Question

我试图为webView显示一个循环的不确定加载指示器，但是尽管在这里阅读了大量的答案，我的构建失败了。我收到错误java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.ProgressBar.setVisibility(int)' on a null object reference。我在fragment.xml文件中设置了进度条，如下所示：

<ProgressBar
    android:id="@+id/prgrsbar"
    style="?android:attr/progressBarStyleLarge"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:visibility="gone"
    android:indeterminateDrawable="@drawable/progress" >
</ProgressBar>

并在其中创建了一个空的progress.xml文件，其中包含以下内容：

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

最后，这是我正在使用的片段onCreateView活动代码：

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    //code here



    View rootView = inflater.inflate(R.layout.fragment_first, container, false);

    String url = "http://winn-brown.co.uk/shmee/";
    WebView view = (WebView) rootView.findViewById(R.id.webview);
    view.getSettings().setJavaScriptEnabled(true);
    view.loadUrl(url);

    view.setWebViewClient(new WebViewClient() {

        private ProgressBar prgrsBar;
        public void onPageStarted(WebView view, String url, Bitmap favicon) {
            super.onPageStarted(view, url, favicon);
            prgrsBar.setVisibility(View.VISIBLE);
        }

        public void onPageFinished(WebView view, String url) {
            // do your stuff here
            Log.i("message", "website loaded");

        }
    });


    return rootView;
}

在这一行private ProgressBar prgrsBar;上，它表示“私有字段'prgrsBar'永远不会被分配，尽管在片段的xml文件中有id。如果我在这里遗漏了明显的东西，请道歉。

Answer 1

添加

$scope.hasAdminRole = function(roles) {
    var isAdmin = false;
    for(var i = 0; i < roles.length; i++) {
        if (roles[i].name == 'Admin') {
            isAdmin = true;
            break;
        }
    }

    return isAdmin;
}

以下

prgrsBar = (ProgressBar)rootView.findViewById(R.id.prgrsbar);

Answer 2

您需要在poly = [{"x":0.0, "y":25.0}, {"x":28.5,"y":23.4}, {"x":33.0,"y":21.0}, {"x":39.0,"y":1.5}]; svg.selectAll("polygon") .data([poly]) .enter().append("polygon") .attr("points",function(d) { return d.map(function(d) { return [scaleX(d.x),scaleY(d.y)].join(","); }).join(" "); }) .attr("stroke","white") .attr("stroke-width",1) .attr("fill", "none") .attr("class", "feature") .on("click", function(d){ alert("HEO"); });

中进行此次调用后从xml文件中获取进度条的引用

onCreateView

片段中的webview的不确定进度条

2 个答案: