearLayout ll_blue;
    private Context context;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        context = SecondActivity.this;
        setContentView(R.layout.activity_second);
        imageView0 = (ImageView) findViewById(R.id.imageView0);
        imageView1 = (ImageView) findViewById(R.id.imageView1);
        imageView2 = (ImageView) findViewById(R.id.imageView2);
        imageView3 = (ImageView) findViewById(R.id.imageView3);


        ll_blue = (LinearLayout) findViewById(R.id.ll_blue);

        imageView0.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(v);

                v.startDrag(null, shadowBuilder, imageView0, 0);
                //震动反馈
                v.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, HapticFeedbackConstants.FLAG_IGNORE_GLOBAL_SETTING);

                return true;
            }
        });
        imageView1.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(v);

                v.startDrag(null, shadowBuilder, imageView1, 1);
                //震动反馈
                v.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, HapticFeedbackConstants.FLAG_IGNORE_GLOBAL_SETTING);

                return true;
            }
        });
        imageView2.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(v);

                v.startDrag(null, shadowBuilder, imageView2, 2);
                //震动反馈
                v.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, HapticFeedbackConstants.FLAG_IGNORE_GLOBAL_SETTING);

                return true;
            }
        });
        imageView3.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View v) {
                View.DragShadowBuilder shadowBuilder = new View.DragShadowBuilder(v);

                v.startDrag(null, shadowBuilder, imageView3, 3);
                //震动反馈
                v.performHapticFeedback(HapticFeedbackConstants.LONG_PRESS, HapticFeedbackConstants.FLAG_IGNORE_GLOBAL_SETTING);

                return true;
            }
        });


        ll_blue.setOnDragListener(new View.OnDragListener() {
            @Override
            public boolean onDrag(View v, DragEvent event) {
                //v 永远是设置该监听的view，这里即fl_blue
                String simpleName = v.getClass().getSimpleName();
                Log.w("111", "view name:" + simpleName);

                //获取事件
                int action = event.getAction();
                switch (action) {
                    case DragEvent.ACTION_DRAG_STARTED:
                        Log.i("111", "开始拖拽");
                        break;

                    case DragEvent.ACTION_DRAG_ENTERED:
                        Log.i("111", "拖拽的view进入监听的view时");
                        break;
                    case DragEvent.ACTION_DRAG_EXITED:
                        Log.i("111", "拖拽的view离开监听的view时");
                        break;
                    case DragEvent.ACTION_DRAG_LOCATION:
                        float x = event.getX();
                        float y = event.getY();
                        long l = SystemClock.currentThreadTimeMillis();
                        Log.i("111", "拖拽的view在监听view中的位置:x =" + x + ",y=" + y);
                        break;
                    case DragEvent.ACTION_DROP:
                        Log.i("111", "释放拖拽的view");
//                      这里拿到的是 startDrag 里面第三个参数
                        ImageView imageView = (ImageView) event.getLocalState();
//                      判断拖拽的是第一张图
                        if (imageView.getId() == R.id.imageView0) {
                            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 200);
//                        layoutParams.topMargin = (int) event.getY() - imageView1.getWidth() / 2;
//                        layoutParams.leftMargin = (int) event.getX() - imageView1.getHeight() / 2;
                            ((ViewGroup) imageView.getParent()).removeView(imageView);
//                        ll_blue.addView(imageView1, layoutParams);


                            int getY = px2dip(context, event.getY());
//                            每个子控件的高度都是200，两个就是400，三个就是600，四个就是800
                            if (getY < 200) {
                                ll_blue.addView(imageView, 0);
                            }
                            if (getY > 200 && getY < 400) {
                                ll_blue.addView(imageView, 1);
                            }
                            if (getY > 400 && getY < 600) {
                                ll_blue.addView(imageView, 2);
                            }
                            if (getY > 600 && getY < 800) {
                                ll_blue.addView(imageView, 3);
                            }
                        }
//                      判断拖拽的是第二张图
                        if (imageView.getId() == R.id.imageView1) {
                            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 200);
//                        layoutParams.topMargin = (int) event.getY() - imageView1.getWidth() / 2;
//                        layoutParams.leftMargin = (int) event.getX() - imageView1.getHeight() / 2;
                            ((ViewGroup) imageView.getParent()).removeView(imageView);
//                        ll_blue.addView(imageView1, layoutParams);


                            int getY = px2dip(context, event.getY());
                            if (getY < 200) {
                                ll_blue.addView(imageView, 0);
                            }
                            if (getY > 200 && getY < 400) {
                                ll_blue.addView(imageView, 1);
                            }
                            if (getY > 400 && getY < 600) {
                                ll_blue.addView(imageView, 2);
                            }
                            if (getY > 600 && getY < 800) {
                                ll_blue.addView(imageView, 3);
                            }
                        }
//                      判断拖拽的是第三张图
                        if (imageView.getId() == R.id.imageView2) {
                            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 200);
//                        layoutParams.topMargin = (int) event.getY() - imageView1.getWidth() / 2;
//                        layoutParams.leftMargin = (int) event.getX() - imageView1.getHeight() / 2;
                            ((ViewGroup) imageView.getParent()).removeView(imageView);
//                        ll_blue.addView(imageView1, layoutParams);


                            int getY = px2dip(context, event.getY());
                            if (getY < 200) {
                                ll_blue.addView(imageView, 0);
                            }
                            if (getY > 200 && getY < 400) {
                                ll_blue.addView(imageView, 1);
                            }
                            if (getY > 400 && getY < 600) {
                                ll_blue.addView(imageView, 2);
                            }
                            if (getY > 600 && getY < 800) {
                                ll_blue.addView(imageView, 3);
                            }
                        }
//                      判断拖拽的是第四张图
                        if (imageView.getId() == R.id.imageView3) {
                            LinearLayout.LayoutParams layoutParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 200);
//                        layoutParams.topMargin = (int) event.getY() - imageView1.getWidth() / 2;
//                        layoutParams.leftMargin = (int) event.getX() - imageView1.getHeight() / 2;
                            ((ViewGroup) imageView.getParent()).removeView(imageView);
//                        ll_blue.addView(imageView1, layoutParams);


                            int getY = px2dip(context, event.getY());
                            if (getY < 200) {
                                ll_blue.addView(imageView, 0);
                            }
                            if (getY > 200 && getY < 400) {
                                ll_blue.addView(imageView, 1);
                            }
                            if (getY > 400 && getY < 600) {
                                ll_blue.addView(imageView, 2);
                            }
                            if (getY > 600 && getY < 800) {
                                ll_blue.addView(imageView, 3);
                            }
                        }
                        break;
                    case DragEvent.ACTION_DRAG_ENDED:
                        Log.i("111", "结束拖拽");
                        break;
                }
                //是否响应拖拽事件，true响应，返回false只能接受到ACTION_DRAG_STARTED事件，后续事件不会收到
                return true;
            }
        });


    }
    /**
     * dp转为px
     * Android内部是px
     *
     * @param context  上下文
     * @param dipValue dp值
     * @return
     */
    public static int dip2px(Context context, float dipValue) {
        Resources r = context.getResources();
        return (int) TypedValue.applyDimension(
                TypedValue.COMPLEX_UNIT_DIP, dipValue, r.getDisplayMetrics());
    }
    /**
     * 根据手机的分辨率从 px(像素) 的单位 转成为 dp
     */
    public static int px2dip(Context context, float pxValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }


}

布局文件：activity_second.xml中

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <ScrollView
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <LinearLayout
            android:id="@+id/ll_blue"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="#4043f1"
            android:orientation="vertical"
            >
            <ImageView
                android:id="@+id/imageView0"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:src="@mipmap/mn1"
                android:scaleType="fitXY"
                />
            <ImageView
                android:id="@+id/imageView1"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:src="@mipmap/mn2"
                android:scaleType="fitXY"
                />
            <ImageView
                android:id="@+id/imageView2"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:src="@mipmap/mn3"
                android:scaleType="fitXY"
                />
            <ImageView
                android:id="@+id/imageView3"
                android:layout_width="match_parent"
                android:layout_height="200dp"
                android:src="@mipmap/mn4"
                android:scaleType="fitXY"
                />

        </LinearLayout>

    </ScrollView>

</LinearLayout>

缓存拖拽后的位置（就是下次再打开的时候是你拖拽的位置）在源码中有：
源码下载：
https://download.csdn.net/download/zhaihaohao1/10890390