Android自定义日历控件(继承系统控件实现)

主要步骤

1. 编写布局
2. 继承LinearLayout设置子控件
3. 设置数据
4. 继承TextView实现有圆圈背景的TextView
5. 添加Attribute
6. 添加长按事件

1.编写布局

<?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">

    <RelativeLayout
        android:id="@+id/header"
        android:layout_width="match_parent"
        android:layout_height="30dp">

        <ImageView
            android:id="@+id/btn_pre"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignParentLeft="true"
            android:layout_alignParentStart="true"
            android:src="@mipmap/ic_launcher" />

        <ImageView
            android:id="@+id/btn_next"
            android:layout_width="30dp"
            android:layout_height="30dp"
            android:layout_alignParentEnd="true"
            android:layout_alignParentRight="true"
            android:src="@mipmap/ic_launcher" />

        <TextView
            android:id="@+id/txtData"
            android:layout_width="wrap_content"
            android:layout_height="match_parent"
            android:layout_centerInParent="true"
            android:gravity="center"
            android:text="@string/app_name" />

    </RelativeLayout>

    <LinearLayout
        android:id="@+id/week_header"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:orientation="horizontal">

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="1" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="2" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="3" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="4" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="5" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="6" />

        <TextView
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:gravity="center"
            android:text="7" />
    </LinearLayout>

    <GridView
        android:id="@+id/grid"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:numColumns="7" />

</LinearLayout>

2.继承LinearLayout设置子控件

public class CalendarView extends LinearLayout {
    private ImageView btnPre;
    private ImageView btnNext;
    private TextView txtData;
    private GridView gridView;
    private Calendar calendar = Calendar.getInstance();
    private String displayFormat;
    public NewViewListener viewListener;

    public void setViewListener(NewViewListener viewListener) {
        this.viewListener = viewListener;
    }

    public CalendarView(Context context) {
        super(context);
    }

    public CalendarView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initControl(context, attrs);
    }

    public CalendarView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initControl(context, attrs);
    }

    private void initControl(Context context, AttributeSet attributeSet) {
        bindControl(context);
        bindControlEvent();
        setAttribute(attributeSet);
        renderCalender();
    }

    private void bindControl(Context context) {
        LayoutInflater.from(context).inflate(R.layout.new_view, this);
        btnNext = (ImageView) findViewById(R.id.btn_next);
        btnPre = (ImageView) findViewById(R.id.btn_pre);
        txtData = (TextView) findViewById(R.id.txtData);
        gridView = (GridView) findViewById(R.id.grid);
    }

    private void bindControlEvent() {
        btnNext.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                calendar.add(Calendar.MONTH, +1);
                renderCalender();
            }
        });
        btnPre.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                calendar.add(Calendar.MONTH, -1);
                renderCalender();
            }
        });
    }
 }

3.设置数据

private void renderCalender() {

        //返回"月+日"格式的数据
        SimpleDateFormat sdf = new SimpleDateFormat(displayFormat, Locale.CHINA);
        txtData.setText(sdf.format(calendar.getTime()));

        ArrayList<Date> cells = new ArrayList<>();

        Calendar calendar2 = (Calendar) this.calendar.clone();
        //设置月的第一天为1
        calendar2.set(Calendar.DAY_OF_MONTH, 1);

        //获取当前周数的前一天
        int prevDays = calendar2.get(Calendar.DAY_OF_WEEK) - 1;
        //运算日历加上加前一周
        calendar2.add(Calendar.DAY_OF_MONTH, -prevDays);

        int maxCellCount = 6 * 7;

        //将日历里的日期数据添加到ArrayList
        while (cells.size() < maxCellCount) {
            cells.add(calendar2.getTime());
            calendar2.add(Calendar.DAY_OF_MONTH, 1);
        }

        gridView.setAdapter(new MyAdapter(getContext(), cells));
        gridView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
                if (viewListener == null) {
                    return false;
                } else {
                    viewListener.onItemLongPress((Date) parent.getItemAtPosition(position));
                    return true;
                }
            }
        });
    }

    private class MyAdapter extends ArrayAdapter<Date> {

        LayoutInflater layoutInflater;

        MyAdapter(@NonNull Context context, ArrayList<Date> dates) {
            super(context, R.layout.calendar_text_day, dates);
            layoutInflater = LayoutInflater.from(context);
        }

        @NonNull
        @Override
        public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
            Date date = getItem(position);
            if (convertView == null) {
                convertView = layoutInflater.inflate(R.layout.calendar_text_day, parent, false);
            }
            int day = date.getDate();
            ((CalendarTextView) convertView).setText(String.valueOf(day));
            Date now = new Date();

            boolean isSameMonth = false;
            if (date.getMonth() == now.getMonth()) {
                isSameMonth = true;
            }

            if (isSameMonth) {
                ((CalendarTextView) convertView).setTextColor(Color.DKGRAY);
            }

            if (now.getDate() == date.getDate() && now.getMonth() == date.getMonth() && now.getYear() == date.getYear()) {
                ((CalendarTextView) convertView).setNow(true);
            }
            return convertView;
        }
    }

4. 圆圈背景TextView

public class CalendarTextView extends AppCompatTextView {
    private Paint paint;
    private boolean isNow = false;

    public void setNow(boolean now) {
        isNow = now;
    }

    public CalendarTextView(Context context) {
        super(context);
    }

    public CalendarTextView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        initControl();
    }

    public CalendarTextView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initControl();
    }


    private void initControl() {
        paint = new Paint();
        paint.setStyle(Paint.Style.STROKE);
        paint.setColor(Color.RED);
        paint.setStrokeWidth(2);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (isNow) {
            canvas.translate(getWidth() / 2, getHeight() / 2);
            canvas.drawCircle(0, 0, getWidth() / 2, paint);
            setTextColor(Color.RED);
        }
    }
}

5.添加Attribute

1. 添加attrs文件

   <?xml version="1.0" encoding="utf-8"?>
   <resources>
       <declare-styleable name="CalendarView">
           <attr name="dateFormat" format="string" />
       </declare-styleable>
   </resources>
   

2. 将Arrtibute参数设置到控件

   private void setAttribute(AttributeSet attributeSet) {
       TypedArray ta = getContext().obtainStyledAttributes(attributeSet, R.styleable.CalendarView);
       try {
           displayFormat = ta.getString(R.styleable.CalendarView_dateFormat);
           if (displayFormat == null) {
               displayFormat = "MMM yyy";
           }
       } finally {
           ta.recycle();
       }
   }
   

3. 在布局中加入命名空间引入

   <com.example.jiyang.newview.CalendarView xmlns:CalendarView="http://schemas.android.com/apk/res/com.example.jiyang.newview"
       android:id="@+id/newView"
       android:layout_width="match_parent"
       android:layout_height="match_parent"
       android:padding="10dp"
       CalendarView:dateFormat="MMMM yyyy" />
   

6.添加长按事件

1. 定义长按接口

   public interface NewViewListener {
       void onItemLongPress(Date day);
   }
   

2. CalenderView中调用

gridView.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
if (viewListener == null) {
return false;
} else {
viewListener.onItemLongPress((Date) parent.getItemAtPosition(position));
return true;
}
}
});
```

3. Activity中实现接口方法

@Override
public void onItemLongPress(Date day) {
DateFormat df = SimpleDateFormat.getDateInstance();
Toast.makeText(this, df.format(day), Toast.LENGTH_SHORT).show();
}
```

总结

• Attribute的使用

  1. 定义attrs文件
  2. 注意命名空间。自定义View不能使用app:，而要使用xmlns:自定义一个命名空间
  3. TypedArray放入try{}finaly{}中，要在finally中释放TypedArray typedArray.recycle()

• 通过继承布局实现自定义View时，加载布局
  需要LayoutInflater.from(context).inflate(R.layout.new_view, this);不能LayoutInflater.from(context).inflate(R.layout.new_view, this,false);