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Android 系统开发实用指南

1. 将程序运行到手机上

某些代码只有在真机运行时才能看到效果。接下来我们将介绍几种常用的功能。

2. 使用通知

在 Android 系统中，通知是一种有特色的功能。当某个应用程序在后台时需要发送提示信息时，可以使用通知来实现。

2.1 通知的基本用法

示例

public class MainActivity extends AppCompatActivity {
    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Button button = (Button) findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @RequiresApi(api = Build.VERSION_CODES.O)
            @Override
            public void onClick(View view) {
                NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
                NotificationChannel channel = new NotificationChannel("1", "MY_CHANNEL", NotificationManager.IMPORTANCE_DEFAULT);
                manager.createNotificationChannel(channel);
                Notification notification = new NotificationCompat.Builder(MainActivity.this, "1")
                        .setContentTitle("This is title")
                        .setContentText("This is text")
                        .setWhen(System.currentTimeMillis())
                        .setSmallIcon(R.mipmap.ic_launcher)
                        .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
                        .build();
                manager.notify(1, notification);
            }
        });
    }
}

2.2 通知的进阶技巧

在上节中我们只发送了简单的通知。在本节中我们将讨论如何为通知设置更高级的功能。

给通知设置点击事件

Intent intent = new Intent(MainActivity.this, MainActivity2.class);
PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 0, intent, 0);
// ... // 示例中省略部分代码
 Notification notification = new NotificationCompat.Builder(MainActivity.this, "1")
     .setContentTitle("This is title")
     .setContentText("This is text")
     .setWhen(System.currentTimeMillis())
     .setSmallIcon(R.mipmap.ic_launcher)
     .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
     .setContentIntent(pendingIntent)
     .setAutoCancel(true)
     .build();

给通知设置提示音

Intent intent = new Intent(MainActivity.this, MainActivity2.class);
PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 0, intent, 0);
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
NotificationChannel channel = new NotificationChannel("2", "MY_CHANNEL", NotificationManager.IMPORTANCE_DEFAULT);
channel.setSound(
    Uri.parse("android.resource://"+MainActivity.this.getPackageName()+"/raw/"+R.raw.music),
    null
);
manager.createNotificationChannel(channel);
Notification notification = new NotificationCompat.Builder(MainActivity.this, "2")
    .setContentTitle("This is title")
    .setContentText("This is text")
    .setWhen(System.currentTimeMillis())
    .setSmallIcon(R.mipmap.ic_launcher)
    .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
    .setContentIntent(pendingIntent)
    .setAutoCancel(true)
    .build();
manager.notify(1, notification);

给通知设置震动

Intent intent = new Intent(MainActivity.this, MainActivity2.class);
PendingIntent pendingIntent = PendingIntent.getActivity(MainActivity.this, 0, intent, 0);
NotificationManager manager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
NotificationChannel channel = new NotificationChannel("3", "MY_CHANNEL", NotificationManager.IMPORTANCE_DEFAULT);
channel.setSound(
    Uri.parse("android.resource://"+MainActivity.this.getPackageName()+"/raw/"+R.raw.music),
    null
);
channel.setVibrationPattern(new long[]{
    0, 1000, 1000, 1000 // 震动模式
});
manager.createNotificationChannel(channel);
Notification notification = new NotificationCompat.Builder(MainActivity.this, "3")
    .setContentTitle("This is title")
    .setContentText("This is text")
    .setWhen(System.currentTimeMillis())
    .setSmallIcon(R.mipmap.ic_launcher)
    .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
    .setContentIntent(pendingIntent)
    .setAutoCancel(true)
    .build();
manager.notify(1, notification);

2.3 通知的高级功能

在本节中我们将学习如何为通知设置更多属性。

设置长文字

Notification notification = new NotificationCompat.Builder(MainActivity.this, "4")
    .setContentTitle("This is title")
    .setStyle(new NotificationCompat.BigTextStyle().bigText("很长的文本"))
    .setWhen(System.currentTimeMillis())
    .setSmallIcon(R.mipmap.ic_launcher)
    .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
    .setContentIntent(pendingIntent)
    .setAutoCancel(true)
    .build();

设置图片

Notification notification = new NotificationCompat.Builder(MainActivity.this, "4")
    .setContentTitle("This is title")
    .setStyle(new NotificationCompat.BigPictureStyle().bigPicture(BitmapFactory.decodeResource(getResources(), R.drawable.apple)))
    .setWhen(System.currentTimeMillis())
    .setSmallIcon(R.mipmap.ic_launcher)
    .setLargeIcon(BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher))
    .setContentIntent(pendingIntent)
    .setAutoCancel(true)
    .build();

设置通知优先级

NotificationChannel channel = new NotificationChannel("5", "MY_CHANNEL", NotificationManager.IMPORTANCE_HIGH);