Android基础之四大组件(Activity | Service | Broadcast Receiver | Content Provider)详解 | 含代码地址_activities、 broadcastreceiver、services以及content pr

<activity android:name=".SecondActivity"
    android:launchMode="singleTask"
    android:taskAffinity="com.example.laughter.task_1"/>

Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);

<activity android:name=".SecondActivity"
        android:launchMode="singleTask"
        android:taskAffinity="com.example.laughter.task_1"/>

Intent intent = new Intent(MainActivity.this, SecondActivity.class);
startActivity(intnet);

<activity android:name="com.example.android.tst.secondActivity"
            android:label = @string/title>
	    <intent-filter>
		    <action android:name="com.example.android.tst.secondActivity/>
		    <category android:name="android.intent.category.DEFAULT"/>
	    <intent-filter/>
</activity>

Intent intent = new Intent("com.example.android.tst.secondActivity");

Intent intent = new Intent(MainActivity.this,OtherActivity.class);
intent.putExtra("a",a);
startActivityForResult(intent,1000);
 
// 在MainActivity中获取返回值
@Override
protected void onActivityResult(int requestCode, int resultCode	,Intent data) {
	super.onActivityResult(requestCode,resultCode,data);
	if(requestCode == 1000){
		if(resultCode == 1001){
			int c = data.getExtra("c",0);
		}
	}
}

Intent intent = new Intent();
intnet.putExtra("c",c);
setResult(1001,int);
finish();

​

<application
....>
...
    <service
			android:name=".MyService"
            android:enabled="true"
            android:exported="true">
	</service>
</application>

Intent startIntent = new Intent(this,MyService.class);
startService(startIntent);

Intent stopIntent = new Intent(this,MyService.class);
stopService(stopIntent);

public class MyService extends Service{
    Intent intent = new Intent(this, MainActivity.class);
    PendingIntent pi = PendingIntent.getActivity(this, 0 , intent, 0);
    Notification notification  = new NotificationCompat.Builder(this)
        .setContentTitle(" this is content titile")
        .setContentText("this is content text")
        .setWhen(System.currentTimeMillis())
        .setSmallIcon(R.mipmap.ic_launcher);
    .setLargeIcon(BitmapFactory.decodeResource(getResource(),R.mipmap.ic_launcher))
        .setContentIntent(pi)
        .build();
    // startForeground()方法是将MyService变成一个前台服务，并在系统状态栏显示出来
    startForeground(1,notification);
}

public class MyService extends Service{
    ...
        @Override
        public int onStartCommand(Intent intent , int flags, int startId){
        new Thread(new Runnable(){
            public void run(){
                //处理具体的逻辑
                //如此写的话需要手动调用stopService()或者stopSelf()方法去让服务器停止
                stopSelf();
            }
        }).start();
        return super.onStartCommand(intent, flags, startId);
    }
}

public class MyIntentService extends IntentService{
    
	public MyIntentService(){
        // 调用父类的有参构造方法
		super("MyIntentService");  
	}
    
	@Override
	protected void onHandleIntent(Intent intent){	
		// 打印当前的线程ID
		Log.e("mylog","Thread id is” + Thread.cuttentThread().getId();
		// 写一些需要处理的逻辑
	}
              
	@Override
	public void onDestory(){
		super.onDestory();
		Log.e("mylog","on Destory executed");
	}
}
Intent intent = new Intent(this, MyIntentService.class);
startServcie(intent);
// 并且，执行完毕会自动关闭

<receiver 
	android:enable="true"/"false"
	
    //此broadcastReceiver 是否接受其他应用发出的广播
	//默认值时由receiver中有无intent-filter决定，如果有，默认true，否则默认false
	android:exported="true"/"false"
	android:icon="drawable resource"
	android:label="string resource"
	
    //继承BroadcastReceiver子类的类名
    android:name=".mBroadcastReceiver"
        
	//具有相应权限的广播发送者发送的广播才能被此BroadcastReceiver所接收；
    android:permission="string"
        
	//BroadcastReceiver运行所处的进程
	//默认为app的进程，可以指定独立的进程
	//注：Android四大基本组件都可以通过此属性指定自己的独立进程
    android:process="string" >
 
		//用于指定此广播接收器将接收的广播类型
		//本示例中给出的是用于接收网络状态改变时发出的广播
 		<intent-filter>
			<action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
 		</intent-filter>
 </receiver>

<receiver 
   //此广播接收者类是mBroadcastReceiver
    android:name=".mBroadcastReceiver" >
     //用于接收网络状态改变时发出的广播
      <intent-filter>
          <action android:name="android.net.conn.CONNECTIVITY_CHANGE" />
      </intent-filter>
</receiver>

//实例化BroadcastReceiver子类 &  IntentFilter
mBroadcastReceiver mBroadcastReceiver = new mBroadcastReceiver();
IntentFilter intentFilter = new IntentFilter();
 
//设置接收广播的类型
intentFilter.addAction(android.net.conn.CONNECTIVITY_CHANGE);
 
//动态注册：调用Context的registerReceiver（）方法
registerReceiver(mBroadcastReceiver, intentFilter);
 
//动态注册广播后，需要在相应位置记得销毁广播
unregisterReceiver(mBroadcastReceiver);

​

public class MyProvider extends ContentProvider{
    @Override
    public boolean onCreate() {
        return false;
    }
    @Override
    public Cursor query(Uri uri, String[] projection, Stirng selection, String[] selectionArgs, String sortOrder){
        return null;
    }
    @Overrride
    public Uri insert(Uri uri , ContentValues values){
        return null;
    }
    @Override
    public int update(Uri uri, ContentValuse values, String selection, String[] selectionArgs){
        return 0;
    }
    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs){
        return 0;
    }
    @Override
    public String getType(Uri uri）{
        return null；
    }
}

Cursor cursor = getContentResolver().query(
	uri,
	projection,
	selection,
	selectionArgs,
	sortOrder
);

if(cursor != null){
    while(cursor.moveToNext()) {
        String column1 = cursor.getString(cursor.getColumnIndex("column1"));
        int column2 = cursor.getInt(cursor.getColumnIndex("column2"));
    }
    cursor.close();
}

ContentValues values = new ContentValues();
values.put(“column1”, "text");
values.put("column2", 1);
getContentResolver().insert(uri, values);

ContentValues valuse = new ContentValues();
valuse.put("column1", "");
getContentResolver().update(uri, values, "column1 = ? and column2 = ?", new String[]{"text", 1});

getContentResolver().delete(uri , "column2 = ?", new String[]{ "1"});

if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS) != PackageManager.PERMISSION_GRANTED) {
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_CONTACTS}, 1);
}else {
    // 读取联系人
    readContacts();
}
 
private void readContacts(){
    Cursor cursor = null;
    try{
        // 查询联系人数据
        cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,null,null,null,null);
        if(cursor != null){
            while(cursor.moveToNext()){
                // 获取联系人姓名
                String name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
                // 获取联系人电话号码
                String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));
                list.add(name+"\n"+number);
            }
        }
    }catch(Exception e){
        e.printStackTrace()
    }finally{
        if(cursor != null){
            cursor.close();
        }
    }
}
 
@Override
public void onRequestPermissionResult(int requestCode, String[] permissions, int[] grantResults){
    switch(requestCode){
        case 1:
            if(grantResults.length >0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                readContacts();
            }else {
                // 您拒绝了权限
            }
    }
}