Question

我想从MainActivity打开一个片段，我有gridview.i是android的新手，这是第一次使用片段。这是我的主要活动：

package com.example.grasu.petrosani;

import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.design.widget.NavigationView;
import android.support.design.widget.TabLayout;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.support.v4.view.ViewPager;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.ThemedSpinnerAdapter;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.GridView;

public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener,AdapterView.OnItemClickListener{
    private DrawerLayout DrawerLayout;
    private NavigationView Drawer;
GridView gridview;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Drawer = findViewById(R.id.nav_view);
        Drawer.setNavigationItemSelectedListener(this);
        DrawerLayout = findViewById(R.id.drawer_layout);

        CategoryAdapter adapter = new CategoryAdapter(this, getSupportFragmentManager());



      gridview=findViewById(R.id.album_Gridview);
gridview.setAdapter(new GridViewAdapter(this));
    }


    @Override
    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
        return false;
    }


    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        if (parent.getId()==R.id.album_Gridview){
            switch (position) {
                case 0:

            }
            }
        }
    }

this is my xml for activity main:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true">


<FrameLayout
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <GridView
        android:id="@+id/album_Gridview"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:numColumns="2"
        android:layout_marginTop="10dp">

    </GridView>

</FrameLayout>
    <android.support.design.widget.NavigationView
    android:id="@+id/nav_view"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:fitsSystemWindows="true"
        android:duplicateParentState="true"
        app:menu="@menu/drawer_view"/>

</android.support.v4.widget.DrawerLayout>

这是我想从gridview打开的片段：

package com.example.grasu.petrosani;

import android.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class InfoFragment extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.info, container, false);

        return rootView;
    }}

我尝试使用FragmentManager fm = getSupportFragmentManager（）; FragmentTransaction ft = fm.beginTransaction（）; ft.replace（CurrentClass.this，MainActivity.class）;但是它没有用。我必须修改我的mainactivity来扩展fragmentActivity吗？

Answer 1

你可以试试像 -

创建新活动。
在上面创建的活动中添加片段。
在您的GridView项目点击中，通过意图打开新活动，例如 - startActivity(new Intent(MainActivity.this, NewActivity.class));

Answer 2

请按照以下代码：

@a={};File.foreach('f1.txt') do |f| # foreach ensures reading line by line without slurping the entire file into memory
  # add first word as key = create array with rest of data and add note if it is number or stirng
  @a[f.split.first] = [f.split.last, (f.scan(/\d+/).empty?) ? "string" : "number"]
  puts
end

=> {"Number"=>["1", "number"], "Date"=>["01/01/2001", "number"], "Name"=>["John", "string"], "Age"=>["20", "number"], "Job"=>["Programmer", "string"]}

我怎么能从gridview打开一个片段？

2 个答案: