问题描述
我想在微调项目列表上单击项目时显示一个片段。 我现在的问题是,当我单击微调器上的一项时,我的 Viewpager 上没有显示片段。 程序没有错误。只是片段没有出现。
谁能帮我解决这个问题。非常感谢!
我的代码是:
活动:
package com.hello.menu;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import androidx.viewpager.widget.ViewPager;
import com.hello.About;
import com.hello.Home;
import com.hello.R;
public class SpinnersFragment extends AppCompatActivity {
ViewPager viewPager;
Spinner spinner;
String[] city ={"Fragment1","Fragment2"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.menu_spinner_fragment);
Toolbar toolbar = findViewById(R.id.toolbar);
toolbar.setNavigationOnClickListener(v -> onBackpressed());
spinner = (Spinner) findViewById(R.id.spinner);
viewPager = (ViewPager) findViewById(R.id.view_pager);
ArrayAdapter<String> adapter = new ArrayAdapter<>(SpinnersFragment.this,R.layout.app_text_spinner,city);
adapter.setDropDownViewResource(R.layout.support_simple_spinner_dropdown_item);
spinner.setAdapter(adapter);
spinner.setonItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> adapterView,View view,int i,long l) {
switch (i) {
case 0:
getFragment (new Home());
break;
case 1:
getFragment (new About());
break;
}
}
@Override
public void onnothingSelected(AdapterView<?> parent) {
}
});
}
private void getFragment(Fragment fragment) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.replace(R.id.view_pager,fragment);
fragmentTransaction.commit();
}
@Override
public void startActivity (Intent intent) {
super.startActivity(intent);
overridePendingTransitionEnter();
}
protected void overridePendingTransitionEnter() {
overridePendingTransition(R.anim.slide_from_right,R.anim.slide_to_left);
}
protected void overridePendingTransitionExit() {
overridePendingTransition(R.anim.slide_from_left,R.anim.slide_to_right);
}
@Override
public void onBackpressed() {
super.onBackpressed();
overridePendingTransitionExit();
this.finish();
}
@Override
public void onPause() {
super.onPause();
}
@Override
public void onResume() {
super.onResume();
}
@Override
public void onDestroy() {
super.onDestroy();
}
}
布局:
<?xml version="1.0" encoding="utf-8"?>
<androidx.coordinatorlayout.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.appbar.AppBarLayout
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="@color/vista_green"
app:elevation="0dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
app:navigationIcon="@drawable/ic_arrow_back_white"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minHeight="?attr/actionBarSize"
app:elevation="0dp" />
<TextView
android:text="Hello"
android:gravity="center"
android:textAppearance="@style/TitleBar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize" />
</RelativeLayout>
</com.google.android.material.appbar.AppBarLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.appcompat.widget.AppCompatSpinner
android:id="@+id/spinner"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="8dp"
android:padding="15dp"
android:gravity="center"
android:spinnerMode="dropdown" />
<androidx.viewpager.widget.ViewPager
android:id="@+id/view_pager"
android:layout_marginTop="10dp"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior" />
</LinearLayout>
<View
android:layout_alignParentBottom="true"
android:layout_width="match_parent"
android:layout_height="@dimen/spacing_medium"
android:background="@drawable/brand_lines" />
</RelativeLayout>
</LinearLayout>
</androidx.coordinatorlayout.widget.CoordinatorLayout>
解决方法
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