Android Criminal实例--（1）创建fragment并添加至activity

女爷i 2022-05-18 04:55 224阅读 0赞

这个例子是从Android权威编程指南第七章开始。  
效果：  
![这里写图片描述][70]

*  将这个界面显示在fragment中，并将fragment添加到activity中。
 *  xml代码

fragment\_crime

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

*  以及container容器代码，这个容器用于存放fragment，是CrimeActivity的layout文件，将crime\_fragment添加到容器中，fragments的界面内容就可以通过activity显示出来。

crime\_activity:

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

*  接下来编写实体类  
    如代码所示，存放的是每一个fragment的id（独一无二），crime的标题，时间，以及是否被解决的情况

import java.util.Date;
    import java.util.UUID;
    
    public class Crime { 
    
        private UUID id;//专门用于生成唯一id
        private String mTitle;
        private boolean isChecked;
        private Date mDate;
    
        public Crime(){
            id=UUID.randomUUID();
            mDate=new Date();
        }
    
        public UUID getId() {
            return id;
        }
    
        public String getTitle() {
            return mTitle;
        }
    
        public void setTitle(String title) {
            mTitle = title;
        }
    
        public boolean isChecked() {
            return isChecked;
        }
    
        public void setChecked(boolean checked) {
            isChecked = checked;
        }
    
        public Date getDate() {
            return mDate;
        }
    
        public void setDate(Date date) {
            mDate = date;
        }
    }

*  接下来初始化控件，包括title，details，button，checkbox等

public class CrimeFragment extends Fragment { 
    
        Crime mCrime;
        private EditText crime_title;
        private Button crime_date;
        private CheckBox isSolved;
    
        @Nullable
        @Override
        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
            View view=inflater.inflate(R.layout.framgent_crime,container,false);
    
            crime_title=(EditText)view.findViewById(R.id.crime_title);
            crime_title.addTextChangedListener(new TextWatcher() {
                @Override
                public void beforeTextChanged(CharSequence s, int start, int count, int after) {
    
                }
    
                @Override
                public void onTextChanged(CharSequence s, int start, int before, int count) {
    
                }
    
                @Override
                public void afterTextChanged(Editable s) {
    
                }
            });
    
            crime_date=(Button)view.findViewById(R.id.crime_date);
            crime_date.setText(mCrime.getDate().toString());
            crime_date.setEnabled(false);
    
            isSolved=(CheckBox)view.findViewById(R.id.crime_solved);
            isSolved.setOnCheckedChangeListener(new OnCheckedChangeListener() {
                @Override
                public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    
                }
            });
    
            return view;
        }
    
    
        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            mCrime=new Crime();
        }
    }

*  接下来是在activity中添加fragment

public class CrimeActivity extends AppCompatActivity { 
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_crime);
    
            FragmentManager fm=getSupportFragmentManager();
            Fragment fragment=fm.findFragmentById(R.id.crime_container);
            if(fragment==null){
                fragment=new CrimeFragment();
                fm.beginTransaction()
                        .add(R.id.crime_container,fragment)
                        .commit();
            }
        }
    }

[70]: /images/20220518/b03227f1e332414ebef8dc6789114a5d.png