java - 从 url 加载位图

Question

如果我刷新图库 Activity 错误，我的位图图库出现问题。我从子 Activity 返回到画廊错误..

日志猫

06-05 03:22:24.848    2366-2366/com.skripsi.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.skripsi.test, PID: 2366
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.skripsi.test/com.skripsi.test.Detail_bengkel}: java.lang.NullPointerException
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2318)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:149)
            at android.app.ActivityThread.main(ActivityThread.java:5268)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.NullPointerException
            at com.skripsi.test.GalleryAdapter.loadBitmap(GalleryAdapter.java:63)
            at com.skripsi.test.Detail_bengkel.onCreate(Detail_bengkel.java:138)
            at android.app.Activity.performCreate(Activity.java:5403)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2270)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2396)
            at android.app.ActivityThread.access$800(ActivityThread.java:139)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1293)
            at android.os.Handler.dispatchMessage(Handler.java:102)
            at android.os.Looper.loop(Looper.java:149)
            at android.app.ActivityThread.main(ActivityThread.java:5268)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:515)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:609)
            at dalvik.system.NativeStart.main(Native Method)

galleryadapter.java:63

String url = getItem(position).toString();

detail_bengkel.java:138

imageViewURL.setImageBitmap(galleryAdapter.loadBitmap(3));

帮帮我..

抱歉英语不好..

谢谢你..

Answer 1

问题是您使用参数3调用getItems，它返回null，因为该位置没有任何内容。您需要使用有效索引访问适配器中的项目。

例如，如果您想在 ImageView 中显示适配器中的最后一个图像。

if (galleryAdapter.getCount() > 0){
    imageViewURL.setImageBitmap(galleryAdapter.loadBitmap(galleryAdapter.getCount() - 1));
}