Android 实现带进度条的WebView的实例

android 实现带进度条的webview的实例

1. webview加载网页方法

//加载本地资源
loadurl("file:///android_asset/example.html");
//加载网络资源
loadurl("http://baidu.com");

2. 带进度的drawable文件view_progress_webview

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

  <item android:id="@android:id/progress">
    <clip>
      <shape>
        <solid android:color="#31ce15"/>
        <corners android:radius="2dp"/>
      </shape>
    </clip>
  </item>

</layer-list>

颜色值为进度颜色，根据需要更换

3. progresswebview类

/**
 * 带进度条的webview
 * @author gq
 */
public class progresswebview extends webview {

  private progressbar progressbar;
  private context mcontext;

  public progresswebview(context context, attributeset attrs) {
    super(context, attrs);
    this.mcontext = context;
    progressbar = new progressbar(context, null, android.r.attr.progressbarstylehorizontal);
    progressbar.setlayoutparams(new layoutparams(layoutparams.fill_parent, 5, 0, 0));

    drawable drawable = context.getresources().getdrawable(r.drawable.view_progress_webview);
    progressbar.setprogressdrawable(drawable);
    addview(progressbar);

    //主要处理解析，渲染网页等浏览器做的事情
    setwebviewclient(new webviewclient() {
      @override
      public void onreceivederror(webview view, int errorcode, string description, string failingurl) {
        super.onreceivederror(view, errorcode, description, failingurl);
        //加载失败时候,显示自定义的页面
        if (errorlistener != null) {
          errorlistener.onerror();
        }
      }
    });
    //辅助webview处理javascript的对话框，网站图标，网站title，加载进度等
    setwebchromeclient(new webchromeclient());

    getsettings().setsupportzoom(true);//是否可以缩放
    getsettings().setbuiltinzoomcontrols(true);
    getsettings().setjavascriptenabled(true);//支持js
    getsettings().setlayoutalgorithm(websettings.layoutalgorithm.narrow_columns);
    getsettings().setusewideviewport(true);
    getsettings().setloadwithoverviewmode(true);
    getsettings().setsaveformdata(true);
    getsettings().setdomstorageenabled(true);

    //优先使用缓存
    getsettings().setcachemode(websettings.load_cache_else_network);

    //禁用长按
    setonlongclicklistener(new onlongclicklistener() {
      @override
      public boolean onlongclick(view view) {
        return true;
      }
    });

    //如果在浏览器下载,调用浏览器默认下载+通知栏
    setdownloadlistener(new downloadlistener() {
      @override
      public void ondownloadstart(string url, string useragent, string contentdisposition, string mimetype, long contentlength) {
        uri uri = uri.parse(url);
        intent intent = new intent(intent.action_view, uri);
        mcontext.startactivity(intent);
      }
    });
  }


  public class webchromeclient extends android.webkit.webchromeclient {
    @override
    public void onprogresschanged(webview view, int newprogress) {
      if (newprogress == 100) {
        progressbar.setvisibility(gone);
      } else {
        if (progressbar.getvisibility() == gone)
          progressbar.setvisibility(visible);
        progressbar.setprogress(newprogress);
      }
      super.onprogresschanged(view, newprogress);
    }

    @override
    public void onreceivedtitle(webview view, string title) {
      super.onreceivedtitle(view, title);
      if (titlelistener != null)
        titlelistener.gettitle(title);
    }

  }


  @override
  protected void onscrollchanged(int l, int t, int oldl, int oldt) {
    layoutparams lp = (layoutparams) progressbar.getlayoutparams();
    lp.x = l;
    lp.y = t;
    progressbar.setlayoutparams(lp);
    super.onscrollchanged(l, t, oldl, oldt);
  }

  private titlelistener titlelistener;

  public interface titlelistener {
    void gettitle(string title);
  }

  public void setontitlelistener(titlelistener titlelistener) {
    this.titlelistener = titlelistener;
  }

  private errorlistener errorlistener;

  public interface errorlistener {
    void onerror();
  }

  public void setonerrorlistener(errorlistener errorlistener) {
    this.errorlistener = errorlistener;
  }

}

4. 使用

/**
* 公共webview
*/
public class basicwebactivity extends activity {

  protected progresswebview progresswebview;
  private textview title;//标题栏
  private textview tv_none;//加载失败显示文字

  @override
  protected void oncreate(bundle savedinstancestate) {
    super.oncreate(savedinstancestate);
    setcontentview(r.layout.common_webview);

    title = (textview) findviewbyid(r.id.title);
    tv_none = (textview) findviewbyid(r.id.tv_none);
    progresswebview = (progresswebview) findviewbyid(r.id.progresswebview);

    string url = getintent().getstringextra("url");
    progresswebview.setontitlelistener(new progresswebview.titlelistener() {
      @override
      public void gettitle(string title) {
        title.settext(title);
      }
    });
    progresswebview.setonerrorlistener(new progresswebview.errorlistener() {
      @override
      public void onerror() {
        tv_none.settext("url资源失效");
      }
    });
    //加载网页
    progresswebview.loadurl(url);
  }

 //重写返回键
  @override
  public boolean onkeydown(int keycode, keyevent event) {
    if (keycode == keyevent.keycode_back) {
      if (progresswebview.cangoback()) {
        progresswebview.goback();//返回上一层页面
        return true;
      } else {
        finish();//关闭页面
      }
    }
    return super.onkeydown(keycode, event);
  }
}

其中common_webview就包含一个title一个progresswebview就不贴代码了。

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