java - 如何用 SQLITE 中的 Strings[] 替换 String[] 常量

Question

我目前正在研究实现图像网格视图的通用图像加载器。我能够使用预定义的图像路径运行该项目。请帮助找到更好的解决方案。

基于此：

问题是我想使用保存在我的数据库中的一组 URL 字符串，例如file:///storage/sdcard0/folder/folder/folder/Image.jpg

现在我在活动 A中有这个：

public class LoadMainMenuActivty  extends BaseActivity {

    private static final String TEST_FILE_NAME = "Universal Image Loader @#&=+-_.,!()~'%20.png";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        new Constants(this.getBaseContext());


        setContentView(R.layout.load_main_menu_activity);

        File testImageOnSdCard = new File(Environment.getExternalStorageDirectory(), TEST_FILE_NAME);
        if (!testImageOnSdCard.exists()) {
            copyTestImageToSdCard(testImageOnSdCard);
        }

        new createFolders().execute();
        // Initialize Buttons
        Button btnOrderByList = (Button) findViewById(R.id.btnOrder);



        // Button Start Application
        // btnStartApp = (Button) findViewById(R.id.btnStartApp);
        btnOrderByList.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {

                // Perform action on click
                // Launch Add New product Activity
                Intent i = new Intent(getApplicationContext(),
                        LoadMainGroupsActivty.class);
                // Closing all previous activities
                // i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
                startActivity(i);

            }
        });

    }

    public void onImageGridClick(View view) {
        Log.d("Error", "Here");
        Intent intent = new Intent(this, ImageGridActivity.class);
        intent.putExtra(Extra.IMAGES, IMAGES);
        startActivity(intent);
    }



    @Override
    public void onBackPressed() {
        imageLoader.stop();
        super.onBackPressed();
    }

    private void copyTestImageToSdCard(final File testImageOnSdCard) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    InputStream is = getAssets().open(TEST_FILE_NAME);
                    FileOutputStream fos = new FileOutputStream(testImageOnSdCard);
                    byte[] buffer = new byte[8192];
                    int read;
                    try {
                        while ((read = is.read(buffer)) != -1) {
                            fos.write(buffer, 0, read);
                        }
                    } finally {
                        fos.flush();
                        fos.close();
                        is.close();
                    }
                } catch (IOException e) {
                    L.w("Can't copy test image onto SD card");
                }
            }
        }).start();
    }

    /**
     * Background Async Task to Load all product by making HTTP Request
     * */
    class createFolders extends AsyncTask<String, String, String> {

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
        }

        protected String doInBackground(String... params) {
        //Creating folders in SD card


        }

    }

}

在常量类中：

public final class Constants {

    static DatabaseHandler db = new DatabaseHandler(getContext());
    static Context context;

    public Constants(Context context)
    {
        Constants.context = context;
    }

    static Context getContext()
    {
        return Constants.context;

    }

    ///public static final List<String> IMAGES = db.getImagePath();
    //Not sure with this

    static String[] paths = db.getImagePath();
    public static final String[] IMAGES = new String[] {
            // Heavy images
            "file:///storage/sdcard0/folder/folder/folder/image.jpg",
            "https://lh4.googleusercontent.com/-K2FMuOozxU0/T3R4lRAiBTI/AAAAAAAAAE8/a3Eh9JvnnzI/s1024/sample_image_02.jpg",
            "https://lh5.googleusercontent.com/-SCS5C646rxM/T3R4l7QB6xI/AAAAAAAAAFE/xLcuVv3CUyA/s1024/sample_image_03.jpg",
            "https://lh6.googleusercontent.com/-f0NJR6-_Thg/T3R4mNex2wI/AAAAAAAAAFI/45oug4VE8MI/s1024/sample_image_04.jpg",
            "https://lh3.googleusercontent.com/-n-xcJmiI0pg/T3R4mkSchHI/AAAAAAAAAFU/EoiNNb7kk3A/s1024/sample_image_05.jpg",
            "https://lh3.googleusercontent.com/-X43vAudm7f4/T3R4nGSChJI/AAAAAAAAAFk/3bna6D-2EE8/s1024/sample_image_06.jpg",
            "https://lh5.googleusercontent.com/-MpZneqIyjXU/T3R4nuGO1aI/AAAAAAAAAFg/r09OPjLx1ZY/s1024/sample_image_07.jpg",
            "https://lh6.googleusercontent.com/-ql3YNfdClJo/T3XvW9apmFI/AAAAAAAAAL4/_6HFDzbahc4/s1024/sample_image_08.jpg",
            "https://lh5.googleusercontent.com/-Pxa7eqF4cyc/T3R4oasvPEI/AAAAAAAAAF0/-uYDH92h8LA/s1024/sample_image_09.jpg",
            "https://lh4.googleusercontent.com/-Li-rjhFEuaI/T3R4o-VUl4I/AAAAAAAAAF8/5E5XdMnP1oE/s1024/sample_image_10.jpg",
            "https://lh5.googleusercontent.com/-_HU4fImgFhA/T3R4pPVIwWI/AAAAAAAAAGA/0RfK_Vkgth4/s1024/sample_image_11.jpg",
            "https://lh6.googleusercontent.com/-0gnNrVjwa0Y/T3R4peGYJwI/AAAAAAAAAGU/uX_9wvRPM9I/s1024/sample_image_12.jpg",
            "https://lh3.googleusercontent.com/-HBxuzALS_Zs/T3R4qERykaI/AAAAAAAAAGQ/_qQ16FaZ1q0/s1024/sample_image_13.jpg",
            "https://lh4.googleusercontent.com/-cKojDrARNjQ/T3R4qfWSGPI/AAAAAAAAAGY/MR5dnbNaPyY/s1024/sample_image_14.jpg",
            "https://lh3.googleusercontent.com/-WujkdYfcyZ8/T3R4qrIMGUI/AAAAAAAAAGk/277LIdgvnjg/s1024/sample_image_15.jpg",
            "https://lh6.googleusercontent.com/-FMHR7Vy3PgI/T3R4rOXlEKI/AAAAAAAAAGs/VeXrDNDBkaw/s1024/sample_image_16.jpg",
            "https://lh4.googleusercontent.com/-mrR0AJyNTH0/T3R4rZs6CuI/AAAAAAAAAG0/UE1wQqCOqLA/s1024/sample_image_17.jpg",
            "https://lh6.googleusercontent.com/-z77w0eh3cow/T3R4rnLn05I/AAAAAAAAAG4/BaerfWoNucU/s1024/sample_image_18.jpg",
            "https://lh5.googleusercontent.com/-aWVwh1OU5Bk/T3R4sAWw0yI/AAAAAAAAAHE/4_KAvJttFwA/s1024/sample_image_19.jpg",
            "https://lh6.googleusercontent.com/-q-js52DMnWQ/T3R4tZhY2sI/AAAAAAAAAHM/A8kjp2Ivdqg/s1024/sample_image_20.jpg",
            "https://lh5.googleusercontent.com/-_jIzvvzXKn4/T3R4t7xpdVI/AAAAAAAAAHU/7QC6eZ10jgs/s1024/sample_image_21.jpg",
            "https://lh3.googleusercontent.com/-lnGi4IMLpwU/T3R4uCMa7vI/AAAAAAAAAHc/1zgzzz6qTpk/s1024/sample_image_22.jpg",
            "https://lh5.googleusercontent.com/-fFCzKjFPsPc/T3R4u0SZPFI/AAAAAAAAAHk/sbgjzrktOK0/s1024/sample_image_23.jpg",
            "https://lh4.googleusercontent.com/-8TqoW5gBE_Y/T3R4vBS3NPI/AAAAAAAAAHs/EZYvpNsaNXk/s1024/sample_image_24.jpg",
            "https://lh6.googleusercontent.com/-gc4eQ3ySdzs/T3R4vafoA7I/AAAAAAAAAH4/yKii5P6tqDE/s1024/sample_image_25.jpg",
            "https://lh5.googleusercontent.com/--NYOPCylU7Q/T3R4vjAiWkI/AAAAAAAAAH8/IPNx5q3ptRA/s1024/sample_image_26.jpg",
            "https://lh6.googleusercontent.com/-9IJM8so4vCI/T3R4vwJO2yI/AAAAAAAAAIE/ljlr-cwuqZM/s1024/sample_image_27.jpg",
            "https://lh4.googleusercontent.com/-KW6QwOHfhBs/T3R4w0RsQiI/AAAAAAAAAIM/uEFLVgHPFCk/s1024/sample_image_28.jpg",
            "https://lh4.googleusercontent.com/-z2557Ec1ctY/T3R4x3QA2hI/AAAAAAAAAIk/9-GzPL1lTWE/s1024/sample_image_29.jpg",
            "https://lh5.googleusercontent.com/-LaKXAn4Kr1c/T3R4yc5b4lI/AAAAAAAAAIY/fMgcOVQfmD0/s1024/sample_image_30.jpg",
            "https://lh4.googleusercontent.com/-F9LRToJoQdo/T3R4yrLtyQI/AAAAAAAAAIg/ri9uUCWuRmo/s1024/sample_image_31.jpg",
            "https://lh4.googleusercontent.com/-6X-xBwP-QpI/T3R4zGVboII/AAAAAAAAAIs/zYH4PjjngY0/s1024/sample_image_32.jpg",
            "https://lh5.googleusercontent.com/-VdLRjbW4LAs/T3R4zXu3gUI/AAAAAAAAAIw/9aFp9t7mCPg/s1024/sample_image_33.jpg",
            "https://lh6.googleusercontent.com/-gL6R17_fDJU/T3R4zpIXGjI/AAAAAAAAAI8/Q2Vjx-L9X20/s1024/sample_image_34.jpg",
            "https://lh3.googleusercontent.com/-1fGH4YJXEzo/T3R40Y1B7KI/AAAAAAAAAJE/MnTsa77g-nk/s1024/sample_image_35.jpg",
            "https://lh4.googleusercontent.com/-Ql0jHSrea-A/T3R403mUfFI/AAAAAAAAAJM/qzI4SkcH9tY/s1024/sample_image_36.jpg",
            "https://lh5.googleusercontent.com/-BL5FIBR_tzI/T3R41DA0AKI/AAAAAAAAAJk/GZfeeb-SLM0/s1024/sample_image_37.jpg",
            "https://lh4.googleusercontent.com/-wF2Vc9YDutw/T3R41fR2BCI/AAAAAAAAAJc/JdU1sHdMRAk/s1024/sample_image_38.jpg",
            "https://lh6.googleusercontent.com/-ZWHiPehwjTI/T3R41zuaKCI/AAAAAAAAAJg/hR3QJ1v3REg/s1024/sample_image_39.jpg",
            // Light images
            "http://tabletpcssource.com/wp-content/uploads/2011/05/android-logo.png",
            "http://simpozia.com/pages/images/stories/windows-icon.png",
            "https://si0.twimg.com/profile_images/1135218951/gmail_profile_icon3_normal.png",
            "http://www.krify.net/wp-content/uploads/2011/09/Macromedia_Flash_dock_icon.png",
            "http://radiotray.sourceforge.net/radio.png",
            "http://www.bandwidthblog.com/wp-content/uploads/2011/11/twitter-logo.png",
            "http://weloveicons.s3.amazonaws.com/icons/100907_itunes1.png",
            "http://weloveicons.s3.amazonaws.com/icons/100929_applications.png",
            "http://www.idyllicmusic.com/index_files/get_apple-iphone.png",
            "http://www.frenchrevolutionfood.com/wp-content/uploads/2009/04/Twitter-Bird.png",
            "http://3.bp.blogspot.com/-ka5MiRGJ_S4/TdD9OoF6bmI/AAAAAAAAE8k/7ydKtptUtSg/s1600/Google_Sky%2BMaps_Android.png",
            "http://www.desiredsoft.com/images/icon_webhosting.png",
            "http://goodereader.com/apps/wp-content/uploads/downloads/thumbnails/2012/01/hi-256-0-99dda8c730196ab93c67f0659d5b8489abdeb977.png",
            "http://1.bp.blogspot.com/-mlaJ4p_3rBU/TdD9OWxN8II/AAAAAAAAE8U/xyynWwr3_4Q/s1600/antivitus_free.png",
            "http://cdn3.iconfinder.com/data/icons/transformers/computer.png",
            "http://cdn.geekwire.com/wp-content/uploads/2011/04/firefox.png?7794fe",
            "https://ssl.gstatic.com/android/market/com.rovio.angrybirdsseasons/hi-256-9-347dae230614238a639d21508ae492302340b2ba",
            "http://androidblaze.com/wp-content/uploads/2011/12/tablet-pc-256x256.jpg",
            "http://www.theblaze.com/wp-content/uploads/2011/08/Apple.png",
            "http://1.bp.blogspot.com/-y-HQwQ4Kuu0/TdD9_iKIY7I/AAAAAAAAE88/3G4xiclDZD0/s1600/Twitter_Android.png",
            "http://3.bp.blogspot.com/-nAf4IMJGpc8/TdD9OGNUHHI/AAAAAAAAE8E/VM9yU_lIgZ4/s1600/Adobe%2BReader_Android.png",
            "http://cdn.geekwire.com/wp-content/uploads/2011/05/oovoo-android.png?7794fe",
            "http://icons.iconarchive.com/icons/kocco/ndroid/128/android-market-2-icon.png",
            "http://thecustomizewindows.com/wp-content/uploads/2011/11/Nicest-Android-Live-Wallpapers.png",
            "http://c.wrzuta.pl/wm16596/a32f1a47002ab3a949afeb4f",
            "http://macprovid.vo.llnwd.net/o43/hub/media/1090/6882/01_headline_Muse.jpg",
            // Special cases
            "http://cdn.urbanislandz.com/wp-content/uploads/2011/10/MMSposter-large.jpg", // very large image
            "file:///sdcard/Universal Image Loader @#&=+-_.,!()~'%20.png", // Image from SD card with encoded symbols
            "assets://Living Things @#&=+-_.,!()~'%20.jpg", // Image from assets
            "drawable://" + R.drawable.ic_launcher, // Image from drawables
            "http://upload.wikimedia.org/wikipedia/ru/b/b6/Как_кот_Ñ?_мышами_воевал.png", // Link with UTF-8
            "https://www.eff.org/sites/default/files/chrome150_0.jpg", // Image from HTTPS
            "http://bit.ly/soBiXr", // Redirect link
            "http://img001.us.expono.com/100001/100001-1bc30-2d736f_m.jpg", // EXIF
            "", // Empty link
            "http://wrong.site.com/corruptedLink", // Wrong link
    };



    public static class Config {
        public static final boolean DEVELOPER_MODE = false;
    }

    public static class Extra {
        public static final String IMAGES = "com.nostra13.example.universalimageloader.IMAGES";
        public static final String IMAGE_POSITION = "com.nostra13.example.universalimageloader.IMAGE_POSITION";
    }
}

图像网格活动：

public class ImageGridActivity extends AbsListViewBaseActivity {

    String[] imageUrls;

    DisplayImageOptions options;

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ac_image_grid);

        Bundle bundle = getIntent().getExtras();
        imageUrls = bundle.getStringArray(Extra.IMAGES);

        options = new DisplayImageOptions.Builder()
            .showStubImage(R.drawable.ic_stub)
            .showImageForEmptyUri(R.drawable.ic_empty)
            .showImageOnFail(R.drawable.ic_error)
            .cacheInMemory(true)
            .cacheOnDisc(true)
            .bitmapConfig(Bitmap.Config.RGB_565)
            .build();

        listView = (GridView) findViewById(R.id.gridview);
        ((GridView) listView).setAdapter(new ImageAdapter());
        listView.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                startImagePagerActivity(position);
            }
        });
    }

    private void startImagePagerActivity(int position) {
        Intent intent = new Intent(this, ImageGridActivity.class);
        intent.putExtra(Extra.IMAGES, imageUrls);
        intent.putExtra(Extra.IMAGE_POSITION, position);
        startActivity(intent);
    }

    public class ImageAdapter extends BaseAdapter {
        @Override
        public int getCount() {
            return imageUrls.length;
        }

        @Override
        public Object getItem(int position) {
            return null;
        }

        @Override
        public long getItemId(int position) {
            return position;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            final ImageView imageView;
            if (convertView == null) {
                imageView = (ImageView) getLayoutInflater().inflate(R.layout.item_grid_image, parent, false);
            } else {
                imageView = (ImageView) convertView;
            }

            imageLoader.displayImage(imageUrls[position], imageView, options);

            return imageView;
        }
    }
}

数据库处理器：

@SuppressWarnings("null")
    public String[] getImagePath()
    {
        String [] paths = null;
        String selectQuery = "SELECT * FROM " + TABLE_PATH;



        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery, null);

        int i = 1;
        // looping through all rows and adding to list
        if (cursor.moveToFirst()) {
            do {

                paths[i] = cursor.getString(0).toString();
                Log.d("getPathImage:", cursor.getString(0).toString());
                i++;
            } while (cursor.moveToNext());
        }

         return paths;



    }

老实说，我不知道如何或在哪里将从数据库返回的图像分配到IMAGES

public static final String[] IMAGES = new String[] {
"file:///storage/sdcard0/folder/folder/folder/Image.jpg",};

Answer 1

public List<String> getImagePath()
{
    ArrayList<String> paths = new ArrayList<String>();
    String selectQuery = "SELECT * FROM " + TABLE_PATH;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {

            paths.add(cursor.getString(0).toString());
            Log.d("getPathImage:", cursor.getString(0).toString());
        } while (cursor.moveToNext());
    }

     return paths;
}

然后

      DBHandler db = new DBHandler(ActivityName.this);
      db.open();
      ArrayList<String> list = getImagePath();

现在您可以在您的适配器类中使用该列表，并使用它来使用通用图像加载器显示图像。

附带说明，您可以从 sdcard 获取图像的路径并使用 UIL 显示图像。所以你不需要为此目的的数据库。

更多关于如何使用 UIL。

获取路径后

    ListView lv =(ListView) findViewById(R.id.listView);
    LazyAdapter adapter = new LazyAdapter(ActivityName.this,list);
    lv.setAdapter(adapter);       

懒惰的Adaper

public class LazyAdapter extends BaseAdapter {

private Activity activity;
private ArrayList path;
private LayoutInflater inflater=null;
public ImageLoader imageLoader; 
DisplayImageOptions options;

public LazyAdapter(Activity a, ArrayList<String> paths) {
    activity = a;
    path = paths;
    inflater = (LayoutInflater)activity.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    File cacheDir = StorageUtils.getOwnCacheDirectory(a, "MyFolderCache");


 // Get singletone instance of ImageLoader
   imageLoader = ImageLoader.getInstance();
 // Create configuration for ImageLoader (all options are optional)
    ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(a)
              // You can pass your own memory cache implementation
             .discCacheExtraOptions(1024, 1024, CompressFormat.PNG, 100)
             .discCache(new UnlimitedDiscCache(cacheDir)) // You can pass your own disc cache implementation
             .discCacheFileNameGenerator(new HashCodeFileNameGenerator())
             .enableLogging()
             .build();
 // Initialize ImageLoader with created configuration. Do it once.
 imageLoader.init(config);
    //imageLoader.init(ImageLoaderConfiguration.createDefault(a));
   // imageLoader=new ImageLoader(activity.getApplicationContext());
    options = new DisplayImageOptions.Builder()
    .showStubImage(R.drawable.ic_launcher)
    .cacheInMemory()
    .cacheOnDisc()
    .displayer(new RoundedBitmapDisplayer(20))
    .build();
}



public int getCount() {
    return path.size();
}

public Object getItem(int position) {
    return position;
}

public long getItemId(int position) {
    return position;
}

public View getView(int position, View convertView, ViewGroup parent) {
    View vi=convertView;
    ViewHolder vh = new ViewHolder();;
    if(convertView==null)
    {

    vi = inflater.inflate(R.layout.row, null);   
    vh.iv=(ImageView)vi.findViewById(R.id.ivv); 
    vh.pb= (ProgressBar)vi.findViewById(R.id.pb); 
    vh.tv = (TextView) vi.findViewById(R.id.textView1);
    vh.tv1= (TextView) vi.findViewById(R.id.textView2);

    }
    vh.tv.setText("Image in postion =");
    vh.tv1.setText(""+position);
    display(vh.iv, data[position], vh.pb);
    //imageLoader.displayImage(path.get(position).toString(), image,options);

    return vi;
}

public void display(ImageView img, String url, final ProgressBar spinner)
{
    imageLoader.displayImage(url, img, options, new ImageLoadingListener() {
        @Override
        public void onLoadingStarted(String imageUri, View view) {
         spinner.setVisibility(View.VISIBLE);
        }
        @Override
        public void onLoadingFailed(String imageUri, View view, FailReason failReason) {
         spinner.setVisibility(View.GONE);


        }
        @Override
        public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
         spinner.setVisibility(View.GONE);
        }
        @Override
        public void onLoadingCancelled(String imageUri, View view) {

        }

});
}
 public static class ViewHolder
 {
  ImageView iv;
  TextView tv,tv1;
  ProgressBar pb;

 }
}    

行.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
    android:id="@+id/imageView1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:src="@drawable/ic_launcher" />
 <ProgressBar 
    android:id="@+id/pb"
    android:layout_centerInParent="true"
    android:layout_gravity="center"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"/>

 <TextView
     android:id="@+id/textView1"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_above="@+id/textView2"
     android:layout_alignParentLeft="true"
     android:layout_marginBottom="21dp"
     android:layout_marginLeft="31dp"
     android:text="TextView" />

 <TextView
     android:id="@+id/textView2"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_alignLeft="@+id/textView1"
     android:layout_alignParentBottom="true"
     android:text="TextView" />

  </RelativeLayout>

您检查 UIL @ Caching images and display 的示例

要从 sdcard 获取图像，请考虑您的文件夹包含图像。

private File[] listFile;
ArrayList<String> f = new ArrayList<String>();

public void getFromSdcard()
{
    File file = new File(android.os.Environment.getExternalStorageDirectory(),"MyFolder");

        if (file.isDirectory())
        {
            listFile = file.listFiles();
             for (int i = 0; i < listFile.length; i++)
            {
                f.add(listFile[i].getAbsolutePath());
            }   

        }
}

Answer 2

只需在after中替换您的if子句，如下所示： DatabaseHandlerCursor cursor = db.rawQuery(selectQuery, null);

cursor.moveToFirst();
while (cursor.isAfterLast() == false) {
List<String> list = new ArrayList<String>();
 list.add(cursor.getString(0).toString());
 cursor.moveToNext();
 }
 String[] paths = list.toArray(new String[list .size()]);
 return paths;

Answer 3

你不能做这个 ：

String [] paths = null;

然后这个：

paths[i] = cursor.getString(0).toString(); // i is 0 initially

这会抛出ArrayIndexOutOfBoundsException.

您可以List<String>为此目的使用 a 而不是String[]. List<String>使用其add()方法将每个元素添加到。

List<String> pathList = new ArrayList<String>();
pathList.add(cursor.getString(0));

然后从该方法返回一个数组：

return pathList.toArray(new String[pathList.size()]);