我想開發瀏覽器應用程序，但我得到錯誤

Question

我是新來的Android我想開發一個瀏覽器應用程序，現在我正在嘗試開發它，在這裏我得到錯誤。我嘗試了另一種方法，也就是詢問您必須打開哪種瀏覽器，但對於我而言，我只想在我的應用中打開。

WebviewActivity.java

package com.example.admin.fristapp; 

import android.app.Activity; 
import android.os.AsyncTask; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.webkit.WebResourceRequest; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 

public class WebviewActivity extends Activity { 
    WebView webview1; 
    // String url = "http://www.google.com"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_webview); 
     webview1 = (WebView) findViewById(R.id.webview1); 
     // webview1.loadUrl(url); 

     //MyBrowser my ; 

     new Background().execute(); 


    } 

    public class MyBrowser extends WebViewClient { 
     @Override 
     public boolean shouldOverrideUrlLoading(WebView view, String url) { 
      view.loadUrl(url); 
      return true; 
     } 
    } 




    public class Background extends AsyncTask<String,String,String> 
    { 
     @Override 
     protected void onPostExecute(String s) 
     { 
      super.onPostExecute(s); 
     } 
     @Override 
     protected void onPreExecute() 
     { 
      super.onPreExecute(); 
     } 

     @Override 
     protected String doInBackground(String... strings) 
     { 
      search(); 
      return null; 
     } 
    } 
    public void search() 
    { 
     webview1.setWebViewClient(new WebviewActivity.MyBrowser()); 
     String url = "http://www.google.com"; 
     webview1.getSettings().setJavaScriptEnabled(true); 
     webview1.loadUrl(url); 
    } 
} 

logcat的

java.lang.Throwable: A WebView method was called on thread 'AsyncTask #4'. All WebView methods must be called on the same thread. (Expected Looper Looper (main, tid 1) {180a245b} called on null, FYI main Looper is Looper (main, tid 1) {180a245b}) 
                      at android.webkit.WebView.checkThread(WebView.java:2290) 

Afteredit

import android.app.Activity; 
import android.os.AsyncTask; 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.webkit.WebResourceRequest; 
import android.webkit.WebView; 
import android.webkit.WebViewClient; 

public class WebviewActivity extends Activity { 
    WebView webview; 
    String url = "http://www.google.com"; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_webview); 

     webview =(WebView)findViewById(R.id.webview1); 
       //WebView(WebviewActivity.this); 
     webview.loadUrl(url); 

     webview.setWebViewClient(new WebViewClient() { 
      @Override 
      public boolean shouldOverrideUrlLoading(WebView view, String url) { 
       view.loadUrl(url); 
       return false; 
      } 

      @Override 
      public void onPageFinished(WebView view, String url) { 
       super.onPageFinished(view, url); 

       // Do your code when page finished 
      } 
     }); 

Answer 1

您正在加載中WebView一個URL中doInBackground()米ethod。 你應該在UI線程上做。

loadUrl()已經在做所有事情的異步。所以不需要AsyncTask。在onCreate()方法中移動您的代碼。

如果你想顯示加載的指標，你需要如下使用：

WebView webview = new WebView(MainActivity.this); 

webview.setWebViewClient(new WebViewClient() { 
    @Override 
    public boolean shouldOverrideUrlLoading(WebView view, String url) {  
     view.loadUrl(url);  
     return false; 
    } 

    @Override 
    public void onPageFinished(WebView view, String url) { 
      super.onPageFinished(view, url); 

      // Do your code when page finished 
    } 
}); 

webview.loadUrl(url);