Blog-03-在Service中启动Activity与优化

在Service中启动Activity

1、创建主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、创建在Service中启动的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、创建Service,命名为MyService。需要特别注意的是在Service启动Activity与普通启动Activity不同，需要设置Intent.FLAG_ACTIVITY_NEW_TASK 才可以正常启动。实例中增加到5秒延迟后启动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中声明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中启动Main2Activity如下图：

在此流程就可以完成在Service中启动Activity的功能。