Question

我有一个带有WeView的Activity，它加载了一个url，我希望在加载网站时显示一些等待对话框，所以我试过这个：

private ProgressDialog dialog = new ProgressDialog(MyNameActivity.this);

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
                .permitAll().build();
        StrictMode.setThreadPolicy(policy);
        setContentView(R.layout.web_view_activity);

        WebView wv;
        wv = (WebView) findViewById(R.id.areaWebSolver);
        wv.setWebViewClient(new WebViewClient() {
            @Override
            public boolean shouldOverrideUrlLoading(WebView view, String url) {
                view.loadUrl(url);
                return true;
            }
            @Override
        public void onPageFinished(WebView view, String url) {                  
            if (dialog.isShowing()) {
                dialog.dismiss();
            }
        }

        });
        dialog.setMessage("Loading..Please wait.");
            dialog.setCanceledOnTouchOutside(false);
            dialog.show();
        wv.loadUrl(url);

        WebSettings webSettings = wv.getSettings();
        webSettings.setJavaScriptEnabled(true);

    }

不幸的是不起作用，应用程序崩溃了source not found ...如果我尝试删除进度对话框代码，则活动有效。怎么了？我怎么能解决这个问题？

Answer 1

您可以在ThreadPolicy方法之后出于任何原因设置setContentView()，并且您的进度对话框永远不会获得Context，而您下面的语句将根本不会加载活动上下文。< / p>

private ProgressDialog dialog = new ProgressDialog(this);

找到适合我的伪代码。

private ProgressDialog dialog;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.web_view_activity);
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);

    dialog = new ProgressDialog(this);
    dialog.setMessage("Loading..Please wait.");
    dialog.setCanceledOnTouchOutside(false);
    dialog.show();

    WebView wv = (WebView) findViewById(R.id.areaWebSolver);
    wv.setWebViewClient(new WebViewClient() {
        @Override
        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }
        @Override
        public void onPageFinished(WebView view, String url) {                  
           if (dialog.isShowing()) {
              dialog.dismiss();
           }
        }
        ...
    }

未找到的源可能是由于您链接的其他一些外部库，而且它们在IDE的类路径中不可用。 READ HERE了解更多信息。

Answer 2

此

     private ProgressDialog dialog = new ProgressDialog(MyNameActivity.this);
     //This will give you NullPointerException. 
     // You can use the activity context after you set the content to the activity.

应该是

     private ProgressDialog dialog;   
    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
            .permitAll().build();
    StrictMode.setThreadPolicy(policy);
    setContentView(R.layout.web_view_activity); 
    dialog = new ProgressDialog(MyNameActivity.this);
    .... 
    }

Answer 3

您应该在网络视图活动中使用进度条

// Just find 
 progressBar = (ProgressBar) findViewById(R.id.progressBar1);
//in onCreate Method of activity and than after 

    @Override
            public void onPageFinished(WebView view, String url) {
                // TODO Auto-generated method stub
                super.onPageFinished(view, url);
                progressBar.setVisibility(View.GONE);
            }
      //Progress bar gone in onFinished method of webview.

<强> XML：

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

    <WebView
        android:id="@+id/webview01"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent" >
    </WebView>

    <ProgressBar
        android:id="@+id/progressBar1"
        style="?android:attr/progressBarStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerHorizontal="true"
        android:layout_centerVertical="true" />

</RelativeLayout>

Answer 4

我认为这会对你有帮助。

private ProgressDialog dialog;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.web_view_activity);
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder()
        .permitAll().build();
StrictMode.setThreadPolicy(policy);



WebView wv = (WebView) findViewById(R.id.areaWebSolver);
wv.setWebViewClient(new WebViewClient() {
    @Override
    public boolean shouldOverrideUrlLoading(WebView view, String url) {
    dialog = new ProgressDialog(this);
    dialog.setMessage("Loading..Please wait.");
    dialog.setCanceledOnTouchOutside(false);

    if(!dialog.showing()){
      view.loadUrl(url);
      dialog.show();
        return true;
    }

    }
    @Override
    public void onPageFinished(WebView view, String url) {                  
       if (dialog.isShowing()) {
          dialog.dismiss();
       }
    }
    ...
}

加载WebView崩溃问题时的PrgressDialog

4 个答案: