Android移动应用开发中常见的经验技巧总结
转:http://wwwdevstorecn/essay/essayInfo/6128.html
1. 对话保持的解决方案。
要求:
1、app中使用webview访问具体网站的内容,但是app与服务器的沟通是使用HttpUrlConnection来完成。
2、webview访问时不需要再次登陆,继承app的登陆状态。
会话未保持的现象:
1、虽然app已经登录服务器,但是在webview中还是提示需要登录。
2、app下一次对服务器的请求也会失败,提示session过期。
解决方案:
1、获取到HttpUrlConnection中服务器返回的session id。
2、本地保存session id,每次对服务器的请求,手动添加。
3、将此session id设置到持有webview的activity中的CookieManager里
1 网络处理类 NetHelper 2 3 /** 4 * 发送登陆请求,并将SESSIONID保存起来 5 * @param urlPath 登陆请求的地址 6 * @return 返回的内容 7 * */ 8 public static String login(String urlPath) { 9 10 ......省略号...... 11 12 try { 13 URL url = new URL(urlPath); 14 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 15 16 //设置请求方式 17 conn.setRequestMethod("GET"); 18 conn.setConnectTimeout(5000); 19 // conn.setReadTimeout(5000); 20 21 int responseCode = conn.getResponseCode(); 22 if (responseCode == HttpURLConnection.HTTP_OK) { 23 InputStream is = conn.getInputStream(); 24 cookList = conn.getHeaderFields().get("Set-Cookie"); 25 if ((sessionId == null) && (cookList != null)) { 26 for (String value : cookList) { 27 if ((value != null) && (value.toUpperCase().indexOf(";") > 0)) { 28 sessionId = value.split(";")[0]; 29 } 30 } 31 } 32 33 ......省略号...... 34 35 } 36 }catch (Exception e){ 37 e.printStackTrace(); 38 } 39 ......省略号...... 40 }/** 41 * 发送一条请求,将内容以字符串返回 42 * @param urlPath 请求的地址 43 * @return 返回的内容 44 * */ 45 public static String request(String urlPath) { 46 47 ......省略号...... 48 49 try { 50 URL url = new URL(urlPath); 51 HttpURLConnection conn = (HttpURLConnection) url.openConnection(); 52 if(sessionId !=null ){ 53 conn.setRequestProperty("Cookie",sessionId); 54 } 55 conn.setRequestMethod("GET"); 56 conn.setConnectTimeout(5000); 57 // conn.setReadTimeout(5000); 58 59 ......省略号...... 60 61 } catch (Exception e) { 62 e.printStackTrace(); 63 } 64 65 ......省略号...... 66 67 }持有webview的Activity MainActivity 68 69 private CookieManager cookieManager; 70 71 cookieManager = CookieManager.getInstance(); 72 cookieManager.setAcceptCookie(true); 73 clearSession(); 74 75 private void clearSession() { 76 if (NetHelper.cookList != null) { 77 cookieManager.removeSessionCookie(); 78 } 79 } 80 81 //在第一次请求的时候,设置一次session即可 82 private void setSession(String url) { 83 if (NetHelper.cookList != null) { 84 String values = NetHelper.cookList.toString(); 85 cookieManager.setCookie(url, values); //设置cookie 86 CookieSyncManager.getInstance().sync(); //同步 87 } 88 }
2. 自定义控件的实现方案
自定义控件的实现方式(详细内容可以参考压缩包中的<自定义控件.pdf>):
1、继承方式
当简单控件不满足需求时,通过继承重写简单控件,实现对控件的定制。
2、组合方式
当单个控件不满足需求时,可以采用多个控件的组合,实现对控件的定制。
3、控件自绘方式
通过继承自view,重写onDraw方法实现。
项目中的具体应用:
1、登录邮箱的自动补全功能实现(纯代码实现布局)。
2、弹窗滚轮的实现(代码加布局文件)
3、TabButton的实现(两种实现方式)
A、 登录邮箱的自动补全功能实现:
效果:
实现原理:
1、继承重写简单控件AutoCompleteTextView
2、编写自定义数据适配器和布局文件,并实现文字变化监听器
3、通过组合方式,实现右侧的删除图标。并根据焦点和文字的变化,动态显示右侧删除图标。
1、通过继承自简单控件AutoCompleteTextView实现帐号自动补全
关键代码:
1 public class AutoComplete extends AutoCompleteTextView { 2 3 private static final String[] emailSuffix = { 4 "@qq.com", "@163.com", "@126.com", "@gmail.com", "@sina.com", "@hotmail.com", 5 "@yahoo.cn", "@sohu.com", "@foxmail.com", "@139.com", "@yeah.net", "@vip.qq.com", 6 "@vip.sina.com"}; 7 8 ......省略号...... 9 10 //构造函数原型要正确,留给系统调用 11 12 public AutoComplete(Context context) { 13 super(context); 14 mContext = context; 15 } 16 17 public AutoComplete(Context context, AttributeSet attrs) { 18 super(context, attrs); 19 mContext = context; 20 } 21 22 public void init(ImageView imageView) { 23 mImageView = imageView; 24 final MyAdatper adapter = new MyAdatper(mContext); 25 setAdapter(adapter); 26 addTextChangedListener(new TextWatcher() { 27 @Override 28 public void afterTextChanged(Editable s) { 29 if (isTextWatch) { 30 String input = s.toString(); 31 32 ......省略号...... 33 34 adapter.clearList(); //注意要清空数据,根据输入的变化,自动生成数据 35 if (input.length() > 0) { 36 for (int i = 0; i < emailSuffix.length; ++i) { 37 adapter.addListData(input + emailSuffix[i]); 38 } 39 } 40 adapter.notifyDataSetChanged(); 41 showDropDown();//该行代码会造成崩溃 42 } 43 } 44 }); 45 //当输入一个字符的时候就开始检测 46 setThreshold(1); 47 } 48 49 private class ViewHolder { 50 TextView tv_Text; 51 } 52 53 class MyAdatper extends BaseAdapter implements Filterable { 54 private List<String> mList; 55 private Context mContext; 56 private MyFilter mFilter; 57 58 ......省略号...... 59 60 public void clearList() { 61 mList.clear(); 62 } 63 64 public void addListData(String strData) { 65 mList.add(strData); 66 } 67 68 @Override 69 public View getView(int position, View convertView, ViewGroup parent) { 70 View view; 71 ViewHolder viewHolder; 72 73 if (convertView == null) { 74 view = LayoutInflater.from(mContext).inflate(R.layout.activity_autocomplete_item, null); 75 viewHolder = new ViewHolder(); 76 viewHolder.tv_Text = (TextView) view.findViewById(R.id.tv_autocomplete); 77 view.setTag(viewHolder); 78 } else { 79 view = convertView; 80 viewHolder = (ViewHolder) view.getTag(); 81 } 82 83 viewHolder.tv_Text.setText(mList.get(position)); 84 85 return view; 86 } 87 88 ......省略号...... 89 90 }
activity_autocomplete_item 下拉列表布局文件
1 <?xml version="1.0" encoding="utf-8"?> 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 3 android:orientation="vertical" 4 android:layout_width="match_parent" 5 android:background="@color/White" 6 android:layout_height="wrap_content"> 7 8 <TextView 9 android:id="@+id/tv_autocomplete" 10 android:padding="15dp" 11 android:textSize="20sp" 12 android:singleLine="true" 13 android:textColor="@color/Black" 14 android:layout_width="match_parent" 15 android:layout_height="wrap_content" /> 16 17 </LinearLayout>
上面自动补全的效果图:
2、通过组合方式实现帐号自动补全复杂控件
关键代码:
1 public class AdvancedAutoCompleteTextView extends RelativeLayout { 2 private Context mContext; 3 private AutoComplete mAutoComplete; //上面的自定义控件 4 private ImageView mImageView; //右侧的图标控件 5 6 ......省略号...... 7 8 @Override 9 protected void onFinishInflate() { 10 super.onFinishInflate(); 11 initViews(); 12 } 13 //代码方式,初始化布局 14 private void initViews() { 15 RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT); 16 params.addRule(RelativeLayout.ALIGN_PARENT_LEFT); 17 params.addRule(RelativeLayout.CENTER_VERTICAL); 18 mAutoComplete = new AutoComplete(mContext); 19 mAutoComplete.setLayoutParams(params); 20 mAutoComplete.setPadding(0, 0, 40, 0); 21 mAutoComplete.setSingleLine(true); 22 mAutoComplete.setInputType(InputType.TYPE_TEXT_VARIATION_EMAIL_ADDRESS); 23 mAutoComplete.setFitsSystemWindows(true); 24 mAutoComplete.setEms(10); 25 mAutoComplete.setHint("URS账号"); 26 mAutoComplete.setImeOptions(EditorInfo.IME_ACTION_NEXT 27 | EditorInfo.IME_FLAG_NO_EXTRACT_UI | EditorInfo.IME_FLAG_NO_FULLSCREEN); 28 mAutoComplete.setDropDownHorizontalOffset(0); 29 mAutoComplete.setDropDownVerticalOffset(2); 30 mAutoComplete.setBackgroundResource(R.drawable.edit_text_background); 31 32 RelativeLayout.LayoutParams p = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, LayoutParams.FILL_PARENT); 33 p.addRule(RelativeLayout.ALIGN_PARENT_RIGHT); 34 p.addRule(RelativeLayout.CENTER_VERTICAL); 35 p.rightMargin = 10; 36 mImageView = new ImageView(mContext); 37 mImageView.setLayoutParams(p); 38 mImageView.setScaleType(ImageView.ScaleType.FIT_CENTER); 39 mImageView.setImageResource(R.drawable.unselect); 40 mImageView.setClickable(true); 41 mImageView.setOnClickListener(new View.OnClickListener() { 42 @Override 43 public void onClick(View v) { 44 setText(""); 45 } 46 }); 47 48 this.addView(mAutoComplete); 49 this.addView(mImageView); 50 //监听获取焦点事件,目的:输入帐号时,右侧图标的显示 51 mAutoComplete.setOnFocusChangeListener(new OnFocusChangeListener() { 52 @Override 53 public void onFocusChange(View v, boolean hasFocus) { 54 if (hasFocus && !mAutoComplete.getText().toString().isEmpty()) { 55 mAutoComplete.setShow(false); //如果获取首次获取焦点,此时文本不为空,则显示,并禁止文本改变监听里的设置 56 mImageView.setImageResource(R.drawable.item_delete); 57 } else if (hasFocus) { 58 mAutoComplete.setShow(true);//如果获取首次获取焦点,此时文本为空,则不改变,并开启文本改变监听里的设置 59 } else { 60 mAutoComplete.setShow(false); 61 mImageView.setImageResource(R.drawable.unselect); 62 } 63 } 64 }); 65 66 //对AutoComplete自定义控件初始化,一定要放到最后.否则,会由于AutoComplete初始化未完成,就弹窗,而崩溃 67 68 mAutoComplete.init(mImageView); 69 } 70 }
B、弹窗滚轮的实现
效果:
实现原理:
1、继承重写简单控件ScrollView,实现滚动效果,并添加回调接口,用于获取选择的内容。
2、为自定义控件添加内容,其中每一项为一个TextView,用于内容显示。
3、通过自绘添加上下两条直线,实现选中状态。
4、最后利用popup弹窗,加载整个视图,显示弹窗滚动效果。
1、通过继承ScrollView实现滚动,并向布局添加具体项
关键代码:
1 ublic class WheelView extends ScrollView { 2 3 //选择后的回调接口 4 public interface OnWheelViewListener { 5 void onSelected(int selectedIndex, String item); 6 } 7 8 ......省略号...... 9 10 //初始化,并创建布局 11 private void init(Context context) { 12 this.context = context; 13 this.setVerticalScrollBarEnabled(false); 14 15 views = new LinearLayout(context); //为自定义控件创建线性布局 16 views.setOrientation(LinearLayout.VERTICAL); 17 this.addView(views); 18 19 //异步任务,根据滚动的位置自动调整待显示的数据,该异步任务会在滚动事件触发式执行 20 scrollerTask = new Runnable() { 21 public void run() { 22 if (itemHeight == 0) { 23 return; 24 } 25 int newY = getScrollY(); 26 if (initialY - newY == 0) { // stopped 27 final int remainder = initialY % itemHeight; 28 final int divided = initialY / itemHeight; 29 30 if (remainder == 0) { 31 selectedIndex = divided + offset; 32 onSeletedCallBack(); 33 } else { 34 if (remainder > itemHeight / 2) { 35 WheelView.this.post(new Runnable() { 36 @Override 37 public void run() { 38 WheelView.this.smoothScrollTo(0, initialY - remainder + itemHeight); 39 selectedIndex = divided + offset + 1; 40 onSeletedCallBack(); 41 } 42 }); 43 } else { 44 WheelView.this.post(new Runnable() { 45 @Override 46 public void run() { 47 WheelView.this.smoothScrollTo(0, initialY - remainder); 48 selectedIndex = divided + offset; 49 onSeletedCallBack(); 50 } 51 }); 52 } 53 } 54 } else { 55 initialY = getScrollY(); 56 WheelView.this.postDelayed(scrollerTask, newCheck); 57 } 58 } 59 }; 60 } 61 62 //往布局添加数据 63 64 private void initData() { 65 displayItemCount = offset * 2 + 1; 66 67 //添加新view之前,必须移除旧的,否则不正确 68 views.removeAllViews(); 69 70 for (String item : items) { 71 views.addView(createView(item)); 72 } 73 74 refreshItemView(0); 75 } 76 77 private TextView createView(String item) { 78 TextView tv = new TextView(context); 79 tv.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); 80 tv.setSingleLine(true); 81 tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 20); 82 tv.setText(item); 83 tv.setGravity(Gravity.CENTER); 84 int padding = dip2px(15); 85 tv.setPadding(padding, padding, padding, padding); 86 if (0 == itemHeight) { 87 itemHeight = getViewMeasuredHeight(tv); 88 views.setLayoutParams(new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, itemHeight * displayItemCount)); 89 LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) this.getLayoutParams(); 90 this.setLayoutParams(new LinearLayout.LayoutParams(lp.width, itemHeight * displayItemCount)); 91 } 92 return tv; 93 } 94 95 ......省略号...... 96 97 @Override //上下直线的自绘 98 public void setBackgroundDrawable(Drawable background) { 99 100 if (viewWidth == 0) { 101 viewWidth = ((Activity) context).getWindowManager().getDefaultDisplay().getWidth(); 102 } 103 104 if (null == paint) { 105 paint = new Paint(); 106 paint.setColor(Color.parseColor("#83cde6")); 107 paint.setStrokeWidth(dip2px(1f)); 108 } 109 110 background = new Drawable() { 111 @Override 112 public void draw(Canvas canvas) { 113 canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[0], viewWidth * 5 / 6, 114 115 obtainSelectedAreaBorder()[0], paint); 116 117 canvas.drawLine(viewWidth * 1 / 6, obtainSelectedAreaBorder()[1], viewWidth * 5 / 6, 118 119 obtainSelectedAreaBorder()[1], paint); 120 121 } 122 }; 123 124 super.setBackgroundDrawable(background); 125 } 126 127 }
2、动态加载布局,并利用PopupWindow弹窗显示。
关键代码:
1 private void addView(int num){ 2 3 ......省略号...... 4 5 wheel_layout_view = LayoutInflater.from(this).inflate(R.layout.wheel_view, null); 6 7 ......省略号...... 8 9 }
布局文件 wheel_view 效果图
1 private void popupWindows(List<String> list){ 2 if (wheel_layout_view != null){ 3 4 mPopupWindow = null; 5 mPopupWindow = new PopupWindow(wheel_layout_view); 6 mPopupWindow.setWidth(ViewGroup.LayoutParams.MATCH_PARENT); 7 mPopupWindow.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT); 8 9 //点击外部,自动消失 10 mPopupWindow.setFocusable(true); 11 mPopupWindow.setOutsideTouchable(true); 12 13 ......省略号...... 14 15 mPopupWindow.showAtLocation(ll_weidu_condition, Gravity.BOTTOM, 0, 0); 16 } 17 }
C、TabButton的实现
效果:
1、利用.9.png图标实现(简单、美观)
属性定义attrs.xml:
1 <?xml version="1.0" encoding="utf-8"?> 2 <resources> 3 <!-- 自定义的button控件,用于日期的选择--> 4 <declare-styleable name="TabButton"> 5 <attr name="normal_bg_res" format="reference" /> 6 <attr name="selected_bg_res" format="reference" /> 7 </declare-styleable> 8 </resources>
布局文件:
1 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 2 xmlns:custom="http://schemas.android.com/apk/res-auto" //声明自定义属性空间 3 4 ......省略号...... 5 6 android:orientation="vertical"> 7 8 ......省略号...... 9 10 <xxxxxxxxxxx.customui.TabButton 11 style="@style/commonButton" 12 android:layout_width="0dp" 13 android:layout_margin="0dp" 14 android:layout_weight="1" 15 android:layout_height="40dp" 16 android:text="昨天" 17 android:textSize="22sp" 18 android:gravity="center" 19 android:background="@drawable/btn_left" 20 android:textColor="@color/blue" 21 custom:normal_bg_res="@drawable/btn_left" 22 custom:selected_bg_res="@drawable/btn_left_selected" 23 android:id="@+id/bt_yesterday" /> 24 25 ......省略号...... 26 27 </LinearLayout>
关键代码:
1 public class TabButton extends Button { 2 private int normal_bg_res; 3 private int selected_bg_res; 4 5 public TabButton(Context context) { 6 super(context); 7 } 8 9 public TabButton(Context context, AttributeSet attrs) { 10 super(context, attrs); 11 12 TypedArray typeArray = context.obtainStyledAttributes(attrs, R.styleable.TabButton); 13 normal_bg_res = typeArray.getResourceId(R.styleable.TabButton_normal_bg_res, 0); 14 selected_bg_res = typeArray.getResourceId(R.styleable.TabButton_selected_bg_res, 0); 15 16 typeArray.recycle(); 17 } 18 19 public void setSelected(boolean selected) { 20 if (selected) { 21 setBackgroundResource(selected_bg_res); 22 setTextColor(Color.WHITE); 23 } else { 24 setBackgroundResource(normal_bg_res); 25 setTextColor(getResources().getColor(R.color.blue)); 26 } 27 } 28 }
2、利用布局文件实现(复杂、灵活)。
更多样式,可以参数官方的SDK(android-sdk-windows\platforms\android-1.5\data\res\)
布局样式button_style:
1 <?xml version="1.0" encoding="utf-8"?> 2 <selector xmlns:android="http://schemas.android.com/apk/res/android"> 3 <item android:state_pressed="true"> 4 <shape android:shape="rectangle"> 5 <solid android:color="#0d76e1" /> 6 </shape> 7 </item> 8 9 <item android:state_focused="true"> 10 <shape android:shape="rectangle"> 11 <solid android:color="@color/Grey" /> 12 </shape> 13 </item> 14 15 <item> 16 <shape android:shape="rectangle"> 17 <solid android:color="@color/Grey" /> 18 </shape> 19 </item> 20 </selector>
样式应用:
1 <Button android:id="@+id/tab_button" 2 android:layout_width="wrap_content" 3 android:layout_height="wrap_content" 4 android:background="@drawable/button_style">
3. 蒙板效果的实现
1、不保留标题栏蒙板的实现
效果:
原理:
1、弹窗时,设置背景窗体的透明度
2、取消弹窗时,恢复背景窗体的透明度
关键代码:
1 private void popupWindows(List<String> list){ 2 //产生背景变暗效果 3 WindowManager.LayoutParams lp=getWindow().getAttributes(); 4 lp.alpha = 0.4f; 5 getWindow().setAttributes(lp); 6 7 ......省略号...... 8 9 mPopupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() { 10 @Override 11 public void onDismiss() { 12 WindowManager.LayoutParams lp = getWindow().getAttributes(); 13 lp.alpha = 1f; 14 getWindow().setAttributes(lp); 15 } 16 }); 17 18 ......省略号...... 19 20 }
2、保留标题栏蒙板的实现
效果:
原理:
1、根据需求,设置蒙板布局大小。
2、弹窗时,显示蒙板布局
2、取消弹窗时,隐藏蒙板布局
关键代码:
1、蒙板布局实现:
1 <!-- popup蒙板 --> 2 <LinearLayout 3 android:id="@+id/ll_popup_hide" 4 android:layout_width="match_parent" 5 android:background="@color/hide_bg" 6 android:orientation="vertical" 7 android:layout_height="match_parent"> 8 </LinearLayout> 9 10 <color name="hide_bg">#88323232</color>
2、代码处理
1 ll_popup_hide.setVisibility(View.VISIBLE); //显示蒙板 2 ll_popup_hide.setVisibility(View.INVISIBLE); //隐藏蒙板
4. Activity的回收与操作超时的处理
1、Activity的回收
针对多个activity退出的处理
关键代码:
1、新建活动管理类:
1 public class ActivityCollector { 2 private static List<Activity> activityList = new ArrayList<Activity>(); 3 public static void addActivity(Activity activity){ 4 activityList.add(activity); 5 } 6 public static void removeActivity(Activity activity){ 7 activityList.remove(activity); 8 } 9 10 public static void finishAllButLast(){ 11 Activity activity = activityList.get(activityList.size()-1); 12 removeActivity(activity); 13 14 for (Activity activityItem: activityList){ 15 if (!activityItem.isFinishing()){ 16 activityItem.finish(); 17 } 18 } 19 20 activityList.clear(); 21 activityList.add(activity); 22 } 23 24 public static void finishAll(){ 25 for (Activity activity: activityList){ 26 if (!activity.isFinishing()){ 27 activity.finish(); 28 } 29 } 30 31 activityList.clear(); 32 } 33 }
2、创建基类BaseActivity,并使所有的activity继承自该基类 。在创建时,添加到活动管理器,销毁时,从活动管理器中移除。
1 public class BaseActivity extends Activity { 2 @Override 3 protected void onCreate(Bundle savedInstanceState) { 4 super.onCreate(savedInstanceState); 5 ActivityCollector.addActivity(this); 6 } 7 8 @Override 9 protected void onDestroy() { 10 super.onDestroy(); 11 ActivityCollector.removeActivity(this); 12 } 13 }
如果需要销毁所有activity,只需调用finishAll()即可
2、操作超时处理
原理:
1、在activity的stop函数中,根据app进程IMPORTANCE_FOREGROUND判断app在前台或后台
2、在activity的onResume函数中,做超时检查。
关键代码:
1 abstract public class TimeOutCheckActivity extends BaseActivity { 2 private boolean isLeave = false; 3 4 @Override 5 protected void onCreate(Bundle savedInstanceState) { 6 super.onCreate(savedInstanceState); 7 pref = getSharedPreferences(Constant.CONFIG_NAME, Context.MODE_PRIVATE); 8 } 9 10 /** 11 * 回调函数,方便测试 12 * @return 13 */ 14 abstract protected String getTag(); 15 16 ......省略号...... 17 18 /*** 19 * 当用户使程序恢复为前台显示时执行onResume()方法,在其中判断是否超时. 20 */ 21 @Override 22 protected void onResume() { 23 // Log.i("Back",getTag() + ",onResume,是否在前台:" + isOnForeground()); 24 super.onResume(); 25 if (isLeave) { 26 isLeave = false; 27 timeOutCheck(); 28 } 29 } 30 31 @Override 32 protected void onStop() { 33 super.onStop(); 34 if (!isOnForeground()){ 35 if (!isLeave && isOpenALP()) { 36 isLeave = true; 37 saveStartTime(); 38 } 39 } 40 } 41 42 public void timeOutCheck() { 43 long endtime = System.currentTimeMillis(); 44 if (endtime - getStartTime() >= Constant.TIMEOUT_ALP * 1000) { 45 Util.toast(this, "超时了,请重新验证"); 46 String alp = pref.getString(Constant.ALP, null); 47 if (alp == null || alp == "") { 48 } else { 49 Intent intent = new Intent(this, UnlockGesturePasswordActivity.class); 50 intent.putExtra("pattern", alp); 51 intent.putExtra("login",false); //手势验证,不进行登录验证 52 intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK); 53 // 打开新的Activity 54 startActivityForResult(intent, Constant.REQ_COMPARE_PATTERN_TIMEOUT_CHECK); 55 } 56 } 57 } 58 59 public void saveStartTime() { 60 pref.edit().putLong(Constant.START_TIME, System.currentTimeMillis()).commit(); 61 } 62 63 public long getStartTime() { 64 long startTime = 0; 65 try { 66 startTime = pref.getLong(Constant.START_TIME, 0); 67 }catch (Exception e){ 68 startTime = 0; 69 } 70 return startTime; 71 } 72 73 /** 74 * 程序是否在前端运行,通过枚举运行的app实现。防止重复超时检测多次,保证只有一个activity进入超时检测 75 *当用户按home键时,程序进入后端运行,此时会返回false,其他情况引起activity的stop函数的调用,会返回true 76 * @return 77 */ 78 public boolean isOnForeground() { 79 ActivityManager activityManager = (ActivityManager) getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE); 80 String packageName = getApplicationContext().getPackageName(); 81 82 List<ActivityManager.RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses(); 83 if (appProcesses == null) 84 return false; 85 86 for (ActivityManager.RunningAppProcessInfo appProcess : appProcesses) { 87 if (appProcess.processName.equals(packageName) 88 && appProcess.importance == ActivityManager.RunningAppProcessInfo.IMPORTANCE_FOREGROUND) { 89 return true; 90 } 91 } 92 93 return false; 94 } 95 }
补充说明:
可以根据importance的不同来判断前台或后台,RunningAppProcessInfo 里面的常量IMTANCE就是上面所说的前台后台,其实IMOPORTANCE是表示这个app进程的重要性,因为系统回收时候,会根据IMOPORTANCE来回收进程的。具体可以去看文档。
1 public static final int IMPORTANCE_BACKGROUND = 400//后台 2 public static final int IMPORTANCE_EMPTY = 500//空进程 3 public static final int IMPORTANCE_FOREGROUND = 100//在屏幕最前端、可获取到焦点 4 可理解为Activity生命周期的OnResume(); 5 public static final int IMPORTANCE_SERVICE = 300//在服务中 6 public static final int IMPORTANCE_VISIBLE = 7 200//在屏幕前端、获取不到焦点可理解为Activity生命周期的OnStart();