在Service中啟動Activity

1、建立主Activity，MainActivity。

public class MainActivity extends AppCompatActivity {    @Override
    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent = new Intent(MainActivity.this
 
, MyService.class);
        startService(intent);
    }
}

2、建立在Service中啟動的Activity，Main2Activity。

public class Main2Activity extends AppCompatActivity {    private static final String TAG = "Main2Activity";    @Override
    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        Log.d(TAG, "onCreate"
 
);
    }

}

3、建立Service,命名為MyService。需要特別注意的是在Service啟動Activity與普通啟動Activity不同，需要設定Intent.FLAG_ACTIVITY_NEW_TASK 才可以正常啟動。例項中增加到5秒延遲後啟動Main2Activity。

public class MyService extends Service {    private static final String TAG = "MyService";    public MyService() {
    }    @Override
    public IBinder onBind
 
(Intent intent) {        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }    @Override
    public void onCreate() {        super.onCreate();
        Log.e(TAG, "--------->onCreate: ");        new Handler().postDelayed(new Runnable() {            @Override
            public void run() {
                Intent intent = new Intent(MyService.this, Main2Activity.class);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK );
                startActivity(intent);
            }
        }, 3 * 1000);
    }    @Override
    public void onDestroy() {        super.onDestroy();
    }
}

4、在AndroidManifest中宣告MyService。

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="realmusic.ace.com.myapplication">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service
            android:name=".MyService"
            android:enabled="true"
            android:exported="true" />

        <activity
            android:name=".Main2Activity"
            android:label="@string/title_activity_main2"
            android:theme="@style/AppTheme.NoActionBar"></activity>
    </application></manifest>

5、在MyService中啟動Main2Activity如下圖：

在此流程就可以完成在Service中啟動Activity的功能。

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