app中默认启动的activity

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Android app中默认启动的activity

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在一个app中，可以有多个activity ，每个activity都是同等级的。我们需要设置那些要显示在launcher中

<intent-filter><actionandroid:name="android.intent.action.MAIN"/><categoryandroid:name="android.intent.category.LAUNCHER"/></intent-filter>

通过 action.main 与category.LAUNCHER 配合使用，可以设置activity 在launcher显示。
默认启动项，满足上述的 intent filter的activity 就可以作为默认启动页面。

当AndroidMainfest.xml 中存在多个activity，且多个activity的 intent filter 属性都满足 action.main,category.launcher 时，
默认启动的activity 为最上面的activity。

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"package="com.mylauncher"><application    android:allowBackup="true"    android:name=".MyApplication"    android:icon="@mipmap/ic_launcher"    android:label="@string/app_name"    android:supportsRtl="true"    android:theme="@style/AppTheme">    <activity android:name=".MainActivity" android:label="activity1">        <intent-filter>            <action android:name="android.intent.action.MAIN" />            <category android:name="android.intent.category.LAUNCHER" />        </intent-filter>    </activity>    <activity android:name=".MainActivity2" android:label="activyt2">        <intent-filter>            <action android:name="android.intent.action.MAIN" />            <category android:name="android.intent.category.LAUNCHER" />        </intent-filter>    </activity></application></manifest>

public class MainActivity extends Activity implements View.OnClickListener {private EditText editText;private Button btn;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    Log.d("onCreate",this.getClass().getName());    editText = (EditText) findViewById(R.id.edit);    btn = (Button) findViewById(R.id.save);    btn.setOnClickListener(this);}@Overridepublic void onClick(View view) {    if (view.getId() == R.id.save){        String data = editText.getText().toString();        if (null!=data){            MyApplication application = (MyApplication) getApplication();            application.setData(data);        } else {            Toast.makeText(this,"data is null!",Toast.LENGTH_LONG).show();        }    }}}

public class MainActivity2 extends Activity implements View.OnClickListener {private EditText editText;private Button btn;@Overrideprotected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    Log.d("onCreate",this.getClass().getName());    editText = (EditText) findViewById(R.id.edit);    btn = (Button) findViewById(R.id.save);    btn.setOnClickListener(this);}@Overridepublic void onClick(View view) {    if (view.getId() == R.id.save){        String data = editText.getText().toString();        if (null!=data){            MyApplication application = (MyApplication) getApplication();            application.setData(data);        } else {            Toast.makeText(this,"data is null!",Toast.LENGTH_LONG).show();        }    }}}

运行结果

01-06 15:54:12.019 25400-25400/com.mylauncher D/onCreate: com.mylauncher.MainActivity

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