day06三级缓存二次采样

SD卡操作

(1)Environment.getExternalStorageState();// 判断SD卡是否
(2)Environment.getExternalStorageDirectory(); 获取SD卡的根目录
(3)Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES); 获取SD卡公开目录

//读写操作的权限

//写
//判断是否插入SD卡if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){File file = Environment.getExternalStorageDirectory();Toast.makeText(MainActivity.this,file.getAbsolutePath()+"",Toast.LENGTH_SHORT).show();File file1=new File(file,"Download");File file2=new File(file1,"mars.txt");FileOutputStream fos =null;try {fos=new FileOutputStream(file2);fos.write("战神刘大瑞".getBytes());} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {fos.close();} catch (IOException e) {e.printStackTrace();}}}else {Toast.makeText(MainActivity.this,"没有安装SD卡",Toast.LENGTH_SHORT).show();}//下载if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){new MyThread().start();}else {Toast.makeText(MainActivity.this,"没有安装SD卡",Toast.LENGTH_SHORT).show();}//线程
public class MyThread extends Thread {@Overridepublic void run() {super.run();File file = Environment.getExternalStorageDirectory();File file1=new File(file,"Download");File file2=new File(file1,"mars.jpg");
//        File file2=new File(file1,"mars.mp4");//mp4格式FileOutputStream fos = null;try {fos = new FileOutputStream(file2);//                URL url=new URL("http://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4");//mp4格式URL url=new URL("https://img04.sogoucdn.com/app/a/100520024/09cc6117a797b1e6e5f758de4b967ff6");HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();urlConnection.setRequestMethod("GET");urlConnection.connect();if (urlConnection.getResponseCode()==200){InputStream is = urlConnection.getInputStream();byte[] bys = new byte[1024];int len =0;while((len =is.read(bys))!=-1){fos.write(bys,0,len);}}} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} finally {try {fos.close();} catch (IOException e) {e.printStackTrace();}}}
}
//从sd卡读取图片if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){imageView.setImageBitmap(BitmapFactory.decodeFile("/sdcard/Download/mars.jpg"));}else {Toast.makeText(MainActivity.this,"没有安装SD卡",Toast.LENGTH_SHORT).show();}

三级缓存

//没有缓存的弊端：费流量, 加载速度慢
//加入缓存的优点：省流量，支持离线浏览
//读写权限

//从缓存中获取
public class CacheUtils {//获得手机的最大内存static long max =Runtime.getRuntime().maxMemory();//实例化一个内存对象static LruCache<String,Bitmap> lruCache=new LruCache<String,Bitmap>((int) (max/8)){@Overrideprotected int sizeOf(String key, Bitmap value) {//返回每张图片的大小return value.getByteCount();}};public static Bitmap getBitmap(String key){Bitmap bitmap = lruCache.get(key);return bitmap;}// 键 图片在内存中的名字//值 图片bitmap对象public static void setBitmap(String key,Bitmap bitmap){lruCache.put(key,bitmap);}
}//从SD卡中获取
public class SDUtils {// bitmap--->路径  BitmapFactory.decodeFile(文件路径)//根据路径获得Bitmap对象public static Bitmap getBitmap(String filepath){if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){Bitmap bitmap = BitmapFactory.decodeFile(filepath);return bitmap;}return null;}//从SD读取   根据路径---->Bitmap.compress()  压缩//将bitmap对象按照指定路径存储public  static void setBitmap(String filepath,Bitmap bitmap){if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){try {//参数一 图片的格式 JPG PNG  参数二 质量 0-100 参数三 输出流bitmap.compress(Bitmap.CompressFormat.JPEG,100,new FileOutputStream(filepath));} catch (FileNotFoundException e) {e.printStackTrace();}}}
}//从网络获取
public class NetUtils {//根据网址得到Bitmappublic static Bitmap getBitmap(String url){Bitmap bitmap =null;try {//直接获取异步返回的结果bitmap = new Myask().execute(url).get();} catch (ExecutionException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();}return bitmap;}static class Myask extends AsyncTask<String,String,Bitmap>{@Overrideprotected Bitmap doInBackground(String... strings) {try {URL url=new URL(strings[0]);HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();urlConnection.setRequestMethod("GET");urlConnection.connect();if (urlConnection.getResponseCode()==200){InputStream inputStream = urlConnection.getInputStream();Bitmap bitmap = BitmapFactory.decodeStream(inputStream);return bitmap;}} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return null;}}
}
//主类
public class MainActivity extends AppCompatActivity {Button button;ImageView imageView;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);button=findViewById(R.id.btn);imageView=findViewById(R.id.iv);button.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {Bitmap bitmap = CacheUtils.getBitmap("liurui");if (bitmap==null){bitmap = SDUtils.getBitmap("/sdcard/Pictures/liurui.jpg");if (bitmap==null){bitmap = NetUtils.getBitmap("https://img01.sogoucdn.com/app/a/100520024/b555532f376c51331f44c4d2c13a934c");if (bitmap==null){Toast.makeText(MainActivity.this,"你个死鬼,你让我上哪找图片去",Toast.LENGTH_SHORT).show();}else {Toast.makeText(MainActivity.this,"从网络中获取的",Toast.LENGTH_SHORT).show();imageView.setImageBitmap(bitmap);SDUtils.setBitmap("/sdcard/Pictures/liurui.jpg",bitmap);CacheUtils.setBitmap("liurui",bitmap);}}else {Toast.makeText(MainActivity.this,"从SD卡中获取的",Toast.LENGTH_SHORT).show();imageView.setImageBitmap(bitmap);CacheUtils.setBitmap("liurui",bitmap);}}else {Toast.makeText(MainActivity.this,"从内存中获取的",Toast.LENGTH_SHORT).show();imageView.setImageBitmap(bitmap);}}});}
}

二级采样

//Bitmap.compress(CompressFormat format, int quality, OutputStream stream)
Bitmap被压缩成的图片格式
压缩的质量控制，范围0~100
输出流

//主类
public class MainActivity extends AppCompatActivity {GridView gridView;ArrayList<String> arrayList=new ArrayList<>();@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);gridView=findViewById(R.id.gri);for (int i = 0; i < 9; i++) {arrayList.add("/sdcard/Download/mars.jpg");}Myad myad=new Myad(MainActivity.this);myad.notifyDataSetChanged();gridView.setAdapter(myad);}
}
// 适配器类
public class Myad extends BaseAdapter {MainActivity activity;public Myad(MainActivity activity) {this.activity = activity;}@Overridepublic int getCount() {return activity.arrayList.size();}@Overridepublic Object getItem(int position) {return null;}@Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder viewh;if (convertView==null){viewh=new ViewHolder();convertView=View.inflate(activity,R.layout.item_layout,null);viewh.imageView=convertView.findViewById(R.id.iv);convertView.setTag(viewh);}else {viewh = (ViewHolder)convertView.getTag();}String s = activity.arrayList.get(position);BitmapFactory.Options options=new BitmapFactory.Options();options.inJustDecodeBounds=true;int outWidth = options.outWidth;int outHeight = options.outHeight;int size = 1;while(outWidth/size>200||outHeight/size>200){size=size*2;}options.inJustDecodeBounds=false;options.inSampleSize=size;Bitmap bitmap = BitmapFactory.decodeFile(s, options);viewh.imageView.setImageBitmap(bitmap);return convertView;}class ViewHolder{ImageView imageView;}
}

//按钮一按照100%质量压缩到SD卡中，按钮二按照50%质量压缩到SD卡
//主类
public class MainActivity extends AppCompatActivity {Button button1,button2;ImageView imageView1,imageView2;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);button1=findViewById(R.id.btn1);button2=findViewById(R.id.btn2);imageView1=findViewById(R.id.iv1);imageView2=findViewById(R.id.iv2);//https://img03.sogoucdn.com/app/a/100520024/f9237f51fa52b174dab2fb1601820a85button1.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {File f = Environment.getExternalStorageDirectory();File file=new File(f,"Pictures");File file1=new File(file,"mars1.jpg");Bitmap bitmap = NetUtils.getBitmap("https://img03.sogoucdn.com/app/a/100520024/f9237f51fa52b174dab2fb1601820a85");try {//参数一 图片的格式 参数二 图片质量 0-100  参数三：输出流bitmap.compress(Bitmap.CompressFormat.JPEG,100,new FileOutputStream(file1));} catch (FileNotFoundException e) {e.printStackTrace();}Bitmap bitmap1 = SDUtils.getBitmap("/sdcard/Pictures/mars1.jpg");imageView1.setImageBitmap(bitmap1);}});button2.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {File f = Environment.getExternalStorageDirectory();File file=new File(f,"Pictures");File file1=new File(file,"mars2.jpg");Bitmap bitmap = NetUtils.getBitmap("https://img03.sogoucdn.com/app/a/100520024/f9237f51fa52b174dab2fb1601820a85");try {//参数一 图片的格式 参数二 图片质量 0-100  参数三：输出流bitmap.compress(Bitmap.CompressFormat.JPEG,50,new FileOutputStream(file1));} catch (FileNotFoundException e) {e.printStackTrace();}Bitmap bitmap2 = SDUtils.getBitmap("/sdcard/Pictures/mars2.jpg");imageView2.setImageBitmap(bitmap2);}});}
}
//sd卡工具类
public class SDUtils {// bitmap--->路径  BitmapFactory.decodeFile(文件路径)//根据路径获得Bitmap对象public static Bitmap getBitmap(String filepath){if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){Bitmap bitmap = BitmapFactory.decodeFile(filepath);return bitmap;}return null;}//从SD读取   根据路径---->Bitmap.compress()  压缩//将bitmap对象按照指定路径存储public  static void setBitmap(String filepath,Bitmap bitmap){if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)){try {//参数一 图片的格式 JPG PNG  参数二 质量 0-100 参数三 输出流bitmap.compress(Bitmap.CompressFormat.JPEG,100,new FileOutputStream(filepath));} catch (FileNotFoundException e) {e.printStackTrace();}}}
}
//网络工具类
public class NetUtils {//根据网址得到Bitmappublic static Bitmap getBitmap(String url){Bitmap bitmap =null;try {//直接获取异步返回的结果bitmap = new Myask().execute(url).get();} catch (ExecutionException e) {e.printStackTrace();} catch (InterruptedException e) {e.printStackTrace();}return bitmap;}static class Myask extends AsyncTask<String,String,Bitmap>{@Overrideprotected Bitmap doInBackground(String... strings) {try {URL url=new URL(strings[0]);HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();urlConnection.setRequestMethod("GET");urlConnection.connect();if (urlConnection.getResponseCode()==200){InputStream inputStream = urlConnection.getInputStream();Bitmap bitmap = BitmapFactory.decodeStream(inputStream);return bitmap;}} catch (MalformedURLException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return null;}}
}

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day06三级缓存二次采样

SD卡操作

三级缓存

二级采样

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