未来的功能是否还需要AssetManager？

Question

何时创建和关闭AssetManager实例。

我的程序出现了一个错误。DDMS显示...

07-04 18:44:59.241: DEBUG/KeyguardViewMediator(65): pokeWakelock(5000)
07-04 18:44:59.541: DEBUG/KeyguardViewMediator(65): pokeWakelock(5000)
07-04 18:45:00.101: INFO/ARMAssembler(65): generated scanline__00000077:03545404_00000004_00000000 [ 47 ipp] (67 ins) at [0x33b540:0x33b64c] in 9815520 ns
07-04 18:45:00.281: INFO/ARMAssembler(65): generated scanline__00000177:03515104_00001001_00000000 [ 91 ipp] (114 ins) at [0x33c088:0x33c250] in 2206721 ns
07-04 18:45:00.561: WARN/ActivityManager(65): finishReceiver called but no pending broadcasts
07-04 18:45:10.843: DEBUG/AndroidRuntime(277): Shutting down VM
07-04 18:45:10.843: WARN/dalvikvm(277): threadid=1: thread exiting with uncaught exception (group=0x4001d800)
07-04 18:45:11.191: ERROR/AndroidRuntime(277): FATAL EXCEPTION: main
07-04 18:45:11.191: ERROR/AndroidRuntime(277): android.content.res.Resources$NotFoundException: File res/layout/simple_spinner_item.xml from xml type layout resource ID #0x1090008
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.content.res.Resources.loadXmlResourceParser(Resources.java:1916)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.content.res.Resources.loadXmlResourceParser(Resources.java:1871)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.content.res.Resources.getLayout(Resources.java:731)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.LayoutInflater.inflate(LayoutInflater.java:318)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:332)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.ArrayAdapter.getView(ArrayAdapter.java:323)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.AbsSpinner.onMeasure(AbsSpinner.java:192)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.TableRow.getColumnsWidths(TableRow.java:308)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.TableLayout.findLargestCells(TableLayout.java:497)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.TableLayout.measureVertical(TableLayout.java:462)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.TableLayout.onMeasure(TableLayout.java:428)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1012)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:381)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.LinearLayout.measureVertical(LinearLayout.java:526)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.View.measure(View.java:8171)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.os.Looper.loop(Looper.java:123)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.app.ActivityThread.main(ActivityThread.java:4627)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at java.lang.reflect.Method.invokeNative(Native Method)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at java.lang.reflect.Method.invoke(Method.java:521)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at dalvik.system.NativeStart.main(Native Method)
07-04 18:45:11.191: ERROR/AndroidRuntime(277): Caused by: java.lang.RuntimeException: Assetmanager has been closed
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.content.res.AssetManager.openXmlBlockAsset(AssetManager.java:483)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     at android.content.res.Resources.loadXmlResourceParser(Resources.java:1898)
07-04 18:45:11.191: ERROR/AndroidRuntime(277):     ... 36 more

我不会发布所有的代码，因为它非常长，但我的程序结构类似于以下内容...

public class myAppActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        usesAnInstanceOfAssetManager();
        addsTextToASpinner(); 
    }


    private void usesAnInstanceOfAssetManager() {
        AssetManager assetManager = getAssets();
        ///blah blah blah.....
        assetManager.close();
        return;
    }

    public void addsTextToASpinner(){
        // code to add text fields to a spinner
        // executing this function caused the error shown above
        return;
    }
}

我注意到以下的语句:

07-04 18:45:11.191: ERROR/AndroidRuntime(277): Caused by: java.lang.RuntimeException: Assetmanager has been closed

所以问题似乎在于第一个函数"usesAnInstanceOfAssetManager"关闭了asset manager，而第二个函数需要assetManager。我在函数“usesAnInstanceOfAssetManager”中注释掉了assetManager.close()行，我的应用程序没有崩溃。所以我的问题是....

使用AssetManager的最佳实践是什么？我只能在程序中使用一次吗？我认为声明一个实例并在完成后关闭它是适当的做法，但情况并非如此。 AssetManager是否是“静态”的？我总是需要它吗？

- b10hazard

Answer 1

据我所见，AssetManager是由系统创建的，因此无需打开或关闭AssertManager。

应用程序需要做的是打开/关闭它使用的inputStream。如果我说错了，请纠正我。

- Happier

Answer 2

我假设在调用AddTextToSpinner()方法后，你可以关闭AssetManager。 如果你需要在其他地方使用它，只需重新打开即可。

如果您需要有关AssetManager的更多信息，请访问此链接： http://developer.android.com/reference/android/content/res/AssetManager.html

我使用AssetManager的方式如下：

我调用parseXMLFile()方法， 在其中打开我的AssetManager， 我打开我的XML文件，读取并将数据存储在对象中， 然后关闭AssetManager。

这样我只使用一次AssetManager，以后在我的应用程序中我只需要处理这些对象。

希望这是你要找的答案！

- kevin

---

你说的“我打开我的AssetManager”是什么意思？它本身没有打开函数。 - BeniBela