Question

我正在关注android编程的教程，但我遇到了一个问题。我有一个循环视图，填充了一个数组列表，但是当我运行应用程序时，循环视图就在那里，因为我可以看到顶部和底部的阴影，但它没有填充视图。

CrimeLab.java

package com.example.moore.criminalintent;

import android.content.Context;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

/**
 * Created by moore on 13/07/2016.
 */
public class CrimeLab {
    private static CrimeLab sCrimeLab;
    private List<Crime> mCrimes;

    public static CrimeLab get(Context context){
        if (sCrimeLab == null){
            sCrimeLab = new CrimeLab(context);
        }
        return sCrimeLab;
    }

    private CrimeLab(Context context){
        mCrimes = new ArrayList<>();
        for (int i = 100; i<100; i++){
            Crime crime = new Crime();
            crime.setTitle("Crime :" + i);
            crime.setSovled(i%2 == 0);
            mCrimes.add(crime);
        }
    }

    public List<Crime> getCrimes(){
        return mCrimes;
    }

    public Crime getCrime(UUID id){
        for (Crime crime : mCrimes){
            if (crime.getID().equals(id)){
                return crime;
            }
        }
        return null;
    }

}

CrimeListActivity.java

public class CrimeListActivity extends SingleFragmentActivity {
    @Override
    protected Fragment createFragment() {
        return new CrimeListFragment();
    }
}

CrimeListFragment.java

package com.example.moore.criminalintent;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import java.util.List;

/**
 * Created by moore on 14/07/2016.
 */
public class CrimeListFragment extends Fragment {
    private RecyclerView mCrimeRecyclerView;
    private CrimeAdapter mAdapter;


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

        mCrimeRecyclerView = (RecyclerView) view.findViewById(R.id.crime_recycler_view);
        mCrimeRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));

        updateUI();

        return view;
    }

    public void updateUI(){
        CrimeLab crimeLab = CrimeLab.get(getActivity());
        List<Crime> crimes = crimeLab.getCrimes();

        mAdapter = new CrimeAdapter(crimes);
        mCrimeRecyclerView.setAdapter(mAdapter);
    }

    private class CrimeHolder extends RecyclerView.ViewHolder{
        public TextView mTitleTextView;

        public CrimeHolder(View itemView){
            super(itemView);
            mTitleTextView = (TextView) itemView;
        }
    }

    private class CrimeAdapter extends RecyclerView.Adapter<CrimeHolder>{
        private List<Crime> mCrimes;

        public CrimeAdapter(List<Crime> crimes){
            mCrimes = crimes;
        }

        @Override
        public CrimeHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
            View view = layoutInflater.inflate(android.R.layout.simple_list_item_1, parent, false);
            return new CrimeHolder(view);
        }

        @Override
        public void onBindViewHolder(CrimeHolder holder, int position) {
            Crime crime = mCrimes.get(position);
            holder.mTitleTextView.setText(crime.getTitle());
        }

        @Override
        public int getItemCount() {
            return mCrimes.size();
        }
    }


}

SingleFragmentActivity.java

package com.example.moore.criminalintent;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;

/**
 * Created by moore on 14/07/2016.
 */
public abstract class SingleFragmentActivity extends FragmentActivity {
    protected abstract Fragment createFragment();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fragment);

        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.fragment_container);

        if(fragment == null){
            fragment = createFragment();
            fm.beginTransaction().add(R.id.fragment_container, fragment).commit();
        }
    }
}

activity_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="com.example.moore.criminalintent.CrimeActivity">


    <include layout="@layout/content_fragment" />


</android.support.design.widget.CoordinatorLayout>

content_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.example.moore.criminalintent.CrimeActivity"
    tools:showIn="@layout/activity_fragment">

    <FrameLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/fragment_container"
        android:layout_width="match_parent"
        android:layout_height="match_parent"></FrameLayout>
</RelativeLayout>

fragment_crime.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/Crime_title_label"
        style="?android:listSeparatorTextViewStyle"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/crime_title"
        android:hint="@string/crime_title_hint"/>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/crime_detail_label"
        style="?android:listSeparatorTextViewStyle"/>
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/crime_date"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"/>
    <CheckBox
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/crime_solved"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:text="@string/crime_solved_label"/>


</LinearLayout>

fragment_crime_list.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.RecyclerView
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/crime_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent"/>

任何有关我的代码错误的帮助都会非常棒。

Answer 1

问题在于这个方法

private CrimeLab(Context context){
    mCrimes = new ArrayList<>();
    for (int i = 100; i<100; i++){ // here is the problem
        Crime crime = new Crime();
        crime.setTitle("Crime :" + i);
        crime.setSovled(i%2 == 0);
        mCrimes.add(crime);
    }
}

将其更改为

private CrimeLab(Context context) {
    mCrimes = new ArrayList<>();
    for (int i = 100; i > 1; i--) {
        Crime crime = new Crime();
        crime.setTitle("Crime :" + i);
        crime.setSovled(i % 2 == 0);
        mCrimes.add(crime);
    }
}

RecycleView未显示TextView

1 个答案: