android sd卡状态、路径、可用空间，内存

sd卡状态、路径、可用空间byte，参考http://ai4work.blog.163.com/blog/static/189873306201182310304586/

内存，参考http://blog.csdn.net/hudashi/article/details/7050897

manifest权限：

<!-- 在SDCard中创建与删除文件权限 -->
    <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS"/>
    <!-- 往SDCard写入数据权限 -->
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

code：

package com.test;

import android.app.Activity;
import android.app.ActivityManager;
import android.os.Bundle;
import android.os.Environment;
import android.os.StatFs;
import android.util.Log;

public class Test2 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        int i = 0;
        while (i < 1) {
            try {
                System.out.println("1: " + checkSDCard());
                String path = getExternalStoragePath();
                System.out.println("2: " + path);
                if (path != null) {
                    System.out.println("3: " + (getAvailableStore(path)>>20) + "MB");
                }
                displayBriefMemory();
            } catch (Exception e) {
                e.printStackTrace();
            }
            i++;
        }

    }

    //内存相关
    private void displayBriefMemory() {    
        final ActivityManager activityManager = (ActivityManager) getSystemService(ACTIVITY_SERVICE);    
        ActivityManager.MemoryInfo info = new ActivityManager.MemoryInfo();   
        activityManager.getMemoryInfo(info);    
        Log.i("System.out", "系统剩余内存:"+(info.availMem >> 20)+"MB");   
        Log.i("System.out", "系统是否处于低内存运行："+info.lowMemory);
        Log.i("System.out", "当系统剩余内存低于" + (info.threshold >> 20) + "MB时就看成低内存运行");
    } 
    
    // 检查SD卡状态
    private boolean checkSDCard() {
        if (Environment.getExternalStorageState().equals(
                Environment.MEDIA_MOUNTED)) {
            return true;
        }
        return false;
    }

    // 获取SD卡路径
    public static String getExternalStoragePath() {
        // 获取SdCard状态
        String state = android.os.Environment.getExternalStorageState();

        // 判断SdCard是否存在并且是可用的

        if (android.os.Environment.MEDIA_MOUNTED.equals(state)) {

            if (android.os.Environment.getExternalStorageDirectory().canWrite()) {

                return android.os.Environment.getExternalStorageDirectory()
                        .getPath();

            }

        }

        return null;

    }

    /**
     * 　　* 获取存储卡的剩余容量，单位为字节
     * 
     * 　　* @param filePath
     * 
     * 　　* @return availableSpare
     * 
     * 　　
     */

    public static long getAvailableStore(String filePath) {

        // 取得sdcard文件路径

        StatFs statFs = new StatFs(filePath);

        // 获取block的SIZE

        long blocSize = statFs.getBlockSize();

        // 获取BLOCK数量

        // long totalBlocks = statFs.getBlockCount();

        // 可使用的Block的数量

        long availaBlock = statFs.getAvailableBlocks();

        // long total = totalBlocks * blocSize;

        long availableSpare = availaBlock * blocSize;

        return availableSpare;

    }

}