当我单击按钮以显示下一个活动时，它仅显示白屏 [英] when i click on button to showing next activity it shows only white screen

问题描述

当我单击按钮时，它仅显示白屏，而不显示下一个活动的视图.我不知道为什么会发生这种情况，请给我解决方案…… 我的整个代码在这里

When i click on button it shows onlywhite screen not the view of next activity. I can't find why it happen pls give me solution...... my whole code is here

ActivityMain.java

ActivityMain.java

package com.rahul.intentswitchingwithdata;

import android.content.Intent; 
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {
   @Override
   protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
   }
   public void go(View v){
         Intent i= new Intent(this,Next.class);
         startActivity(i);}
 }

activity_main.xml

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:id="@+id/activity_main"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      tools:context="com.rahul.intentswitchingwithdata.MainActivity">

      <TextView
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:text="Hello World!" />
      <Button
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:onClick="go"/>
</RelativeLayout>

Next.java

Next.java

public class Next extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState, PersistableBundle 
    persistentState) {       
    super.onCreate(savedInstanceState, persistentState);
    setContentView(R.layout.next);
   }
}

next.xml

 ?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:background="#123"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
   <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello"/>

  </LinearLayout>

manifest.xml

manifest.xml

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

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

</manifest>

推荐答案

您覆盖"了错误的onCreate方法:

you have "overridden" the wrong onCreate method:

 @Override
    public void onCreate(Bundle savedInstanceState, PersistableBundle 
    persistentState)

您应该改用它:

 @Override
    public void onCreate(Bundle savedInstanceState){...code}

onCreate(Bundle)用于初始化，意味着您的所有UI初始化(如视图)均已完成，

onCreate(Bundle) is used for initialization mean where your all UI initialization like view are done ,docs link for depth details

onCreate(Bundle, PersistableBundle)本身暗示，它用于持久性平均重用旧意图(此活动首次提供)，同时重新创建它，您可以通过在活动中添加persistableMode标志来启用重用，以便活动将在重新启动后持续存在.尝试使用此文档链接获取其他选项的详细信息.

onCreate(Bundle, PersistableBundle) as it, itself suggesting , it is used for persistent mean reuse the old intent (supplied first time to this activity) while recreating it , you can enable reusing by adding a persistableMode flag to your activity so that activity will be persisted across reboots . try this doc link for other options details .

注意::您只能在API级别21(Android Lollipop 5.0)或更高版本中使用onCreate(Bundle, PersistableBundle).

Note : You can only use onCreate(Bundle, PersistableBundle) in API level 21(Android Lollipop 5.0) or above.

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