[安卓]手机管家(二十) 缓存清理

来一个生成缓存的应用

在cachedir下写点东西就好

<TextView        android:id="@+id/textView1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="@string/hello_world" />    <Button        android:id="@+id/button1"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_below="@+id/textView1"        android:layout_centerHorizontal="true"        android:layout_marginTop="77dp"        android:text="Button"        android:onClick="makecache"/>

public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);getCache();}public void makecache(View v){File file = new File(getCacheDir()+"/cache.txt");        try {FileWriter fw = new FileWriter(file);fw.write("hello world");fw.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();}}//获取当前缓存信息public void getCache(){}}

用到反射知识

这里还需要aidl，注意包名

获得缓存信息

//获取当前缓存信息public void getCache(){PackageManager pm = getPackageManager();try {//获得字节码Class<?> loadclass = MainActivity.class.getClassLoader().loadClass("android.content.pm.PackageManager");    Method method = loadclass.getMethod("getPackageSizeInfo", String.class,IPackageStatsObserver.class);    method.invoke(pm, "com.example.makecache",new MyPackageManagerObserver());} catch (ClassNotFoundException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (NoSuchMethodException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalAccessException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (IllegalArgumentException e) {// TODO Auto-generated catch blocke.printStackTrace();} catch (InvocationTargetException e) {// TODO Auto-generated catch blocke.printStackTrace();}}class MyPackageManagerObserver extends IPackageStatsObserver.Stub{@Overridepublic void onGetStatsCompleted(PackageStats pStats, boolean succeeded)throws RemoteException {// TODO Auto-generated method stublong cache = pStats.cacheSize; //bytelong data = pStats.dataSize;long code = pStats.codeSize;String cacheString = Formatter.formatFileSize(getApplicationContext(), cache);String dataString = Formatter.formatFileSize(getApplicationContext(), data);String codeString = Formatter.formatFileSize(getApplicationContext(), code);System.out.println("MainActivity.MyPackageManagerObserver.onGetStatsCompleted()"+"cache: "+cacheString+"data: "+dataString+"code: "+codeString);}}

我们是要PackageManager下的getPackageSizeInfo方法，但是这个方法比较敏感，有一个hidden标签，是被隐藏的，不能通过常用的调用方法去获取，所以需要反射，通过他的字节码去找到他，用到了getmethod方法，然后通过invoke去调用，第二个参数表示包名，第三个参数表示一个observer，这个observer里有一个callback，前面你获取到包名什么的，我来计算，所以在手机上打开setting里的APP查看缓存信息时，过一会才有，是在计算信息

权限  获得缓存信息是比较敏感的，只有通过反射才能搞到，权限是必须的

<uses-permission android:name="android.permission.GET_PACKAGE_SIZE"/>

以上是demo，现在来做做看

关于布局，其中有一个进度条ProgressBar，一半默认是圆圈，这里做成长条形，需要定义其风格

另外  layer-list 
将多个图片或上面两种效果按照顺序层叠起来，这需要单独定义一个XML

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical" >        <TextView         android:layout_width="fill_parent"        android:layout_height="60dp"        android:text="缓存清理"        android:background="#00FF00"        android:gravity="center"        android:textSize="25sp"/>    <ProgressBar        android:id="@+id/pb_clearcache_scan"        android:progressDrawable="@drawable/progress_horizontal"        style="?android:attr/progressBarStyleHorizontal"        android:layout_width="fill_parent"        android:layout_height="wrap_content" />      <TextView         android:layout_height="wrap_content"        android:layout_width="fill_parent"        android:id="@+id/tv_cacheclear_scanning"        android:singleLine="true"/>    <Button        android:layout_height="wrap_content"        android:layout_width="wrap_content"        android:text="清理缓存"        android:onClick="clearall"        android:visibility="gone"        android:layout_gravity="center_horizontal"        android:id="@+id/bt_cacheclear_clearall"/>    <ListView        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:id="@+id/lv_clearcache_cachelist"/>   </LinearLayout>

在drawable中定义的layer-list  

<layer-list xmlns:android="http://schemas.android.com/apk/res/android">       <item android:id="@android:id/background">       <bitmap android:src="@drawable/security_progress_bg"/>    </item>        <item android:id="@android:id/secondaryProgress">        <bitmap android:src="@drawable/security_progress"/>       </item>        <item android:id="@android:id/progress">       <bitmap android:src="@drawable/security_progress"/>    </item>   </layer-list>

CleanCacheActivity架子

public class CleanCacheActivity extends Activity {private ProgressBar pb_clearcache_scan;private ListView lv_clearcache_cachelist;private TextView tv_cacheclear_scanning;private Button bt_cacheclear_clearall;@Overrideprotected void onCreate(Bundle savedInstanceState) {// TODO Auto-generated method stubsuper.onCreate(savedInstanceState);        setContentView(R.layout.activity_cacheclear);        pb_clearcache_scan = (ProgressBar) findViewById(R.id.pb_clearcache_scan);    tv_cacheclear_scanning = (TextView) findViewById(R.id.tv_cacheclear_scanning);    lv_clearcache_cachelist = (ListView) findViewById(R.id.lv_clearcache_cachelist);    bt_cacheclear_clearall = (Button) findViewById(R.id.bt_cacheclear_clearall);        getAllCache();}//获取当前APP缓存private void getAllCache() {// TODO Auto-generated method stub}}