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此代碼DiskLruCache空指針異常工作正常我真正的設備上，但讓空指針異常，如果我跑我的emulator-在模擬器
應用DiskLruImageCache.java
public DiskLruImageCache(Context context, String uniqueName,
int diskCacheSize, CompressFormat compressFormat, int quality) {
try {
final File diskCacheDir = getDiskCacheDir(context, uniqueName);
mDiskCache = DiskLruCache.open(diskCacheDir, APP_VERSION,
VALUE_COUNT, diskCacheSize);
mCompressFormat = compressFormat;
mCompressQuality = quality;
} catch (IOException e) {
e.printStackTrace();
}
}
public void put(String key, Bitmap data) {
DiskLruCache.Editor editor = null;
try {
editor = mDiskCache.edit(key);
// showMsg("Editor = "+ editor);
if (editor == null) {
return;
}
if (writeBitmapToFile(data, editor)) {
mDiskCache.flush();
editor.commit();
if (BuildConfig.DEBUG) {
}
} else {
editor.abort();
if (BuildConfig.DEBUG) {
}
}
} catch (IOException e) {
if (BuildConfig.DEBUG) {
}
try {
if (editor != null) {
editor.abort();
}
} catch (IOException ignored) {
}
}
}
public Bitmap getBitmap(String key) {
Bitmap bitmap = null;
DiskLruCache.Snapshot snapshot = null;
try {
snapshot = mDiskCache.get(key);
if (snapshot == null) {
return null;
}
final InputStream in = snapshot.getInputStream(0);
if (in != null) {
final BufferedInputStream buffIn = new BufferedInputStream(in);
bitmap = BitmapFactory.decodeStream(buffIn).copy(
Config.ARGB_4444, true);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (snapshot != null) {
snapshot.close();
}
}
if (BuildConfig.DEBUG) {
}
return bitmap;
}
我的logcat ：
07-09 08:29:45.877: E/AndroidRuntime(2266): FATAL EXCEPTION: main
07-09 08:29:45.877: E/AndroidRuntime(2266): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.apper.main/com.apper.main.MyFragmentActivity}: java.lang.NullPointerException
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.app.ActivityThread.access$600(ActivityThread.java:141)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.os.Handler.dispatchMessage(Handler.java:99)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.os.Looper.loop(Looper.java:137)
07-09 08:29:45.877: E/AndroidRuntime(2266): at android.app.ActivityThread.main(ActivityThread.java:5041)
07-09 08:29:45.877: E/AndroidRuntime(2266): at java.lang.reflect.Method.invokeNative(Native Method)
07-09 08:29:45.877: E/AndroidRuntime(2266): at java.lang.reflect.Method.invoke(Method.java:511)
07-09 08:29:45.877: E/AndroidRuntime(2266): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
07-09 08:29:45.877: E/AndroidRuntime(2266): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
07-09 08:29:45.877: E/AndroidRuntime(2266): at dalvik.system.NativeStart.main(Native Method)
07-09 08:29:45.877: E/AndroidRuntime(2266): Caused by: java.lang.NullPointerException
07-09 08:29:45.877: E/AndroidRuntime(2266): at com.apper.util.DiskLruImageCache.getBitmap(DiskLruImageCache.java:109)
我試着在m上設置外部存儲ŸAndroid清單，但沒有luck-
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
「DiskLruImageCache」中第109行的內容是什麼？ – Raghunandan
'snapshot = mDiskCache.get（key）;'。模擬器上的mDiskCache爲null，但實際設備並非如此。 –