Java 无法将片段强制转换为android.app.Activity(私有案例)
你好!请具体帮我处理我的案子。我读过关于这个问题的解决方案,但我不知道如何把它应用到我自己身上 07-13 18:55:28.339 3850-3850/com.zheil.zodiac E/AndroidRuntime:致命异常:main 进程:com.zheil.zodiac,PID:3850 java.lang.RuntimeException:无法实例化活动组件信息{com.zheil.zodiac/com.zheil.zodiac.FirstFragment}: java.lang.ClassCastException:com.zheil.zodiac.FirstFragment不能为空 播放到android.app.Activity 在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2608)上 在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2767)上 位于android.app.ActivityThread.-wrap12(ActivityThread.java) 在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1514)上 位于android.os.Handler.dispatchMessage(Handler.java:102) 位于android.os.Looper.loop(Looper.java:163) 位于android.app.ActivityThread.main(ActivityThread.java:6221) 位于java.lang.reflect.Method.invoke(本机方法) 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run上(ZygoteInit.java:904) 位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794) 原因:java.lang.ClassCastException:com.zheil.zodiac.FirstFragment无法强制转换为android.app.Activity 位于android.app.Instrumentation.newActivity(Instrumentation.java:1079) 在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2598)上 在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2767)上 位于android.app.ActivityThread.-wrap12(ActivityThread.java) 在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1514)上 位于android.os.Handler.dispatchMessage(Handler.java:102) 位于android.os.Looper.loop(Looper.java:163) 位于android.app.ActivityThread.main(ActivityThread.java:6221) 位于java.lang.reflect.Method.invoke(本机方法) 在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run上(ZygoteInit.java:904) 位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794) 片段:Java 无法将片段强制转换为android.app.Activity(私有案例),java,android,android-activity,fragment,classcastexception,Java,Android,Android Activity,Fragment,Classcastexception,你好!请具体帮我处理我的案子。我读过关于这个问题的解决方案,但我不知道如何把它应用到我自己身上 07-13 18:55:28.339 3850-3850/com.zheil.zodiac E/AndroidRuntime:致命异常:main 进程:com.zheil.zodiac,PID:3850 java.lang.RuntimeException:无法实例化活动组件信息{com.zheil.zodiac/com.zheil.zodiac.FirstFragment}: java.lang.C
package com.zheil.zodiac;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class FirstFragment extends Fragment {
private TextView textView2;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_first, container, false);
textView2 = (TextView) view.findViewById(R.id.textView2);
String textFromActivity = getArguments().getString("1");
textView2.setText(textFromActivity);
return view;
}
}
代码的一部分是主要活动:
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
// Создадим новый фрагмент
Fragment fragment = null;
Class fragmentClass = null;
// Handle navigation view item clicks here.
int id = item.getItemId();
switch (id) {
case R.id.nav_camera:
// Handle the camera action
fragmentClass = FirstFragment.class;
break;
case R.id.nav_gallery:
fragmentClass = SecondFragment.class;
break;
case R.id.nav_slideshow:
break;
case R.id.nav_manage:
break;
case R.id.nav_share:
break;
}
try {
assert fragmentClass != null;
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
// Вставляем фрагмент, заменяя текущий фрагмент
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction().replace(R.id.container, fragment).commit();
// Выделяем выбранный пункт меню в шторке
item.setChecked(true);
// Выводим выбранный пункт в заголовке
setTitle(item.getTitle());
Bundle bundle = new Bundle();
bundle.putString("1", String.valueOf(getMapLastIntent().get("aries")));
fragment.setArguments(bundle);
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
请在片段类中添加实例
不需要创建
类的实例和typecast,只需执行此操作
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
Fragment fragment = null;
int id = item.getItemId();
switch (id) {
case R.id.nav_camera:
fragment = new FirstFragment();
break;
case R.id.nav_gallery:
fragment = SecondFragment();
break;
case R.id.nav_slideshow:
break;
case R.id.nav_manage:
break;
case R.id.nav_share:
break;
}
FragmentManager fragmentManager = getSupportFragmentManager();
Bundle bundle = new Bundle();
bundle.putString("1",String.valueOf(getMapLastIntent().get("aries")));
fragment.setArguments(bundle);
fragmentManager.beginTransaction().replace(R.id.container, fragment).commit();
item.setChecked(true);
setTitle(item.getTitle());
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
您应该提供指向您认为是“关于此问题的解决方案”的页面的链接?不同的信息将传输到我的片段,包括单个静态信息。我想使用你可以通过bundle传递的类或者在你的fragment类中创建静态方法。在这种情况下如何定义布局格式?我的意思是传输数据的设计,你犯了一个愚蠢的错误,你在片段转换后通过bundle把值放在片段中,在片段转换之前把值放在片段中,看起来更新了代码。
@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
Fragment fragment = null;
int id = item.getItemId();
switch (id) {
case R.id.nav_camera:
fragment = new FirstFragment();
break;
case R.id.nav_gallery:
fragment = SecondFragment();
break;
case R.id.nav_slideshow:
break;
case R.id.nav_manage:
break;
case R.id.nav_share:
break;
}
FragmentManager fragmentManager = getSupportFragmentManager();
Bundle bundle = new Bundle();
bundle.putString("1",String.valueOf(getMapLastIntent().get("aries")));
fragment.setArguments(bundle);
fragmentManager.beginTransaction().replace(R.id.container, fragment).commit();
item.setChecked(true);
setTitle(item.getTitle());
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}