Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
760 views
in Technique[技术] by (71.8m points)

java - Android Bitmap from URL always null

I'm trying to download an image from a URL and convert it into a bitmap, but the line

Bitmap myBitmap = BitmapFactory.decodeStream(input);

always causes the debugger to skip to the following line

return null;

without ever actually printing out the stack trace and the Exception variable also doesn't exist in the variables listed in the Debugger. I read a lot about how there might be issues with urls not actually leading to images, not well formated images and the like but it still has the same issue with a hardcoded image that I'm positive exists.

public static Bitmap getBitmapFromURL(String src) {
    try {
        URL url = new URL(
                "http://www.helpinghomelesscats.com/images/cat1.jpg");
        HttpURLConnection connection = (HttpURLConnection) url
                .openConnection();
        connection.setDoInput(true);
        connection.connect();
        InputStream input = connection.getInputStream();
        Bitmap myBitmap = BitmapFactory.decodeStream(input);
        return myBitmap;
    } catch (IOException e) {
        e.printStackTrace();
        return null;
    }
}

Since it seems like the manifest.xml file might be involved I've edited to add here.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.delivery"
android:versionCode="1"
android:versionName="1.0">

<uses-permission android:name="android.permission.CALL_PHONE"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.INTERNET"></uses-permission>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"></uses-permission>

<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".IntroPage"
              android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".Browse"></activity>
    <activity android:name=".ViewProduct"></activity>
    <activity android:name=".ViewOrder"></activity>
    <activity android:name=".GetAddress"></activity>
    <activity android:name=".ConfirmOrder"></activity>
</application>

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

following code work for all type of images.

    try {

        URL url = new URL("http://www.helpinghomelesscats.com/images/cat1.jpg");
        InputStream in = url.openConnection().getInputStream(); 
        BufferedInputStream bis = new BufferedInputStream(in,1024*8);
        ByteArrayOutputStream out = new ByteArrayOutputStream();

        int len=0;
        byte[] buffer = new byte[1024];
        while((len = bis.read(buffer)) != -1){
            out.write(buffer, 0, len);
        }
        out.close();
        bis.close();

        byte[] data = out.toByteArray();
        Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);
        imageView.setImageBitmap(bitmap);
    }
    catch (IOException e) {
        e.printStackTrace();
    }

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...