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超好看的下拉刷新动画Android代码实现

︶ㄣ速达网 メ
米米素材网V管理员 / 阅读
0723

超好看的下拉刷新动画Android代码实现，效果简单大方，具有一定的参考价值，感兴趣的小伙伴们可以参考一下

最近看到了好多高端、大气、上档次的动画效果，如果给你的项目中加上这些动画，相信你的app一定很优秀，今天给大家分析一下来自yalantis的一个超好看的下拉刷新动画。

首先我们看一下效果如何：

超好看的下拉刷新动画Android代码实现

怎么样？是不是很高大上？接下来我们看一下代码：

一、首先我们需要自定义刷新的动态refreshview（也就是下拉时候的头）
1.初始化头所占用的dimens

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private void initiatedimens() {
    mscreenwidth = mcontext.getresources().getdisplaymetrics().widthpixels;
    mjettopoffset = mparent.gettotaldragdistance() * 0.5f;
    mtop = -mparent.gettotaldragdistance();
  }

2.为头填充图片，设置图片的大小
分别为左边的云彩，右边的云彩，中间的云彩还有中间的飞机，飞机是带有动画的，下面会介绍飞机的动画

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private void createbitmaps() {
    mleftclouds = bitmapfactory.decoderesource(mcontext.getresources(), r.drawable.clouds_left);
    mrightclouds = bitmapfactory.decoderesource(mcontext.getresources(), r.drawable.clouds_right);
    mfrontclouds = bitmapfactory.decoderesource(mcontext.getresources(), r.drawable.clouds_center);
    mjet = bitmapfactory.decoderesource(mcontext.getresources(), r.drawable.airplane);
 
    mjetwidthcenter = mjet.getwidth() / 2;
    mjetheightcenter = mjet.getheight() / 2;
    mfrontcloudwidthcenter = mfrontclouds.getwidth() / 2;
    mfrontcloudheightcenter = mfrontclouds.getheight() / 2;
 
    mrightcloudswidthcenter = mrightclouds.getwidth() / 2;
    mrightcloudsheightcenter = mrightclouds.getheight() / 2;
    mleftcloudswidthcenter = mleftclouds.getwidth() / 2;
    mleftcloudsheightcenter = mleftclouds.getheight() / 2;
  }

3.然后我们来画这个头

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public void draw(@nonnull canvas canvas) {
    final int savecount = canvas.save();
 
    // draw background.
    canvas.drawcolor(mcontext.getresources().getcolor(r.color.sky_background));
 
    if (isrefreshing) {
      // set up new set of wind
      while (mwinds.size() < wind_set_amount) {
        float y = (float) (mparent.gettotaldragdistance() / (math.random() * random_y_coefficient));
        float x = random(min_wind_x_offset, max_wind_x_offset);
 
        // magic with checking interval between winds
        if (mwinds.size() > 1) {
          y = 0;
          while (y == 0) {
            float tmp = (float) (mparent.gettotaldragdistance() / (math.random() * random_y_coefficient));
 
            for (map.entry<float, float> wind : mwinds.entryset()) {
              // we want that interval will be greater than fifth part of draggable distance
              if (math.abs(wind.getkey() - tmp) > mparent.gettotaldragdistance() / random_y_coefficient) {
                y = tmp;
              } else {
                y = 0;
                break;
              }
            }
          }
        }
 
        mwinds.put(y, x);
        drawwind(canvas, y, x);
      }
 
      // draw current set of wind
      if (mwinds.size() >= wind_set_amount) {
        for (map.entry<float, float> wind : mwinds.entryset()) {
          drawwind(canvas, wind.getkey(), wind.getvalue());
        }
      }
 
      // we should to create new set of winds
      if (minversedirection && mnewwindset) {
        mwinds.clear();
        mnewwindset = false;
        mwindlinewidth = random(min_wind_line_width, max_wind_line_width);
      }
 
      // needed for checking direction
      mlastanimationtime = mloadinganimationtime;
    }
 
    drawjet(canvas);
    drawsideclouds(canvas);
    drawcenterclouds(canvas);
 
    canvas.restoretocount(savecount);
  }
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/**
   * draw wind on loading animation
   *
   * @param canvas - area where we will draw
   * @param y    - y position fot one of lines
   * @param xoffset - x offset for on of lines
   */
  private void drawwind(canvas canvas, float y, float xoffset) {
    /* we should multiply current animation time with this coefficient for taking all screen width in time
    removing slowing of animation with dividing on {@link #slow_down_animation_coefficient}
    and we should don't forget about distance that should "fly" line that depend on screen of device and x offset
    */
    float cof = (mscreenwidth + xoffset) / (loading_animation_coefficient / slow_down_animation_coefficient);
    float time = mloadinganimationtime;
 
    // horrible hack for revers animation that should work like restart animation
    if (mlastanimationtime - mloadinganimationtime > 0) {
      minversedirection = true;
      // take time from 0 to end of animation time
      time = (loading_animation_coefficient / slow_down_animation_coefficient) - mloadinganimationtime;
    } else {
      mnewwindset = true;
      minversedirection = false;
    }
 
    // taking current x position of drawing wind
    // for fully disappearing of line we should subtract wind line width
    float x = (mscreenwidth - (time * cof)) + xoffset - mwindlinewidth;
    float xend = x + mwindlinewidth;
 
    canvas.drawline(x, y, xend, y, mwindpaint);
  }
 
  private void drawsideclouds(canvas canvas) {
    matrix matrixleftclouds = mmatrix;
    matrix matrixrightclouds = madditionalmatrix;
    matrixleftclouds.reset();
    matrixrightclouds.reset();
 
    // drag percent will newer get more then 1 here
    float dragpercent = math.min(1f, math.abs(mpercent));
 
    boolean overdrag = false;
 
    // but we check here for overdrag
    if (mpercent > 1.0f) {
      overdrag = true;
    }
 
    float scale;
    float scalepercentdelta = dragpercent - scale_start_percent;
    if (scalepercentdelta > 0) {
      float scalepercent = scalepercentdelta / (1.0f - scale_start_percent);
      scale = side_clouds_initial_scale + (side_clouds_final_scale - side_clouds_initial_scale) * scalepercent;
    } else {
      scale = side_clouds_initial_scale;
    }
 
    // current y position of clouds
    float dragyoffset = mparent.gettotaldragdistance() * (1.0f - dragpercent);
 
    // position where clouds fully visible on screen and we should drag them with content of listview
    int cloudsvisibleposition = mparent.gettotaldragdistance() / 2 - mleftcloudsheightcenter;
 
    boolean needmovecloudswithcontent = false;
    if (dragyoffset < cloudsvisibleposition) {
      needmovecloudswithcontent = true;
    }
 
    float offsetrightx = mscreenwidth - mrightclouds.getwidth();
    float offsetrighty = (needmovecloudswithcontent
        ? mparent.gettotaldragdistance() * dragpercent - mleftclouds.getheight()
        : dragyoffset)
        + (overdrag ? mtop : 0);
 
    float offsetleftx = 0;
    float offsetlefty = (needmovecloudswithcontent
        ? mparent.gettotaldragdistance() * dragpercent - mleftclouds.getheight()
        : dragyoffset)
        + (overdrag ? mtop : 0);
 
    // magic with animation on loading process
    if (isrefreshing) {
      if (checkcurrentanimationpart(animationpart.first)) {
        offsetlefty += getanimationpartvalue(animationpart.first) / y_side_clouds_slow_down_cof;
        offsetrightx -= getanimationpartvalue(animationpart.first) / x_side_clouds_slow_down_cof;
      } else if (checkcurrentanimationpart(animationpart.second)) {
        offsetlefty += getanimationpartvalue(animationpart.second) / y_side_clouds_slow_down_cof;
        offsetrightx -= getanimationpartvalue(animationpart.second) / x_side_clouds_slow_down_cof;
      } else if (checkcurrentanimationpart(animationpart.third)) {
        offsetlefty -= getanimationpartvalue(animationpart.third) / y_side_clouds_slow_down_cof;
        offsetrightx += getanimationpartvalue(animationpart.third) / x_side_clouds_slow_down_cof;
      } else if (checkcurrentanimationpart(animationpart.fourth)) {
        offsetlefty -= getanimationpartvalue(animationpart.fourth) / x_side_clouds_slow_down_cof;
        offsetrightx += getanimationpartvalue(animationpart.fourth) / y_side_clouds_slow_down_cof;
      }
    }
 
    matrixrightclouds.postscale(scale, scale, mrightcloudswidthcenter, mrightcloudsheightcenter);
    matrixrightclouds.posttranslate(offsetrightx, offsetrighty);
 
    matrixleftclouds.postscale(scale, scale, mleftcloudswidthcenter, mleftcloudsheightcenter);
    matrixleftclouds.posttranslate(offsetleftx, offsetlefty);
 
    canvas.drawbitmap(mleftclouds, matrixleftclouds, null);
    canvas.drawbitmap(mrightclouds, matrixrightclouds, null);
  }
 
  private void drawcenterclouds(canvas canvas) {
    matrix matrix = mmatrix;
    matrix.reset();
    float dragpercent = math.min(1f, math.abs(mpercent));
 
    float scale;
    float overdragpercent = 0;
    boolean overdrag = false;
 
    if (mpercent > 1.0f) {
      overdrag = true;
      // here we want know about how mach percent of over drag we done
      overdragpercent = math.abs(1.0f - mpercent);
    }
 
    float scalepercentdelta = dragpercent - scale_start_percent;
    if (scalepercentdelta > 0) {
      float scalepercent = scalepercentdelta / (1.0f - scale_start_percent);
      scale = center_clouds_initial_scale + (center_clouds_final_scale - center_clouds_initial_scale) * scalepercent;
    } else {
      scale = center_clouds_initial_scale;
    }
 
    float parallaxpercent = 0;
    boolean parallax = false;
    // current y position of clouds
    float dragyoffset = mparent.gettotaldragdistance() * dragpercent;
    // position when should start parallax scrolling
    int startparallaxheight = mparent.gettotaldragdistance() - mfrontcloudheightcenter;
 
    if (dragyoffset > startparallaxheight) {
      parallax = true;
      parallaxpercent = dragyoffset - startparallaxheight;
    }
 
    float offsetx = (mscreenwidth / 2) - mfrontcloudwidthcenter;
    float offsety = dragyoffset
        - (parallax ? mfrontcloudheightcenter + parallaxpercent : mfrontcloudheightcenter)
        + (overdrag ? mtop : 0);
 
    float sx = overdrag ? scale + overdragpercent / 4 : scale;
    float sy = overdrag ? scale + overdragpercent / 2 : scale;
 
    if (isrefreshing && !overdrag) {
      if (checkcurrentanimationpart(animationpart.first)) {
        sx = scale - (getanimationpartvalue(animationpart.first) / loading_animation_coefficient) / 8;
      } else if (checkcurrentanimationpart(animationpart.second)) {
        sx = scale - (getanimationpartvalue(animationpart.second) / loading_animation_coefficient) / 8;
      } else if (checkcurrentanimationpart(animationpart.third)) {
        sx = scale + (getanimationpartvalue(animationpart.third) / loading_animation_coefficient) / 6;
      } else if (checkcurrentanimationpart(animationpart.fourth)) {
        sx = scale + (getanimationpartvalue(animationpart.fourth) / loading_animation_coefficient) / 6;
      }
      sy = sx;
    }
 
    matrix.postscale(sx, sy, mfrontcloudwidthcenter, mfrontcloudheightcenter);
    matrix.posttranslate(offsetx, offsety);
 
    canvas.drawbitmap(mfrontclouds, matrix, null);
  }
 
  private void drawjet(canvas canvas) {
    matrix matrix = mmatrix;
    matrix.reset();
 
    float dragpercent = mpercent;
    float rotateangle = 0;
 
    // check overdrag
    if (dragpercent > 1.0f && !mendofrefreshing) {
      rotateangle = (dragpercent % 1) * 10;
      dragpercent = 1.0f;
    }
 
    float offsetx = ((mscreenwidth * dragpercent) / 2) - mjetwidthcenter;
 
    float offsety = mjettopoffset
        + (mparent.gettotaldragdistance() / 2)
        * (1.0f - dragpercent)
        - mjetheightcenter;
 
    if (isrefreshing) {
      if (checkcurrentanimationpart(animationpart.first)) {
        offsety -= getanimationpartvalue(animationpart.first);
      } else if (checkcurrentanimationpart(animationpart.second)) {
        offsety -= getanimationpartvalue(animationpart.second);
      } else if (checkcurrentanimationpart(animationpart.third)) {
        offsety += getanimationpartvalue(animationpart.third);
      } else if (checkcurrentanimationpart(animationpart.fourth)) {
        offsety += getanimationpartvalue(animationpart.fourth);
      }
    }
 
    matrix.settranslate(offsetx, offsety);
 
    if (dragpercent == 1.0f) {
      matrix.prerotate(rotateangle, mjetwidthcenter, mjetheightcenter);
    }
 
    canvas.drawbitmap(mjet, matrix, null);
  }

动画效果已经画好了，下面我们来看看怎么结合下拉刷新来调用吧？
二、我们还需要自定义一个pulltorefreshview（下拉刷新）
1.我们的pulltorefreshview这里需要继承viewgroup
我们先把刚才定义的刷新时的动画加进来

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private refreshview mrefreshview;
<pre name="code" class="java">private imageview mrefreshimageview;
<pre name="code" class="java">mrefreshimageview = new imageview(context);
    mrefreshview = new refreshview(getcontext(), this);
    mrefreshimageview.setimagedrawable(mrefreshview);
 
    addview(mrefreshimageview);

2.然后我们设置ontouchevent()事件

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@override
  public boolean ontouchevent(@nonnull motionevent ev) {
 
    if (!misbeingdragged) {
      return super.ontouchevent(ev);
    }
 
    final int action = motioneventcompat.getactionmasked(ev);
 
    switch (action) {
      case motionevent.action_move: {
        final int pointerindex = motioneventcompat.findpointerindex(ev, mactivepointerid);
        if (pointerindex < 0) {
          return false;
        }
 
        final float y = motioneventcompat.gety(ev, pointerindex);
        final float ydiff = y - minitialmotiony;
        final float scrolltop = ydiff * drag_rate;
        mcurrentdragpercent = scrolltop / mtotaldragdistance;
        if (mcurrentdragpercent < 0) {
          return false;
        }
        float boundeddragpercent = math.min(1f, math.abs(mcurrentdragpercent));
        float extraos = math.abs(scrolltop) - mtotaldragdistance;
        float slingshotdist = mtotaldragdistance;
        float tensionslingshotpercent = math.max(0,
            math.min(extraos, slingshotdist * 2) / slingshotdist);
        float tensionpercent = (float) ((tensionslingshotpercent / 4) - math.pow(
            (tensionslingshotpercent / 4), 2)) * 2f;
        float extramove = (slingshotdist) * tensionpercent / 2;
        int targety = (int) ((slingshotdist * boundeddragpercent) + extramove);
 
        mrefreshview.setpercent(mcurrentdragpercent);
        settargetoffsettop(targety - mcurrentoffsettop, true);
        break;
      }
      case motioneventcompat.action_pointer_down:
        final int index = motioneventcompat.getactionindex(ev);
        mactivepointerid = motioneventcompat.getpointerid(ev, index);
        break;
      case motioneventcompat.action_pointer_up:
        onsecondarypointerup(ev);
        break;
      case motionevent.action_up:
      case motionevent.action_cancel: {
        if (mactivepointerid == invalid_pointer) {
          return false;
        }
        final int pointerindex = motioneventcompat.findpointerindex(ev, mactivepointerid);
        final float y = motioneventcompat.gety(ev, pointerindex);
        final float overscrolltop = (y - minitialmotiony) * drag_rate;
        misbeingdragged = false;
        if (overscrolltop > mtotaldragdistance) {
          setrefreshing(true, true);
        } else {
          mrefreshing = false;
          animateoffsettoposition(manimatetostartposition);
        }
        mactivepointerid = invalid_pointer;
        return false;
      }
    }
 
    return true;
  }

三、最后我们看怎样在activity中使用这个下拉刷新控件
1.先看一下布局文件
这里是我们的下拉刷新空间嵌套着我们的listview，然后我们再给listview填充数据即可

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<relativelayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".pulltorefreshactivity">
 
  <com.hankkin.animationpulltorefreshdemo.pulltorefreshview
    android:id="@+id/pull_to_refresh"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
 
    <listview
      android:id="@+id/list_view"
      android:divider="@null"
      android:dividerheight="0dp"
      android:fadingedge="none"
      android:layout_width="match_parent"
      android:layout_height="match_parent" />
 
  </com.hankkin.animationpulltorefreshdemo.pulltorefreshview>
 
</relativelayout>

2.为listview填充数据
为了我们的效果比较好看，这里我们给listview的每一个item填充不同的颜色，看起来会比较高大上。

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map<string, integer> map;
    list<map<string, integer>> samplelist = new arraylist<map<string, integer>>();
 
 
    int[] colors = {
        r.color.saffron,
        r.color.eggplant,
        r.color.sienna};
 
    int[] tripnames = {
        r.string.trip_to_india,
        r.string.trip_to_italy,
        r.string.trip_to_indonesia};
 
    for (int i = 0; i < tripnames.length; i++) {
      map = new hashmap<string, integer>();
      map.put(sampleadapter.key_name, tripnames[i]);
      map.put(sampleadapter.key_color, colors[i]);
      samplelist.add(map);
    }
 
    listview listview = (listview) findviewbyid(r.id.list_view);
    listview.setadapter(new sampleadapter(this, r.layout.list_item, samplelist));

3.最后，我们再设置一下下拉刷新的监听事件就ok了

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mpulltorefreshview = (pulltorefreshview) findviewbyid(r.id.pull_to_refresh);
    mpulltorefreshview.setonrefreshlistener(new pulltorefreshview.onrefreshlistener() {
      @override
      public void onrefresh() {
        mpulltorefreshview.postdelayed(new runnable() {
          @override
          public void run() {
            mpulltorefreshview.setrefreshing(false);
          }
        }, refresh_delay);
      }
    });

怎么样？有没有很高大上啊？

大家可以动手实践一下，希望对大家的学习有所帮助。