無法找到瀏覽器的提供者信息

Question

我在Coursera的MOOC中，我試圖運行一個讀取書籤並顯示它們的應用程序。

要做到這一點，我需要設置在AndroidManifest一個權限：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="course.labs.permissionslab" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk 
     android:minSdkVersion="8" 
     android:targetSdkVersion="18" /> 

    <uses-permission android:name="com.android.browser.permission.READ_HISTORY_BOOKMARKS"/> 
    <!-- TODO - add uses-permission elements --> 


    <application 
     android:allowBackup="true" 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" 
     android:theme="@style/AppTheme" > 
     <activity 
      android:name=".ActivityLoaderActivity" 
      android:label="@string/title_main" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity 
      android:name=".BookmarksActivity" 
      android:label="@string/title_permissions" > 
     </activity> 
     <activity 
      android:name=".GoToDangerousActivity" 
      android:label="@string/title_activity_customization" > 
     </activity> 
    </application> 

</manifest> 

防止拿到一個SecurityException，但是，當我嘗試在Android設備上運行我的申請，我得到以下錯誤的logcat：

03-02 02:58:13.579: I/Lab-Permissions(15438): Entered loadBookmarks() 
03-02 02:58:13.589: W/dalvikvm(15438): threadid=1: thread exiting with uncaught exception (group=0x4166d498) 
03-02 02:58:13.589: E/ActivityThread(15438): Failed to find provider info for browser 
03-02 02:58:13.589: E/test(15438): Exception 
03-02 02:58:13.609: E/AndroidRuntime(15438): FATAL EXCEPTION: main 
03-02 02:58:13.609: E/AndroidRuntime(15438): java.lang.NullPointerException 
03-02 02:58:13.609: E/AndroidRuntime(15438): at course.labs.permissionslab.BookmarksActivity.loadBookmarks(BookmarksActivity.java:59) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at course.labs.permissionslab.BookmarksActivity.access$0(BookmarksActivity.java:50) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at course.labs.permissionslab.BookmarksActivity$1.onClick(BookmarksActivity.java:32) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.view.View.performClick(View.java:4106) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.view.View$PerformClick.run(View.java:17150) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.os.Handler.handleCallback(Handler.java:615) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.os.Handler.dispatchMessage(Handler.java:92) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.os.Looper.loop(Looper.java:137) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at android.app.ActivityThread.main(ActivityThread.java:4792) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at java.lang.reflect.Method.invokeNative(Native Method) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at java.lang.reflect.Method.invoke(Method.java:511) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:808) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:575) 
03-02 02:58:13.609: E/AndroidRuntime(15438): at dalvik.system.NativeStart.main(Native Method) 

我沒有什麼事情，似乎它沒有找到一個供應商，但我有兩個瀏覽器，所以我不明白這一點。

這是我的BookmarksActive代碼，請忽略調用另一個東西的「危險活動」。

package course.labs.permissionslab; 

import android.app.Activity; 
import android.content.Intent; 
import android.database.Cursor; 
import android.os.Bundle; 
import android.provider.Browser; 
import android.util.Log; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.TextView; 

public class BookmarksActivity extends Activity { 

    private static final String TAG = "Lab-Permissions"; 

    static final String[] projection = { Browser.BookmarkColumns.TITLE, 
      Browser.BookmarkColumns.URL }; 

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

     Button getBookmarksButton = (Button) findViewById(R.id.get_bookmarks_button); 
     getBookmarksButton.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 

       loadBookmarks(); 

      } 
     }); 

     Button goToDangerousActivityButton = (Button) findViewById(R.id.go_to_dangerous_activity_button); 
     goToDangerousActivityButton.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View v) { 

       startGoToDangerousActivity(); 

      } 
     }); 

    } 

    private void loadBookmarks() { 

     Log.i(TAG, "Entered loadBookmarks()"); 

     String text = ""; 

     Cursor query = getContentResolver().query(Browser.BOOKMARKS_URI, 
       projection, null, null, null); 

     query.moveToFirst(); 
     while (query.moveToNext()) { 

      text += query.getString(query 
        .getColumnIndex(Browser.BookmarkColumns.TITLE)); 
      text += "\n"; 
      text += query.getString(query 
        .getColumnIndex(Browser.BookmarkColumns.URL)); 
      text += "\n\n"; 

     } 

     TextView box = (TextView) findViewById(R.id.text); 
     box.setText(text); 

     Log.i(TAG, "Bookmarks loaded"); 
    } 

    private void startGoToDangerousActivity() { 

     Log.i(TAG, "Entered startGoToDangerousActivity()"); 

     Intent dangerous = new Intent(BookmarksActivity.this,GoToDangerousActivity.class); 
      startActivity(dangerous); 
    } 

} 

Answer 1

我不知道瀏覽器設置是否與您的問題有關。轉到設備上首選瀏覽器的「應用程序信息」屏幕。在「按默認啓動」中點擊「清除默認值」按鈕，然後看看會發生什麼。

Answer 2

您的設備可能運行Chrome，而不是AOSP瀏覽器。如果是這樣，而不是Browser.BOOKMARKS_URI，用途：

Uri.parse("content://com.android.chrome.browser/bookmarks") 

即從谷歌

Cursor query = getContentResolver().query(Uri.parse("content://com.android.chrome.browser/bookmarks"), 
       projection, null, null, null); 

Answer 3

下載AOSP安裝Play商店安裝的瀏覽器。您的設備可能沒有Rom附帶的默認瀏覽器。