通过以下四种方式可以实现
通过Toast显示消息提示框
Toast.makeText(MainActivity.this,"或者就是为了改变世界",Toast.LENGTH_SHORT).show();
使用AlertDialog实现对话框
以下是主要代码:
package com.example.pratice6;
import androidx.appcompat.app.AlertDialog;
import androidx.appcompat.app.AppCompatActivity;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
Button b1;
Button b2;
Button b3;
Button b4;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
b1 = findViewById(R.id.b1);
b2 = findViewById(R.id.b2);
b3 = findViewById(R.id.b3);
b4 = findViewById(R.id.b4);
//显示带取消、确定按钮的对话框
b1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//创建AlertDialog对象
AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
alertDialog.setIcon(R.drawable.img1);//设置图标
alertDialog.setTitle("标题");//设置标题
alertDialog.setMessage("活着就是为了改变世界");//设置内容
alertDialog.setButton(DialogInterface.BUTTON_NEGATIVE, "否", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Toast.makeText(MainActivity.this,"您单击了否按钮",Toast.LENGTH_SHORT).show();
}
});
alertDialog.setButton(DialogInterface.BUTTON_POSITIVE, "是", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Toast.makeText(MainActivity.this,"您单击了是按钮",Toast.LENGTH_SHORT).show();
}
});
alertDialog.show();
}
});
//显示带列表的对话框
b2.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//带四个列表项的列表对话框
final String[] items = new String[]{"第一个列表项","第二个列表项","第三个列表项","第四个列表项"};
//创建一个AlertDialog.Builder对象
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setIcon(R.drawable.img1);
builder.setTitle("请做出选择?");
builder.setItems(items, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Toast.makeText(MainActivity.this,"您选择了"+items[i],Toast.LENGTH_SHORT).show();
}
});
builder.create().show();
}
});
//显示带单选列表项的对话框
b3.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final String[] items = new String[]{"第一个单选项","第二个单选项","第三个单选项","第四个单选项","第五个单选项"};
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setIcon(R.drawable.img1);
builder.setTitle("请做出选择");
builder.setSingleChoiceItems(items, 0, new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Toast.makeText(MainActivity.this,"您选择了"+items[i],Toast.LENGTH_SHORT).show();
}
});
builder.setPositiveButton("确定",null);
builder.create().show();
}
});
//显示带多选列表项的对话框
b4.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
final boolean[] checkedItems = new boolean[]{false,true,false,true,false};
final String[] items = new String[]{"第一个多选列表项","第二个多选列表项","第三个多选列表项","第四个多选列表项","第五个多选列表项"};
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setIcon(R.drawable.img1);
builder.setTitle("请做出选择");
builder.setMultiChoiceItems(items, checkedItems, new DialogInterface.OnMultiChoiceClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i, boolean b) {
checkedItems[i] = b;
}
});
builder.setPositiveButton("确定", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
String result = "";
for(int i1=0;i1<checkedItems.length;i1++){
if(checkedItems[i1]){
result+=items[i1]+"、";
}
}
if (!"".equals(result)){
Toast.makeText(MainActivity.this,"您选择了"+result,Toast.LENGTH_SHORT).show();
}
}
});
builder.create().show();
}
});
}
}
使用Notification显示通知
package com.example.pratice7;
import androidx.appcompat.app.AppCompatActivity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends AppCompatActivity {
final int NOTIFYID=0X123;//通知ID
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//创建并发送通知
//获取一个通知管理器
NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
//创建一个通知对象
Notification.Builder notification = new Notification.Builder(MainActivity.this);
notification.setAutoCancel(true);//设置通知打开后自动消失
notification.setSmallIcon(R.drawable.img1);
notification.setContentTitle("这是一个标题");
notification.setContentText("点击查看详情");//通知内容
notification.setWhen(System.currentTimeMillis());//设置发送时间
notification.setDefaults(Notification.DEFAULT_SOUND|Notification.DEFAULT_VIBRATE);//设置声音和振动
//创建一个启动详细页面的Intent对象
Intent intent = new Intent(MainActivity.this,DetailActivity.class);
PendingIntent pi = PendingIntent.getActivity(MainActivity.this,0,intent,0);
notification.setContentIntent(pi);//设置通知栏点击跳转
notificationManager.notify(NOTIFYID,notification.build());//发送通知
}
}
使用BroadcastReceiver(广播接收器)
略
使用AlarmManager设置闹钟
MainActivity中的代码
package com.example.pratice8;
import androidx.appcompat.app.AppCompatActivity;
import android.app.AlarmManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TimePicker;
import android.widget.Toast;
import java.util.Calendar;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TimePicker timePicker = findViewById(R.id.time);
timePicker.setIs24HourView(true);
Button button1 = findViewById(R.id.set);
//为设置闹钟按钮设置单击事件监听器
button1.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
//设置闹钟
Intent intent = new Intent(MainActivity.this,AlarmActivity.class);
//获取显示闹钟的pendingIntent对象
PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this,0,intent,0);
AlarmManager alarm = (AlarmManager) getSystemService(Context.ALARM_SERVICE);//获取AlarmManager对象
Calendar c = Calendar.getInstance();//获取日历对象
c.set(Calendar.HOUR_OF_DAY,timePicker.getCurrentHour());//设置闹钟的小时数
c.set(Calendar.MINUTE,timePicker.getCurrentMinute());//设置闹钟的分钟数
c.set(Calendar.SECOND,0);
alarm.set(AlarmManager.RTC_WAKEUP,c.getTimeInMillis(),pendingIntent);//设置一个闹钟
Toast.makeText(MainActivity.this,"闹钟设置成功",Toast.LENGTH_SHORT).show();
}
});
}
}