Android适配全面总结（二）----版本适配

A class that represents how a persistent notification is to
be presented to the user using the NotificationManager.

The Notification.Builder has been added to make it easier
to construct Notifications.

Notification(int icon, CharSequence tickerText, long when)

This constructor was deprecated in API level 11. 
Use Notification.Builder instead.

//别忘记在清单文件也加上CAMERA权限
//<uses-permission android:name="android.permission.CAMERA" />

// 定义识别码
public static final int CAMERA_OK = 1;

//动态申请拍照权限
if (Build.VERSION.SDK_INT>22){
   if (ContextCompat.checkSelfPermission(this,Manifest.permission.CAMERA)
        != PackageManager.PERMISSION_GRANTED){
           //先判断有没有权限 ，没有就在这里进行权限的申请
           requestPermissions(new String[]{Manifest.permission.CAMERA}, CAMERA_OK);       
    }else {
            //说明已经获取到摄像头权限了，可以去选择照片或者拍照了。
            toSelectPhotoOrOpenCamera();
    }
}else {
      //这个说明系统版本在6.0之下，不需要动态获取权限，直接去选择照片或者拍照。
      toSelectPhotoOrOpenCamera();
}

//在Activity中重写权限获取方法：

/**
* 权限操作结果处理
*/
@Override
public void onRequestPermissionsResult(int requestCode,
                       String[] permissions, int[] grantResults) {
    switch (requestCode) {
        case CAMERA_OK: 
            if (grantResults.length > 0 && grantResults[0]
                         == PackageManager.PERMISSION_GRANTED) {
                 //用户已授权
                toSelectPhotoOrOpenCamera();
            } else {
                //用户拒绝权限
                ToastUtils.show(this, 
                    "缺少相机权限，暂时无法提供扫描功能,请尝试在设置中打开相机权限!", 
                    Toast.LENGTH_LONG);
            }
            break;
        }
    }
}

<manifest>
    ...
    <application>
        ...
        <provider
            android:name="android.support.v4.content.FileProvider"
            android:authorities="com.lzw.demo.fileprovider"
            android:exported="false"
            android:grantUriPermissions="true">
            ...
        </provider>
        ...
    </application>
</manifest>

<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="my_images" path="images/"/>
    ...
</paths>

路径说明：

<files-path name="name" path="path/" />   
   <!--等同于Context.getFilesDir()下面的path文件夹的所有文件--> 

<cache-path name="name" path="path/" />  
   <!--等同于Context.getCacheDir()下面的path文件夹--> 

<external-path name="name" path="path/" /> 
   <!--等同于Environment.getExternalStorageDirectory()下面的path文件夹--> 

<external-files-path name="name" path="path/" /> 
   <!--等同于 Context#getExternalFilesDir(String)下面子文件path文件夹--> 

<external-cache-path name="name" path="path/" /> 
   <!--相当于 Context.getExternalCacheDir()下边的path文件夹--> 

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="com.lzw.demo.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/file_demo" />
</provider>

//适配7.0的fileprovider，imgfile是图片文件路径
public void TakePhotoAdaption(File imgFile){
    Intent cameraIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    //适配android7.0 手机拍照取uri的处理
    if(Build.VERSION.SDK_INT<24){
        //7.0如果用会Uri.fromFile(XXX)会闪退，所以这里要特别做一个判断。
        //imgfile是图片文件路径
        uri = Uri.fromFile(imgFile);
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
    }else{
        //7.0+使用FileProvider.getUriForFile这个api
        uri=FileProvider.getUriForFile(DemoActivity.this,
                "com.lzw.demo.fileprovider",imgFile);
        cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
        //添加这一句表示对目标应用临时授权该Uri所代表的文件
        cameraIntent.addFlags(Intent.FLAG_GRANT_READ_URI_PERMISSION );
    }
    startActivityForResult(cameraIntent, FLAG_CHOOSE_CAMERA);
}

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            NotificationManager manager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
            NotificationChannel mChannel = new NotificationChannel("channel_01",
                    "消息推送", NotificationManager.IMPORTANCE_DEFAULT);
            manager.createNotificationChannel(mChannel);
        }

Context context = DJApplication.getInstance();
        Notification.Builder builder = new Notification.Builder(context);
        builder.setTicker("开始下载");
        builder.setSmallIcon(R.mipmap.ic_launcher);
        builder.setLargeIcon(BitmapFactory.decodeResource(DJApplication.getInstance().getResources(), 
            R.mipmap.ic_launcher));
        builder.setAutoCancel(true);
        PendingIntent pIntent = PendingIntent.getActivity(context, 0, new Intent(), PendingIntent.FLAG_UPDATE_CURRENT);
        builder.setContentTitle("下载中");
        builder.setContentIntent(pIntent);
        builder.setContentText(text);
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            builder.setChannelId("channel_01");//设置有效的通知渠道 ID，这个ID要和之前创建时候的Channel_ID相同
        }
        manager.notify(1,  builder.build());

<uses-permission android:name="android.permission.REQUEST_INSTALL_PACKAGES" />