android settings源代码分析(3)

本章主要分析google settings里面存储模块的代码。

存储模块所在的fragment为：

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<header
android:id="@+id/storage_settings"
android:fragment="com.android.settings.deviceinfo.Memory"
android:icon="@drawable/ic_settings_storage"
android:title="@string/storage_settings" />

我们现在看Memory这个类

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@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
final Context context = getActivity();
mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
mStorageManager = StorageManager.from(context);
mStorageManager.registerListener(mStorageListener);
addPreferencesFromResource(R.xml.device_info_memory);
addCategory(StorageVolumePreferenceCategory.buildForInternal(context));
final StorageVolume[] storageVolumes = mStorageManager.getVolumeList();
for (StorageVolume volume : storageVolumes) {
if (!volume.isEmulated()) {
addCategory(StorageVolumePreferenceCategory.buildForPhysical(context, volume));
}
}
setHasOptionsMenu(true);
}

在onCreate函数中，主要做了几件事情:

1.各种初始化

2.实例化布局，最主要是对Category的添加

3.获取当前挂载的volume，并且实例化为Category

Category最主要的是StorageVolumePreferenceCategory，构造函数如下：

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/**
* Build category to summarize specific physical {@link StorageVolume}.
*/
public static StorageVolumePreferenceCategory buildForPhysical(
Context context, StorageVolume volume) {
return new StorageVolumePreferenceCategory(context, volume);
}
private StorageVolumePreferenceCategory(Context context, StorageVolume volume) {
super(context);
mVolume = volume;
mMeasure = StorageMeasurement.getInstance(context, volume);
mResources = context.getResources();
mStorageManager = StorageManager.from(context);
mUserManager = (UserManager) context.getSystemService(Context.USER_SERVICE);
setTitle(volume != null ? volume.getDescription(context)
: context.getText(R.string.internal_storage));
}

构造函数会被如下函数调用：

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/**
* Build category to summarize internal storage, including any emulated
* {@link StorageVolume}.
*/
public static StorageVolumePreferenceCategory buildForInternal(Context context) {
return new StorageVolumePreferenceCategory(context, null);
}

到这里，主要是在Category里面做一些初始化，对于存储fragment最上面的“内部存储设备”text显示就是在构造函数中完成：

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setTitle(volume != null ? volume.getDescription(context)
: context.getText(R.string.internal_storage));

对于外置设备Category的创建，主要是在：

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/**
* Build category to summarize specific physical {@link StorageVolume}.
*/
public static StorageVolumePreferenceCategory buildForPhysical(
Context context, StorageVolume volume) {
return new StorageVolumePreferenceCategory(context, volume);
}

唯一的区别就是Volume是否为NULL。

创建Category后，主要是对preference的创建，主要是在init函数：

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public void init() {
final Context context = getContext();
removeAll();
final UserInfo currentUser;
try {
currentUser = ActivityManagerNative.getDefault().getCurrentUser();
} catch (RemoteException e) {
throw new RuntimeException("Failed to get current user");
}
final List<UserInfo> otherUsers = getUsersExcluding(currentUser);
final boolean showUsers = mVolume == null && otherUsers.size() > 0;
mUsageBarPreference = new UsageBarPreference(context);
mUsageBarPreference.setOrder(ORDER_USAGE_BAR);
addPreference(mUsageBarPreference);
mItemTotal = buildItem(R.string.memory_size, 0);
mItemAvailable = buildItem(R.string.memory_available, R.color.memory_avail);
addPreference(mItemTotal);
addPreference(mItemAvailable);
mItemApps = buildItem(R.string.memory_apps_usage, R.color.memory_apps_usage);
mItemDcim = buildItem(R.string.memory_dcim_usage, R.color.memory_dcim);
mItemMusic = buildItem(R.string.memory_music_usage, R.color.memory_music);
mItemDownloads = buildItem(R.string.memory_downloads_usage, R.color.memory_downloads);
mItemCache = buildItem(R.string.memory_media_cache_usage, R.color.memory_cache);
mItemMisc = buildItem(R.string.memory_media_misc_usage, R.color.memory_misc);
mItemCache.setKey(KEY_CACHE);
final boolean showDetails = mVolume == null || mVolume.isPrimary();
if (showDetails) {
if (showUsers) {
addPreference(new PreferenceHeader(context, currentUser.name));
}
addPreference(mItemApps);
addPreference(mItemDcim);
addPreference(mItemMusic);
addPreference(mItemDownloads);
addPreference(mItemCache);
addPreference(mItemMisc);
if (showUsers) {
addPreference(new PreferenceHeader(context, R.string.storage_other_users));
int count = 0;
for (UserInfo info : otherUsers) {
final int colorRes = count++ % 2 == 0 ? R.color.memory_user_light
: R.color.memory_user_dark;
final StorageItemPreference userPref = new StorageItemPreference(
getContext(), info.name, colorRes, info.id);
mItemUsers.add(userPref);
addPreference(userPref);
}
}
}
final boolean isRemovable = mVolume != null ? mVolume.isRemovable() : false;
// Always create the preference since many code rely on it existing
mMountTogglePreference = new Preference(context);
if (isRemovable) {
mMountTogglePreference.setTitle(R.string.sd_eject);
mMountTogglePreference.setSummary(R.string.sd_eject_summary);
addPreference(mMountTogglePreference);
}
final boolean allowFormat = mVolume != null;
if (allowFormat) {
mFormatPreference = new Preference(context);
mFormatPreference.setTitle(R.string.sd_format);
mFormatPreference.setSummary(R.string.sd_format_summary);
addPreference(mFormatPreference);
}
final IPackageManager pm = ActivityThread.getPackageManager();
try {
if (pm.isStorageLow()) {
mStorageLow = new Preference(context);
mStorageLow.setOrder(ORDER_STORAGE_LOW);
mStorageLow.setTitle(R.string.storage_low_title);
mStorageLow.setSummary(R.string.storage_low_summary);
addPreference(mStorageLow);
} else if (mStorageLow != null) {
removePreference(mStorageLow);
mStorageLow = null;
}
} catch (RemoteException e) {
}
}

对preference数据进行更新是在：

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public void updateApproximate(long totalSize, long availSize) {
mItemTotal.setSummary(formatSize(totalSize));
mItemAvailable.setSummary(formatSize(availSize));
mTotalSize = totalSize;
final long usedSize = totalSize - availSize;
mUsageBarPreference.clear();
mUsageBarPreference.addEntry(0, usedSize / (float) totalSize, android.graphics.Color.GRAY);
mUsageBarPreference.commit();
updatePreferencesFromState();
}

当点击cache prefrence时，会弹出dialog，主要是在Memory.java中响应：

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public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference) {
if (StorageVolumePreferenceCategory.KEY_CACHE.equals(preference.getKey())) {
ConfirmClearCacheFragment.show(this);
return true;
}

查看ConfirmClearCacheFragment的函数：

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@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
final Context context = getActivity();
final AlertDialog.Builder builder = new AlertDialog.Builder(context);
builder.setTitle(R.string.memory_clear_cache_title);
builder.setMessage(getString(R.string.memory_clear_cache_message));
builder.setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
final Memory target = (Memory) getTargetFragment();
final PackageManager pm = context.getPackageManager();
final List<PackageInfo> infos = pm.getInstalledPackages(0);
final ClearCacheObserver observer = new ClearCacheObserver(
target, infos.size());
for (PackageInfo info : infos) {
pm.deleteApplicationCacheFiles(info.packageName, observer);
}
}
});
builder.setNegativeButton(android.R.string.cancel, null);
return builder.create();
}

会通过PackageManager获取所有安装apk，然后清除所有apk的缓存数据。

点击“卸载SD卡”，会弹出dialog，对应的代码为：

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private void unmount() {
// Check if external media is in use.
try {
if (hasAppsAccessingStorage()) {
// Present dialog to user
showDialogInner(DLG_CONFIRM_UNMOUNT);
} else {
doUnmount();
}
} catch (RemoteException e) {
// Very unlikely. But present an error dialog anyway
Log.e(TAG, "Is MountService running?");
showDialogInner(DLG_ERROR_UNMOUNT);
}
}

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@Override
public Dialog onCreateDialog(int id) {
switch (id) {
case DLG_CONFIRM_UNMOUNT:
return new AlertDialog.Builder(getActivity())
.setTitle(R.string.dlg_confirm_unmount_title)
.setPositiveButton(R.string.dlg_ok, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
doUnmount();
}})
.setNegativeButton(R.string.cancel, null)
.setMessage(R.string.dlg_confirm_unmount_text)
.create();

[java] view plaincopy

private void doUnmount() {
// Present a toast here
Toast.makeText(getActivity(), R.string.unmount_inform_text, Toast.LENGTH_SHORT).show();
IMountService mountService = getMountService();
try {
sLastClickedMountToggle.setEnabled(false);
sLastClickedMountToggle.setTitle(getString(R.string.sd_ejecting_title));
sLastClickedMountToggle.setSummary(getString(R.string.sd_ejecting_summary));
mountService.unmountVolume(sClickedMountPoint, true, false);
} catch (RemoteException e) {
// Informative dialog to user that unmount failed.
showDialogInner(DLG_ERROR_UNMOUNT);
}
}

原文地址：http://blog.csdn.net/zhudaozhuan/article/details/40621335

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