android sdk 小于等于28版本动态权限

读写权限

  1.   private static final int REQUEST_EXTERNAL_STORAGE = 1;
  3.     private static String[] PERMISSIONS_STORAGE = {
  4.             "android.permission.READ_EXTERNAL_STORAGE",
  5.             "android.permission.WRITE_EXTERNAL_STORAGE" };
  7.     //然后通过一个函数来申请
  8.     public static void verifyStoragePermissions(Activity activity) {
  9.         try {
  10.             //检测是否有写的权限
  11.             int permission = ActivityCompat.checkSelfPermission(activity,
  12.                     "android.permission.WRITE_EXTERNAL_STORAGE");
  13.             if (permission != PackageManager.PERMISSION_GRANTED) {
  14.                 // 没有写的权限，去申请写的权限，会弹出对话框
  15.                 ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
  16.             }
  17.             //检测是否有写的权限
  18.             int permission2 = ActivityCompat.checkSelfPermission(activity,
  19.                     "android.permission.READ_EXTERNAL_STORAGE");
  20.             if (permission2 != PackageManager.PERMISSION_GRANTED) {
  21.                 // 没有写的权限，去申请写的权限，会弹出对话框
  22.                 ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
  23.             }
  24.         } catch (Exception e) {
  25.             e.printStackTrace();
  26.         }
  27.     }

调用

protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
verifyStoragePermissions(this);
#……………….
}

完整代码

  1. package com.example.myapplication;
  3. import android.app.Activity;
  4. import android.content.Context;
  5. import android.content.pm.PackageManager;
  7. import android.os.Environment;
  8. import android.support.v4.app.ActivityCompat;
  9. import android.support.v7.app.AppCompatActivity;
  10. import android.os.Bundle;
  11. import android.util.Log;
  12. import android.widget.TextView;
  15. import java.io.File;
  16. import java.io.FileOutputStream;
  17. import java.io.IOException;
  18. import java.io.InputStream;
  19. import java.io.OutputStream;
  20. import java.util.List;
  22. public class MainActivity extends AppCompatActivity {
  24.     // Used to load the 'native-lib' library on application startup.
  25.     static {
  26.         System.loadLibrary("native-lib");
  27.         System.out.println(System.getProperty("java.library.path"));
  29.     }
  30. //    public static String assetFilePath(Context context, String assetName) {
  31. //        File file = new File(context.getFilesDir(), assetName);
  32. //        System.out.println("test android  :"+file.getName());
  33. //        if (file.exists() && file.length() > 0) {
  34. //            System.out.println("test is exists  android:"+file.getAbsolutePath());
  35. //
  36. //            return file.getAbsolutePath();
  37. //        }
  38. //        System.out.println("test is  not exists  android:"+file.getAbsolutePath());
  39. //        return null;
  40. //    }
  42.     public static String assetFilePath(Context context, String assetName) throws IOException {
  43.         File file = new File(context.getFilesDir(), assetName);
  44.         System.out.println("test android  :"+file.getName());
  46.         if (file.exists() && file.length() > 0) {
  47.             System.out.println("test is exists  android:"+file.getAbsolutePath());
  48.             return file.getAbsolutePath();
  49.         }
  50.         System.out.println("test is  not exists  android:"+file.getAbsolutePath());
  51.         try (InputStream is = context.getAssets().open(assetName)) {
  52.             try (OutputStream os = new FileOutputStream(file)) {
  53.                 byte[] buffer = new byte[4 * 1024];
  54.                 int read;
  55.                 while ((read = is.read(buffer)) != -1) {
  56.                     os.write(buffer, 0, read);
  57.                 }
  58.                 os.flush();
  59.             }
  60.             return file.getAbsolutePath();
  61.         }
  62.     }
  64.     @Override
  65.     protected void onCreate(Bundle savedInstanceState) {
  66.         super.onCreate(savedInstanceState);
  67.         setContentView(R.layout.activity_main);
  68.         verifyStoragePermissions(this);
  69.         // 首先判断设备是否挂载SDCard
  70.         boolean isMounted = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);
  72. //        if (isMounted) {
  73. //            try {
  74. //                writeFileToSDCard();
  75. //            } catch (IOException e) {
  76. //                e.printStackTrace();
  77. //                Log.d("SDCard write error ", "test no SDCard！");
  78. //
  79. //            }
  80. //        } else {
  81. //            Log.d("SDCard错误", "test no SDCard！");
  82. //        }
  85. //        try {
  86. //            String fileName=assetFilePath(this,"76.png");
  87. //            String test= gray(fileName,10,1000);
  88. //            System.out.println("test is println  android:"+test);
  89. //
  90. //        } catch (IOException e) {
  91. //            Log.e("PytorchHelloWorld", "test :::Error reading assets", e);
  92. //            finish();
  93. //        }
  94.         int colors[] = {20,0,255};
  95.         Segment("/sdcard/data/test_cuda.mnn","/sdcard/data/56.png","/sdcard/data/result.png","/sdcard/data/mask.png",colors,10);
  96.         TextView tv = findViewById(R.id.sample_text);
  97.         tv.setText(stringFromJNI());
  99.         System.out.println("test system.out.print !");
  101.     }
  102.     /**
  103.      * A native method that is implemented by the 'native-lib' native library,
  104.      * which is packaged with this application.
  105.      */
  106.     private static final int REQUEST_EXTERNAL_STORAGE = 1;
  108.     private static String[] PERMISSIONS_STORAGE = {
  109.             "android.permission.READ_EXTERNAL_STORAGE",
  110.             "android.permission.WRITE_EXTERNAL_STORAGE" };
  112.     //然后通过一个函数来申请
  113.     public static void verifyStoragePermissions(Activity activity) {
  114.         try {
  115.             //检测是否有写的权限
  116.             int permission = ActivityCompat.checkSelfPermission(activity,
  117.                     "android.permission.WRITE_EXTERNAL_STORAGE");
  118.             if (permission != PackageManager.PERMISSION_GRANTED) {
  119.                 // 没有写的权限，去申请写的权限，会弹出对话框
  120.                 ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
  121.             }
  122.             //检测是否有写的权限
  123.             int permission2 = ActivityCompat.checkSelfPermission(activity,
  124.                     "android.permission.READ_EXTERNAL_STORAGE");
  125.             if (permission2 != PackageManager.PERMISSION_GRANTED) {
  126.                 // 没有写的权限，去申请写的权限，会弹出对话框
  127.                 ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
  128.             }
  129.         } catch (Exception e) {
  130.             e.printStackTrace();
  131.         }
  132.     }
  135.     // 写一个文件到SDCard
  136.     private void writeFileToSDCard() throws IOException {
  137.         // 比如可以将一个文件作为普通的文档存储，那么先获取系统默认的文档存放根目录
  138.         File parent_path = Environment.getExternalStorageDirectory();
  140.         // 可以建立一个子目录专门存放自己专属文件
  141.         File dir = new File(parent_path.getAbsoluteFile(), "datatest");
  142.         dir.mkdir();
  143.         System.out.println(parent_path.getAbsoluteFile());
  144.         File file = new File(dir.getAbsoluteFile(), "myfile.txt");
  145.         System.out.println(dir.getAbsoluteFile());
  146.         Log.d("dir  test ", " test " +dir.getAbsoluteFile());
  148.         Log.d("文件路径 test ", file.getAbsolutePath());
  150.         // 创建这个文件，如果不存在
  151.         file.createNewFile();
  153.         FileOutputStream fos = new FileOutputStream(file);
  155.         String data = "hello,world!";
  156.         byte[] buffer = data.getBytes();
  158.         // 开始写入数据到这个文件。
  159.         fos.write(buffer, 0, buffer.length);
  160.         fos.flush();
  161.         fos.close();
  163.         Log.d("文件写入 test ", " test 成功");
  164.     }
  166.     public native String stringFromJNI();
  167.     public native int Segment(String bufModel,String bufInput, String bufOuput,String bufMask,int[]  color,int colorNum);
  169. }