Android 进度条按钮ProgressButton的实现代码

有些app在点击下载按钮的时候，可以在按钮上显示进度，我们可以通过继承原生button，重写ondraw来实现带进度条的按钮。

github：https://github.com/imcloudfloating/progressbar

1.效果：

2.原理：

创建三个gradientdrawable作为按钮背景、进度条背景和进度条前景，通过计算进度条的百分比来设置宽度，然后调用invalidate()重绘。gradientdrawable设置颜色、圆角等参数，当然你也可以直接加载xml作为背景。

3.自定义参数：

在values目录建一个attrs.xml文件

 <?xml version="." encoding="utf-"?>
 <resources>
  <attr name="progresscolor" format="color" />
  <attr name="progressbackcolor" format="color" />
  <attr name="progress" format="integer" />
  <attr name="minprogress" format="integer" />
  <attr name="maxprogress" format="integer" />
  <declare-styleable name="progressbutton">
   <attr name="progresscolor" />
   <attr name="progressbackcolor" />
   <attr name="buttoncolor" format="color" />
   <attr name="cornerradius" format="dimension" />
   <attr name="progress" />
   <attr name="minprogress" />
   <attr name="maxprogress" />
   <attr name="progressmargin" format="dimension" />
  </declare-styleable>
 </resources>

3.按钮类：

在setprogress方法中改变mprogress的值，然后调用invalidate()重绘，因为我这里定义了一个minprogress(默认为0)，所以在计算进度条宽度的时候，当前进度和最大进度都要先减去minprogress再做除法。

if (progresswidth < mcornerradius * 2) {
 progresswidth = mcornerradius * 2;
}

当进度条宽度小于2倍圆角半径的时候，进度条的圆角就和背景的圆角不一致，所以加上了上面这段代码。
获取宽度和高度其实用getwidth()和getheight()也可以，只不过在设计器中没法看到效果，所以我用了getmeasuredwidth()和getmeasuredheight()。

 package com.cloud.customviews;
 import android.content.context;
 import android.content.res.typedarray;
 import android.graphics.canvas;
 import android.graphics.drawable.gradientdrawable;
 import android.support.v.widget.appcompatbutton;
 import android.util.attributeset;
 public class progressbutton extends appcompatbutton {
  private float mcornerradius = ;
  private float mprogressmargin = ;
  private boolean mfinish;
  private int mprogress;
  private int mmaxprogress = ;
  private int mminprogress = ;
  private gradientdrawable mdrawablebutton;
  private gradientdrawable mdrawableprogressbackground;
  private gradientdrawable mdrawableprogress;
  public progressbutton(context context, attributeset attrs) {
   super(context, attrs);
   initialize(context, attrs);
  }
  public progressbutton(context context, attributeset attrs, int defstyle) {
   super(context, attrs, defstyle);
   initialize(context, attrs);
  }
  private void initialize(context context, attributeset attrs) {
   //progress background drawable
   mdrawableprogressbackground = new gradientdrawable();
   //progress drawable
   mdrawableprogress = new gradientdrawable();
   //normal drawable
   mdrawablebutton = new gradientdrawable();
   //get default normal color
   int defaultbuttoncolor = getresources().getcolor(r.color.colorgray, null);
   //get default progress color
   int defaultprogresscolor = getresources().getcolor(r.color.colorgreen, null);
   //get default progress background color
   int defaultbackcolor = getresources().getcolor(r.color.colorgray, null);
   typedarray attr = context.obtainstyledattributes(attrs, r.styleable.progressbutton);
   try {
    mprogressmargin = attr.getdimension(r.styleable.progressbutton_progressmargin, mprogressmargin);
    mcornerradius = attr.getdimension(r.styleable.progressbutton_cornerradius, mcornerradius);
    //get custom normal color
    int buttoncolor = attr.getcolor(r.styleable.progressbutton_buttoncolor, defaultbuttoncolor);
    //set normal color
    mdrawablebutton.setcolor(buttoncolor);
    //get custom progress background color
    int progressbackcolor = attr.getcolor(r.styleable.progressbutton_progressbackcolor, defaultbackcolor);
    //set progress background drawable color
    mdrawableprogressbackground.setcolor(progressbackcolor);
    //get custom progress color
    int progresscolor = attr.getcolor(r.styleable.progressbutton_progresscolor, defaultprogresscolor);
    //set progress drawable color
    mdrawableprogress.setcolor(progresscolor);
    //get default progress
    mprogress = attr.getinteger(r.styleable.progressbutton_progress, mprogress);
    //get minimum progress
    mminprogress = attr.getinteger(r.styleable.progressbutton_minprogress, mminprogress);
    //get maximize progress
    mmaxprogress = attr.getinteger(r.styleable.progressbutton_maxprogress, mmaxprogress);
   } finally {
    attr.recycle();
   }
   //set corner radius
   mdrawablebutton.setcornerradius(mcornerradius);
   mdrawableprogressbackground.setcornerradius(mcornerradius);
   mdrawableprogress.setcornerradius(mcornerradius - mprogressmargin);
   setbackgrounddrawable(mdrawablebutton);
   mfinish = false;
  }
  @override
  protected void ondraw(canvas canvas) {
   if (mprogress > mminprogress && mprogress <= mmaxprogress && !mfinish) {
    //calculate the width of progress
    float progresswidth =
      (float) getmeasuredwidth() * ((float) (mprogress - mminprogress) / mmaxprogress - mminprogress);
    //if progress width less than x corner radius, the radius of progress will be wrong
    if (progresswidth < mcornerradius * ) {
     progresswidth = mcornerradius * ;
    }
    //set rect of progress
    mdrawableprogress.setbounds((int) mprogressmargin, (int) mprogressmargin,
      (int) (progresswidth - mprogressmargin), getmeasuredheight() - (int) mprogressmargin);
    //draw progress
    mdrawableprogress.draw(canvas);
    if (mprogress == mmaxprogress) {
     setbackgrounddrawable(mdrawablebutton);
     mfinish = true;
    }
   }
   super.ondraw(canvas);
  }
  /**
  * set current progress
  */
  public void setprogress(int progress) {
   if (!mfinish) {
    mprogress = progress;
    setbackgrounddrawable(mdrawableprogressbackground);
    invalidate();
   }
  }
  public void setmaxprogress(int maxprogress) {
   mmaxprogress = maxprogress;
  }
  public void setminprogress(int minprogress) {
   mminprogress = minprogress;
  }
  public void reset() {
   mfinish = false;
   mprogress = mminprogress;
  }
 }

 使用：

 <com.cloud.customviews.progressbutton
    android:id="@+id/button_progress_green"
    android:layout_width="dp"
    android:layout_height="wrap_content"
    android:layout_margintop="dp"
    android:textallcaps="false"
    android:textcolor="@color/colorwhite"
    android:text="@string/button_progress"
    app:cornerradius="dp"
    app:progressmargin="dp"
    app:progresscolor="@color/colorgreen"
    app:buttoncolor="@color/colorgreen" />

总结

以上所述是小编给大家介绍的android 进度条按钮progressbutton的实现代码，希望对大家有所帮助