常用工具类，文件和内存的大小获取，shell脚本的执行

/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/package android.cts.util;import android.app.ActivityManager;
import android.app.ActivityManager.MemoryInfo;
import android.app.Instrumentation;
import android.content.Context;
import android.os.ParcelFileDescriptor;
import android.os.StatFs;import java.io.FileInputStream;
import java.io.IOException;public class SystemUtil {
public static long getFreeDiskSize(Context context) {
StatFs statFs = new StatFs(context.getFilesDir().getAbsolutePath());
return (long)statFs.getAvailableBlocks() * statFs.getBlockSize();
} public static long getFreeMemory(Context context) {
MemoryInfo info = new MemoryInfo();
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
activityManager.getMemoryInfo(info);
return info.availMem;
} public static long getTotalMemory(Context context) {
MemoryInfo info = new MemoryInfo();
ActivityManager activityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
activityManager.getMemoryInfo(info);
return info.totalMem; // TODO totalMem N/A in ICS.
} /**
* Executes a shell command using shell user identity, and return the standard output in string
* <p>Note: calling this function requires API level 21 or above
* @param instrumentation {@link Instrumentation} instance, obtained from a test running in
* instrumentation framework
* @param cmd the command to run
* @return the standard output of the command
* @throws Exception
*/
public static String runShellCommand(Instrumentation instrumentation, String cmd)
throws IOException {
ParcelFileDescriptor pfd = instrumentation.getUiAutomation().executeShellCommand(cmd);
byte[] buf = new byte[512];
int bytesRead;
FileInputStream fis = new ParcelFileDescriptor.AutoCloseInputStream(pfd);
StringBuffer stdout = new StringBuffer();
while ((bytesRead = fis.read(buf)) != -1) {
stdout.append(new String(buf, 0, bytesRead));
}
fis.close();
return stdout.toString();
}}