php - Android:无法从 mysql 数据库检索图像 url 并将其显示在 imageView 中

Question

我是 Android 新手，在从服务器中存在的 mysql 数据库检索图像 url 时遇到问题我可以使用 Hashmap 检索字符串，但无法从数据库检索图像 url

我使用适配器类来链接 ListView 和 ImageView 、 TextView 等

任何人都可以检查下面的代码，以便我可以检索图像路径并将其链接到 imageView并显示数据库插入路径中的图像。

MainActivity.java

public class MainActivity extends Activity {
@SuppressLint("NewApi")
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    // Permission StrictMode
    if (android.os.Build.VERSION.SDK_INT > 9) {
        StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
        StrictMode.setThreadPolicy(policy);
    }

    // listView1
    final ListView lstView1 = (ListView)findViewById(R.id.listView1); 

    String url = "http://192.168.1.2/Android/App/sample.php";

    try {
        JSONArray data = new JSONArray(getJSONUrl(url));

        final ArrayList<HashMap<String, String>> MyArrList = new ArrayList<HashMap<String, String>>();
        HashMap<String, String> map;

        for(int i = 0; i < data.length(); i++){
            JSONObject c = data.getJSONObject(i);
            map = new HashMap<String, String>();
            map.put("title", c.getString("title"));
            map.put("artist", c.getString("artist"));
            map.put("duration", c.getString("duration"));
            map.put("image", c.getString("image")); i cant retrieve the image string here is the only problem


            MyArrList.add(map);
        }           

        lstView1.setAdapter(new ImageAdapter(this,MyArrList));

    } catch (JSONException e) {

        e.printStackTrace();
    } catch (Exception e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


}


public class ImageAdapter extends BaseAdapter 
{
    private Context context;
    public ImageView imageView;
    private ArrayList<HashMap<String, String>> MyArr = new ArrayList<HashMap<String, String>>();

    public ImageAdapter(Context c, ArrayList<HashMap<String, String>> list) 
    {

        context = c;
        MyArr = list;
    }

    public int getCount() {

        return MyArr.size();
    }

    public Object getItem(int position) {

        return position;
    }

    public long getItemId(int position) {

        return position;
    }
    public View getView(int position, View convertView, ViewGroup parent) {


        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);


        if (convertView == null) {
            convertView = inflater.inflate(R.layout.activity_column, null); 
        }

        // ColImage
        imageView = (ImageView) convertView.findViewById(R.id.image);
        //imageView.getLayoutParams().height = 50;
        //imageView.getLayoutParams().width = 50;
        //imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
         try
         {
             URL url = new URL("image");
            Bitmap bmp = BitmapFactory.decodeStream(url.openConnection().getInputStream());
            imageView.setImageBitmap(bmp);
         } catch (Exception e) {
             // When Error
             imageView.setImageResource(android.R.drawable.ic_menu_report_image);
         }

        // ColPosition
        TextView tv_title = (TextView) convertView.findViewById(R.id.title);
        tv_title.setText("ID : " + MyArr.get(position).get("title"));

        // ColPicname
        TextView tv_artist = (TextView) convertView.findViewById(R.id.artist);
        //tv_artist.setPadding(50, 0, 0, 0);
        tv_artist.setText("Desc : " + MyArr.get(position).get("artist"));

        TextView tv_duration = (TextView) convertView.findViewById(R.id.duration);
        //tv_artist.setPadding(50, 0, 0, 0);
        tv_duration.setText("Desc : " + MyArr.get(position).get("duration"));

        TextView tv_link = (TextView) convertView.findViewById(R.id.link);
        //tv_artist.setPadding(50, 0, 0, 0);
        tv_link.setText("Desc : " + MyArr.get(position).get("link"));

        return convertView;

    }

} 

/*** Get JSON Code from URL ***/
public String getJSONUrl(String url) {
    StringBuilder str = new StringBuilder();
    HttpClient client = new DefaultHttpClient();
    HttpGet httpGet = new HttpGet(client);
    try 
    {
        HttpResponse response = client.execute(httpGet);
        StatusLine statusLine = response.getStatusLine();
        int statusCode = statusLine.getStatusCode();
        if (statusCode == 200) 
        { 
            HttpEntity entity = response.getEntity();
            InputStream content = entity.getContent();
            BufferedReader reader = new BufferedReader(new InputStreamReader(content));
            String line;
            while ((line = reader.readLine()) != null) 
            {
                str.append(line);
            }
        }   
        else 
        {
            Log.e("Log", "Failed to download file..");
        }
    } 
    catch (ClientProtocolException e) 
    {
        e.printStackTrace();
    } 
    catch (IOException e) 
    {
        e.printStackTrace();
    }
    return str.toString();
}


private static final String TAG = "ERROR";
private static final int IO_BUFFER_SIZE = 4 * 1024;
public static Bitmap loadBitmap(String url) {
    Bitmap bitmap = null;
    InputStream in = null;
    BufferedOutputStream out = null;

    try {
        in = new BufferedInputStream(new URL(url).openStream(), IO_BUFFER_SIZE);

        final ByteArrayOutputStream dataStream = new ByteArrayOutputStream();
        out = new BufferedOutputStream(dataStream, IO_BUFFER_SIZE);
        copy(in, out);
        out.flush();

        final byte[] data = dataStream.toByteArray();
        BitmapFactory.Options options = new BitmapFactory.Options();
        //options.inSampleSize = 1;

        bitmap = BitmapFactory.decodeByteArray(data, 0, data.length,options);
    } catch (IOException e) {
        Log.e(TAG, "Could not load Bitmap from: " + url);
    } finally {
        closeStream(in);
        closeStream(out);
    }

    return bitmap;
}

 private static void closeStream(Closeable stream) {
        if (stream != null) {
            try {
                stream.close();
            } catch (IOException e) {
                android.util.Log.e(TAG, "Could not close stream", e);
            }
        }
    }

 private static void copy(InputStream in, OutputStream out) throws IOException {
    byte[] b = new byte[IO_BUFFER_SIZE];
    int read;
    while ((read = in.read(b)) != -1) {
        out.write(b, 0, read);
    }
}



@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}}

示例.php

<?php
$con = mysql_connect("localhost","root","");
if (!$con){
die('Could not connect: ' . mysql_error());}
mysql_select_db("testdatabase", $con);
$result = mysql_query("SELECT * FROM sample");
while($row = mysql_fetch_assoc($result)){
    $output[] = $row;}

print(json_encode($output));
mysql_close($con);
?>

activity_column.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="wrap_content"
android:background="@drawable/list_selector"
android:orientation="horizontal"
android:padding="5dip" >

<!--  ListRow Left sied Thumbnail image -->
<LinearLayout android:id="@+id/thumbnail" 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="3dip"      
    android:layout_alignParentLeft="true"
    android:background="@drawable/image_bg" 
    android:layout_marginRight="5dip">

    <ImageView
        android:id="@+id/image"   
        android:layout_width="50dip"
        android:layout_height="50dip"
       />

</LinearLayout>

<!-- Title Of Song-->
<TextView
    android:id="@+id/title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignTop="@+id/thumbnail"
    android:layout_toRightOf="@+id/thumbnail"
    android:textColor="#040404"
    android:typeface="sans" 
    android:textSize="15dip"
    android:textStyle="bold"/>

<!-- Artist Name -->
<TextView
    android:id="@+id/artist"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_below="@id/title"
    android:textColor="#343434"
    android:textSize="10dip"
    android:layout_marginTop="1dip"
    android:layout_toRightOf="@+id/thumbnail"
    />

<!-- Rightend Duration -->
<TextView
    android:id="@+id/duration"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_alignTop="@id/title"
    android:gravity="right"
    android:layout_marginRight="5dip"
    android:textSize="10dip"
    android:textColor="#10bcc9"
    android:textStyle="bold"/>

 <!-- Rightend Arrow -->    
 <ImageView 
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/arrow"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"/>

 <TextView
     android:id="@+id/link"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:layout_alignBottom="@+id/thumbnail"
     android:layout_marginLeft="60dp"
     android:layout_toRightOf="@+id/title"
     />
</RelativeLayout>

数据库数据如下

我不知道我在哪里错过了这些方法感谢您的时间和关心我也无法检索图像路径为了检查图像路径是否正在检索，我在 mainActivity.java 中创建了一个虚拟 TextView tv_link，但我得到的值为 null

Answer 1

您使用的 IP 方向错误。

如果您使用 localhost 来测试 IP 应该是“10.0.0.2”而不是 192.168.1.2，那一定是您的 lan 中的本地 IP 地址，但是在 Android 模拟中，localhost 的地址不是 172.0.0.1 或你的局域网IP 192.168.1.2

您必须使用 10.0.0.2

String url = "http://10.0.0.2/Android/App/sample.php";

和

http://10.0.0.2/Android/pictures/sandeep1.jpg

数据库中图像的 URL

如果您确定 url 字符串没问题，请尝试使用 HttpURLConnection

try {

                URL url = new URL(imagen);
                HttpURLConnection connection = (HttpURLConnection)url.openConnection();
                connection.setDoInput(true);
                connection.connect();
                InputStream inputStream = connection.getInputStream();
                foto = BitmapFactory.decodeStream(inputStream);

            } catch (MalformedURLException e) {


                e.printStackTrace();
            } 

如果有错误，将在 catch block 中详细说明