Android实现单页面浮层可拖动view的示例代码

需求是需要在一个已经存在的页面添加一个可拖动的浮层广告。

使用到的技术：viewdraghelper

效果如图：

封装好的类（继承自framelayout）

import android.content.context;
import android.support.annotation.attrres;
import android.support.annotation.nonnull;
import android.support.annotation.nullable;
import android.support.v4.widget.viewdraghelper;
import android.util.attributeset;
import android.view.motionevent;
import android.view.view;
import android.widget.framelayout;

import java.util.arraylist;

/**
 * created by hq on 2017/10/10.
 */
public class dragframelayout extends framelayout {

  string tag = "dragframelayout";
  viewdraghelper draghelper;
  arraylist<view> viewlist;
  public dragframelayout(@nonnull context context) {
    this(context, null);
  }

  public dragframelayout(@nonnull context context, @nullable attributeset attrs) {
    this(context, attrs, 0);
  }

  public dragframelayout(@nonnull context context, @nullable attributeset attrs, @attrres int defstyleattr) {
    super(context, attrs, defstyleattr);
    //第二步：创建存放view的集合
    viewlist = new arraylist<>();

    draghelper = viewdraghelper.create(this, 1.0f, new viewdraghelper.callback() {

      /**
       * 是否捕获childview:
       * 如果viewlist包含child，那么捕获childview
       * 如果不包含child，就不捕获childview
       */
      @override
      public boolean trycaptureview(view child, int pointerid) {
        return viewlist.contains(child);
      }

      @override
      public void onviewpositionchanged(view changedview, int left, int top, int dx, int dy) {
        super.onviewpositionchanged(changedview, left, top, dx, dy);
      }

      /**
       * 当捕获到child后的处理：
       * 获取child的监听
       */
      @override
      public void onviewcaptured(view capturedchild, int activepointerid) {
        super.onviewcaptured(capturedchild, activepointerid);
        if (ondragdroplistener != null) {
          ondragdroplistener.ondragdrop(true);
        }
      }

      /**
       * 当释放child后的处理：
       * 取消监听，不再处理
       */
      @override
      public void onviewreleased(view releasedchild, float xvel, float yvel) {
        super.onviewreleased(releasedchild, xvel, yvel);
        if (ondragdroplistener != null) {
          ondragdroplistener.ondragdrop(false);
        }
      }

      /**
       * 到左边界的距离
       */
      @override
      public int clampviewpositionhorizontal(view child, int left, int dx) {
        return left;
      }

      /**
       * 到上边界的距离
       */
      @override
      public int clampviewpositionvertical(view child, int top, int dy) {
        return top;
      }
    });
  }

  /**
   * 把要实现拖动的子view添加进来
   * @param view
   */
  public void adddragchildview(view view){
    viewlist.add(view);
  }

  @override
  public boolean onintercepttouchevent(motionevent ev) {
    //当手指抬起或事件取消的时候 就不拦截事件
    int actionmasked = ev.getactionmasked();
    if (actionmasked == motionevent.action_cancel || actionmasked == motionevent.action_up) {
      return false;
    }
    return draghelper.shouldintercepttouchevent(ev);
  }

  @override
  public boolean ontouchevent(motionevent event) {
    draghelper.processtouchevent(event);
    return true;
  }
  public interface ondragdroplistener {
    void ondragdrop(boolean captured);
  }

  private ondragdroplistener ondragdroplistener;

  public void setondragdroplistener(ondragdroplistener ondragdroplistener) {
    this.ondragdroplistener = ondragdroplistener;
  }
}

使用方法：

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<com.windfindtech.hqdemo.view.dragframelayout 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:id="@+id/df_content"
tools:context="com.windfindtech.hqdemo.mainactivity">

<imageview
  android:id="@+id/iv1"
  android:layout_width="100dp"
  android:layout_height="100dp"
  android:src="@mipmap/ic_launcher" />

<textview
  android:id="@+id/tv1"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:layout_gravity="center"
  android:text="可拖拽文字" />
</com.windfindtech.hqdemo.view.dragframelayout>

mainactivity.java类

public class mainactivity extends appcompatactivity {

dragframelayout m_dragframelayout;
imageview m_imageview1;
textview m_textview1;
string tag = "";

@override
protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_main);
  m_dragframelayout = (dragframelayout) findviewbyid(r.id.df_content);
  m_imageview1 = (imageview)findviewbyid(r.id.iv1);
  m_textview1 = (textview) findviewbyid(r.id.tv1);
//   m_dragframelayout.adddragchildview(m_imageview1);
  m_dragframelayout.adddragchildview(m_textview1);//具体拖拽动作使用回调即可
}
}

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