[英]App Crashed if trying to get Bitmap Image from Assets Folder in Android ?
[英]Android : ArrayList with Bitmap from assets
我一直在尝试从资产目录中的图像中列出一个列表,这是我的代码
ArrayList<Bitmap> list = new ArrayList<>();
try{
String[] PathFiles = assetManager.list("img");
for (int i = 0; i < PathFiles.length; i++) {
InputStream is = assetManager.open("img/" + PathFiles[i]);
Bitmap bitmap = BitmapFactory.decodeStream(is);
list.add(i, bitmap);
}
}
catch(IOException e)
{
e.printStackTrace();
}
但是,无论何时执行此代码,我的应用程序都会崩溃。 有什么问题吗?
该应用程序的logcat:
10-29 18:19:06.712 18272-18272/com.example.mohammed.myapplication E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.example.mohammed.myapplication, PID: 18272
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.mohammed.myapplication/com.example.mohammed.myapplication.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String[] android.content.res.AssetManager.list(java.lang.String)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2790)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2855)
at android.app.ActivityThread.access$900(ActivityThread.java:181)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1474)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6117)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String[] android.content.res.AssetManager.list(java.lang.String)' on a null object reference
at com.example.mohammed.myapplication.MainActivity.onCreate(MainActivity.java:49)
at android.app.Activity.performCreate(Activity.java:6374)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1119)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2743)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2855)
at android.app.ActivityThread.access$900(ActivityThread.java:181)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1474)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:6117)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
我会说你在这里得到一个NullPointerException
:
list.add(i, bitmap);
您不创建ArrayList
:
ArrayList<Bitmap> list;
尝试使用:
ArrayList<Bitmap> list = new ArrayList<>;
您需要先初始化阵列列表
ArrayList<Bitmap> list=new ArrayList<>();
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