Android：week 12總結 內容觀察者、廣播、服務

目錄

 

Monday

1.內容觀察者

2.廣播1

Tuesday

1.廣播2

2.服務

---

Monday

1.內容觀察者

MainActivity：

package cn.rjxy.myobserver;

import androidx.appcompat.app.AppCompatActivity;

import android.database.ContentObserver;
import android.net.Uri;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Uri uri = Uri.parse("content://cn.rjxy.providertest/info");
        getContentResolver().registerContentObserver(uri, true, new TestObserver(new Handler()));
    }

    private class TestObserver extends ContentObserver{
        public TestObserver(Handler handler){
            super(handler);
            Log.d("***", "TestObserver is created");
        }
        public void onChange(boolean changed){
            super.onChange(changed);
            Log.d("***", "數據發生變化");
        }
    }

    public void onDestroy(){
        super.onDestroy();
        getContentResolver().unregisterContentObserver(new TestObserver(new Handler()));
    }
}

2.廣播1

MainActivity：

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {
    private TestReceiver receiver;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        receiver = new TestReceiver();//實例化
        IntentFilter filter = new IntentFilter("Hello, android.");
        filter.setPriority(100);
        registerReceiver(receiver, filter);
    }

    protected void onDestroy(){
        super.onDestroy();
        unregisterReceiver(receiver);
        //unregisterReceiver(reciever2);
    }

    public void click(View view){
        Intent intent = new Intent("Hello, android.");
        //sendBroadcast(intent);
        sendOrderedBroadcast(intent, null);

        intent.setAction("Hello, world.");
        //sendBroadcast(intent);
        sendOrderedBroadcast(intent, null);
    }
}

 TestReceiver：

package com.example.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class TestReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent){
        Log.d("***", "接收到信息的廣播");
        Log.d("***", intent.getAction());
    }
}

Tuesday

1.廣播2

新加一個java文件，SecondReceiver

package com.example.myapplication;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class SecondReciever extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent){
        Log.d("###", "接收到信息的廣播");
        Log.d("###", intent.getAction());
//        abortBroadcast();
//        Log.d("###","終止廣播");
    }
}

值越大 優先級越高

2.服務

MainActivity：

package com.example.myapplication;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    public void click(View view){
        switch (view.getId()){
            case R.id.start:
                Intent intent = new Intent(MainActivity.this, MyService.class);
                startService(intent);
                break;
            case R.id.close:
                Intent intent1 = new Intent(MainActivity.this, MyService.class);
                stopService(intent1);
                break;
        }
    }
}

MyService：

package com.example.myapplication;

import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;

public class MyService extends Service {
    public MyService() {
    }

    @Override
    public IBinder onBind(Intent intent) {
        // TODO: Return the communication channel to the service.
        throw new UnsupportedOperationException("Not yet implemented");
    }
    @Override
    public void onCreate(){
        super.onCreate();
        Log.d("***", "oncreate");
    }
    public void onDestroy(){
        super.onDestroy();
        Log.d("***", "onDestroy");
    }

    public int onStartCommand(Intent intent, int flag, int startId){
        Log.d("***", "onStartCommand");
        return super.onStartCommand(intent, flag, startId);
    }
}