Question

我正在使用材料设计，在材料设计中我可以将DeveloperNetwork.java返回到MainActivity.java。在下面的API 21设备中，我无法返回KitKat，JellyBean等。发生了什么？我无法搜索如何解决这个问题？这是public class DeveloperNetwork extends ActionBarActivity { Toolbar toolbar; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_developer_network); toolbar = (Toolbar) findViewById(R.id.tb); setSupportActionBar(toolbar); getSupportActionBar().setDisplayHomeAsUpEnabled(true); } @Override public boolean onOptionsItemSelected(MenuItem item) { onBackPressed(); return super.onOptionsItemSelected(item); } }

<activity
    android:name=".Splash"
    android:label="@string/app_name"
    android:screenOrientation="portrait">
    <intent-filter>
        <action android:name="android.intent.action.MAIN" />
        <category android:name="android.intent.category.LAUNCHER" />
    </intent-filter>
</activity>

<activity
    android:name=".MainActivity"
    android:label="@string/title_activity_main"
    android:screenOrientation="portrait">
    <intent-filter>
        <action android:name="com.example.javaclass.MainActivity" />
        <category android:name="android.intent.category.DEFAULT" />
    </intent-filter>
</activity>

<activity
    android:name=".DeveloperNetwork"
    android:label="@string/title_activity_developer_network"
    android:screenOrientation="portrait">
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.example.javaclass.MainActivity" />
</activity>

manifests.java

import matplotlib.pyplot as pt
import numpy as np
fig = pt.figure()
ax = fig.add_subplot(111)
sample = 20
x=np.arange(sample)
y=10*np.sin(2*np.pi*x/20)
pt.plot(x,y)
pt.show()

Answer 1

请尝试将android:parentActivityName属性添加到.DeveloperNetwork活动代码中，如下所示。

  <activity
      android:name=".DeveloperNetwork"
      android:label="@string/title_activity_developer_network"
      android:screenOrientation="portrait"
      android:parentActivityName="com.example.javaclass.MainActivity"
      >
      <meta-data
          android:name="android.support.PARENT_ACTIVITY"
          android:value="com.example.javaclass.MainActivity" />
  </activity>

我可以回到Android下面的API 21设备

1 个答案: