[英]Null Pointer Exception in Bitmap.decodeResources() from xml resource
In my current android project I create two bitmaps from xml resources. 在我当前的android项目中,我从xml资源创建两个位图。 Every time I build my project using the xml bitmaps as the resource for Bitmap.decodeResources()
I get a null pointer exception when I try to access the bitmaps. 每次使用xml位图作为Bitmap.decodeResources()
的资源来构建项目时,当我尝试访问位图时,都会出现空指针异常。 But when I switch to using the straight .png the error goes away. 但是当我切换到使用.png时,错误消失了。
Why is decodeResources()
returning null? 为什么decodeResources()
返回null?
code where the bitmaps are created: 创建位图的代码:
public OvertButton(float x, float y, float width, float height, int pressedId, int unPressedId, Resources res, boolean visible) {
\\these are null if xml bitmap is passed
pressed = BitmapFactory.decodeResource(res, pressedId);
unPressed = BitmapFactory.decodeResource(res, unPressedId);
this.visible = visible;
relocate(x, y);
resize(width, height); //throws NPE when I createScaledBitmap()
ClickableManager.registerClickable(this);
}
resource file 资源文件
<bitmap xmlns:android="http://schemas.android.com/apk/res/android"
android:src="@drawable/play_button_pressed"
android:filter="false"
android:antialias="false"
android:dither="false"/>
and the resize method 和调整大小的方法
@Override
public void resize(float width, float height) {
box.set(box.left, box.top, box.left + width, box.top + height);
Log.d("resize",String.valueOf(height));
pressed = Bitmap.createScaledBitmap(pressed, (int)width, (int)height, true);
unPressed = Bitmap.createScaledBitmap(unPressed, (int)width, (int)height, true);
}
And the logcat 和logcat
04-16 09:45:06.341 11824-11824/com.handmade.eed D/dalvikvm﹕ Late-enabling CheckJNI
04-16 09:45:06.450 11824-11824/com.handmade.eed D/MenuActivity﹕ 2130837594$$$2130837596
04-16 09:45:06.451 11824-11824/com.handmade.eed D/skia﹕ --- SkImageDecoder::Factory returned null
04-16 09:45:06.451 11824-11824/com.handmade.eed D/OvertButton﹕ true2130837591
04-16 09:45:06.457 11824-11824/com.handmade.eed D/OvertButton﹕ false2130837595
04-16 09:45:06.457 11824-11824/com.handmade.eed D/resize﹕ 252.0
04-16 09:45:06.458 11824-11824/com.handmade.eed D/AndroidRuntime﹕ Shutting down VM
04-16 09:45:06.459 11824-11824/com.handmade.eed W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x41610d40)
04-16 09:45:06.461 11824-11824/com.handmade.eed E/AndroidRuntime﹕ FATAL EXCEPTION: main
Process: com.handmade.eed, PID: 11824
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.handmade.eed/com.handmade.eed.MenuActivity}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5102)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at android.graphics.Bitmap.createScaledBitmap(Bitmap.java:615)
at com.handmade.overt.visible.OvertButton.resize(OvertButton.java:61)
at com.handmade.overt.visible.OvertButton.<init>(OvertButton.java:29)
at com.handmade.overt.visible.OvertButton.<init>(OvertButton.java:34)
at com.handmade.eed.MenuActivity.onCreate(MenuActivity.java:72)
at android.app.Activity.performCreate(Activity.java:5248)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2173)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
at android.app.ActivityThread.access$800(ActivityThread.java:139)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5102)
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:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
04-16 09:45:09.872 11824-11824/com.handmade.eed I/Process﹕ Sending signal. PID: 11824 SIG: 9
This is a case of me being dumb but here is the answer for posterity. 这是我愚蠢的情况,但这是后代的答案。 Bitmap
is not the same as BitmapDrawable
Bitmap
与BitmapDrawable
From the Drawable Resources link above: 从上方的“可绘制资源”链接:
COMPILED RESOURCE DATATYPE: 完整的资源数据类型:
Resource pointer to a BitmapDrawable. 指向BitmapDrawable的资源指针。
Thus I had to change this: 因此,我不得不更改此:
Bitmap pressed = BitmapFactory.decodeResource(res, R.drawable.play_button_pressed_res); //this is the id for the xml referring to the png
to either this: 为此:
Drawable pressed = res.getDrawable(R.drawable.play_button_pressed_res);
or this: 或这个:
Bitmap pressed = BitmapFactory.decodeResource(res, R.drawable.play_button_pressed); //this is the id for the png
I decided to use bitmap
because, as I understand, it is faster. 我决定使用bitmap
因为据我所知,它更快。
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