概述：

? 之前我聽到過一則新聞，就是說Ipone中的AssistiveTouch的設計初衷是給殘疾人使用的。而這一功能在亞洲（中國）的使用最為頻繁。

? 雖不知道這新聞的可靠性，但無庸置疑的是它的確給我們操作手機帶來了很大的便捷。在這個設計之前，可能比較容易想到的就是建立快捷方式，而快捷方式的操作結果還是要去加載界面（有時可能是繁重的界面）。一旦走上了這條路，那距離快捷操作的方向可能就漸行漸遠了。

? AssistiveTouch的設計的確很贊。Android也是值得擁有這一棒棒的功能，下面我就來簡單說明一下在Android上要如何實現這一功能。

思路整理：

? 一眼看到這樣的功能，我們可能困惑的是在Android中要怎么在系統桌面的上方添加控件。是的，這是一個難點。從大小上，可能你想到了Dialog，不過Android中的Dialog可不能在系統的桌面上顯示。那你可能又會說不是一種是針對Activity的Dialog主題的模式嗎？是的，這樣的確是解決了在系統桌面的上方彈出窗口了。可是，我們又要對控件進行隨意拖拽，這一點可能對于Android而言并非易事。

? 但是，Android中允許我們在WindowManager上添加View。Android中的窗口機制就是基于WindowManager實現的。WindowManager的作用就是添加View到屏幕，或是從屏幕中移除View。它是顯示View的最底層。

? 好了，的確是這樣的。WindowManger就是實現的關鍵。下面就來實現它吧。

? 不過還有一點需要注意，就我們的EasyTouchView是要基于一個常在的Context來創建，如果EasyTouchView基于了像Activity這樣的短生命周期的Context創建，那么EasyTouchView就會很快隨著Activity的暫停或是銷毀而消失。

實現過程：

EasyTouchView：

package com.bumblebee.remindeasy.widgets;import java.util.Timer; import java.util.TimerTask;import com.bumblebee.remindeasy.R;import android.content.Context; import android.graphics.Color; import android.graphics.drawable.BitmapDrawable; import android.os.Handler; import android.os.Message; import android.view.Gravity; import android.view.LayoutInflater; import android.view.MotionEvent; import android.view.View; import android.view.WindowManager; import android.view.WindowManager.LayoutParams; import android.widget.Button; import android.widget.ImageView; import android.widget.PopupWindow; import android.widget.Toast;public class EasyTouchView extends View {private Context mContext;private WindowManager mWManager;private WindowManager.LayoutParams mWMParams;private View mTouchView;private ImageView mIconImageView = null;private PopupWindow mPopuWin;private ServiceListener mSerLisrener;private View mSettingTable;private int mTag = 0;private int midX;private int midY;private int mOldOffsetX;private int mOldOffsetY;private Toast mToast;private Timer mTimer = null;private TimerTask mTask = null;public EasyTouchView(Context context, ServiceListener listener) {super(context);mContext = context;mSerLisrener = listener;}public void initTouchViewEvent() {initEasyTouchViewEvent();initSettingTableView();}private void initEasyTouchViewEvent() {// 設置載入view WindowManager參數mWManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);midX = mWManager.getDefaultDisplay().getWidth() / 2 - 25;midY = mWManager.getDefaultDisplay().getHeight() / 2 - 44;mTouchView = LayoutInflater.from(mContext).inflate(R.layout.easy_touch_view, null);mIconImageView = (ImageView) mTouchView.findViewById(R.id.easy_touch_view_imageview);mTouchView.setBackgroundColor(Color.TRANSPARENT);mTouchView.setOnTouchListener(mTouchListener);WindowManager wm = mWManager;WindowManager.LayoutParams wmParams = new WindowManager.LayoutParams();mWMParams = wmParams;wmParams.type = 2003; // 這里的2002表示系統級窗口，你也可以試試2003。wmParams.flags = 40; // 設置桌面可控wmParams.width = 100;wmParams.height = 100;wmParams.format = -3; // 透明wm.addView(mTouchView, wmParams);}private void initSettingTableView() {mSettingTable = LayoutInflater.from(mContext).inflate(R.layout.show_setting_table, null);Button commonUseButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_common_use_button);Button screenLockButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_screen_lock_button);Button notificationButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_notification_button);Button phoneButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_phone_button);Button pageButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_page_button);Button cameraButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_camera_button);Button backButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_back_button);Button homeButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_home_button);Button exitTouchButton = (Button) mSettingTable.findViewById(R.id.show_setting_table_item_exit_touch_button);commonUseButton.setOnClickListener(mClickListener);screenLockButton.setOnClickListener(mClickListener);notificationButton.setOnClickListener(mClickListener);phoneButton.setOnClickListener(mClickListener);pageButton.setOnClickListener(mClickListener);cameraButton.setOnClickListener(mClickListener);backButton.setOnClickListener(mClickListener);homeButton.setOnClickListener(mClickListener);exitTouchButton.setOnClickListener(mClickListener);}private OnClickListener mClickListener = new OnClickListener() {@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.show_setting_table_item_common_use_button:hideSettingTable("常用");break;case R.id.show_setting_table_item_screen_lock_button:hideSettingTable("鎖屏");break;case R.id.show_setting_table_item_notification_button:hideSettingTable("通知");break;case R.id.show_setting_table_item_phone_button:hideSettingTable("電話");break;case R.id.show_setting_table_item_page_button:hideSettingTable("1");break;case R.id.show_setting_table_item_camera_button:hideSettingTable("相機");break;case R.id.show_setting_table_item_back_button:hideSettingTable("返回");break;case R.id.show_setting_table_item_home_button:hideSettingTable("主頁");break;case R.id.show_setting_table_item_exit_touch_button:quitTouchView();break;}}};private void quitTouchView() {hideSettingTable("退出");mWManager.removeView(mTouchView);mSerLisrener.OnCloseService(true);clearTimerThead();}private OnTouchListener mTouchListener = new OnTouchListener() {float lastX, lastY;int paramX, paramY;public boolean onTouch(View v, MotionEvent event) {final int action = event.getAction();float x = event.getRawX();float y = event.getRawY();if (mTag == 0) {mOldOffsetX = mWMParams.x; // 偏移量mOldOffsetY = mWMParams.y; // 偏移量}switch (action) {case MotionEvent.ACTION_DOWN:motionActionDownEvent(x, y);break;case MotionEvent.ACTION_MOVE:motionActionMoveEvent(x, y);break;case MotionEvent.ACTION_UP:motionActionUpEvent(x, y);break;default:break;}return true;}private void motionActionDownEvent(float x, float y) {lastX = x;lastY = y;paramX = mWMParams.x;paramY = mWMParams.y;}private void motionActionMoveEvent(float x, float y) {int dx = (int) (x - lastX);int dy = (int) (y - lastY);mWMParams.x = paramX + dx;mWMParams.y = paramY + dy;mTag = 1;// 更新懸浮窗位置mWManager.updateViewLayout(mTouchView, mWMParams);}private void motionActionUpEvent(float x, float y) {int newOffsetX = mWMParams.x;int newOffsetY = mWMParams.y;if (mOldOffsetX == newOffsetX && mOldOffsetY == newOffsetY) {mPopuWin = new PopupWindow(mSettingTable, LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);mPopuWin.setTouchInterceptor(new OnTouchListener() {public boolean onTouch(View v, MotionEvent event) {if (event.getAction() == MotionEvent.ACTION_OUTSIDE) {hideSettingTable();return true;}return false;}});mPopuWin.setBackgroundDrawable(new BitmapDrawable());mPopuWin.setTouchable(true);mPopuWin.setFocusable(true);mPopuWin.setOutsideTouchable(true);mPopuWin.setContentView(mSettingTable);if (Math.abs(mOldOffsetX) > midX) {if (mOldOffsetX > 0) {mOldOffsetX = midX;} else {mOldOffsetX = -midX;}}if (Math.abs(mOldOffsetY) > midY) {if (mOldOffsetY > 0) {mOldOffsetY = midY;} else {mOldOffsetY = -midY;}}mPopuWin.setAnimationStyle(R.style.AnimationPreview);mPopuWin.setFocusable(true);mPopuWin.update();mPopuWin.showAtLocation(mTouchView, Gravity.CENTER, -mOldOffsetX, -mOldOffsetY);if (mTimer == null) {catchSettingTableDismiss();}} else {mTag = 0;}}};private void catchSettingTableDismiss() {mTimer = new Timer();mTask = new TimerTask() {@Overridepublic void run() {if (mPopuWin == null || !mPopuWin.isShowing()) {handler.sendEmptyMessage(0x0);} else {handler.sendEmptyMessage(0x1);}}};mTimer.schedule(mTask, 0, 100);}private void clearTimerThead() {if (mTask != null) {mTask.cancel();mTask = null;}if (mTimer != null) {mTimer.cancel();mTimer = null;}}Handler handler = new Handler() {public void handleMessage(Message msg) {if (msg.what == 0x0) {mIconImageView.setBackgroundDrawable(getResources().getDrawable(R.drawable.touch_ic));} else if (msg.what == 0x1) {mIconImageView.setBackgroundDrawable(getResources().getDrawable(R.drawable.transparent));}};};public void showToast(Context context, String text) {if (mToast == null) {mToast = Toast.makeText(context, text, Toast.LENGTH_SHORT);} else {mToast.setText(text);mToast.setDuration(Toast.LENGTH_SHORT);}mToast.show();}private void hideSettingTable(String content) {hideSettingTable();showToast(mContext, content);}private void hideSettingTable() {if (null != mPopuWin) {mPopuWin.dismiss();}}public interface ServiceListener {public void OnCloseService(boolean isClose);} }
AuxiliaryService：

public class AuxiliaryService extends Service implements ServiceListener {private Intent mIntent;@Overridepublic IBinder onBind(Intent intent) {return null;}public void onCreate() {super.onCreate();new EasyTouchView(this, this).initTouchViewEvent();}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {mIntent = intent;return super.onStartCommand(intent, flags, startId);}@Overridepublic void OnCloseService(boolean isClose) {stopService(mIntent);} }

? 這里有一點需要注意一下。大家可以通過上面的代碼看出，我們啟動EasyTouchView是通過Service來啟動的。一般的EasyTouch都會提供一個鎖屏的功能。要使用一鍵鎖屏就需要激活設備管理器，就要去跳轉到系統的一些界面，而這些界面的啟動不可以是基于Service的，需要基于Activity來做處理。基于Service啟動的過程是閃爍一下后就消失了。

? 這里我們可以在Service中啟動一個我們自己的Activity，然后在這個Activity中啟動這個設置設備管理器的界面。

代碼如下：

public class AuxiliaryActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);requestWindowFeature(Window.FEATURE_NO_TITLE);lockScreen();}private void lockScreen() {DevicePolicyManager mDevicePolicyManager;ComponentName mComponentName;mDevicePolicyManager = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);mComponentName = new ComponentName(this, LockReceiver.class);// 判斷是否有權限if (mDevicePolicyManager.isAdminActive(mComponentName)) {mDevicePolicyManager.lockNow();finish();} else {activeManager(mComponentName);}}/*** 激活設備管理器獲取權限*/private void activeManager(ComponentName componentName) {Intent intent = new Intent(DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN);intent.putExtra(DevicePolicyManager.EXTRA_DEVICE_ADMIN, componentName);intent.putExtra(DevicePolicyManager.EXTRA_ADD_EXPLANATION, "One key lock the screen");startActivity(intent);finish();} }

效果圖：

TouchView

ShowTableView

代碼下載：

http://download.csdn.net/detail/u013761665/8894583

總結

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