Android中的Material Design Date Picker的更多功能

如Android的Material Design Date Picker中所讨论的，它为用户提供了许多功能，并且易于开发人员实现。因此，在本文中，我们将通过示例讨论材料设计日期选择器的更多功能。请注意，UI部分将与第1部分中的文章相同。我们将仅使用Java文件。

功能1：封锁今天日期之前的所有日期

此功能对于开发人员避免用户执行以下操作非常有用。 选择 错误的日期。下面的样本GIF给予获得什么，我们要在这个功能做的想法。

转到MainActivity。 Java文件，并参考以下代码。下面是MainActivity的代码。 Java文件。在代码内部添加了注释，以更详细地了解代码。

Java

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.google.android.material.datepicker.CalendarConstraints;
import com.google.android.material.datepicker.DateValidatorPointForward;
import com.google.android.material.datepicker.MaterialDatePicker;
import com.google.android.material.datepicker.MaterialPickerOnPositiveButtonClickListener;
  
public class MainActivity extends AppCompatActivity {
  
    // button to open the material date picker dialog
    private Button mPickDateButton;
  
    // textview to preview the selected date
    private TextView mShowSelectedDateText;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        // register all the UI widgets with their
        // appropriate IDs
        mPickDateButton = findViewById(R.id.pick_date_button);
        mShowSelectedDateText = findViewById(R.id.show_selected_date);
  
        // create the calendar constraint builder
        CalendarConstraints.Builder calendarConstraintBuilder = new CalendarConstraints.Builder();
          
        // set the validator point forward from june
        // this mean the all the dates before the June month
        // are blocked
        calendarConstraintBuilder.setValidator(DateValidatorPointForward.now());
  
        // instantiate the Material date picker dialog
        // builder
        final MaterialDatePicker.Builder materialDatePickerBuilder = MaterialDatePicker.Builder.datePicker();
        materialDatePickerBuilder.setTitleText("SELECT A DATE");
  
        // now pass the constrained calender builder to
        // material date picker Calendar constraints
        materialDatePickerBuilder.setCalendarConstraints(calendarConstraintBuilder.build());
  
        // now build the material date picker dialog
        final MaterialDatePicker materialDatePicker = materialDatePickerBuilder.build();
  
        // handle the Select date button to open the
        // material date picker
        mPickDateButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // show the material date picker with
                        // supportable fragment manager to
                        // interact with dialog material date
                        // picker dialog fragments
                        materialDatePicker.show(getSupportFragmentManager(), "MATERIAL_DATE_PICKER");
                    }
                });
  
        materialDatePicker.addOnPositiveButtonClickListener(
                new MaterialPickerOnPositiveButtonClickListener() {
                    @SuppressLint("SetTextI18n")
                    @Override
                    public void onPositiveButtonClick(Object selection) {
                        // now update the selected date preview
                        mShowSelectedDateText.setText("Selected Date is : " + materialDatePicker.getHeaderText());
                    }
                });
    }
}

输出：在模拟器上运行

功能2：打开物料日期选择器对话框后，立即选择今天的日期作为默认选择

 看下面的图片。

转到MainActivity。 Java文件，并参考以下代码。下面是MainActivity的代码。 Java文件。在代码内部添加了注释，以更详细地了解代码。

Java

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.google.android.material.datepicker.MaterialDatePicker;
import com.google.android.material.datepicker.MaterialPickerOnPositiveButtonClickListener;
  
public class MainActivity extends AppCompatActivity {
  
    // button to open the material date picker dialog
    private Button mPickDateButton;
  
    // textview to preview the selected date
    private TextView mShowSelectedDateText;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        // register all the UI widgets with their
        // appropriate IDs
        mPickDateButton = findViewById(R.id.pick_date_button);
        mShowSelectedDateText = findViewById(R.id.show_selected_date);
  
        // now create the instance of the regular material
        // date picker
        MaterialDatePicker.Builder materialDateBuilder = MaterialDatePicker.Builder.datePicker();
  
        // get the today's date from the method
        // todayInUtcMilliseconds()
        long today = MaterialDatePicker.todayInUtcMilliseconds();
  
        // now define the properties of the
        // materialDateBuilder
        materialDateBuilder.setTitleText("SELECT A DATE");
  
        // now make today's date selected by default as soon
        // as the dialog opens
        materialDateBuilder.setSelection(today);
  
        // now create the instance of the material date
        // picker and build the dialog
        final MaterialDatePicker materialDatePicker = materialDateBuilder.build();
  
        // handle select date button which opens the
        // material design date picker
        mPickDateButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // now show the material date picker
                        // dialog by passing
                        // getSupportFragmentmanager()
                        materialDatePicker.show(getSupportFragmentManager(), "MATERIAL_DATE_PICKER");
                    }
                });
  
        // now handle the positive button click from the
        // material design date picker
        materialDatePicker.addOnPositiveButtonClickListener(
                new MaterialPickerOnPositiveButtonClickListener() {
                    @SuppressLint("SetTextI18n")
                    @Override
                    public void onPositiveButtonClick(Object selection) {
                        // now update selected date preview text
                        mShowSelectedDateText.setText("Selected Date is : " + materialDatePicker.getHeaderText());
                    }
                });
    }
}

输出：在模拟器上运行

功能3：让用户在范围内选择一个日期

例如选择从2020年三月日至2020年十二月的样本GIF下面给出得到什么，我们要在这个功能做的想法。

转到MainActivity。 Java文件，并参考以下代码。下面是MainActivity的代码。 Java文件。在代码内部添加了注释，以更详细地了解代码。

Java

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.google.android.material.datepicker.CalendarConstraints;
import com.google.android.material.datepicker.MaterialDatePicker;
import com.google.android.material.datepicker.MaterialPickerOnPositiveButtonClickListener;
import java.util.Calendar;
import java.util.TimeZone;
  
public class MainActivity extends AppCompatActivity {
  
    // button to open the material date picker dialog
    private Button mPickDateButton;
  
    // textview to preview the selected date
    private TextView mShowSelectedDateText;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        // register all the UI widgets with their
        // appropriate IDs
        mPickDateButton = findViewById(R.id.pick_date_button);
        mShowSelectedDateText = findViewById(R.id.show_selected_date);
  
        // create the instance of the calendar to set the
        // bounds
        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
  
        // now set the starting bound from current month to
        // previous MARCH
        calendar.set(Calendar.MONTH, Calendar.MARCH);
        long march = calendar.getTimeInMillis();
  
        // now set the ending bound from current month to
        // DECEMBER
        calendar.set(Calendar.MONTH, Calendar.DECEMBER);
        long december = calendar.getTimeInMillis();
  
        // create the instance of the CalendarConstraints
        // Builder
        CalendarConstraints.Builder calendarConstraintBuilder = new CalendarConstraints.Builder();
  
        // and set the start and end constraints (bounds)
        calendarConstraintBuilder.setStart(march);
        calendarConstraintBuilder.setEnd(december);
  
        // instantiate the Material date picker dialog
        // builder
        final MaterialDatePicker.Builder materialDatePickerBuilder = MaterialDatePicker.Builder.datePicker();
        materialDatePickerBuilder.setTitleText("SELECT A DATE");
  
        // now pass the constrained calender builder to
        // material date picker Calendar constraints
        materialDatePickerBuilder.setCalendarConstraints(calendarConstraintBuilder.build());
  
        // now build the material date picker dialog
        final MaterialDatePicker materialDatePicker = materialDatePickerBuilder.build();
  
        // handle the Select date button to open the
        // material date picker
        mPickDateButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // show the material date picker with
                        // supportable fragment manager to
                        // interact with dialog material date
                        // picker dialog fragments
                        materialDatePicker.show(getSupportFragmentManager(), "MATERIAL_DATE_PICKER");
                    }
                });
  
        materialDatePicker.addOnPositiveButtonClickListener(
                new MaterialPickerOnPositiveButtonClickListener() {
                    @SuppressLint("SetTextI18n")
                    @Override
                    public void onPositiveButtonClick(Object selection) {
                        // now update the selected date preview
                        mShowSelectedDateText.setText("Selected Date is : " + materialDatePicker.getHeaderText());
                    }
                });
    }
}

输出：在模拟器上运行

功能4：在特定月份打开物料日期选择器对话框

例如，在八月打开物料日期选择器对话框。下面的样本GIF给予获得什么，我们要在这个功能做的想法。

转到MainActivity。 Java文件，并参考以下代码。下面是MainActivity的代码。 Java文件。在代码内部添加了注释，以更详细地了解代码。

Java

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import com.google.android.material.datepicker.CalendarConstraints;
import com.google.android.material.datepicker.MaterialDatePicker;
import com.google.android.material.datepicker.MaterialPickerOnPositiveButtonClickListener;
import java.util.Calendar;
import java.util.TimeZone;
  
public class MainActivity extends AppCompatActivity {
  
    // button to open the material date picker dialog
    private Button mPickDateButton;
  
    // textview to preview the selected date
    private TextView mShowSelectedDateText;
  
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
  
        // register all the UI widgets with their
        // appropriate IDs
        mPickDateButton = findViewById(R.id.pick_date_button);
        mShowSelectedDateText = findViewById(R.id.show_selected_date);
  
        // create the instance of the calendar to set the
        // bounds
        Calendar calendar = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
  
        // from calendar object get the AUGUST month
        calendar.set(Calendar.MONTH, Calendar.AUGUST);
        long august = calendar.getTimeInMillis();
  
        // create the instance of the CalendarConstraints
        // Builder
        CalendarConstraints.Builder calendarConstraintBuilder = new CalendarConstraints.Builder();
        calendarConstraintBuilder.setOpenAt(august);
  
        // instantiate the Material date picker dialog
        // builder
        final MaterialDatePicker.Builder materialDatePickerBuilder = MaterialDatePicker.Builder.datePicker();
        materialDatePickerBuilder.setTitleText("SELECT A DATE");
  
        // now pass the constrained calender builder to
        // material date picker Calendar constraints
        materialDatePickerBuilder.setCalendarConstraints(calendarConstraintBuilder.build());
  
        // now build the material date picker dialog
        final MaterialDatePicker materialDatePicker = materialDatePickerBuilder.build();
  
        // handle the Select date button to open the
        // material date picker
        mPickDateButton.setOnClickListener(
                new View.OnClickListener() {
                    @Override
                    public void onClick(View v) {
                        // show the material date picker with
                        // supportable fragment manager to
                        // interact with dialog material date
                        // picker dialog fragments
                        materialDatePicker.show(getSupportFragmentManager(), "MATERIAL_DATE_PICKER");
                    }
                });
  
        materialDatePicker.addOnPositiveButtonClickListener(
                new MaterialPickerOnPositiveButtonClickListener() {
                    @SuppressLint("SetTextI18n")
                    @Override
                    public void onPositiveButtonClick(Object selection) {
                        // now update the selected date preview
                        mShowSelectedDateText.setText("Selected Date is : " + materialDatePicker.getHeaderText());
                    }
                });
    }
}

输出：在模拟器上运行

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