android - Activity 创建了两次

Question

我已经设置了锁定方向

并添加了带有 2 个简单类的示例代码，如下所示:

SplashLandscapeActivity.java

public class SplashLandscapeActivity extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("start", "xxxx start Activity SplashLandscapeActivity");
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                startActivity(new Intent(SplashLandscapeActivity.this, TestActivity.class));
                finish();
            }
        }, 500);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("start", "xxxx onDestroy Activity SplashLandscapeActivity");
    }
}

TestActivity.java

public class TestActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("start", "xxxx start Activity TestActivity "
                + getResources().getConfiguration().orientation);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("start", "xxxx onDestroy Activity TestActivity "
                + getResources().getConfiguration().orientation);
    }
}

AndroidManifest.xml

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

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

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

        <activity
            android:name=".TestActivity"
            android:screenOrientation="portrait"/>
    </application>
</manifest>

当我使用new Handler().postDelayed (SplashLandscapeActivity.java) 启动TestActivity时，启动了两次，第一次有Landscape 方向然后切换回portrait。日志显示了一切:

xxxx start Activity SplashLandscapeActivity

xxxx start Activity TestActivity 2 // <== landscape

xxxx onDestroy Activity TestActivity 1

xxxx start Activity TestActivity 1 // <== portrait

xxxx onDestroy Activity SplashLandscapeActivity

如果我删除那个 Handler，TestActivity 现在会像往常一样以纵向启动。

xxxx start Activity SplashLandscapeActivity

xxxx start Activity TestActivity 1

xxxx onDestroy Activity SplashLandscapeActivity

所以，我的问题是:

1- 此系统问题或其预期行为是什么？为什么即使在 Manifest 中设置了固定的 screenOrientation 也会重新启动 activity？

2- 实际上，我的真实项目没有任何 Handler 但有同样的问题 activity 启动了两次(在 Intent.FLAG_ACTIVITY_NEW_TASK | Intent 启动之后.FLAG_ACTIVITY_CLEAR_TASK)。我该如何处理这个问题？

Answer 1

在您的 list 文件中，像这样编辑 TestActivity block

<activity
android:name=".TestActivity"
android:launchMode="singleInstance"
android:screenOrientation="portrait"/>