android - 如何在mysql数据库中上传图片链接的android中显示图片

Question

新闻节目.java

    package com.synergywebdesigners.nima;

    import android.app.Activity;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.graphics.drawable.Drawable;
    import android.text.Html;
    import android.text.Spanned;
    import android.text.method.LinkMovementMethod;
    import android.util.Log;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.ArrayAdapter;
    import android.widget.ImageView;
    import android.widget.TextView;

    import com.squareup.picasso.Picasso;

    import java.io.IOException;
    import java.net.URL;


    public class newsshow  extends  ArrayAdapter<String> {
        private String[] ids;
        private String[] ttitle;
        private String[] tmessage;
        private String[] tcreated;
        private String[] picture;
        private Bitmap[] bitmaps;
        private Activity context;



        public newsshow(Activity context, String[] ids, String[] title, String[] picture,Bitmap[] bitmaps, String[] message, String[] created) {
            super(context, R.layout.list_view_layout, picture);
            this.context = context;
            this.ids = ids;
            this.ttitle = title;
            this.picture= picture;
            this.bitmaps= bitmaps;
            this.tmessage = message;
            this.tcreated = created;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            LayoutInflater inflater = context.getLayoutInflater();
            View listViewItem = inflater.inflate(R.layout.list_view_layout, null, true);
            /// TextView id = (TextView) listViewItem.findViewById(R.id.id);
            TextView title = (TextView) listViewItem.findViewById(R.id.title);
            ImageView image = (ImageView) listViewItem.findViewById(R.id.imageDownloaded);
            TextView message = (TextView) listViewItem.findViewById(R.id.message);
            TextView created = (TextView) listViewItem.findViewById(R.id.created);
            //id.setText(ids[position]+".");
            title.setText(ttitle[position]);
            // spanned=Html.fromHtml(tmessage[position]);
 image.setImageBitmap(Bitmap.createScaledBitmap(bitmaps[position],100,50,true));
            message.setText(Html.fromHtml(tmessage[position]));
            created.setText(tcreated[position]);
            return listViewItem;
        }
    }

新闻.java

package com.synergywebdesigners.nima;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;



public class news extends AppCompatActivity{
    public static final String JSON_URL = "http://www.synergywebdesigners.com/synergywebdesigners.com/ashish/nima/get_all_news.php";
    private ListView listView;
   // SharedPreferences pref;
    TextView textView,textview2,textview3;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_news);
      //  pref = getSharedPreferences("news", MODE_PRIVATE);
        final ListView list = (ListView) findViewById(R.id.listView);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
              // String item =  list.getItemAtPosition(position).toString();
                 textView = (TextView) view.findViewById(R.id.title);
                textview2 = (TextView) view.findViewById(R.id.message);
                textview3 = (TextView) view.findViewById(R.id.created);
                String item2 = textView.getText().toString();
                String item3 = textview2.getText().toString();
                String item4 = textview3.getText().toString();
                Intent i = new Intent(getApplicationContext(),newsview.class);
                i.putExtra("item2",item2);
                i.putExtra("item3",item3);
                i.putExtra("item4",item4);

                startActivity(i);
            }
        });
       listView = (ListView) findViewById(R.id.listView);
        sendRequest();
    }
    private void sendRequest() {
        StringRequest stringRequest = new StringRequest(JSON_URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                showJSON(response);
            }
        },
                new Response.ErrorListener() {
                    @Override
                    public void onErrorResponse(VolleyError error) {
                        Toast.makeText(news.this, error.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                });

        com.android.volley.RequestQueue requestQueue = Volley.newRequestQueue(this);
        requestQueue.add(stringRequest);
    }
    private void showJSON(String json) {
        ParseJSON pj = new ParseJSON(json);
        pj.parseJSON();
        newsshow cl = new newsshow(this, ParseJSON.ids, ParseJSON.ttitle, ParseJSON.picture,ParseJSON.bitmaps, ParseJSON.tmessage, ParseJSON.tcreated);
        listView.setAdapter(cl);
    }
}

解析器.java

package com.synergywebdesigners.nima;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * Created by PC on 16-Dec-16.
 */

public class ParseJSON {
    public static String[] ids;
    public static String[] ttitle;
    public static String[] tmessage;
    public static String[] tcreated;
    public static String[] picture;
    public static Bitmap[] bitmaps;
    public static final String JSON_ARRAY = "result";
    public static final String KEY_ID = "id";
    public static final String KEY_Title = "title";
    public static final String KEY_Message = "message";
    public static final String KEY_Created = "created";
    public static final String KEY_IMAGE ="picture";
    private JSONArray users = null;

    private String json;

    public ParseJSON(String json){
        this.json = json;
        try {
            JSONObject jsonObject = new JSONObject(json);
            users = jsonObject.getJSONArray(JSON_ARRAY);
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
    private Bitmap getImage(JSONObject jo){
        URL url = null;
        Bitmap image = null;
        try {
            url = new URL(jo.getString(KEY_IMAGE));
            image = BitmapFactory.decodeStream(url.openConnection().getInputStream());
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (JSONException e) {
            e.printStackTrace();
        }
        return image;
    }
    protected void parseJSON(){
        JSONObject jsonObject=null;

        try {
            jsonObject = new JSONObject(json);
            users = jsonObject.getJSONArray(JSON_ARRAY);
            ids = new String[users.length()];
            ttitle = new String[users.length()];
            bitmaps = new Bitmap[users.length()];
            picture = new String[users.length()];
            tmessage = new String[users.length()];
            tcreated = new String[users.length()];
            for(int i=0;i<users.length();i++){
                JSONObject jo = users.getJSONObject(i);
                ids[i] = jo.getString(KEY_ID);
                ttitle[i] = jo.getString(KEY_Title);
                picture[i] = users.getJSONObject(i).getString(KEY_IMAGE);
                bitmaps[i]= getImage(jo);
                tmessage[i] = jo.getString(KEY_Message);
                tcreated[i] = jo.getString(KEY_Created);
            }
        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

获取所有新闻.php

   <?php
    define('HOST','localhost');
    define('USER','root');
    define('PASS','');
    define('DB','mrecord');

    $con = mysqli_connect(HOST,USER,PASS,DB);

    $sql = "select * from news ORDER BY created DESC LIMIT 100";

    $res = mysqli_query($con,$sql);

    $result = array();

    while($row = mysqli_fetch_array($res)){
    array_push($result,
    array('id'=>$row[0],
    'title'=>$row[1],
    'picture'=>$row[2],
    'message'=>$row[3],
    'created' =>$row[4]
    ));
    }

    echo json_encode(array('result'=>$result));

    mysqli_close($con);
    ?>

---

新闻节目.xml

---

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_marginLeft="2dp"
    android:layout_marginRight="2dp"
    android:layout_marginTop="10dp">

    <!-- Title Label -->
        <TextView
            android:paddingLeft="20dp"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="New Text"
            android:textAllCaps="true"
            android:textAppearance="?android:attr/textAppearanceMedium"
            android:textColor="#000000"
            android:textStyle="bold"
            android:id="@+id/title"
            android:gravity="center"/>
    <ImageView android:id="@+id/imageDownloaded"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:src="@drawable/abc_ic_menu_copy_mtrl_am_alpha"/>
   <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/message"
        android:layout_marginLeft="20dp"
        android:layout_marginRight="10dp"
        android:layout_marginTop="10dp"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="New Text"
        android:id="@+id/created"
        android:layout_marginLeft="20dp"/>

</LinearLayout>

---

content_news.xml

---

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/content_news"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="2dp"
    android:paddingRight="2dp"
    android:paddingTop="0dp"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:showIn="@layout/activity_news">
    <ScrollView android:layout_height="match_parent"
        android:layout_width="match_parent"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:fillViewport="true">


            <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
                xmlns:tools="http://schemas.android.com/tools"
                android:layout_width="match_parent"
                android:orientation="vertical"
                android:layout_height="wrap_content"
                android:paddingLeft="@dimen/activity_horizontal_margin"
                android:paddingRight="@dimen/activity_horizontal_margin"
                android:paddingTop="1dp"
                android:paddingBottom="16dp">

                <ListView
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:clickable="true"
                    android:id="@+id/listView" />
            </LinearLayout>
        </ScrollView>
</RelativeLayout>

---

activity_news.xml

---

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.synergywebdesigners.nima.news">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_news" />

</android.support.design.widget.CoordinatorLayout>

---

我想从 MySQL 服务器获取图像并在 android 中显示图像。但是每次都会创建 java 空指针异常。

Answer 1

Use Picasso for Image downloading and show in your ImageView

在你的 Gradle 中编译库:

compile 'com.squareup.picasso:picasso:2.5.2'

在您要设置图像的Activity中，喜欢:

Picasso.with(your_activity.this).load(image_url_from_server).into(your_imageView);