要做一個Service要先了解,service無法自己啟動,必須要靠startService()才能啟動。
同樣的啟動後也必須要使用stopService()關閉。
在這邊需要注意的有幾點
1) startService()
2) stopService()
3) AndroidManiFest.xml增加service權限
第一點為開啟service必要條件,當然你要new一個intent
所以就是:
Intent intent = new Intent(MainActivity.this,service_class.class);
startService(intent);
MainActivity為你目前的class,service_class則是另外開的java檔(那邊則是寫service做的事情)
第二點跟第一點很類似,只有差在start / stop的差別
Intent intent = new Intent(MainActivity.this,service_class.class);
stopService(intent);
第三點就是你需要在Android ManiFest.xml裡面新增權限
否則跑起來會有
"
"
這樣的錯誤訊息出現
好了,總結上面 MainActivity該如何寫?
package com.example.service_nonui_demo;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBar;
import android.support.v4.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.os.Build;
public class MainActivity extends ActionBarActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Intent intent = new Intent(MainActivity.this,service_class.class);
startService(intent);
}
@Override
public void onPause(){
super.onPause();
Intent intent = new Intent(MainActivity.this,service_class.class);
stopService(intent);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container,
false);
return rootView;
}
}
}
Service部分
package com.example.service_nonui_demo;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.widget.Toast;
public class service_class extends Service{
@Override
public IBinder onBind(Intent arg0) {
// TODO Auto-generated method stub
return null;
}
@Override
public void onCreate() {
// TODO Auto-generated method stub
super.onCreate();
}
@Override
public void onStart(Intent intent, int startId) {
Toast.makeText(this, "Service start", Toast.LENGTH_SHORT).show();
}
public void onDestroy(){
super.onDestroy();
Toast.makeText(this, "Service stop", Toast.LENGTH_SHORT).show();
}
}
(記得要extends Service!)
Android ManiFest.xml部分
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.service_nonui_demo"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="19" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.service_nonui_demo.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<service android:name="service_class"></service>
</application>
</manifest>
記得要新增紅色字的這一行
如此一來,service就可以啟動了!
service在onStart()的地方開始運作,所以如果要做任何動作,可以寫在裡面喔!
範例只是做一個toast(跳出訊息)而已。
附上範例檔案
**點這裡下載**
End
