在开发中,你是不是没有抽象一个出常用的类,那你可能要为你的懒惰付出很大的代价。要时刻记得自己的工具箱,不断往里面添加一些小小玩意。今天就给大家带来一个很有意思的例子。前后台运行!!
在Android开发中为了使用的方便要把所有的Activity包裹一层形成自己的activity,比如这个activity在创建时加入到一个容器里,在ondestroy时及时清除,可以通过Application管理activity,这个是今天我要介绍的项目背景。
好了,我就直接开始切入题目。
前台,就是当前显示运行的是自己的App;后台,就是自己的App不是激活或者说项目的Activity不在activity堆栈的最顶端。那如何判断呢?
我们离开自己的app可能是通过按键或顶端的提示,亦或者是中途的电话打断,总而言之,就是Activity不是出于运行的状态,所以我们的目标就是监听所有的Activity的状态!!咋一听吓死了,我的项目有好多Activity呢?别忘了我开始说的 我把每个Activity继承于自己的Activity啦,所以实际上我只需要监听一个啦。
好啦,贴代码:
package com.chaoxing.core;import java.util.List;import roboguice.activity.RoboActivity;
import android.app.ActivityManager;
import android.app.KeyguardManager;
import android.app.ActivityManager.RunningAppProcessInfo;public class DefaultActivity extends Activity{@Override
protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);appRunningInBackground = AppRunningInBackground.getInstance(getApplicationContext());
appRunningInBackground.onCreate();
}@Override
protected void onStart() {
super.onStart();
appRunningInBackground.onStart();
}
@Override
protected void onStop() {
super.onStop();
appRunningInBackground.onStop();
}private AppRunningInBackground appRunningInBackground ;}
fragmentActivity也是同理。
import java.util.List;public class AppRunningInBackground {public static boolean notifyShowing = false;
public static boolean isSpecialSystem=false;
private boolean isInstance = false;
ActivityManager activityManager;
KeyguardManager keyguardManager;
private Context context = null;
private static AppRunningInBackground appRunningInBackground = null;
public static AppRunningInBackground getInstance(Context context){
synchronized (AppRunningInBackground.class) {
if(appRunningInBackground == null){
appRunningInBackground = new AppRunningInBackground(context);
}return appRunningInBackground;
}}public AppRunningInBackground(Context context) {
this.context = context;
}
public void onCreate() {
if(!isInstance){
activityManager = (ActivityManager)context.getSystemService(Context.ACTIVITY_SERVICE);
keyguardManager = (KeyguardManager)context.getSystemService(Context.KEYGUARD_SERVICE);
isInstance = true;
} } public void onStart() {
if(notifyShowing && appRunningInBackground != null){
notifyShowing = false;
Intent startIntent = new Intent(AppGlobalConfig.STARTACTIVITY);
context.sendBroadcast(startIntent);
}
}public void onStop() {
if(appRunningInBackground != null && !isAppOnForeground() ){
notifyShowing = true;
Intent startIntent = new Intent(AppGlobalConfig.STOPACTIVITY);
context.sendBroadcast(startIntent);
}
}/**
* 判断程序是否在前台
* @return true 在前台; false 在后台
*/
private boolean isAppOnForeground() {
if(!isSpecialSystem){
boolean isspecial=true;
String packageName = context.getPackageName();
List<RunningAppProcessInfo> appProcesses = activityManager.getRunningAppProcesses();
if (appProcesses == null)
return false;
for (RunningAppProcessInfo appProcess : appProcesses) {
if (appProcess.processName.equals(packageName)) {
if (appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND||appProcess.importance == RunningAppProcessInfo.IMPORTANCE_VISIBLE) {
return true;
}
if (keyguardManager.inKeyguardRestrictedInputMode()) return true;
}
if(isspecial){
if(appProcess.importance == RunningAppProcessInfo.IMPORTANCE_FOREGROUND){
isspecial=false;
}
}
}
if(isspecial){
isSpecialSystem=true;
return !isApplicationBroughtToBackgroundByTask();
}
return false;
}else{
return !isApplicationBroughtToBackgroundByTask();
}
} /**
* 判断当前应用程序是否处于后台,通过getRunningTasks的方式
* @return true 在后台; false 在前台
*/
public boolean isApplicationBroughtToBackgroundByTask() {
List<RunningTaskInfo> tasks = activityManager.getRunningTasks(1);
if (!tasks.isEmpty()) {
ComponentName topActivity = tasks.get(0).topActivity;
if (!topActivity.getPackageName().equals(context.getPackageName())) {
return true;
}
}
return false;
}
}