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实验四 Android项目CriminalIntent应用开发二

Android应用项目开发 实验
2023-09-14 09:14:10 时间

参考文章：

第二个项目CriminalIntent应用开发阶段总结（一）（二）https://www.cnblogs.com/hj0407/

android编程权威指南第七章-CriminalIntent应用https://blog.csdn.net/weixin_43749381/article/details/107465847

Android Criminal实例--（1）创建fragment并添加至activityhttps://blog.csdn.net/ayangann915/article/details/81284856

一、项目创建

二、代码详情

1. values布局

（1）strings.xml

<resources>
    <string name="app_name">学号+姓名</string>
    <string name="hello_blank_fragment">Hello blank fragment</string>
</resources>

2. layout布局

（1）activity_crime_list.xml

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout 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:id="@+id/list_fragment_container"
    tools:context=".CrimeListActivity">

</FrameLayout>

（2）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="Title" />

    <EditText
        android:id="@+id/crime_title"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:minHeight="48dp"
        android:text="crime_title" />

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Details" />

    <Button
        android:id="@+id/crime_date"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:text="Crime Date" />

    <CheckBox
        android:id="@+id/list_item_crime_solved"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:text="解决了" />
</LinearLayout>

（3）fragment_crime_list.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.recyclerview.widget.RecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".CrimeListFragment"
    android:id="@+id/crime_recycleview">

</androidx.recyclerview.widget.RecyclerView>

（4）list_item_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="wrap_content"
    android:id="@+id/list_item"
    android:padding="8dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="horizontal">

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="match_parent"
                    android:orientation="vertical">

                        <TextView
                            android:id="@+id/list_item_crime_title"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text="标题" />

                        <TextView
                            android:id="@+id/list_item_crime_date"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:text="日期" />
                </LinearLayout>

                <LinearLayout
                    android:layout_width="wrap_content"
                    android:layout_height="match_parent"
                    android:orientation="vertical">

                        <CheckBox
                            android:id="@+id/list_item_crime_solved"
                            android:layout_width="wrap_content"
                            android:layout_height="wrap_content"
                            android:layout_marginLeft="16dp"
                            android:layout_marginRight="16dp"
                            android:text="解决了" />
                </LinearLayout>
        </LinearLayout>

</LinearLayout>

3. Java布局

（1）CrimeListActivity

public class CrimeListActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_crime_list);
        //获取FragmentManager
        FragmentManager fm = getSupportFragmentManager();
        Fragment fragment = fm.findFragmentById(R.id.list_fragment_container);
        if (fragment == null) {
            fragment = new CrimeListFragment();
            fm.beginTransaction()
                    .add(R.id.list_fragment_container, fragment)
                    .commit();
        }
    }
}

（2）Crime 

public class Crime implements Serializable {
    private UUID mId;
    private String mTitle;
    private Date mDate;
    private boolean mSolved;

    public Crime() {
        mId = UUID.randomUUID();
        mDate = new Date();
    }

    public Crime(UUID mId, String mTitle, Date mDate, boolean mSolved) {
        this.mId = mId;
        this.mTitle = mTitle;
        this.mDate = mDate;
        this.mSolved = mSolved;
    }

    @Override
    public String toString() {
        return "Crime{" +
                "mId=" + mId +
                ", mTitle='" + mTitle + '\'' +
                ", mDate=" + mDate +
                ", mSolved=" + mSolved +
                '}';
    }

    public String getmTitle() {
        return mTitle;
    }

    public void setmTitle(String mTitle) {
        this.mTitle = mTitle;
    }

    public Date getmDate() {
        return mDate;
    }

    public void setmDate(Date mDate) {
        this.mDate = mDate;
    }

    public boolean ismSolved() {
        return mSolved;
    }

    public void setmSolved(boolean mSolved) {
        this.mSolved = mSolved;
    }

    public UUID getmId() {
        return mId;
    }

    public void setmId(UUID mId) {
        this.mId = mId;
    }
}

（3）CrimeFragment

public class CrimeFragment extends Fragment {
    private Crime crime;
    private EditText crimeTitle;
    private Button crimeDate;
    private CheckBox crimeSolved;

    public CrimeFragment() {

    }

    public static CrimeFragment newInstance(Crime crime) {
        CrimeFragment fragment = new CrimeFragment();
        Bundle args = new Bundle();
        args.putSerializable("crime", crime);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if (getArguments() != null) {
            this.crime = (Crime) getArguments().getSerializable("crime");
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View v = inflater.inflate(R.layout.fragment_crime, container, false);

        crimeTitle = v.findViewById(R.id.crime_title);
        crimeTitle.setText(crime.getmTitle());
        crimeTitle.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
            }

            @Override
            public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
                crime.setmTitle(charSequence.toString());
            }

            @Override
            public void afterTextChanged(Editable editable) {
            }
        });

        crimeDate = v.findViewById(R.id.crime_date);
        crimeDate.setText(crime.getmDate().toString());
        crimeDate.setEnabled(false);

        crimeSolved = v.findViewById(R.id.list_item_crime_solved);
        crimeSolved.setChecked(crime.ismSolved());
        crimeSolved.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(CompoundButton buttonView,
                                         boolean isChecked) {
                crime.setmSolved(isChecked);
            }
        });
        return v;
    }
}

（4）CrimeListFragment

public class CrimeListFragment extends Fragment {

    //为CrimeListFragment配置视图
    private RecyclerView mRecyclerview;
    private CrimeAdapter mCrimeAdapter;

    public CrimeListFragment() {
        // 需要空的公共构造函数
    }

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

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

        mRecyclerview = v.findViewById(R.id.crime_recycleview);
        mRecyclerview.setLayoutManager(new LinearLayoutManager(getActivity()));
        CrimeLab crimeLab = CrimeLab.get(getActivity());
        List<Crime> crimes = crimeLab.getCrimes();
        mCrimeAdapter = new CrimeAdapter(crimes);
        mRecyclerview.setAdapter(mCrimeAdapter);
        return v;
    }

    //创建Adapter内部类
    private class CrimeAdapter extends RecyclerView.Adapter<CrimeHolder> {
        private List<Crime> crimes;

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

        //武装CrimeAdapter
        @NonNull
        @Override
        public CrimeHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
            LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
            return new CrimeHolder(layoutInflater, parent);
        }

        //调用bind(Crime)方法
        @NonNull
        @Override
        public void onBindViewHolder(@NonNull CrimeHolder holder, int position) {
            Crime crime = crimes.get(position);
            holder.bind(crime);
        }

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

    //定义ViewHolder内部类
    private class CrimeHolder extends RecyclerView.ViewHolder {
        private TextView mTitle;
        private TextView mDate;
        private CheckBox mCheckBox;
        private Crime mCrime;

        public CrimeHolder(LayoutInflater inflater, ViewGroup container) {
            super(inflater.inflate(R.layout.list_item_crime, container, false));
            mTitle = itemView.findViewById(R.id.list_item_crime_title);
            mDate = itemView.findViewById(R.id.list_item_crime_date);
            mCheckBox = itemView.findViewById(R.id.list_item_crime_solved);
            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    CrimeFragment crimeFragment = CrimeFragment.newInstance(mCrime);
                    FragmentTransaction transaction = getFragmentManager().beginTransaction();
                    transaction.replace(R.id.list_fragment_container, crimeFragment)
                            .commit();
                    transaction.addToBackStack(null);
                    Toast.makeText(getActivity(), mCrime.getmId() + "clicked", Toast.LENGTH_SHORT).show();
                }
            });
        }

        //将crime显示在布局上
        public void bind(Crime crime) {
            mCrime = crime;
            mTitle.setText(crime.getmTitle());
            mDate.setText(crime.getmDate().toString());
            mCheckBox.setChecked(crime.ismSolved());
        }
    }
}

（5）CrimeLab 

//单实例类
public class CrimeLab {
    //保存该类的唯一实例
    private static CrimeLab sCrimeLab;

    //保存多个Crime的List容器
    private List<Crime> mCrimes;

    //暴露给外部的静态方法，生成或获取该类的唯一实例sCrimeLab
    public static CrimeLab get(Context context) {
        //确保实例的唯一性
        if (sCrimeLab == null)
            sCrimeLab = new CrimeLab(context);
        return sCrimeLab;
    }

    //私有构造函数，使得外部无法new出该对象的实例
    private CrimeLab(Context context) {
        //实例化容器成员
        mCrimes = new ArrayList<>();
        //初始化100个crime表项
        for (int i = 0; i < 100; i++) {
            Crime crime = new Crime();
            crime.setmTitle("Crime #" + i);
            crime.setmSolved(i % 2 == 0);
            mCrimes.add(crime);
        }
    }

    public List<Crime> getCrimes() {
        return mCrimes;
    }
    //根据UUID查找对应的crime表项
    public Crime getCrime(UUID id) {
        for (Crime crime : mCrimes) {
            if (crime.getmId().equals(id))
                return crime;
        }
        return null;
    }
}

三、效果展示

 

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