Android Studio 任务管理器功能思路和代码（一）

首先创建并注册TaskManager主页面，其次绑定task_manager的layout，由于是ListView所以需要一个task_item页面来进行列表元素设置，一下是两个页面代码

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    android:id="@+id/task_manager">    <TextView        style="@style/text_title_style"        android:text="任 务 管 理" />    <View style="@style/view_divide_line_style" />    <RelativeLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_marginTop="5dip">        <TextView            android:id="@+id/tv_task_manager_task_count"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:textSize="15dp"            android:text="进程数:20"/>        <TextView            android:id="@+id/tv_task_manager_task_memory"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_alignParentRight="true"            android:textSize="15dp"            android:text="可用/总内存:50MB/700MB"/>    </RelativeLayout>    <RelativeLayout        android:layout_width="wrap_content"        android:layout_height="wrap_content">        <Button            android:id="@+id/bt_task_manager_noSelect"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="取消"            android:layout_alignParentRight="true"            android:textSize="20dp"            />        <Button            android:id="@+id/bt_task_manager_selectAll"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="全选"            android:layout_toLeftOf="@id/bt_task_manager_noSelect"            android:textSize="20dp"            />    </RelativeLayout>    <FrameLayout        android:layout_width="fill_parent"        android:layout_height="fill_parent" >        <!--       android:cacheColorHint="#00000000" 缓存的颜色  默认是黄色       android:divider="#00ffffff" 分割线       android:dividerHeight="3.0dip" 分割线的宽度        -->        <ListView            android:id="@+id/lv_taskmanager"            android:layout_width="fill_parent"            android:layout_height="fill_parent"            android:cacheColorHint="#00000000"            android:divider="#fff"            android:fastScrollEnabled="true"            android:dividerHeight="1.0dip"            android:paddingLeft="3.0dip"            android:paddingRight="3.0dip" />        <RelativeLayout            android:id="@+id/rl_loading"            android:layout_width="fill_parent"            android:layout_height="fill_parent" >            <LinearLayout                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:orientation="vertical"                android:layout_centerInParent="true"                android:id="@+id/linearLayout">                <ProgressBar                    android:id="@+id/pb"                    android:layout_width="wrap_content"                    android:layout_height="wrap_content"                    android:layout_gravity="center"                    />                <TextView                    android:layout_width="wrap_content"                    android:layout_height="wrap_content"                    android:layout_marginTop="10dip"                    android:text="正在加载应用程序。。"                    android:textColor="#fff"                    android:textSize="22sp" />            </LinearLayout>        </RelativeLayout>    </FrameLayout></LinearLayout>

因为是ListView所以绑定适配器TaskManagerAdapter

 class TaskManagerAdapter extends BaseAdapter {        private LayoutInflater mInflater;        public TaskManagerAdapter() {            // TODO Auto-generated constructor stub            mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);        }        public int getCount() {            // TODO Auto-generated method stub            return taskInfos.size();        }        public Object getItem(int position) {            // TODO Auto-generated method stub            return taskInfos.get(position);        }        public long getItemId(int position) {            // TODO Auto-generated method stub            return position;        }        public View getView(int position, View convertView, ViewGroup parent) {            // TODO Auto-generated method stub            View view = null;            ViewHolder holder = null;            if(convertView != null){                view = convertView;                holder = (ViewHolder) view.getTag();            }else{                view = mInflater.inflate(R.layout.task_item, null);                holder = new ViewHolder();                holder.iv_task_manager_icon = (ImageView) view.findViewById(R.id.iv_task_manager_icon);                holder.tv_task_manager_name = (TextView) view.findViewById(R.id.tv_task_manager_name);                holder.tv_task_manager_memory = (TextView) view.findViewById(R.id.tv_task_manager_memory);            }            TaskInfo taskInfo = taskInfos.get(position);            holder.iv_task_manager_icon.setImageDrawable(taskInfo.getTask_icon());            holder.tv_task_manager_name.setText(taskInfo.getTask_name());            holder.tv_task_manager_memory.setText("占用的内存:" + TextFormat.formatByte(taskInfo.getTask_memory()*1024));            return view;        }    }static class ViewHolder{        ImageView iv_task_manager_icon;        TextView tv_task_manager_name;        TextView tv_task_manager_memory;    }

其次就是获取应用程序的信息了，所以需要一个TaskInfo类

public class TaskInfo {    private Drawable task_icon;    private String task_name;    private String packageName;    private int pid;    private long task_memory;    public TaskInfo() {        super();        // TODO Auto-generated constructor stub    }    public TaskInfo(Drawable task_icon, String task_name, String packageName,                    int pid, long task_memory) {        super();        this.task_icon = task_icon;        this.task_name = task_name;        this.packageName = packageName;        this.pid = pid;        this.task_memory = task_memory;    }    public Drawable getTask_icon() {        return task_icon;    }    public void setTask_icon(Drawable task_icon) {        this.task_icon = task_icon;    }    public String getTask_name() {        return task_name;    }    public void setTask_name(String task_name) {        this.task_name = task_name;    }    public String getPackageName() {        return packageName;    }    public void setPackageName(String packageName) {        this.packageName = packageName;    }    public int getPid() {        return pid;    }    public void setPid(int pid) {        this.pid = pid;    }    public long getTask_memory() {        return task_memory;    }    public void setTask_memory(long task_memory) {        this.task_memory = task_memory;    }    @Override    public String toString() {        return "TaskInfo [task_icon=" + task_icon + ", task_name=" + task_name                + ", packageName=" + packageName + ", pid=" + pid                + ", task_memory=" + task_memory + "]";    }}

接下来就是逻辑功能类TaskUtil的编写了，分别是获取运行的程序的数量，获取运行的程序信息，获取系统可用内存，获取系统总内存。

public class TaskUtil {    /**     * 得到当前正在运行的进程的数量     * @param context     * @return*/    public static int getRuninngAppProcessInfoSize(Context context){        ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);        return ProcessManager.getRunningAppProcesses().size();//        return ActivityManager.    }    /**     * 得到当前系统的总内存     * @param     * @return*/    public static long getTotalMemSize() {        long size=0;        File file = new File("/proc/meminfo");        try {            BufferedReader buffer = new BufferedReader(new InputStreamReader(new FileInputStream(file)));            String memInfo = buffer.readLine();            int startIndex = memInfo.indexOf(":");            int endIndex = memInfo.indexOf("k");            memInfo = memInfo.substring(startIndex + 1, endIndex).trim();            size = Long.parseLong(memInfo);            size *= 1024;            buffer.close();        } catch (java.io.IOException e) {            e.printStackTrace();        }        return size;    }   /**     * 得到当前系统的可用内存     * @param     * @return*/   public static long getAvailMem(Context context){       ActivityManager.MemoryInfo memoryInfo = new ActivityManager.MemoryInfo();       ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);       ActivityManager.MemoryInfo outInfo = new ActivityManager.MemoryInfo();       am.getMemoryInfo(outInfo);       long availMem = outInfo.availMem/1; // byte       return availMem;   }   public static long getAviableMemSize() {       long size=0;       File file = new File("/proc/meminfo");       try {           BufferedReader buffer = new BufferedReader(new InputStreamReader(new FileInputStream(file)));           String memInfos=new String();           String memInfo = null;           int i=0;           while ((memInfos=buffer.readLine())!=null){               i++;               if (i==2){                   memInfo = memInfos;               }           }           int startIndex = memInfo.indexOf(":");           int endIndex = memInfo.indexOf("k");           memInfo = memInfo.substring(startIndex + 1, endIndex).trim();           size = Long.parseLong(memInfo);           buffer.close();       } catch (java.io.IOException e) {           e.printStackTrace();       }       return size;   }    //得到进程所有的信息    public static List<TaskInfo> getTaskInfos(Context context){        List<TaskInfo> taskInfos = new ArrayList<TaskInfo>();        //应用程序包管理器        PackageManager pm = context.getPackageManager();        //应用程序管理器        ActivityManager am = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);        List<AndroidAppProcess> runningAppProcessInfos = ProcessManager.getRunningAppProcesses();        for (AndroidAppProcess info:runningAppProcessInfos){            TaskInfo taskInfo = new TaskInfo();            String packageName = info.name;            taskInfo.setPackageName(packageName);            try {                ApplicationInfo appInfo = pm.getApplicationInfo(packageName,0);                Drawable task_icon = appInfo.loadIcon(pm);                String task_name = appInfo.loadLabel(pm).toString();                if(task_icon == null){                    taskInfo.setTask_icon(context.getResources().getDrawable(R.drawable.tubiao));                }else {                    taskInfo.setTask_icon(task_icon);                }                taskInfo.setTask_name(task_name);            }catch (Exception e){                e.printStackTrace();                // 系统内核进程 没有名称                taskInfo.setTask_name(packageName);                Drawable icon = context.getResources().getDrawable(                        R.mipmap.ic_launcher);                taskInfo.setTask_icon(icon);            }            //获取程序内存            int pid = info.pid;            taskInfo.setPid(pid);            Debug.MemoryInfo[] memoryInfos = am.getProcessMemoryInfo(new int[]{info.pid});            Debug.MemoryInfo memoryInfo = memoryInfos[0];            long task_memory = memoryInfo.getTotalPrivateDirty();//KB单位            taskInfo.setTask_memory(task_memory);            if (taskInfo != null) {                taskInfos.add(taskInfo);            }        }        return taskInfos;    }}

需要注意的是安卓5.0版本后就无法通过ActivityManager来获取运行程序信息了，需要用ProcessManager类来获取运行程序信息，所以需要通过该网页下载下面包导入才行。
http://download.csdn.net/detail/luoyangwyb/9241279
该网址是来自于一个高手的博客分享。

还有一个根据数值大小转换成不同的单位的类

public class TextFormat {    public static String formatByte(long size) {        //如果字节数少于1024，则直接以B为单位，否则先除于1024，后3位因太少无意义        if (size < 1024) {            return String.valueOf(size) + "byte";        } else {            size = size / 1024;        }        //如果原字节数除于1024之后，少于1024，则可以直接以KB作为单位        //因为还没有到达要使用另一个单位的时候        //接下去以此类推        if (size < 1024) {            return String.valueOf(size) + "KB";        } else {            size = size / 1024;        }        if (size < 1024) {            //因为如果以MB为单位的话，要保留最后1位小数，            //因此，把此数乘以100之后再取余            size = size * 100;            return String.valueOf((size / 100)) + "."                    + String.valueOf((size % 100)) + "MB";        } else {            //否则如果要以GB为单位的，先除于1024再作同样的处理            size = size * 100 / 1024;            return String.valueOf((size / 100)) + "."                    + String.valueOf((size % 100)) + "GB";        }    }}

接下来就是最终的主页面TaskManager类的编写了。
通过onCreate方法加载页面，然后找就绑定id为监听做准备。接下来就是调用程序运行数量，再开新线程去传输加载完成新号，来通过Handler接受数据并处理页面，当通过加载完成时，调用可用内存和总内存方法，隐藏加载进度条，并显示ListView即可

public class TaskManager extends Activity {    protected static final int SUCCESS_GET_TASKINFO = 0;    private TextView tv_task_manager_task_count;    private TextView tv_task_manager_task_memory;    private RelativeLayout rl_loading;    private ListView lv_taskmanager;    private boolean isChecked;    private ActivityManager am;    private List<TaskInfo> taskInfos;    private SharedPreferences sp;    private TaskManagerAdapter mAdapter;    private LinearLayout task_manager;    private Handler mHandler = new Handler(){        public void handleMessage(android.os.Message msg) {            switch (msg.what) {                case SUCCESS_GET_TASKINFO:                    //可用内存                    String availMemStr = TextFormat.formatByte(TaskUtil.getAvailMem(getApplication()));                    //总内存                    String totalMemStr = TextFormat.formatByte(TaskUtil.getTotalMemSize());                    tv_task_manager_task_memory.setText("可用/总内存:" + availMemStr +"/" + totalMemStr);                    mAdapter = new TaskManagerAdapter();                    rl_loading.setVisibility(View.GONE);                    lv_taskmanager.setAdapter(mAdapter);                    break;                default:                    break;            }        };    };    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.task_manager);        tv_task_manager_task_count = (TextView) findViewById(R.id.tv_task_manager_task_count);        tv_task_manager_task_memory = (TextView) findViewById(R.id.tv_task_manager_task_memory);        rl_loading = (RelativeLayout) findViewById(R.id.rl_loading);        lv_taskmanager = (ListView) findViewById(R.id.lv_taskmanager);        task_manager = (LinearLayout) findViewById(R.id.task_manager);        am = (ActivityManager) getSystemService(Context.ACTIVITY_SERVICE);        // 进程数目        int size = TaskUtil.getRuninngAppProcessInfoSize(this);        tv_task_manager_task_count.setText("进程数：" + size);        new Thread(){            @Override            public void run() {                taskInfos = TaskUtil.getTaskInfos(getApplicationContext());                Message msg = new Message();                msg.what = SUCCESS_GET_TASKINFO;                mHandler.sendMessage(msg);            }        }.start();    }}

今天还没有做完，仅仅完成显示运行程序的功能，并没有实现程序结束选定分类等功能。 接下来继续努力吧。