对于那些想知道我是如何做到的人。我使用 Job Scheduler 是因为它是一项需要建立 wifi 连接的任务。
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最后,我得到了这个
首先,为每个活动声明一个文本视图。
<TextView
android:id="@+id/messageLogin"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/wifitoSlow"
android:textColor="@color/magnitude0"
android:background="@color/magnitude7"
android:gravity="center"
android:visibility="gone"
/>
然后我创建一个 WfiJob 类,它有需要 NETWORK_TYPE_ANY 的 JobCheduler,它每 5 秒执行一次。
public class WifiJob {
public void createWifiJob(int jobNumber, Context context){
//We are defining a jobObject that will have a jobNumber and a serviceName that will run only if a network connection exits
JobScheduler jobScheduler = (JobScheduler)context.getSystemService(Context.JOB_SCHEDULER_SERVICE);
jobScheduler.schedule(new JobInfo.Builder(jobNumber, new ComponentName(context.getApplicationContext(), WifiJobScheduler.class))
.setRequiredNetworkType(JobInfo.NETWORK_TYPE_ANY)
.setRequiresDeviceIdle(false)
.setPeriodic(5000).build());
}
}
然后是从 JobService 扩展而来的 WifiJobScheduler。在这里,我也有 WifiStrenghtListener ,它是一个接口,它将向活动广播消息,以便可以显示文本视图。
public class WifiJobScheduler extends JobService{
private static final String TAG = "SyncService";
public static WifiStrenghtListener wifiStrenghtListener=null;
//private boolean messageIsShowed = false;
//The onStartJob is performed in the main thread, if you start asynchronous processing in this method, return true otherwise false.
@Override
public boolean onStartJob(JobParameters params) {
Log.i(TAG, "on start job: " + params.getJobId());
PowerManager pm = (PowerManager) getSystemService(Context.POWER_SERVICE);
if(AppUtilities.isInteractive(pm) ){ //if the device is active
int wifiStrenght = WifiUtilities.getWifiStrengh(getApplicationContext());
Log.i(TAG, "wifi strengh ........... : " + wifiStrenght);
if(wifiStrenghtListener!=null){
if(wifiStrenght<4 && !AppUtilities.messageIsShowed){
wifiStrenghtListener.showSlowSignalOnTop(View.VISIBLE);
AppUtilities.messageIsShowed = true;
}else if(wifiStrenght>3 && AppUtilities.messageIsShowed){
wifiStrenghtListener.showSlowSignalOnTop(View.GONE);
AppUtilities.messageIsShowed = false;
}
}
}else{
cancelAllJobs();
Log.i(TAG, "job canceled........");
}
return false; // true if we're not done yet and we are going to run this on a thread
}
// If the job fails for some reason, return true from on the onStopJob to restart the job.
@Override
public boolean onStopJob(JobParameters params) {
return true;
}
public void cancelAllJobs() {
JobScheduler tm = (JobScheduler) getSystemService(Context.JOB_SCHEDULER_SERVICE);
tm.cancelAll();
}
public interface WifiStrenghtListener{
void showSlowSignalOnTop(int visible);
}
}
订阅活动的控制器。
public class WifiJobSchedulerController {
public void setWifiJobSchedulerControllerInstance(WifiJobScheduler.WifiStrenghtListener listener){
WifiJobScheduler.wifiStrenghtListener = listener;
}
}
最后,您需要实现接口并订阅活动。
public class LoginActivity extends AppCompatActivity implements WifiJobScheduler.WifiStrenghtListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_login);
//register wifistrenght status listener
new WifiJobSchedulerController().setWifiJobSchedulerControllerInstance(this);
}
@Override
public void showSlowSignalOnTop(int visible) {
TextView message = (TextView)findViewById(R.id.messageLogin);
message.setVisibility(visible);
}
}